For clarity,
?
In IQ SSB RX image is the same as saying opposing unwanted sideband.
So if a signal is tuned for 1KHZ tome the image is always dial frequency
- +1khz or 2khz away.? If the QDX QSD (IC4) translates the spectrum
down to two audio channels one with a 90degree offset. So the audio
applied to ADC(IC10) has no sideband suppression as that is done in
software.? This remains true at the 12khz IF.? ?There are many questions
in my mind about the internal processes.
?
So if there is poor or no opposing sideband suppression one or the other
audio channel is not working (IC4, IC7and IC9 or even IC11) and of
course paths between them.??
?
The sweep is inconclusive as the scale is unclear.? if its HZ then opposing
sideband is bonkers.? IF it Khz something else is going on.? The manual
is unclear as to what that screen shows.
?
In the sweep the image (opposing sideband)? is not suppressed.
?
FYI even if not suppressed the SSB will sound good, however when
tuning across a carrier with both sideband present it will tune down
to? zero and then up.
?
In this case we are talking about a spurious frequency aifits ~24khz away.
We call that a spur.
?
The spur can be related to digital noise from PS, Oscillating opamp,?
and even a harmonic or sub-harmonic of the A/D sample rate. or
other external signal.? ?FYI the sample rate is 48ksps.
?
--
Allison
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