Re: [time-nuts] An embedded NTP server
In message 50e4c479.5080...@earthlink.net, Jim Lux writes: On 1/2/13 11:37 AM, Poul-Henning Kamp wrote: Actually, the OS is not important, floating point support is. floating point support in the sense that the compiler supports it and generates appropriate code to use software FP or hardware FP as available? Either, as long as it is precise and you have room for it. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] An embedded NTP server
In message cahjg12qxpb9px8dp6ngk-x575etnsfc+csqr6acsrx7gfw-...@mail.gmail.com , Tom Harris writes: +1 for Forth! Indeed, but for me that is only an indulgence :-) +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! ARM is a very intelligent design, unfortunately it is falling prey to the curse that hits any successful CPU: more and more complicated instructions gets added to help this one important case... This curse already claimed IBM's mainframe CPU and x86 cpus, and with the thumb2 set, ARM is caving too. But it is a damn good CPU still. 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? Depends how much code you want to write yourself. The advantage of having an OS, is that somebody else maintains a lot of the code for you and you get features like TCP/IP and SSH for free. The disadvantage is that you need more flash to hold all that junk. In general, you should reuse as much code as you can, life is too short to write another UDP checksum subroutine. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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.
Re: [time-nuts] An embedded NTP server
On 1/3/13 12:53 AM, Poul-Henning Kamp wrote: In general, you should reuse as much code as you can, life is too short to write another UDP checksum subroutine. You captured it exactly.. The thrill of implementing sin() is long past. Heck, I'd be happy with something that ran Matlab/Octave/SciPy etc...interpreting and all. ___ 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] A New Years Resolution.
Please don't do that - start a complete new thread instead by posting a completely new message (i.e. not a reply). The threading on many engines doesn't use the subject line at all. Regards, David Partridge -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Max Robinson Sent: 02 January 2013 04:27 To: Time Nuts; HP Equipment; Fun with Tubes; Fun with Transistors; Blind Like Me Subject: [time-nuts] A New Years Resolution. I hereby resolve to look at the subject line of every message I send and change it if necessary. Regards. Max. K 4 O DS. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscr...@yahoogroups.com ___ 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
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] Questions about TAC frontend, and some measurements
On Sun, 23 Dec 2012 22:45:40 +0100 Fabio Eboli fabi...@quipo.it wrote: Il 2012-12-23 07:42 Bruce Griffiths ha scritto: The classic TAC using current mode switching is similar to the attached circuit schematic. http://pastebin.com/EkgqmgfE I have a couple of small questions about this circuit. Why are Q2 and Q13 driven by Vth? As there are inverted versions of the Discharge and Ramp signals available, wouldn't it make sense to use those to drive Q2 and Q13? I guess it would enhance switching speed. What is the reason behind the emitter followers Q1 and Q9? Respecitvely, why shouldnt R3/R4, R7/R8 be connected directly to V+/V-? Is there a special reson why the current source around Q9 is set to 20mA and the one around Q4 to 10mA? Is it because Q14/Q15 are driven by a 20mA current source while Q18/Q19 by a 10mA source? Am i correct, that the only current source whos value really matters is the one around Q11? If so, wouldn't it be beneficial to use a stable reference voltage (probably coupled with the ADC reference) to be used in an opamp based current source against GND or V- and a current mirror (cascode or wilson) to drive Q18/Q19 (while leaving the other LED based current sources as they are, including Q16)? Attila Kinali -- There is no secret ingredient -- Po, Kung Fu Panda ___ 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] Some Quartz short term stabilities
Here is an update of measurements of some Quartz short term stabilities. It's interesting to see that the 10811-60111 that some turn their noses up at can turn in excellent stability as well! QUARTZ 1 SEC. 10 SEC. 100 SEC. 1K SEC. 10811-601096.11-12 2.52-12 8.78-12 10811-601091.65-12 1.91-12 9.79-12 10811-601091.65-12 1.99-12 1.11-12 10811-601095.47-12 1.16-12 2.38-12 105 STYLE #T 7.60-13 2.01-12 3.94-12 10811-601111.27-12 2.65-12 1.93-12 105 STYLE #2 1.14-12 1.57-12 2.26-12 105 STYLE #3 1.31-12 1.58-12 2.68-12 10811-601113.04-12 5.54-12 1.47-12 105 STYLE #4 1.38-12 3.49-12 4.84-12 10811-601092.05-12 2.89-12 3.24-12 10811-601111.36-12 1.17-12 1.75-12 105 STYLE #5 1.14-12 2.09-12 2.51-12 FTS 1200 #17.14-13 1.48-12 1.92-12 10543A2.86-11 1.05-11 1.63-11 10544A4.08-12 2.95-12 7.79-12 10811-601111.24-12 2.10-12 2.09-12 10811-601111.48-12 1.59-12 1.54-12 10544A1.89-12 2.99-12 5.01-12 105 style #6 2.88-12 2.88-12 7.37-12 105 style #7 9.69-13 2.30-12 3.49-12 10544-60511 8.20-13 2.11-12 2.51-12 Piezo clone 2.57-12 2.23-12 2.17-12 5060Aosconly 4.04-12 5.94-128.42-12 1.30-11 10811-60111 2.59-12 3.87-12 5.77-12 105 STYLE 8 8.0-13 2.0-12 9.0-12 10811- 2.0-12 1.0-12 2.5-12 10811- 1.5-12 2.5-12 3.0-12 10811- 2.2-12 2.5-12 3.4-12 10811- 2.1-12 2.0-12 3.3-12 10811- 1.8-12 1.4-12 5.0-12 10811- 2.0-12 2.0-12 3.2-12 10811-601201.3-12 1.3-12 1.2-12 10811- 2.0-12 1.8-12 2.8-12 Motorola DOXO 1.05-12 1.0-121.03-12 *** CHERRY PICKED units ** FTS 1200 #2 2.99-13 4.30-13 7.69-13 8.65-13 ** FTS/datum 1000B 8.69-13 1.15-12 9.20-13 ** FTS 9110 6.50-13 2.68-13 3.90-13 ** Datum 1115C6.88-13 5.83-13 9.34-13 ** 10811-601096.22-13 6.43-13 3.66-13 ** 10811-601095.25-13 4.20-13 6.78-13 ** 10811-601117.60-13 7.80-13 7.15-13 ** 10811-601112.16-12 4.89-13 1.24-12 ** 10811-601116.02-13 3.11-13 3.46-13 -- -60109spec 2.50-125.00-12 1.00-11 -- -60111spec 1.00-12* * -- 10811Aspec 5.00-12 5.00-12 1.00-11 ___ 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] Questions about TAC frontend, and some measurements
On Thu, 3 Jan 2013 21:28:17 +0100 Attila Kinali att...@kinali.ch wrote: What is the reason behind the emitter followers Q1 and Q9? Respecitvely, why shouldnt R3/R4, R7/R8 be connected directly to V+/V-? Scratch that question. Looking at the schematics again, it became obvious. Attila Kinali -- There is no secret ingredient -- Po, Kung Fu Panda ___ 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] Some Quartz short term stabilities
Hi I wonder who made the Motorola DOCXO? Bob On Jan 3, 2013, at 3:41 PM, cdel...@juno.com wrote: Here is an update of measurements of some Quartz short term stabilities. It's interesting to see that the 10811-60111 that some turn their noses up at can turn in excellent stability as well! QUARTZ 1 SEC. 10 SEC. 100 SEC. 1K SEC. 10811-601096.11-12 2.52-12 8.78-12 10811-601091.65-12 1.91-12 9.79-12 10811-601091.65-12 1.99-12 1.11-12 10811-601095.47-12 1.16-12 2.38-12 105 STYLE #T 7.60-13 2.01-12 3.94-12 10811-601111.27-12 2.65-12 1.93-12 105 STYLE #2 1.14-12 1.57-12 2.26-12 105 STYLE #3 1.31-12 1.58-12 2.68-12 10811-601113.04-12 5.54-12 1.47-12 105 STYLE #4 1.38-12 3.49-12 4.84-12 10811-601092.05-12 2.89-12 3.24-12 10811-601111.36-12 1.17-12 1.75-12 105 STYLE #5 1.14-12 2.09-12 2.51-12 FTS 1200 #17.14-13 1.48-12 1.92-12 10543A2.86-11 1.05-11 1.63-11 10544A4.08-12 2.95-12 7.79-12 10811-601111.24-12 2.10-12 2.09-12 10811-601111.48-12 1.59-12 1.54-12 10544A1.89-12 2.99-12 5.01-12 105 style #6 2.88-12 2.88-12 7.37-12 105 style #7 9.69-13 2.30-12 3.49-12 10544-60511 8.20-13 2.11-12 2.51-12 Piezo clone 2.57-12 2.23-12 2.17-12 5060Aosconly 4.04-12 5.94-128.42-12 1.30-11 10811-60111 2.59-12 3.87-12 5.77-12 105 STYLE 8 8.0-13 2.0-12 9.0-12 10811- 2.0-12 1.0-12 2.5-12 10811- 1.5-12 2.5-12 3.0-12 10811- 2.2-12 2.5-12 3.4-12 10811- 2.1-12 2.0-12 3.3-12 10811- 1.8-12 1.4-12 5.0-12 10811- 2.0-12 2.0-12 3.2-12 10811-601201.3-12 1.3-12 1.2-12 10811- 2.0-12 1.8-12 2.8-12 Motorola DOXO 1.05-12 1.0-121.03-12 *** CHERRY PICKED units ** FTS 1200 #2 2.99-13 4.30-13 7.69-13 8.65-13 ** FTS/datum 1000B 8.69-13 1.15-12 9.20-13 ** FTS 9110 6.50-13 2.68-13 3.90-13 ** Datum 1115C6.88-13 5.83-13 9.34-13 ** 10811-601096.22-13 6.43-13 3.66-13 ** 10811-601095.25-13 4.20-13 6.78-13 ** 10811-601117.60-13 7.80-13 7.15-13 ** 10811-601112.16-12 4.89-13 1.24-12 ** 10811-601116.02-13 3.11-13 3.46-13 -- -60109spec 2.50-125.00-12 1.00-11 -- -60111spec 1.00-12* * -- 10811Aspec 5.00-12 5.00-12 1.00-11 ___ 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] Some Quartz short term stabilities
Bob, On 04/01/13 01:41, Bob Camp wrote: Hi I wonder who made the Motorola DOCXO? Wouln't that be CTS in todays name-space? 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.
Re: [time-nuts] Some Quartz short term stabilities
Hi Motorola went out of the DOCXO business back in the 1960's. Everything past about 1980 was made by somebody else and a Motorola label was put on it. The part of the business they spun off to CTS made TCXO's, XO's, and crystals. Bob On Jan 3, 2013, at 7:53 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Bob, On 04/01/13 01:41, Bob Camp wrote: Hi I wonder who made the Motorola DOCXO? Wouln't that be CTS in todays name-space? 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. ___ 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.
