I see IQ data is available by assigning it to one of the VAC outputs. I'm wondering how folks might be using this. In other words, what are you doing with the IQ information
One thought/ question. Is anyone using it to enhance signal readability through, perhaps, averaging many times per second to average out the noise? If so, what software are you using to do the sampling?
Thanks
Ron
N4XD
Using I/Q data to enhance signal readability
Re: Using I/Q data to enhance signal readability
The IQ data stream available from Thetis via VAC is the raw 2nd IF data prior to passband filtering, demodulation and other processing. It is the same data that forms the basis of the spectral display.
There are very few software applications that use this data. Perhaps the most noteworthy is CW Skimmer. Another is MAP65 EME software.
These app's primarily seek to use IQ data because of the greater processing bandwidth it offers, up to 192KHz, not because the data offers any additional opportunities for signal processing over and above the normal audio data stream. E.g. CW Skimmer can decode all CW signals on a 192KHz band segment instead of a 10KHz band segment (the maximum allowable passband filter).
You would be hard pressed to improve upon the noise reduction and noise blanking algorithms already present in Thetis. And those algorithms are using the same IQ data after final passband filtering (except for the Spectral Noise Blanker, SNB, which acts on the entire 2nd IF). They go well beyond averaging in the sophistication of their processing.
73,
Scott
There are very few software applications that use this data. Perhaps the most noteworthy is CW Skimmer. Another is MAP65 EME software.
These app's primarily seek to use IQ data because of the greater processing bandwidth it offers, up to 192KHz, not because the data offers any additional opportunities for signal processing over and above the normal audio data stream. E.g. CW Skimmer can decode all CW signals on a 192KHz band segment instead of a 10KHz band segment (the maximum allowable passband filter).
You would be hard pressed to improve upon the noise reduction and noise blanking algorithms already present in Thetis. And those algorithms are using the same IQ data after final passband filtering (except for the Spectral Noise Blanker, SNB, which acts on the entire 2nd IF). They go well beyond averaging in the sophistication of their processing.
73,
Scott