Re: [time-nuts] 10MHz Square to Sine Wave Conversion
I was thinking along these lines. Cooking up a 3-pole filter in the form of a Pi-filter should be a good start, and then add traps for third and possibly fifth overtones that will not get much damping initially can be done if you need it pretty clean. Cheers, Magnus On 07/17/2015 04:07 AM, Graham / KE9H wrote: All you need is a 10 MHz low pass filter. How far down do you need the harmonics/spurious to be? If 40 dB suppression of the 2nd and 3rd harmonics is adequate, (you can't see the distortion with the eye on an oscilloscope) you can make your own for about $2 in parts, not including a PC board or housing. Feel free to copy the low pass filter (L1, C9, C10) from here: http://openhpsdr.org/wiki/index.php?title=EXCALIBUR Or for about $35, you could get the same performance from an inline BNC filter from Minicircuits. http://www.minicircuits.com/pdfs/BLP-10.7+.pdf If you need more harmonic suppression, buy two and put them in series. --- Graham == --- Graham == On Thu, Jul 16, 2015 at 12:49 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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 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] 10MHz Square to Sine Wave Conversion
For the life of me I can't find the link to the schematic or any mention of it in the archives. Google fail. However, I was able to find some screen shots and pictures from the Chebyshev filter that I built from the docs that I originally found here. This should get you started if you want to roll your own. Mini-Circuits makes a filter if memory serves, but this is a very cheap and fun project if you already have a little project box. Screen shots show simulation and most importantly, the values of the parts in the project. The 0.06uH inductor was hand wound and tweaked till I got it right. S parameters were measured with the cover ON and the cover does de-tune the circuit so you have to compensate before buttoning it up. https://goo.gl/photos/UiqRrFRNYczvcbNh6 -Bob N3XKB On Thu, Jul 16, 2015 at 11:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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.
Re: [time-nuts] 10MHz Square to Sine Wave Conversion
You can't use the square wave? You could put in a resonant circuit that will select the fundamental but other issues arise, such as phase noise and harmonic content. How much harmonic content can you tolerate? There is a host of ways to do this job but much depends on your requirements. Bob K6DDX On Thursday, July 16, 2015 2:03 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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.
Re: [time-nuts] 10MHz Square to Sine Wave Conversion
Hi, What distortion level would you like to achieve? Regards, Vasco Soares Em 2015-07-16 18:49, skipp Isaham via time-nuts escreveu: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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.
Re: [time-nuts] 10MHz Square to Sine Wave Conversion
Here's the URL to the document I was referring to: http://www.w1ghz.org/small_proj/10MHz_Filter_for_GPS_Reference.zip And I see in my simulation I have the inductor and cap in the center of the schematic reversed, however it was built properly. -Bob On Thu, Jul 16, 2015 at 3:24 PM, Bob Darlington rdarling...@gmail.com wrote: For the life of me I can't find the link to the schematic or any mention of it in the archives. Google fail. However, I was able to find some screen shots and pictures from the Chebyshev filter that I built from the docs that I originally found here. This should get you started if you want to roll your own. Mini-Circuits makes a filter if memory serves, but this is a very cheap and fun project if you already have a little project box. Screen shots show simulation and most importantly, the values of the parts in the project. The 0.06uH inductor was hand wound and tweaked till I got it right. S parameters were measured with the cover ON and the cover does de-tune the circuit so you have to compensate before buttoning it up. https://goo.gl/photos/UiqRrFRNYczvcbNh6 -Bob N3XKB On Thu, Jul 16, 2015 at 11:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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.
Re: [time-nuts] 10MHz Square to Sine Wave Conversion
How good does the sine wave need to be? The usual method is to use a low-pass filter A CLC pi filter works. On Thu, Jul 16, 2015 at 10:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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. -- 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] 10MHz Square to Sine Wave Conversion
Hi The simple approach is to buffer it with a few ‘125 buffers in parallel. Then convert to sine wave with a T-network matching section. There are a lot of matching calculators on the web. Something in the 50 to 200 ohm input range and 50 ohm output is a reasonable way to go. More gates and higher power = more output. Lower input impedance = more output. Bob On Jul 16, 2015, at 1:49 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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.
Re: [time-nuts] 10MHz Square to Sine Wave Conversion
All you need is a 10 MHz low pass filter. How far down do you need the harmonics/spurious to be? If 40 dB suppression of the 2nd and 3rd harmonics is adequate, (you can't see the distortion with the eye on an oscilloscope) you can make your own for about $2 in parts, not including a PC board or housing. Feel free to copy the low pass filter (L1, C9, C10) from here: http://openhpsdr.org/wiki/index.php?title=EXCALIBUR Or for about $35, you could get the same performance from an inline BNC filter from Minicircuits. http://www.minicircuits.com/pdfs/BLP-10.7+.pdf If you need more harmonic suppression, buy two and put them in series. --- Graham == --- Graham == On Thu, Jul 16, 2015 at 12:49 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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.
Re: [time-nuts] 10MHz Square to Sine Wave Conversion
Hi, A while back I ordered an item of equipment from a very excellent eBay seller, johnkw40. He may be a member of the list, I'm not sure. He included a schematic for a low pass filter circuit to filter a 10 MHz square wave to a sine wave. A quick analysis shows that it is a 5th order chebyshev filter with a cutoff frequency of about 14MHz. You could do better, but this filter can be built with only five standard value passives, which is quite convenient. I made a little SMT version of it and ordered the boards on OshPark. It seems to work pretty well. The circuit schematic and a screen shot of the response is attached. Any comments from the list on how that looks would be welcome. Dan On Jul 16, 2015, at 10:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start Sent from my iPhone Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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.
Re: [time-nuts] 10MHz Square to Sine Wave Conversion
A would have thought a simple band pass filter would do the job by tuning out the harmonics. On Fri, Jul 17, 2015 at 3:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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. -- -- Teach your kids Science, or somebody else will :/ ja...@ball.net vk2...@google.com vk2f...@google.com callsign: vk2vjb ___ 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] 10MHz Square to Sine Wave Conversion
Hi Skipp, I suggest you a simple passive filter with harmonic notch as this: http://www.timeok.it/files/5_and_10mhz_low_pass_notch_filter.pdf Obviously you have to made the 10MHz version, Ciao, Luciano On Thu 16/07/15 19:49 , skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] and follow the instructions there. Links: -- [1] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts Message sent via Atmail Open - http://atmail.org/ ___ 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] 10MHz Square to Sine Wave Conversion
Skipp wrote: The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions A simple Tee network works well (see below). The input resistor can be chosen from 50 to around 200 ohms to suit the particular output circuit used in your unit. As the value is reduced, the sine wave output will increase (until you hit the current limit of the GPSDO output stage). Use the lowest value that still gives good distortion performance. If the sinewave output amplitude is too large, increase the input resistor. If the sinewave output amplitude is too small, you can either add a linear amplifier after the filter, or run the square wave from the GPSDO into several high-current CMOS gates in parallel and then through the Tee network (in that case, you would use one input resistor from each of the output gates rather than tie the gate outputs directly to each other). Best regards, Charles ___ 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] 10MHz Square to Sine Wave Conversion
Hi If you run a filter with a shunt capacitor input (as opposed to the series L proposed by Charles, the current in the driving gate goes way up. It’s driving a short at the harmonic frequencies and it does not like this. If you want more power with a simple T, just run the T. No resistor at the input or output. You can get 18 dbm this way. A single gate providing 18 dbm probably will not last very long. A gate in a “3.3V only” family may not be happy with the ringing on the filter input. This of course begs the question - do you *need* more than 18 dbm? Bob On Jul 16, 2015, at 11:10 PM, D W watsondani...@gmail.com wrote: Hi, A while back I ordered an item of equipment from a very excellent eBay seller, johnkw40. He may be a member of the list, I'm not sure. He included a schematic for a low pass filter circuit to filter a 10 MHz square wave to a sine wave. A quick analysis shows that it is a 5th order chebyshev filter with a cutoff frequency of about 14MHz. You could do better, but this filter can be built with only five standard value passives, which is quite convenient. I made a little SMT version of it and ordered the boards on OshPark. It seems to work pretty well. The circuit schematic and a screen shot of the response is attached. Any comments from the list on how that looks would be welcome. Dan image2.png On Jul 16, 2015, at 10:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start Sent from my iPhone Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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 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] 10MHz Square to Sine Wave Conversion
Hi But your 3 pole will not be as good as my 5 pole. My 5 pole will not be as good as the next poster’s 13 pole. My 5 added traps will not do as much as the next poster’s 13 traps. What *will* happen as all of these parts are added: 1) It becomes a real mess to properly lay out and align 2) Even with good equipment, you will need ever more accurate parts to implement it 3) The sensitivity of the result to minor parts variation will keep going up. (I get -180 dbc here and “only” -120 dbc 1% away). 4) The odds of anybody actually building one go down probably as the square of the number of parts involved. The simple filter topology posted earlier by Charles is indeed quite adequate. You can get -60 dbc harmonics without going very crazy on the design. Part values can either be calculated from formulas that have existed for 80 years or you can play with simulation. Bob On Jul 17, 2015, at 4:07 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: I was thinking along these lines. Cooking up a 3-pole filter in the form of a Pi-filter should be a good start, and then add traps for third and possibly fifth overtones that will not get much damping initially can be done if you need it pretty clean. Cheers, Magnus On 07/17/2015 04:07 AM, Graham / KE9H wrote: All you need is a 10 MHz low pass filter. How far down do you need the harmonics/spurious to be? If 40 dB suppression of the 2nd and 3rd harmonics is adequate, (you can't see the distortion with the eye on an oscilloscope) you can make your own for about $2 in parts, not including a PC board or housing. Feel free to copy the low pass filter (L1, C9, C10) from here: http://openhpsdr.org/wiki/index.php?title=EXCALIBUR Or for about $35, you could get the same performance from an inline BNC filter from Minicircuits. http://www.minicircuits.com/pdfs/BLP-10.7+.pdf If you need more harmonic suppression, buy two and put them in series. --- Graham == --- Graham == On Thu, Jul 16, 2015 at 12:49 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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 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] 10MHz Square to Sine Wave Conversion
I have a Mini-Circuits BLP-10.7 that I picked up at a Flea Market that does the job. And no, I do not want to sell it !! 73, Dick, W1KSZ On 7/16/2015 10:47 PM, Jason Ball wrote: A would have thought a simple band pass filter would do the job by tuning out the harmonics. On Fri, Jul 17, 2015 at 3:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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.
Re: [time-nuts] 10MHz Square to Sine Wave Conversion
It is the simplest solution because you have not to tune the notch filter but you have -20dB on 2nd harmonic and -40dB for the third instead -50dB (min for both) if you made a low-pass with notch filters. Luciano On Fri 17/07/15 05:10 , D W watsondani...@gmail.com wrote: Hi, A while back I ordered an item of equipment from a very excellent eBay seller, johnkw40. He may be a member of the list, I'm not sure. He included a schematic for a low pass filter circuit to filter a 10 MHz square wave to a sine wave. A quick analysis shows that it is a 5th order chebyshev filter with a cutoff frequency of about 14MHz. You could do better, but this filter can be built with only five standard value passives, which is quite convenient. I made a little SMT version of it and ordered the boards on OshPark. It seems to work pretty well. The circuit schematic and a screen shot of the response is attached. Any comments from the list on how that looks would be welcome. Dan On Jul 16, 2015, at 10:49 AM, skipp Isaham via time-nuts wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start Sent from my iPhone Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] 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 [2] and follow the instructions there. Links: -- [1] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts[2] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts Message sent via Atmail Open - http://atmail.org/ ___ 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] 10MHz Square to Sine Wave Conversion
Charles Wenzel has very simple but good working solution, here is : http://www.wenzel.com/documents/waveform.html On 7/17/2015 8:20 AM, Richard Solomon wrote: I have a Mini-Circuits BLP-10.7 that I picked up at a Flea Market that does the job. And no, I do not want to sell it !! 73, Dick, W1KSZ On 7/16/2015 10:47 PM, Jason Ball wrote: A would have thought a simple band pass filter would do the job by tuning out the harmonics. On Fri, Jul 17, 2015 at 3:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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 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] 10MHz Square to Sine Wave Conversion
Hi The narrower the bandpass of the network, the more delay it will have. The more delay it has, the more phase shift you will have over temperature. With a “low Q” T network, the phase shift is pretty small. It is likely you will have as much shift in other parts of your system as in a Q = 1 match network. Bob On Jul 17, 2015, at 2:23 PM, Michael mikenet...@comcast.net wrote: Before I waste time simulating too much... Does anyone have any intuition around temperature dependence of these designs? Is one 'style' significantly better than another? I'm far more concerned about phase shift of the fundamental during temperature swings than I am relative harmonic levels/phase moving around. Michael Hi But your 3 pole will not be as good as my 5 pole. My 5 pole will not be as good as the next poster’s 13 pole. My 5 added traps will not do as much as the next poster’s 13 traps. What *will* happen as all of these parts are added: 1) It becomes a real mess to properly lay out and align 2) Even with good equipment, you will need ever more accurate parts to implement it 3) The sensitivity of the result to minor parts variation will keep going up. (I get -180 dbc here and “only” -120 dbc 1% away). 4) The odds of anybody actually building one go down probably as the square of the number of parts involved. The simple filter topology posted earlier by Charles is indeed quite adequate. You can get -60 dbc harmonics without going very crazy on the design. Part values can either be calculated from formulas that have existed for 80 years or you can play with simulation. Bob ___ 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] 10MHz Square to Sine Wave Conversion
Hi Ok, so one more vote for a gate driving a T network. Bob On Jul 17, 2015, at 2:21 PM, Alex Pummer a...@pcscons.com wrote: Charles Wenzel has very simple but good working solution, here is : http://www.wenzel.com/documents/waveform.html On 7/17/2015 8:20 AM, Richard Solomon wrote: I have a Mini-Circuits BLP-10.7 that I picked up at a Flea Market that does the job. And no, I do not want to sell it !! 73, Dick, W1KSZ On 7/16/2015 10:47 PM, Jason Ball wrote: A would have thought a simple band pass filter would do the job by tuning out the harmonics. On Fri, Jul 17, 2015 at 3:49 AM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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 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] 10MHz Square to Sine Wave Conversion
Bob, I intended nothing aiming for perfect. My initial proposal was actually for a 1 pole low-pass and then a block at 30 MHz for third overtone, but I never put that in mail-form. Cheers, Magnus On 07/17/2015 02:57 PM, Bob Camp wrote: Hi But your 3 pole will not be as good as my 5 pole. My 5 pole will not be as good as the next poster’s 13 pole. My 5 added traps will not do as much as the next poster’s 13 traps. What *will* happen as all of these parts are added: 1) It becomes a real mess to properly lay out and align 2) Even with good equipment, you will need ever more accurate parts to implement it 3) The sensitivity of the result to minor parts variation will keep going up. (I get -180 dbc here and “only” -120 dbc 1% away). 4) The odds of anybody actually building one go down probably as the square of the number of parts involved. The simple filter topology posted earlier by Charles is indeed quite adequate. You can get -60 dbc harmonics without going very crazy on the design. Part values can either be calculated from formulas that have existed for 80 years or you can play with simulation. Bob On Jul 17, 2015, at 4:07 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: I was thinking along these lines. Cooking up a 3-pole filter in the form of a Pi-filter should be a good start, and then add traps for third and possibly fifth overtones that will not get much damping initially can be done if you need it pretty clean. Cheers, Magnus On 07/17/2015 04:07 AM, Graham / KE9H wrote: All you need is a 10 MHz low pass filter. How far down do you need the harmonics/spurious to be? If 40 dB suppression of the 2nd and 3rd harmonics is adequate, (you can't see the distortion with the eye on an oscilloscope) you can make your own for about $2 in parts, not including a PC board or housing. Feel free to copy the low pass filter (L1, C9, C10) from here: http://openhpsdr.org/wiki/index.php?title=EXCALIBUR Or for about $35, you could get the same performance from an inline BNC filter from Minicircuits. http://www.minicircuits.com/pdfs/BLP-10.7+.pdf If you need more harmonic suppression, buy two and put them in series. --- Graham == --- Graham == On Thu, Jul 16, 2015 at 12:49 PM, skipp Isaham via time-nuts time-nuts@febo.com wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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 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] 10MHz Square to Sine Wave Conversion
Before I waste time simulating too much... Does anyone have any intuition around temperature dependence of these designs? Is one 'style' significantly better than another? I'm far more concerned about phase shift of the fundamental during temperature swings than I am relative harmonic levels/phase moving around. Michael Hi But your 3 pole will not be as good as my 5 pole. My 5 pole will not be as good as the next poster’s 13 pole. My 5 added traps will not do as much as the next poster’s 13 traps. What *will* happen as all of these parts are added: 1) It becomes a real mess to properly lay out and align 2) Even with good equipment, you will need ever more accurate parts to implement it 3) The sensitivity of the result to minor parts variation will keep going up. (I get -180 dbc here and “only” -120 dbc 1% away). 4) The odds of anybody actually building one go down probably as the square of the number of parts involved. The simple filter topology posted earlier by Charles is indeed quite adequate. You can get -60 dbc harmonics without going very crazy on the design. Part values can either be calculated from formulas that have existed for 80 years or you can play with simulation. Bob ___ 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] 10MHz Square to Sine Wave Conversion
Hi If you attach a filter with a shunt capacitor (capacitor to ground) at it’s input to the output of a logic gate, that gate will pull far more current than it would without a shunt capacitor being present. You can try to minimize this with a series resistor, but that’s only a partial fix. Bob On Jul 17, 2015, at 5:49 AM, tim...@timeok.it wrote: It is the simplest solution because you have not to tune the notch filter but you have -20dB on 2nd harmonic and -40dB for the third instead -50dB (min for both) if you made a low-pass with notch filters. Luciano On Fri 17/07/15 05:10 , D W watsondani...@gmail.com wrote: Hi, A while back I ordered an item of equipment from a very excellent eBay seller, johnkw40. He may be a member of the list, I'm not sure. He included a schematic for a low pass filter circuit to filter a 10 MHz square wave to a sine wave. A quick analysis shows that it is a 5th order chebyshev filter with a cutoff frequency of about 14MHz. You could do better, but this filter can be built with only five standard value passives, which is quite convenient. I made a little SMT version of it and ordered the boards on OshPark. It seems to work pretty well. The circuit schematic and a screen shot of the response is attached. Any comments from the list on how that looks would be welcome. Dan On Jul 16, 2015, at 10:49 AM, skipp Isaham via time-nuts wrote: re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start Sent from my iPhone Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts [1] 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 [2] and follow the instructions there. Links: -- [1] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts[2] http://webmail.timeok.it/parse.php?redirect=https://www.febo.com/cgi-bin/ma ilman/listinfo/time-nuts Message sent via Atmail Open - http://atmail.org/ ___ 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] 10MHz Square to Sine Wave Conversion
re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot 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.
