[time-nuts] External clock for Analog to Digital Converter inGPS Rx front-end

[Bilal Amin]

Hi John and Bruce,

Thank you for your ideas. Now I have a much better picture for the 
experiment using the comparator. Now, my only concern is a noise generator. 
I have searched and found out that all the commercially available now 
generators are very expensive and some what out of my price range.
What would you guys suggest for a noise generator? Do you think generating 
noise using a zener diode circuit is a good idea? Or any cheap noise 
generators are available in the market. Any one has any experience? As I am 
working in 8Ms/s zone, therefore the noise generator should be of high 
specs.
I have a signal generator (Agilent Tech. 8648A). I can use the PM option in 
this signal generator to get the results, but again the only problem is a 
noise generator which I can use at the modulating input of the signal 
generator to modulate the RF signal.

Cheers

Bilal


----- Original Message ----- 
From: "John Miles" <jmiles at pop.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Saturday, March 03, 2007 3:28 PM
Subject: Re: [time-nuts] External clock for Analog to Digital Converter 
inGPS Rx front-end


> Yep, that's great as long as the comparator's already there or can be 
> easily
> added.  I was mainly wrinkling my nose at the idea of adding hybrid
> combiners and the like, just to introduce some jitter.
>
> -- john, KE5FX
>
>> > Well, sure, but it also causes all kinds of secondary distortion
>> > effects (such as potential clipping at the rails of whatever you're
>> > feeding the signal into).  I don't think AM'ing the signal when you
>> > want PM is a good idea, when it's so easy to apply PM by itself.
>>
>> He's feeding a digital clock to an A/D.  Someplace he has to
>> "clip" the sine
>> wave to make a digital signal.
>>
>> Feeding noise into the other side of the comparator seems like a good
>> approach to me.
>>
>>
>>
>
>
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