[time-nuts] Spectrum Analyzer Specifications

[Bob Bownes]

Don't really need anyone who can order up bare boards in bulk anymore. Many
of the board houses will make them on demand for single customers. They fit
them into empty spaces in larger board orders.

I'd love one if someone is willing to draw it up. I'll even put together a
Mouser BOM that can be shared if N8UR will layout the board. :)

Bob
KI2L


On Thu, Mar 24, 2016 at 1:31 PM, John Ackermann N8UR <jra at febo.com> wrote:

> I'd be willing to assist with board layout if someone wanted to make this
> into a real project (e.g., fully developed schematic).  TAPR might be
> talked into supplying at least bare boards; we'd have to get a sense of
> demand before committing to a full kit or assembled unit.
>
> John
> ----
>
> On 3/24/2016 9:04 AM, jimlux wrote:
>
>> More like $40 in parts, without a board, etc.
>> The RPD-1 is $20.70
>> LT1678/LT1679 is a nice low noise opamp that does rail to rail and is
>> about $5
>> etc
>>
>>
>>
>> On 3/24/16 4:42 AM, Bob Camp wrote:
>>
>>> 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
>>>
>>>
>>>>>
>>>> Any documentation on this $40 phase noise test set?
>>>>
>>>> Rick N6RK
>>>>
>>>
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