Re: Active device measurements.

Nick Kennedy

I've done the active DUT, testing a small signal amplifier.  I used attenuators as you suggested to keep signals within limits.

I don't know about the 1 watt though.  I guess you'd need about 30 dB of gain beyond the PHSNA, so that would take two or more stages.  Probably could put something together from EMRFD.  Then you might need something like the -40 dB tap from the original Hayward - Larking article to look at the output of your 10 W amp.  The flattness of your intermediate 0 dB to 30 dB amplifier would affect the result of your testing of the amplifier, so you'd have to factor that in ... sort of like we do now with PHSNA's frequency compensation polynomials.

Have fun with it!

Nick, WA5BDU

On Thu, Dec 4, 2014 at 11:13 AM, f4hga@... [PHSNA] <PHSNA@...> wrote:


First of all, thank you all for this great project, and all the good work I have seen so far in the various locations.

I have some questions related to active devices (ie: amplifiers).

I would like to know how to make measurements on an active DUT ?

- For the output, an attenuator can be positioned to reduce the output power, but what about the input ?

I built a few QRP amps (1w in, 10 w out), that requires an input signal level above what the PHSNA can provide. What could be done here ?

Thanks in advance for your answer.



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