On Mon,8/31/2015 10:04 AM, Yngvi (TF3Y) wrote:
Even though I'm personally most interested in CW I wonder if there is
any recent two tone SSB tests that's been published?
I've published some SSB bandwidth measurements using pink noise as
excitation. Because pink noise contains all frequencies, the spectra
resembles music and speech, and is dynamic, it excites IMD in a manner
comparable to speech.
http://k9yc.com/P3_Spectrum_Measurements.pdf
http://k9yc.com/FTDX5000_Report.pdf
So far, I've measured only a few rigs using pink noise, but of those
I've measured, I've seen very little difference between them.
On the air is a very different story -- it's VERY common to see
distortion on SSB signals in the form of both upper and lower sidebands
on audio peaks. Because it is present in both sidebands, I strongly
suspect it's caused by power amps that are over-driven, or poorly tuned,
or improperly biased. We hear it as splatter (sometimes as wide as 10-20
kHz), and see it on the P3 and horizontal lines corresponding to audio
peaks.
73, Jim K9YC
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