Well, there is an option to tell the plugin the signal is inverted by checking the approprite box build in the plugin interface. Checking it results in no response at all, so guess the image signal (if it's indeed an image one) is not inverted.
Regarding damaged image signal, one of my SDR's has a direct sampling HF Mode (Q branch) I use for freqs below 30 Mhz for HF bands, while connected to a longwire antenna.
Using direct sampling HF mode above 30 Mhz results in massive signal cloning, a.k.a aliasing, from the HF band to all frequencies above in periods of 28.8Mhz, which is the real SDR sampling rate before dropping samples and quantization process.
Those alias signals are actually "ghost" signals copied from lower to higher bands.
However, these are not damaged at all and has the same sound quality as the original signals in the HF band.
You said image TETRA signal can be damaged beyond repair due to noise or some non-linear transformation applied to it that renders it useless.
Compared to alias signals from HF band to all higher bands, that are not damaged, what are the odds that a TETRA signal "shifted" just a bit from 915-921 to 915-938 will be damaged so bad that that the plugin will be completely unable to decode?
I mean, the aliased HF signals "shifts" are on much larger scale than the TETRA's, stiil no damage is done.
According to the above, don't you think most of chances are a non-standart TETRA system rather than "ghost" signals?
Consider I used 3 diiferenet SDR's and got the same result.
Yes.
Check the MSYS terminal and net info screenshot here https://www.rtl-sdr.com/tetra-decoder-plugin-for-sdr-now-available/.
