Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
I'm kind of late to the party on this one, and don't want to reopen and send it off on a tangent. I agree with the injection-lock method, but just want to suggest that since most uPs and uCs have their own CMOS oscillator built in, the simplest solution would be to just use that as intended, with a cheap 16 MHz crystal or ceramic resonator, and injection lock it to a low impedance version of the 10 MHz clock, via an RCD network. It may need a variable cap to tweak the resonator to the lock frequency. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Ed you are late to the dance. But do offer an additional piece of the puzzle. RCD I will guess is a RC differentiator. And your suggestion does get rid of a separate oscillator. It wasn't my post. But would guess you just jam the diff pulse into the osc amp in that the xtal feeds? Regards Paul WB8TSL On Mon, Jan 7, 2013 at 5:30 PM, Ed Breya e...@telight.com wrote: I'm kind of late to the party on this one, and don't want to reopen and send it off on a tangent. I agree with the injection-lock method, but just want to suggest that since most uPs and uCs have their own CMOS oscillator built in, the simplest solution would be to just use that as intended, with a cheap 16 MHz crystal or ceramic resonator, and injection lock it to a low impedance version of the 10 MHz clock, via an RCD network. It may need a variable cap to tweak the resonator to the lock frequency. Ed __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Actually, I was referring to an RC and Diode network in anticipation of the possible need for more signal shaping flexibility, depending on the signals and circuitry. The built-in oscillators are usually self-biased CMOS inverters intended to go with crystals, and usually a couple of small phase shift caps to ground. If you inject the right amount of reference frequency at the input, the oscillator should sync up. Since it's for a fixed frequency, the required lock range can be quite small - it needs to be enough to compensate for drift in the resonator and circuits - so the injection level probably can be small. Since the oscillator input has plenty of gain, and the reference is likely a very low impedance, I think a fairly high impedance passive coupling network to link the two should suffice, without any extra active circuitry. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
A week ago I asked about a 10 MHz to 16 MHz multiplier. Thanks very much for the suggestions and interesting discussion. What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb A few of you wanted to know more background. Some portable microcontroller-based timer/counters use a 16 MHz xtal timebase. To transparently give them atomic accuracy I thought it would be a cute hack to simply feed them 16 MHz as derived from a good 10 MHz (which we all have). For a quick test I used a house 10 MHz referenced DS345 to produce the 16 MHz square wave. I know some DDS have round-off error but the DS345, at least at this frequency, maintained phase to the nanosecond. Not wanting to tie up my DS345 indefinitely, I wondered for this fixed 10:16 (5:8) frequency ratio if there was cheap, simple, or clever solution. The TAPR Clock-Block came to mind. The ICS525 chip it uses is cheap (under $5) and trivial to configure so that was clearly one solution. But I was curious what the group would propose. Anyway, thanks to all who contributed. If there are any stones left unturned, send me email off-line. /tvbattachment: DS345-16MHz.jpg___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Don't leave us in suspense :-) What method did you decide to use? Joe Gray W5JG On Mon, Jan 7, 2013 at 8:54 PM, Tom Van Baak t...@leapsecond.com wrote: A week ago I asked about a 10 MHz to 16 MHz multiplier. Thanks very much for the suggestions and interesting discussion. What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb A few of you wanted to know more background. Some portable microcontroller-based timer/counters use a 16 MHz xtal timebase. To transparently give them atomic accuracy I thought it would be a cute hack to simply feed them 16 MHz as derived from a good 10 MHz (which we all have). For a quick test I used a house 10 MHz referenced DS345 to produce the 16 MHz square wave. I know some DDS have round-off error but the DS345, at least at this frequency, maintained phase to the nanosecond. Not wanting to tie up my DS345 indefinitely, I wondered for this fixed 10:16 (5:8) frequency ratio if there was cheap, simple, or clever solution. The TAPR Clock-Block came to mind. The ICS525 chip it uses is cheap (under $5) and trivial to configure so that was clearly one solution. But I was curious what the group would propose. Anyway, thanks to all who contributed. If there are any stones left unturned, send me email off-line. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
On 1/4/2013 4:48 PM, Bob Camp wrote: Hi As I recall the spec was: 1) Cheap 2) no phase slips on the 16 MHz relative to 10 MHz 3) Cheap Bob GAK! Here is the original from TVB What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb This cluster f**k of responses losing track of the original but blathering on for days is so typical of the group lately. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
THis is exactly what they are talking about the 74HC390 can do over 50MHz and costs abut 30 cents. You don't need ECL or anything so exotic the 30 cent part will work. Set it for divide by 5. I guess this is imperfect enough that there is some fourth harmonic content in the 2MHz square wave, then you select that with a narrow band filter and amplify it to whatever you need. A smart design might try and add fourth harmonics be using a slightly not-symetric 2MHz square wave My question is about the phase noise of the final 16MHz signal. Do crystal filters clean up the signal. It seems that after several 16MHz crystals in series the output should look a lot like an XO. On Thu, Jan 3, 2013 at 6:02 PM, Tom Miller tmil...@skylinenet.net wrote: Isn't there a fast divide by N counter that you could set to 10? Maybe even in ECL? - Original Message - From: David davidwh...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, January 03, 2013 8:49 PM Subject: Re: [time-nuts] 10 MHz - 16 MHz clock multiplier They do not exist as I found out (again) not long ago. The last 7490 made was LS (low power schottky) and I use quite a few of them. Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they apparently either never went into production or very few were produced. The closest non-TTL alternative that I found was the 74HC390 or 74HCT390 which is basically two 7490 counters in one package. On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3...@gmail.com wrote: Where can one get some of these mythical 74HC90 's and 74AC90 's that have been mentioned. None of the usual places have them, ie ebay, digi-key, farnell, or even the Chinese. Also data-sheets are not to be found. Thanks On 4/01/2013 5:13 AM, Bill Fuqua wrote: One way is to divide by 10 and then multiply by 16. Divide by 10 and then follow by 4 tuned frequency doublers. This should introduce little phase noise. Another way to do it is to divide by 10, then pass the output thru a narrow 16 MHz filter and amplify. Sounds difficult but the filter can be one or two 16 MHz crystals followed by a simple amplifier. Look at the reference input circuit for a PTS-160. The output of the divide by 10 needs to be asymmetrical so it produces even harmonics. If you are using a divide divide by 52 such as a 74HC90, divide by 2 first then by 5. Ideally the pulse width should be a half period of 16 MHz for the maximum harmonic content at 16 MHz. You can take the output of the frequency divider and send it to a NAND gate. One input of the gate is directly connected and the other is delayed. You can use an RC with a variable capacitor to ground to get it just right. Just adjust the capacitor to get the maximum output from your filter amplifier. 73 Bill wa4lav At 07:41 PM 1/2/2013 +, you wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Paul Wade built a board recently to do just this. www.w1ghz.org. Bob On Fri, Jan 4, 2013 at 12:16 PM, Chris Albertson albertson.ch...@gmail.comwrote: THis is exactly what they are talking about the 74HC390 can do over 50MHz and costs abut 30 cents. You don't need ECL or anything so exotic the 30 cent part will work. Set it for divide by 5. I guess this is imperfect enough that there is some fourth harmonic content in the 2MHz square wave, then you select that with a narrow band filter and amplify it to whatever you need. A smart design might try and add fourth harmonics be using a slightly not-symetric 2MHz square wave My question is about the phase noise of the final 16MHz signal. Do crystal filters clean up the signal. It seems that after several 16MHz crystals in series the output should look a lot like an XO. On Thu, Jan 3, 2013 at 6:02 PM, Tom Miller tmil...@skylinenet.net wrote: Isn't there a fast divide by N counter that you could set to 10? Maybe even in ECL? - Original Message - From: David davidwh...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, January 03, 2013 8:49 PM Subject: Re: [time-nuts] 10 MHz - 16 MHz clock multiplier They do not exist as I found out (again) not long ago. The last 7490 made was LS (low power schottky) and I use quite a few of them. Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they apparently either never went into production or very few were produced. The closest non-TTL alternative that I found was the 74HC390 or 74HCT390 which is basically two 7490 counters in one package. On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3...@gmail.com wrote: Where can one get some of these mythical 74HC90 's and 74AC90 's that have been mentioned. None of the usual places have them, ie ebay, digi-key, farnell, or even the Chinese. Also data-sheets are not to be found. Thanks On 4/01/2013 5:13 AM, Bill Fuqua wrote: One way is to divide by 10 and then multiply by 16. Divide by 10 and then follow by 4 tuned frequency doublers. This should introduce little phase noise. Another way to do it is to divide by 10, then pass the output thru a narrow 16 MHz filter and amplify. Sounds difficult but the filter can be one or two 16 MHz crystals followed by a simple amplifier. Look at the reference input circuit for a PTS-160. The output of the divide by 10 needs to be asymmetrical so it produces even harmonics. If you are using a divide divide by 52 such as a 74HC90, divide by 2 first then by 5. Ideally the pulse width should be a half period of 16 MHz for the maximum harmonic content at 16 MHz. You can take the output of the frequency divider and send it to a NAND gate. One input of the gate is directly connected and the other is delayed. You can use an RC with a variable capacitor to ground to get it just right. Just adjust the capacitor to get the maximum output from your filter amplifier. 73 Bill wa4lav At 07:41 PM 1/2/2013 +, you wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Chris Albertson wrote: My question is about the phase noise of the final 16MHz signal. Do crystal filters clean up the signal. It seems that after several 16MHz crystals in series the output should look a lot like an XO. For offsets out to 100 Hz or so, using a crystal filter will cause the signal to have the same flicker noise that an oscillator built with that crystal would have. Thus don't try to use some junky clock crystals to make a crystal filter as described in numerous ham radio articles about receiver IF filters. If you have a residual phase noise measurement system like the Agilent E5505A and a very low flicker noise source, you can actually measure your filter crystals. Of course, the crystal time base in the source has to be better than the crystals you are measuring. You also have to avoid overdriving the crystal. This will require a low noise buffer amplifier to bring the signal back up to a high level. Now after considering all that, crystal clean up filters don't sound like such a great idea unless you have no alternative. Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 10 MHz - 16 MHz clock multiplier
If you divide by 5 the phase noise sideband amplitude (voltage) will be divided by 5. That is a reduction of 14db for all phase noise sideband frequencies . Then when you multiply that by 8 you will add the phase noise sidebands will be multiplied by 8 or 3x6db or 18 db. So the end result will be a factor (if I did my math right in my head, which is getting more difficult these days) 4db increase. The crystal filter will reduce the phase noise sidebands to some degree. That is to say if you had a perfect filter you could pass only the carrier with out the sidebands and thus no phase noise. However, if your filter has 1kHz bandwidth you would only eliminate the sidebands beyond 500 Hz on either side of the carrier. So the answer is sort of yes. When I read the email about multiply by 16 and divide by 10 it occurred to me that it would be easier to divide and then multiply and then I began to brain storm, which is hard to do when you stay up too late. If you chose to use a crystal ladder you need to use 16 MHz parallel resonant crystals since the series resonance will be slightly less than 16 MHz. These crystals are rather cheap. If you want to use a simple high Q (narrow bandwidth) phasing type filter you need to use a crystal with a 16MHz series resonance and use a termination resistance greater than the crystals series resistance. You can adjust the crystal filters bandwidth by changing the termination resistance. This type of filter was mostly used in early vacuum tube receivers. They usually shot for a minimum bandwidth of 500 Hz or so. you need to adjust the phasing capacitor so it equals the crystals parallel capacitance to minimize feed thru. Experimenting with these filters is a lot of fun. I have made lots of crystal filters. I even have a digital crystal impedance meter so I can compare crystals. If reducing phase sidebands in not a goal all you need is a filter that will eliminate all the other 2 MHz harmonics. 73 Bill wa4lav At 05:37 PM 1/4/2013 +, time-nuts-requ...@febo.com wrote: THis is exactly what they are talking about the 74HC390 can do over 50MHz and costs abut 30 cents. You don't need ECL or anything so exotic the 30 cent part will work. Set it for divide by 5. I guess this is imperfect enough that there is some fourth harmonic content in the 2MHz square wave, then you select that with a narrow band filter and amplify it to whatever you need. A smart design might try and add fourth harmonics be using a slightly not-symetric 2MHz square wave My question is about the phase noise of the final 16MHz signal. Do crystal filters clean up the signal. It seems that after several 16MHz crystals in series the output should look a lot like an XO. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
On 1/4/13 10:25 AM, Rick Karlquist wrote: Chris Albertson wrote: My question is about the phase noise of the final 16MHz signal. Do crystal filters clean up the signal. It seems that after several 16MHz crystals in series the output should look a lot like an XO. For offsets out to 100 Hz or so, using a crystal filter will cause the signal to have the same flicker noise that an oscillator built with that crystal would have. Thus don't try to use some junky clock crystals to make a crystal filter as described in numerous ham radio articles about receiver IF filters. An excellent point.. After all, what is a crystal oscillator but essentially a noise source followed by a crystal filter. Now after considering all that, crystal clean up filters don't sound like such a great idea unless you have no alternative. I can't think of a good practical example, but say you had a kind of noisy source, and a box full of crystals that happened to be at the same frequency, and for some odd reason, you didn't just build an oscillator with the crystal. (perhaps some sort of distribution amp system where you want all the outputs to be coherent to some reference, and the reference is noisy?) Rick Karlquist N6RK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 10 MHz - 16 MHz clock multiplier
At 07:51 PM 1/4/2013 +, you wrote: My question is about the phase noise of the final 16MHz signal. Do crystal filters clean up the signal. It seems that after several 16MHz crystals in series the output should look a lot like an XO. For offsets out to 100 Hz or so, using a crystal filter will cause the signal to have the same flicker noise that an oscillator built with that crystal would have. Thus don't try to use some junky clock crystals to make a crystal filter as described in numerous ham radio articles about receiver IF filters. If you have a residual phase noise measurement system like the Agilent E5505A and a very low flicker noise source, you can actually measure your filter crystals. Of course, the crystal time base in the source has to be better than the crystals you are measuring. You also have to avoid overdriving the crystal. This will require a low noise buffer amplifier to bring the signal back up to a high level. Now after considering all that, crystal clean up filters don't sound like such a great idea unless you have no alternative. Rick Karlquist N6RK Flicker noise (1/f ) noise would be introduced by an amplifier and not by the filter. I am only suggesting ways to multiply the frequency. You could use LC filters or a crystal filter. Using 3 doublers would do the job just as well. Naturally if you are concerned about flicker noise you could simply make the 2 MHz signal higher in amplitude before selecting the 8th harmonic. I was not saying your going to clean up a good crystal oscillator with a crystal filter. I though you were talking about generating 16MHz from 10MHz in a clean way. Using a microcontroller or even most synthesizers techniques would make it even worse. The PTS synthesizers have fairly good phase noise when they use frequency multiplication, division, mixing, comb generation and filtering on the most part to achieve low phase noise. The later models use a DDS at the lower frequency levels but do have greater phase noise close to the carrier. In fact in the SGA unit the reference input goes thru a transistor ( to distort it) and then into a series 10MHz crystal filter so that it can accept either a 5 or 10 MHz input. The crystal also helps filter out any birdies that may be on the reference signal. The filter should be fairly high Q since it has 47 Ohm drive impedance and 100 Ohm load impedance. 73 Bill wa4lav ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
How about getting back to basics. Is it a one off, if production how many and what are the specification requirements? Otherwise on this list it can go on for a year. Bert Kehren In a message dated 1/4/2013 6:11:14 P.M. Eastern Standard Time, wlfuq...@uky.edu writes: At 07:51 PM 1/4/2013 +, you wrote: My question is about the phase noise of the final 16MHz signal. Do crystal filters clean up the signal. It seems that after several 16MHz crystals in series the output should look a lot like an XO. For offsets out to 100 Hz or so, using a crystal filter will cause the signal to have the same flicker noise that an oscillator built with that crystal would have. Thus don't try to use some junky clock crystals to make a crystal filter as described in numerous ham radio articles about receiver IF filters. If you have a residual phase noise measurement system like the Agilent E5505A and a very low flicker noise source, you can actually measure your filter crystals. Of course, the crystal time base in the source has to be better than the crystals you are measuring. You also have to avoid overdriving the crystal. This will require a low noise buffer amplifier to bring the signal back up to a high level. Now after considering all that, crystal clean up filters don't sound like such a great idea unless you have no alternative. Rick Karlquist N6RK Flicker noise (1/f ) noise would be introduced by an amplifier and not by the filter. I am only suggesting ways to multiply the frequency. You could use LC filters or a crystal filter. Using 3 doublers would do the job just as well. Naturally if you are concerned about flicker noise you could simply make the 2 MHz signal higher in amplitude before selecting the 8th harmonic. I was not saying your going to clean up a good crystal oscillator with a crystal filter. I though you were talking about generating 16MHz from 10MHz in a clean way. Using a microcontroller or even most synthesizers techniques would make it even worse. The PTS synthesizers have fairly good phase noise when they use frequency multiplication, division, mixing, comb generation and filtering on the most part to achieve low phase noise. The later models use a DDS at the lower frequency levels but do have greater phase noise close to the carrier. In fact in the SGA unit the reference input goes thru a transistor ( to distort it) and then into a series 10MHz crystal filter so that it can accept either a 5 or 10 MHz input. The crystal also helps filter out any birdies that may be on the reference signal. The filter should be fairly high Q since it has 47 Ohm drive impedance and 100 Ohm load impedance. 73 Bill wa4lav ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Hi As I recall the spec was: 1) Cheap 2) no phase slips on the 16 MHz relative to 10 MHz 3) Cheap Bob On Jan 4, 2013, at 7:18 PM, ewkeh...@aol.com wrote: How about getting back to basics. Is it a one off, if production how many and what are the specification requirements? Otherwise on this list it can go on for a year. Bert Kehren In a message dated 1/4/2013 6:11:14 P.M. Eastern Standard Time, wlfuq...@uky.edu writes: At 07:51 PM 1/4/2013 +, you wrote: My question is about the phase noise of the final 16MHz signal. Do crystal filters clean up the signal. It seems that after several 16MHz crystals in series the output should look a lot like an XO. For offsets out to 100 Hz or so, using a crystal filter will cause the signal to have the same flicker noise that an oscillator built with that crystal would have. Thus don't try to use some junky clock crystals to make a crystal filter as described in numerous ham radio articles about receiver IF filters. If you have a residual phase noise measurement system like the Agilent E5505A and a very low flicker noise source, you can actually measure your filter crystals. Of course, the crystal time base in the source has to be better than the crystals you are measuring. You also have to avoid overdriving the crystal. This will require a low noise buffer amplifier to bring the signal back up to a high level. Now after considering all that, crystal clean up filters don't sound like such a great idea unless you have no alternative. Rick Karlquist N6RK Flicker noise (1/f ) noise would be introduced by an amplifier and not by the filter. I am only suggesting ways to multiply the frequency. You could use LC filters or a crystal filter. Using 3 doublers would do the job just as well. Naturally if you are concerned about flicker noise you could simply make the 2 MHz signal higher in amplitude before selecting the 8th harmonic. I was not saying your going to clean up a good crystal oscillator with a crystal filter. I though you were talking about generating 16MHz from 10MHz in a clean way. Using a microcontroller or even most synthesizers techniques would make it even worse. The PTS synthesizers have fairly good phase noise when they use frequency multiplication, division, mixing, comb generation and filtering on the most part to achieve low phase noise. The later models use a DDS at the lower frequency levels but do have greater phase noise close to the carrier. In fact in the SGA unit the reference input goes thru a transistor ( to distort it) and then into a series 10MHz crystal filter so that it can accept either a 5 or 10 MHz input. The crystal also helps filter out any birdies that may be on the reference signal. The filter should be fairly high Q since it has 47 Ohm drive impedance and 100 Ohm load impedance. 73 Bill wa4lav ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
I think the thread branched and as I recall started something like this. Someone needed a Simple 16 Mhz for a uproc made from a 10 Mhz source. Two reasonable answers were given. Injection locked oscillator Typical div and mult/filter. A third and kind of interesting for me a Ti chip soic digital pll. Then the thread went a whole bunch of directions. Wonder if who ever needed an answer got the answer? Regards Paul WB8TSL On Fri, Jan 4, 2013 at 7:18 PM, ewkeh...@aol.com wrote: How about getting back to basics. Is it a one off, if production how many and what are the specification requirements? Otherwise on this list it can go on for a year. Bert Kehren In a message dated 1/4/2013 6:11:14 P.M. Eastern Standard Time, wlfuq...@uky.edu writes: At 07:51 PM 1/4/2013 +, you wrote: My question is about the phase noise of the final 16MHz signal. Do crystal filters clean up the signal. It seems that after several 16MHz crystals in series the output should look a lot like an XO. For offsets out to 100 Hz or so, using a crystal filter will cause the signal to have the same flicker noise that an oscillator built with that crystal would have. Thus don't try to use some junky clock crystals to make a crystal filter as described in numerous ham radio articles about receiver IF filters. If you have a residual phase noise measurement system like the Agilent E5505A and a very low flicker noise source, you can actually measure your filter crystals. Of course, the crystal time base in the source has to be better than the crystals you are measuring. You also have to avoid overdriving the crystal. This will require a low noise buffer amplifier to bring the signal back up to a high level. Now after considering all that, crystal clean up filters don't sound like such a great idea unless you have no alternative. Rick Karlquist N6RK Flicker noise (1/f ) noise would be introduced by an amplifier and not by the filter. I am only suggesting ways to multiply the frequency. You could use LC filters or a crystal filter. Using 3 doublers would do the job just as well. Naturally if you are concerned about flicker noise you could simply make the 2 MHz signal higher in amplitude before selecting the 8th harmonic. I was not saying your going to clean up a good crystal oscillator with a crystal filter. I though you were talking about generating 16MHz from 10MHz in a clean way. Using a microcontroller or even most synthesizers techniques would make it even worse. The PTS synthesizers have fairly good phase noise when they use frequency multiplication, division, mixing, comb generation and filtering on the most part to achieve low phase noise. The later models use a DDS at the lower frequency levels but do have greater phase noise close to the carrier. In fact in the SGA unit the reference input goes thru a transistor ( to distort it) and then into a series 10MHz crystal filter so that it can accept either a 5 or 10 MHz input. The crystal also helps filter out any birdies that may be on the reference signal. The filter should be fairly high Q since it has 47 Ohm drive impedance and 100 Ohm load impedance. 73 Bill wa4lav ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
HI Ok, it's TimeNuts, we need numbers… Say no phase slips is 0.1 UI on the 16 MHz. That would be a jitter number of 6.25 ns RMS. Bob On Jan 4, 2013, at 7:18 PM, ewkeh...@aol.com wrote: How about getting back to basics. Is it a one off, if production how many and what are the specification requirements? Otherwise on this list it can go on for a year. Bert Kehren In a message dated 1/4/2013 6:11:14 P.M. Eastern Standard Time, wlfuq...@uky.edu writes: At 07:51 PM 1/4/2013 +, you wrote: My question is about the phase noise of the final 16MHz signal. Do crystal filters clean up the signal. It seems that after several 16MHz crystals in series the output should look a lot like an XO. For offsets out to 100 Hz or so, using a crystal filter will cause the signal to have the same flicker noise that an oscillator built with that crystal would have. Thus don't try to use some junky clock crystals to make a crystal filter as described in numerous ham radio articles about receiver IF filters. If you have a residual phase noise measurement system like the Agilent E5505A and a very low flicker noise source, you can actually measure your filter crystals. Of course, the crystal time base in the source has to be better than the crystals you are measuring. You also have to avoid overdriving the crystal. This will require a low noise buffer amplifier to bring the signal back up to a high level. Now after considering all that, crystal clean up filters don't sound like such a great idea unless you have no alternative. Rick Karlquist N6RK Flicker noise (1/f ) noise would be introduced by an amplifier and not by the filter. I am only suggesting ways to multiply the frequency. You could use LC filters or a crystal filter. Using 3 doublers would do the job just as well. Naturally if you are concerned about flicker noise you could simply make the 2 MHz signal higher in amplitude before selecting the 8th harmonic. I was not saying your going to clean up a good crystal oscillator with a crystal filter. I though you were talking about generating 16MHz from 10MHz in a clean way. Using a microcontroller or even most synthesizers techniques would make it even worse. The PTS synthesizers have fairly good phase noise when they use frequency multiplication, division, mixing, comb generation and filtering on the most part to achieve low phase noise. The later models use a DDS at the lower frequency levels but do have greater phase noise close to the carrier. In fact in the SGA unit the reference input goes thru a transistor ( to distort it) and then into a series 10MHz crystal filter so that it can accept either a 5 or 10 MHz input. The crystal also helps filter out any birdies that may be on the reference signal. The filter should be fairly high Q since it has 47 Ohm drive impedance and 100 Ohm load impedance. 73 Bill wa4lav ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
I would not use the 4046 these days. It has a dead band around zero phase error. I would use the 9046 which has no dead band. In addition the integrator supply is a cleaner design. It is a current source. The data sheet explains it. http://www.nxp.com/documents/data_sheet/74HCT9046A.pdf In addition the internal VCO is rated at 17 MHz (typ - 5.5V supply). Depending on how much jitter you can handle a low cost VCXO will give better performance than the on chip osc. Hz/Volt of the VCO is important in keeping jitter down. Smaller is better. Use the type 2 phase detector. (PC2) If you don't mind the extra chips run the phase detector at between 100KHz and 400KHz. It is a matter of the speed of the technology. 1 MHz is pushing it. It might also be a good idea to bias the internal VCO with a trimpot and let the phase detector just supply the correction. Well it is starting to get complicated. Simon Message: 2 Date: Wed, 2 Jan 2013 21:19:16 -0800 From: WarrenS warrensjmail-...@yahoo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] 10 MHz - 16 MHz clock multiplier Message-ID: 87417D31224740BFB6BBB320B762E80D@Warcon28Gz Content-Type: text/plain; format=flowed; charset=iso-8859-1; reply-type=original Tom For simple, cheap, low performance and fast to build with junk box parts, hard to beat: What I made long ago for myself (before time-nut days). I still use it today for low end stuff, and it is all done with standard 74HC DIP parts. The main IC is a 74HCT4046 Phase lock loop with internal Osc. The internal osc output is divided by 16 using a 74HC93. The 10MHz ref is divide by 10 using a 74HC90 The two 1 MHz signals are feed into it's phase comparator. A couple of resistors and caps and I have a low tech 16 / 8 / 4 / 2 / 1 MHz tracking ref. With a couple of tweaks, I got the noise jitter down to a couple of ns as measured with a scope. 16 MHz is pushing the limits of the internal Osc, but I did not have any trouble getting there using less than the recommended osc cap. ws What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb Engineering is the art of making what you want from what you can get at a profit. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 10 MHz - 16 MHz clock multiplier
One way is to divide by 10 and then multiply by 16. Divide by 10 and then follow by 4 tuned frequency doublers. This should introduce little phase noise. Another way to do it is to divide by 10, then pass the output thru a narrow 16 MHz filter and amplify. Sounds difficult but the filter can be one or two 16 MHz crystals followed by a simple amplifier. Look at the reference input circuit for a PTS-160. The output of the divide by 10 needs to be asymmetrical so it produces even harmonics. If you are using a divide divide by 52 such as a 74HC90, divide by 2 first then by 5. Ideally the pulse width should be a half period of 16 MHz for the maximum harmonic content at 16 MHz. You can take the output of the frequency divider and send it to a NAND gate. One input of the gate is directly connected and the other is delayed. You can use an RC with a variable capacitor to ground to get it just right. Just adjust the capacitor to get the maximum output from your filter amplifier. 73 Bill wa4lav At 07:41 PM 1/2/2013 +, you wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Where can one get some of these mythical 74HC90 's and 74AC90 's that have been mentioned. None of the usual places have them, ie ebay, digi-key, farnell, or even the Chinese. Also data-sheets are not to be found. Thanks On 4/01/2013 5:13 AM, Bill Fuqua wrote: One way is to divide by 10 and then multiply by 16. Divide by 10 and then follow by 4 tuned frequency doublers. This should introduce little phase noise. Another way to do it is to divide by 10, then pass the output thru a narrow 16 MHz filter and amplify. Sounds difficult but the filter can be one or two 16 MHz crystals followed by a simple amplifier. Look at the reference input circuit for a PTS-160. The output of the divide by 10 needs to be asymmetrical so it produces even harmonics. If you are using a divide divide by 52 such as a 74HC90, divide by 2 first then by 5. Ideally the pulse width should be a half period of 16 MHz for the maximum harmonic content at 16 MHz. You can take the output of the frequency divider and send it to a NAND gate. One input of the gate is directly connected and the other is delayed. You can use an RC with a variable capacitor to ground to get it just right. Just adjust the capacitor to get the maximum output from your filter amplifier. 73 Bill wa4lav At 07:41 PM 1/2/2013 +, you wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Am 04.01.2013 01:59, schrieb Max: Where can one get some of these mythical 74HC90 's and 74AC90 's that have been mentioned. None of the usual places have them, ie ebay, digi-key, farnell, or even the Chinese. Also data-sheets are not to be found. you can't find 'em because they're not there(Lou Reed, Busload Of Faith) regards, Gerhard ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
They do not exist as I found out (again) not long ago. The last 7490 made was LS (low power schottky) and I use quite a few of them. Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they apparently either never went into production or very few were produced. The closest non-TTL alternative that I found was the 74HC390 or 74HCT390 which is basically two 7490 counters in one package. On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3...@gmail.com wrote: Where can one get some of these mythical 74HC90 's and 74AC90 's that have been mentioned. None of the usual places have them, ie ebay, digi-key, farnell, or even the Chinese. Also data-sheets are not to be found. Thanks On 4/01/2013 5:13 AM, Bill Fuqua wrote: One way is to divide by 10 and then multiply by 16. Divide by 10 and then follow by 4 tuned frequency doublers. This should introduce little phase noise. Another way to do it is to divide by 10, then pass the output thru a narrow 16 MHz filter and amplify. Sounds difficult but the filter can be one or two 16 MHz crystals followed by a simple amplifier. Look at the reference input circuit for a PTS-160. The output of the divide by 10 needs to be asymmetrical so it produces even harmonics. If you are using a divide divide by 52 such as a 74HC90, divide by 2 first then by 5. Ideally the pulse width should be a half period of 16 MHz for the maximum harmonic content at 16 MHz. You can take the output of the frequency divider and send it to a NAND gate. One input of the gate is directly connected and the other is delayed. You can use an RC with a variable capacitor to ground to get it just right. Just adjust the capacitor to get the maximum output from your filter amplifier. 73 Bill wa4lav At 07:41 PM 1/2/2013 +, you wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Isn't there a fast divide by N counter that you could set to 10? Maybe even in ECL? - Original Message - From: David davidwh...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, January 03, 2013 8:49 PM Subject: Re: [time-nuts] 10 MHz - 16 MHz clock multiplier They do not exist as I found out (again) not long ago. The last 7490 made was LS (low power schottky) and I use quite a few of them. Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they apparently either never went into production or very few were produced. The closest non-TTL alternative that I found was the 74HC390 or 74HCT390 which is basically two 7490 counters in one package. On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3...@gmail.com wrote: Where can one get some of these mythical 74HC90 's and 74AC90 's that have been mentioned. None of the usual places have them, ie ebay, digi-key, farnell, or even the Chinese. Also data-sheets are not to be found. Thanks On 4/01/2013 5:13 AM, Bill Fuqua wrote: One way is to divide by 10 and then multiply by 16. Divide by 10 and then follow by 4 tuned frequency doublers. This should introduce little phase noise. Another way to do it is to divide by 10, then pass the output thru a narrow 16 MHz filter and amplify. Sounds difficult but the filter can be one or two 16 MHz crystals followed by a simple amplifier. Look at the reference input circuit for a PTS-160. The output of the divide by 10 needs to be asymmetrical so it produces even harmonics. If you are using a divide divide by 52 such as a 74HC90, divide by 2 first then by 5. Ideally the pulse width should be a half period of 16 MHz for the maximum harmonic content at 16 MHz. You can take the output of the frequency divider and send it to a NAND gate. One input of the gate is directly connected and the other is delayed. You can use an RC with a variable capacitor to ground to get it just right. Just adjust the capacitor to get the maximum output from your filter amplifier. 73 Bill wa4lav At 07:41 PM 1/2/2013 +, you wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Ahhh, the beauty of the 74xx90 is that you can have a symetrical output by using the divide by two after the divide by five. Max On 4/01/2013 1:02 PM, Tom Miller wrote: Isn't there a fast divide by N counter that you could set to 10? Maybe even in ECL? - Original Message - From: David davidwh...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, January 03, 2013 8:49 PM Subject: Re: [time-nuts] 10 MHz - 16 MHz clock multiplier They do not exist as I found out (again) not long ago. The last 7490 made was LS (low power schottky) and I use quite a few of them. Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they apparently either never went into production or very few were produced. The closest non-TTL alternative that I found was the 74HC390 or 74HCT390 which is basically two 7490 counters in one package. On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3...@gmail.com wrote: Where can one get some of these mythical 74HC90 's and 74AC90 's that have been mentioned. None of the usual places have them, ie ebay, digi-key, farnell, or even the Chinese. Also data-sheets are not to be found. Thanks On 4/01/2013 5:13 AM, Bill Fuqua wrote: One way is to divide by 10 and then multiply by 16. Divide by 10 and then follow by 4 tuned frequency doublers. This should introduce little phase noise. Another way to do it is to divide by 10, then pass the output thru a narrow 16 MHz filter and amplify. Sounds difficult but the filter can be one or two 16 MHz crystals followed by a simple amplifier. Look at the reference input circuit for a PTS-160. The output of the divide by 10 needs to be asymmetrical so it produces even harmonics. If you are using a divide divide by 52 such as a 74HC90, divide by 2 first then by 5. Ideally the pulse width should be a half period of 16 MHz for the maximum harmonic content at 16 MHz. You can take the output of the frequency divider and send it to a NAND gate. One input of the gate is directly connected and the other is delayed. You can use an RC with a variable capacitor to ground to get it just right. Just adjust the capacitor to get the maximum output from your filter amplifier. 73 Bill wa4lav At 07:41 PM 1/2/2013 +, you wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Oh, there are lots, well, at least some presetable synchronous counters in fast logic families that could be used but that would require extra glue logic. Alternatively if you just want to divide by 5 or some other small fixed number, you can use a couple of flip-flips and gates. On Thu, 03 Jan 2013 21:02:32 -0500, Tom Miller tmil...@skylinenet.net wrote: Isn't there a fast divide by N counter that you could set to 10? Maybe even in ECL? - Original Message - From: David davidwh...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, January 03, 2013 8:49 PM Subject: Re: [time-nuts] 10 MHz - 16 MHz clock multiplier They do not exist as I found out (again) not long ago. The last 7490 made was LS (low power schottky) and I use quite a few of them. Actually, I have seen a datasheet for a 74HC90 and 74HCT90 but they apparently either never went into production or very few were produced. The closest non-TTL alternative that I found was the 74HC390 or 74HCT390 which is basically two 7490 counters in one package. On Fri, 04 Jan 2013 11:59:01 +1100, Max vk3...@gmail.com wrote: Where can one get some of these mythical 74HC90 's and 74AC90 's that have been mentioned. None of the usual places have them, ie ebay, digi-key, farnell, or even the Chinese. Also data-sheets are not to be found. Thanks On 4/01/2013 5:13 AM, Bill Fuqua wrote: One way is to divide by 10 and then multiply by 16. Divide by 10 and then follow by 4 tuned frequency doublers. This should introduce little phase noise. Another way to do it is to divide by 10, then pass the output thru a narrow 16 MHz filter and amplify. Sounds difficult but the filter can be one or two 16 MHz crystals followed by a simple amplifier. Look at the reference input circuit for a PTS-160. The output of the divide by 10 needs to be asymmetrical so it produces even harmonics. If you are using a divide divide by 52 such as a 74HC90, divide by 2 first then by 5. Ideally the pulse width should be a half period of 16 MHz for the maximum harmonic content at 16 MHz. You can take the output of the frequency divider and send it to a NAND gate. One input of the gate is directly connected and the other is delayed. You can use an RC with a variable capacitor to ground to get it just right. Just adjust the capacitor to get the maximum output from your filter amplifier. 73 Bill wa4lav At 07:41 PM 1/2/2013 +, you wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 10 MHz - 16 MHz clock multiplier
At 12:58 AM 1/4/2013 +, time-nuts-requ...@febo.com wrote: Where can one get some of these mythical 74HC90 's and 74AC90 's that have been mentioned. None of the usual places have them, ie ebay, digi-key, farnell, or even the Chinese. Also data-sheets are not to be found. Thanks This is what happens when one stays up too late 74HC390. However, any discussion on the technical merits? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
On 1/3/2013 6:22 PM, David wrote: Alternatively if you just want to divide by 5 or some other small fixed number, you can use a couple of flip-flips and gates. Flip-flips are good for digitally implementing tick-tick clocks, right? :-) (Use flop-flops for tock-tock.) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
tmil...@skylinenet.net said: Isn't there a fast divide by N counter that you could set to 10? Maybe even in ECL? The 74xx16y are 4 bit loadable counters. 2 are binary, 2 are decimal. I think 1 of each pair has a synchronous reset/clear, the other is async. Mouser has the 74AC161 and 74AC163 in stock. They are binary. I think you need an inverter to hook up the ripple carry out to load them to 6 to make a divide by 10. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 10 MHz - 16 MHz clock multiplier
What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Tom. OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref. Thats pretty easy as they say. As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires BPF but pretty easy also. Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a 16 Mhz osc. Thats actually the easiest of the approaches. Regards Paul On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baak t...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Since injection locking is possible when the ratio of the 2 frequencies involved is a rational number, a 16 MHz oscillator can be directly injection locked to a 10MHz signal without the need for dividers etc. Bruce paul swed wrote: Tom. OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref. Thats pretty easy as they say. As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires BPF but pretty easy also. Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a 16 Mhz osc. Thats actually the easiest of the approaches. Regards Paul On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baakt...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Bruce is right about that fact. Thanks. Square up the 10 Mhz. Diff the leading edge (It actually doesn't matter) maybe 2-5pf cap and 300 ohm R to ground. Feed this into a transistor that is in the bottom end of a one transistor oscillator. There are actually several ways to inject. Think of a totem pole of 2 transistors. Use google and do a search and you will see what I am talking about. There were some articles that the spread spectrum hams used that describe it. On Wed, Jan 2, 2013 at 2:48 PM, Bruce Griffiths bruce.griffi...@xtra.co.nzwrote: Since injection locking is possible when the ratio of the 2 frequencies involved is a rational number, a 16 MHz oscillator can be directly injection locked to a 10MHz signal without the need for dividers etc. Bruce paul swed wrote: Tom. OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref. Thats pretty easy as they say. As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires BPF but pretty easy also. Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a 16 Mhz osc. Thats actually the easiest of the approaches. Regards Paul On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baakt...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/**mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Hi I think I'd second the thought of join with an ARM or something like it that will be happy with 10 MHz in. Next choice would be a PIC24 / dsPIC33 that's also happy with 10 MHz in. The money you will pay for the clock conversion chip(s) will go a long way spent on a CPU. Bob On Jan 2, 2013, at 1:54 PM, Tom Van Baak t...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
What's the simplest way to generate 16 MHz from 10 MHz? Well, it's a few dollars and *is* a TSSOP, but I've been playing with TI's CDCE913/925/937/949 series. They're nice little I2C-programmable fractional-N PLL chips. You can either program them in software, or save the config to on-board flash and pin-select various configs. They also have onboard varactors and EFC inputs for making a VCXO. The on-board VCXO range is 80 to 230 MHz, so I'd multiply the 10 MHz up to 160 MHz and then divide by 10. I like to throw one in a circuit and know that I can generate whatever clocks I need in software. They're also pin-compatible, so if you lay down a pad for a part larger than needed, you have spare outputs in case you need them for something. (The second digit in the P/N is the number of PLLs; the third is the number of outputs.) The main limitation is that there's no way to produce a desired phase relationship between different divisors for e.g. a half-speed clock. Looking for something cheaper, I can see SiLabs' Si51210 factory- programmable part, which is cheaper in quantity, but I don't know the minimum order quantities. It depends what you mean by simplest; the injection-locking idea is definitely the simplest circuit, but it does require some up-front work to find coupling capacitor values that work reliably over tolerance. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Am 02.01.2013 19:54, schrieb Tom Van Baak: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. Probably not the simplest way, but straightforward maybe you can recycle parts of it: http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1.pdf http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1_layout.png That's how I did (optional) 10 MHz --- 32 MHz for my DG8SAQ VNWA. parts are cheap available @ digikey. regards, Gerhard ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
I looked at the TI chip that really seems simple. On Wed, Jan 2, 2013 at 3:58 PM, Gerhard Hoffmann dk...@arcor.de wrote: Am 02.01.2013 19:54, schrieb Tom Van Baak: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. Probably not the simplest way, but straightforward maybe you can recycle parts of it: http://www.hoffmann-**hochfrequenz.de/downloads/**vnwa_sync_1.1.pdfhttp://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1.pdf http://www.hoffmann-**hochfrequenz.de/downloads/**vnwa_sync_1.1_layout.pnghttp://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1_layout.png That's how I did (optional) 10 MHz --- 32 MHz for my DG8SAQ VNWA. parts are cheap available @ digikey. regards, Gerhard __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
I wrote: The on-board VCXO range is 80 to 230 MHz, so I'd multiply the 10 MHz up to 160 MHz and then divide by 10. In case it's not obvious, I meant to write the on-chip VCO. Obviously it's *not* a crystal oscillator; I just failed to supervise my typing fingers carefully enough. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
The optimum width of the injection pulse is equal to 1/2 the period of the output frequency of the injection locked oscillator. In this case a pulse width of around 31.25ns Bruce paul swed wrote: Bruce is right about that fact. Thanks. Square up the 10 Mhz. Diff the leading edge (It actually doesn't matter) maybe 2-5pf cap and 300 ohm R to ground. Feed this into a transistor that is in the bottom end of a one transistor oscillator. There are actually several ways to inject. Think of a totem pole of 2 transistors. Use google and do a search and you will see what I am talking about. There were some articles that the spread spectrum hams used that describe it. On Wed, Jan 2, 2013 at 2:48 PM, Bruce Griffiths bruce.griffi...@xtra.co.nzwrote: Since injection locking is possible when the ratio of the 2 frequencies involved is a rational number, a 16 MHz oscillator can be directly injection locked to a 10MHz signal without the need for dividers etc. Bruce paul swed wrote: Tom. OK the challenge simple. CD4046 16 MHz vco and div by 8 using a 2 Mhz ref. Thats pretty easy as they say. As an alternative and very easy 10 MHz div 2 2MHz X 4 X 2. This requires BPF but pretty easy also. Lastly an injection osc. 10 Mhz div to 2 Mhz differentiate and feed to a 16 Mhz osc. Thats actually the easiest of the approaches. Regards Paul On Wed, Jan 2, 2013 at 1:54 PM, Tom Van Baakt...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/**mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Tom, This may not be the answer you are looking for, but the simplest way may be to use a uC that has a PLL for clock generation. Didier On Wed, Jan 2, 2013 at 12:54 PM, Tom Van Baak t...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Interesting problem Re: 10 MHz - 16 MHz clock multiplier What is low cost?? Serious question. john k6iql -Original Message- From: time-nuts-request time-nuts-requ...@febo.com To: time-nuts time-nuts@febo.com Sent: Wed, Jan 2, 2013 9:19 pm Subject: time-nuts Digest, Vol 102, Issue 10 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: 10 MHz - 16 MHz clock multiplier (Didier Juges) 2. Re: An embedded NTP server (Tom Harris) 3. Re: An embedded NTP server (Jim Lux) 4. Re: An embedded NTP server (Michael Tharp) 5. Re: clock-block any need ? (Magnus Danielson) -- Message: 1 Date: Wed, 2 Jan 2013 19:31:52 -0600 From: Didier Juges shali...@gmail.com To: Tom Van Baak t...@leapsecond.com, Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] 10 MHz - 16 MHz clock multiplier Message-ID: CAMQqFu=ghst14ygddgw8pvjrnmnryyfne13g06p+qrmv48a...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 Tom, This may not be the answer you are looking for, but the simplest way may be to use a uC that has a PLL for clock generation. Didier On Wed, Jan 2, 2013 at 12:54 PM, Tom Van Baak t...@leapsecond.com wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Message: 2 Date: Thu, 3 Jan 2013 12:34:15 +1100 From: Tom Harris celephi...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] An embedded NTP server Message-ID: cahjg12qxpb9px8dp6ngk-x575etnsfc+csqr6acsrx7gfw-...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 +1 for Forth! +1 for your opinions on PICs AVRs. We can buy low end NXP ARM Cortex M0 chips (e.g. LPC1113) for less than the PIC18 we were using before, and it has a real compiler and (unlike the real world) evidence of intelligent design! Do you really need an OS? Surely for a box that is only ever going to be an NTP server you just need a network interface and good maths? I've just seen a later comment where you mention floating point support, but would 64 bit integer maths work just as well? On 3 January 2013 06:25, Chris Albertson albertson.ch...@gmail.com wrote: On Wed, Jan 2, 2013 at 11:16 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: I've given up on PIC and Atmel microcontrollers and their antiquated CPU designs. My life is too short to fight odd-ball compilers, when I can get a real 32 bit CPU and a good compiler instead. That is a valid point if you are building a one-off project. Your time is worth something. But if you plan to sell a million AA cell battery chargers using a 32-bit controller is uneconomical. These will always be a bigger market for 8-bit chips then for 32-bit chips. For an NTP server I'd go with something that can run an OS and the NTP reverence implementation. ARM (and others) can do that. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Tom Harris celephi...@gmail.com -- Message: 3 Date: Wed, 02 Jan 2013 18:26:24 -0800 From: Jim Lux jim...@earthlink.net To: time-nuts@febo.com Subject: Re: [time-nuts] An embedded NTP server Message-ID: 50e4ec50.1030...@earthlink.net Content-Type: text/plain; charset=ISO-8859-1; format=flowed On 1/2/13 5:34 PM, Tom Harris wrote: +1 for Forth! +1 for your opinions on PICs AVRs. We can buy low end NXP ARM Cortex M0 chips (e.g. LPC1113) for less than the PIC18 we were using before, and it has a real compiler and (unlike the real world) evidence of intelligent design! Do you really need an OS? Surely for a box that is only ever
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
How about simply using a 16MHz GPSDO? We have shipped FireFly-1A units with 16MHz Ocxo.. Those can also generate 16MHz out of a 1PPS reference. Bye, Said Sent From iPhone On Jan 2, 2013, at 12:58, Gerhard Hoffmann dk...@arcor.de wrote: Am 02.01.2013 19:54, schrieb Tom Van Baak: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. Probably not the simplest way, but straightforward maybe you can recycle parts of it: http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1.pdf http://www.hoffmann-hochfrequenz.de/downloads/vnwa_sync_1.1_layout.png That's how I did (optional) 10 MHz --- 32 MHz for my DG8SAQ VNWA. parts are cheap available @ digikey. regards, Gerhard ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
Tom For simple, cheap, low performance and fast to build with junk box parts, hard to beat: What I made long ago for myself (before time-nut days). I still use it today for low end stuff, and it is all done with standard 74HC DIP parts. The main IC is a 74HCT4046 Phase lock loop with internal Osc. The internal osc output is divided by 16 using a 74HC93. The 10MHz ref is divide by 10 using a 74HC90 The two 1 MHz signals are feed into it's phase comparator. A couple of resistors and caps and I have a low tech 16 / 8 / 4 / 2 / 1 MHz tracking ref. With a couple of tweaks, I got the noise jitter down to a couple of ns as measured with a scope. 16 MHz is pushing the limits of the internal Osc, but I did not have any trouble getting there using less than the recommended osc cap. ws What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10 MHz - 16 MHz clock multiplier
On 02/01/13 19:54, Tom Van Baak wrote: What's the simplest way to generate 16 MHz from 10 MHz? This will be for clocking a microcontroller at 16 MHz given 10 MHz (Cs/Rb/GPSDO). Low price and low parts count is a goal; jitter is not a concern but absolute long-term phase coherence is a must. The ICS525 (as in TAPR Clock-Block) is a good candidate but I was wondering if there's something cheaper, less functional, and maybe not SSOP. Any suggestions? One approach is to divide by 5 to get 2 MHz, but recalling that the 20% PWM factor (top bit of divide by 5 counter) has a strong 8th overtone compared to the 40% PWM factor, an LC-tank at 16 MHz and a simple gain-stage (such as the Wenzel sine input) should be able to pull it off. The divide by 5 is standard TTL/CMOS of your choosing. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
