EMRFD Message Archive 9702

Message Date From Subject
9702 2014-02-09 17:56:10 Richard Johnson Noise generator
Hello:

If you have a spectrum analyzer but no tracking generator can you tune filters by passing broadband noise through the filter and observing the spectrum while tuning?

What are the trade offs with this technique?

Thanks for the help.
rich
9703 2014-02-09 18:43:22 ashhar_farhan Re: Noise generator
I tired this. The zener noise has a very unstable amplitude across the spectrum. You need to measure the filters against a reference that was hard to establish.

- f
Sent from BlackBerry® on Airtel

9704 2014-02-10 09:50:36 Sandeep Lohia Re: Noise generator
Hi Group, M new here, & this my first mail

a zener source of noise (though unstable amplitude) seems economic to
me in time domain (something every one can have)

Richard
no fancy setup here, but brought a RTL -SDR to read strength of that
filtered noise, for lower spectrum I already have some sample &
hold...

On 10/02/2014, farhanbox@gmail.com <farhanbox@gmail.com> wrote:
> I tired this. The zener noise has a very unstable amplitude across the
> spectrum. You need to measure the filters against a reference that was hard
> to establish.
>
> - f
> Sent from BlackBerry® on Airtel
>
> -----Original Message-----
>
9705 2014-02-10 09:51:46 Sandeep Lohia Re: Noise generator
Hi Group, M new here, & this being my first mail

a zener source of noise (though unstable amplitude) seems economic to
me in time respect domain (something every one can have)

Richard
no fancy setup here, but brought a RTL -SDR, also on the way to up
converter as to read signal strength of that filtered/unfilterd noise,

for lower spectrum I already have some homebrewed sample & hold...
in past I tried homebrewed (DR2E) as to check spurs (unwanted noise)
of DDS AD98xx series & it worked great.





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