[Amps] Checking for IMD

[Michael Tope]

----- Original Message ----- 
From: "Gary Schafer" <garyschafer at comcast.net>

>> Sounds like the Flex Radio SDR-1000 would be ideally suited
>> for this task. It has very a simple conversion scheme, high
>> dynamic-range, and no analog AGC (either derived or applied).
>> With a 44 KHz sampling rate sound card it should easily provide
>> 15 to 20 KHz of useable spectrum viewing with good dynamic
>> range.
>>
>> 73, Mike W4EF...........................................................
>
> Isn't that an FM radio? If so no good for a spectrum analyzer front end.
>

No, Gary, it's an HF receiver/transceiver that uses a PC soundcard
to handle IF filtering and demodulation:

http://www.flex-radio.com/

http://www.flex-radio.com/articles_files/SDR-1000%20April%202005%20QST%20Review.pdf

With a quality sound card, the close-in dynamic range of this rig
rivals some of the better high-end HF transceivers, and it is doing
that with absolutely no analog AGC, which says to me that the
analog stages ahead of the DSP must be very linear. Since filtering
is DSP based, this scheme should be capable of very narrow
resolution bandwidth.

I mean if somebody could write the code to turn one of these
things into a poor man's HF spectrum analyzer capable of doing
quality transmitter IMD measurements, I'd probably buy one.

73, Mike W4EF...................................................