----- Original Message ----- From: "Dr Bruce Griffiths" <[EMAIL PROTECTED]> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com>
Sent: Monday, March 19, 2007 9:25 PM Subject: Re: [time-nuts] Producing jitter with Phase Modulation
Bilal Amin wrote:Hi Everyone,Some days back I emailed on the group regarding the jitter in the sampling clock of ADC. I have tried the phase modulation method for producing the jitter. I used the HP 8648B Signal generator for this experiment. I modulated the RF wave (at 10 MHz) with noise using the modulating input of the Signal Generator. For noise I used a Noise gen. from General Radio Company. It has three options for frequency. 10K, 100K and 5 M Hz. I observed the output using an oscilloscope. The output wave form was jittery. BUT when changed the noise from 5M to 100K there was an increase in jitter. Can any one help me out there, why this is happening? According to my understanding decreasing the bandwidth of noise results in decrease in jitter as well. Also I want to calculate the jitter at the output. i.e. the amount of noise I am adding. I think I wont be able to do it over the oscilloscope. Any ideas ?Regards Bilal _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nutsBilal The 8648B phase modulation input has a bandwidth of 10Hz to about 10kHz. The resultant phase modulation dependency on the noise generator settings depends on the noise generator specifications. What was the noise generator model, or can you provide a circuit diagram so the effect of the noise generator settings can be deduced? Bruce _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Hi Bruce,I am attaching the schematic with this email. It is actually Random Noise Generator by General Radio Company 1390 B. It is a very old model but I have a limited budget so I am trying to do the experiment using this. I need to produce 10 MHz jittery clock and the maximum frequency for this noise gen. is 5MHz as you can see from schematic.
Regards Bilal Bilal
Schematic.pdf
Description: Adobe PDF document
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