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Measurements >> Other Measurements >> [q] noise in the signal generator
https://designers-guide.org/forum/YaBB.pl?num=1185935134

Message started by Renekim on Jul 31^st, 2007, 7:25pm

Title: [q] noise in the signal generator
Post by Renekim on Jul 31^st, 2007, 7:25pm

Dear all,

I might have a silly question. I am trying to measure SNR of a sigma delta modulator (continuous time). Normally the SNR is around 60dB. I am wondering if the noise (thermal or whatever) from the signal generator could be negligible in this case. The signal frequency is around 500KHz. ( I mean if the noise from the signal generator is usually much smaller than the noise shaped quantization noise, so I don't need to do some correction to get rid of the signal generator noise when I measure the SNR. )
Thank you for your time.

Title: Re: [q] noise in the signal generator
Post by ee05s030 on Jul 31^st, 2007, 10:04pm

Check out the signal generator's datasheet for the noise power in ur freq range of interest or,
If u have a spectrum analyzer, u can determine the noise contributed by the signal generator or,
just do a idle channel test on ur modulator by removing the signal generator and see if the noise floor reduces. if it does, one possibility is that the signal generator is not good enough to be used for determining the peformance of ur modulator