[time-nuts] Spectrum Analyzer Specifications

[Bob Camp]

Hi

Pretty simple:

Double balanced mixer, RPD-1 is one option, there are others.

Fairly simple L/C lowpass between the mixer and an op-amp. 

20 db positive (non-inverting) op-amp amplifier string after the mixer 

Output of the string goes to the sound card. Use a good (dual / quad) audio op amp 

Quadrature amp picks off the output of the first op amp stage, switch and resistors to set gain, pot to set op point.

====

So what you have is an old style quadrature phase noise amp and “PLL”. More or less a very junior version
of the 3048 test box. Like any setup of this sort, you check two similar oscillators. They run in quadrature and
you do a few “measure this with switch in position A” sort of things to set things up each time. 

Nothing exotic.

Bob



> On Mar 24, 2016, at 12:25 AM, Richard (Rick) Karlquist <richard at karlquist.com> wrote:
> 
> 
> 
> On 3/23/2016 3:56 PM, Bob Camp wrote:
> 
>> and standard covered. If you want to do spurs, spend $40 and build a phase
>> noise test set that will drive the sound card on your PC.
>> 
>> Lots of choices ….
>> 
>> Bob
>> 
> 
> Any documentation on this $40 phase noise test set?
> 
> Rick N6RK
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