I always have a problem when it comes to trying to make perfect
measurements when in reality it is the entire system that counts. That is
to say if you exciter is good enough to put on the air and you goal is to
add an amplifier and put the pair on the air, then just make a simple two
tone test using the two. If you keep searching for perfection on a
measurement you will likely not get around to making it. You will just keep
talking about it and not get down to it or make it so complicated and so
expensive that it just will not practical.
Try making a simple and easy measurement first. Results with and with
out amplifier. The amplifier is not going to make the IMD better. If the
result are the same then the amplifier's IMD is better that the exciter and
plan a more complex measurement.
I just don't know how we designed and built stuff before pocket
calculators and computers.
73
Bill wa4lav
At 05:08 PM 8/11/2006 -0400, Tom W8JI wrote:
> > Very true! And if the separation between tones is down
> > below, say, 100 Hz, then the power supply regulation (or
> > lack of same) starts to enter into the picture. To test
> > the RF
> > block alone be sure to use separation of at least 1 kHz.
> > But to test the entire system we have the dilemma of how
> > to simulate voice.
>
>That would require syllabic variations along with two tones.
>It isn't difficult to do that.
>
> > How pure does each tone of a tone pair have to be to
> > check IMD using a two-tone test?
>
> Do you mean for hum and noise?
>
>73 Tom
>
>
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