Re: [time-nuts] what is the best way to multiply a 10 Mhz signal?
Von: Stephen Farthing squir...@gmail.com Betreff: [time-nuts] what is the best way to multiply a 10 Mhz signal? I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? I did 5 MHz * 7 = 35 which is about the same, with CMOS gates and filtering. ( in the style propagated by Wenzel) This took a lot of filtering to get rid of the last spurii. Too much ado. I recommend a 70 MHz VCXO and locking this to the 10 MHz source. regrds, 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] what is the best way to multiply a 10 Mhz signal?
I'm certainly not the expert but can't you place a divide by 7 counter in the feedback loop of a phase lock loop. There is a fast version of the 4046 PPL chip that does 100Mhz and a divide by 7 is easy to rig with TTL. On Tue, Dec 21, 2010 at 8:35 AM, Stephen Farthing squir...@gmail.com wrote: I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? -- = 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] what is the best way to multiply a 10 Mhz signal?
On 21/12/10 16:35, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR What is the application? What will the DDS output frequency be? Maybe you could use a 70MHz (or whatever frequency you need) VCO as the DDS clock and use the DDS as a programmable divider to produce a 10MHz output. This could be phase locked to the 10MHz output from the LPRO-101. -- Linux 2.6.35 ___ 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] what is the best way to multiply a 10 Mhz signal?
I used to be in the synthesizer business (Zeta Labs) in a previous life. I learned to ask the customers: what you are trying to accomplish as the end goal, before tackling a messy problem like multiplying by 7. Maybe you don't need to multiply by 7, but we can't tell from your question. Rick Karlquist N6RK On 12/21/2010 8:35 AM, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR ___ 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] what is the best way to multiply a 10 Mhz signal?
Interesting. When I used to use and build DDSs back in the early 70's, we typically used 2.56 times the maximum required frequency for a clock, to get above Nyquist and allow adequate filtering stop-band rejection. At the time we could not go much higher due to limitations in device speeds, especially the D/A. Today you can easily use a much higher clock frequency which would simplify filtering and reduce gain variations. At 70 MHz clock you are only at 2.333 Nyquist. Even at 2.56 by the time you get to your desired goal of 30 MHz, you will have what looks just about like a square wave. So, filtering will be a must, and, after filtering, you will find that your amplitude output will greatly decrease with frequency. The other question is phase noise objectives. If that is not a real concern, then as suggested, maybe a simple locked VCO would be the way to go. 73 - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Stephen Farthing Sent: Tuesday, December 21, 2010 12:57 PM To: Richard (Rick) Karlquist; time-nuts@febo.com Subject: Re: [time-nuts] what is the best way to multiply a 10 Mhz signal? Hi Rich Thanks for the replyI have an AD9834 DDS chip I want to use for a Frequency generator with an accuracy of 1 Hz from 0-30 Mhz. . This part can be clocked at 75 Mhz - but unlike other DDS chips seems to have no internal clock multipliers. So it seems to me if I can some how generate a 70 Mhz clock signal from my rubidium standard I can solve the problem. 73s Steve On 21 December 2010 17:36, Richard (Rick) Karlquist rich...@karlquist.comwrote: I used to be in the synthesizer business (Zeta Labs) in a previous life. I learned to ask the customers: what you are trying to accomplish as the end goal, before tackling a messy problem like multiplying by 7. Maybe you don't need to multiply by 7, but we can't tell from your question. Rick Karlquist N6RK On 12/21/2010 8:35 AM, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR -- It is vain to do with more that which can be done with less. ___ 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] what is the best way to multiply a 10 Mhz signal?
This might explain a way to do it http://physics.eou.edu/courses/phys345/lab14_pll.pdf What this is doing is simple. It is a 70Mhz voltage controlled oscillator who's frequency is controlled such that every 7th cycle the phase matches your 10MHz reference. The example above does divide by 10 or 128 but 7 is the same thing. The way to make a divide by 7 is to have a counter feed a comparator and on match the comparator resets the counter. The reset signal is your output. It requires two 50 cent chips Can you use 80Mhz or 100Mhz. Either of these is easier and uses one less chip. On Tue, Dec 21, 2010 at 9:57 AM, Stephen Farthing squir...@gmail.com wrote: Hi Rich Thanks for the replyI have an AD9834 DDS chip I want to use for a Frequency generator with an accuracy of 1 Hz from 0-30 Mhz. . This part can be clocked at 75 Mhz - but unlike other DDS chips seems to have no internal clock multipliers. So it seems to me if I can some how generate a 70 Mhz clock signal from my rubidium standard I can solve the problem. 73s Steve On 21 December 2010 17:36, Richard (Rick) Karlquist rich...@karlquist.comwrote: I used to be in the synthesizer business (Zeta Labs) in a previous life. I learned to ask the customers: what you are trying to accomplish as the end goal, before tackling a messy problem like multiplying by 7. Maybe you don't need to multiply by 7, but we can't tell from your question. Rick Karlquist N6RK On 12/21/2010 8:35 AM, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR -- It is vain to do with more that which can be done with less. ___ 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] what is the best way to multiply a 10 Mhz signal?
You may want to check out the 10MHz locked 1GHz clock I did (using ADF4107 and a 1GHz Crystek CVCO) http://www.qslnet.de/member/on4iy/1gclock/xlock-1g.html and associated DDS to generate oddbal frequencies. http://www.qslnet.de/member/on4iy/9912.html Includes some PN measurements. Xtof. On 21/12/10 19:18, Mike Feher wrote: Interesting. When I used to use and build DDSs back in the early 70's, we typically used 2.56 times the maximum required frequency for a clock, to get above Nyquist and allow adequate filtering stop-band rejection. At the time we could not go much higher due to limitations in device speeds, especially the D/A. Today you can easily use a much higher clock frequency which would simplify filtering and reduce gain variations. At 70 MHz clock you are only at 2.333 Nyquist. Even at 2.56 by the time you get to your desired goal of 30 MHz, you will have what looks just about like a square wave. So, filtering will be a must, and, after filtering, you will find that your amplitude output will greatly decrease with frequency. The other question is phase noise objectives. If that is not a real concern, then as suggested, maybe a simple locked VCO would be the way to go. 73 - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Stephen Farthing Sent: Tuesday, December 21, 2010 12:57 PM To: Richard (Rick) Karlquist; time-nuts@febo.com Subject: Re: [time-nuts] what is the best way to multiply a 10 Mhz signal? Hi Rich Thanks for the replyI have an AD9834 DDS chip I want to use for a Frequency generator with an accuracy of 1 Hz from 0-30 Mhz. . This part can be clocked at 75 Mhz - but unlike other DDS chips seems to have no internal clock multipliers. So it seems to me if I can some how generate a 70 Mhz clock signal from my rubidium standard I can solve the problem. 73s Steve On 21 December 2010 17:36, Richard (Rick) Karlquist rich...@karlquist.comwrote: I used to be in the synthesizer business (Zeta Labs) in a previous life. I learned to ask the customers: what you are trying to accomplish as the end goal, before tackling a messy problem like multiplying by 7. Maybe you don't need to multiply by 7, but we can't tell from your question. Rick Karlquist N6RK On 12/21/2010 8:35 AM, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm ___ 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] what is the best way to multiply a 10 Mhz signal?
Christophe Huygens wrote: I'll bet your DDS will run at 80 MHz at room temp. Since this a one-off project, test it to see if it works to 80 MHz with some design margin. Now you can cascade 3 doublers. The reconstruction filter is now stop 50, pass 30 instead of stop 40 pass 30. That is WAY easier to build. 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.
