[time-nuts] Producing jitter with Phase Modulation

[Bilal Amin]

----- Original Message ----- 
From: "Dr Bruce Griffiths" <bruce.griffiths at xtra.co.nz>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at 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
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>>
> Bilal
>
> 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
>
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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
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