Re: QMX S9+ noise on receive
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Bruce, Another way you might be suffering high noise while having acceptable sweeps is if there is a problem with IC401, the stereo DAC that drives the headphone amplifiers.
Finally, sitting between the PCM1804 and the CS4334 stereo DAC is the MCU. All the digital numbers that represent audio signals pass through the MCU, communicating in and out using the I2S serial data bus. It is possible, though less likely, that something is wrong along that path.
All of the above requires an oscilloscope at a minimum, and perhaps even a logic analyzer to resolve.
On this forum I have seen virtually no reports of CS4334 problems or of I2S data corruption. There have been some MCU failures, but usually they are not subtle ;-(
The PCM1804 has been something of a problem child in QMX and several of us are trying to suss out why that is. My bet is on the PCM.
JZ KJ4A?
Hi Bruce.? I'm listening to 15M CW right now and the band is full of CQ TEST. SKCC contest, I think.? So, AFAIK, my mid-band QMX is working just fine.? I've had QSOs on every band where my antenna is resonant...
John's assessment is probably spot on.? But a little noise on the ADC I/Q diagnostic doesn't seem to have impaired my QMX, for whatever reason.?
.rr
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