[time-nuts] Spectrum Analyzer Specifications
Bob Camp
kb8tq at n1k.org
Thu Mar 24 11:42:15 UTC 2016
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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