github f4exb/sdrangel v2.2.1
Tx full baseband interpolation chain (phase 2)

latest releases: v7.22.4, v7.22.3, v7.22.1.1...
8 years ago

Tx full baseband interpolation chain (phase 2)

Half-band interpolator filter chain in up channelizer. Rational resampler interpolator in the modulator. Arbitrary sample rates in the File Sink to test all possible configurations. Decimation is also possible so any rate can be implemented (ex: 32 kS/s).

Interpolator/Decimator support

This is experimental in the AM modulator and demodulator. It allows rates lower than 48 kS/s in both. However there are race conditions with the audio system as the 48 kS/s rate cannot be exactly on spot with the interpolator/decimator input or output. This results in audible clicks but is a clear improvement from the original.

Decimators and interpolators filters improvements

These optimizations allow lowering the spurs below -72.5 dBc on Tx. On Rx there was no measurements done but a significant improvement in spurs rejection in the presence of a strong signal is expected

Half-band filter improvement

Optimized filter coefficients. Increased filter order to 48 for the half-band decimators (Rx). Changed algorithm to use the double buffer technique. CPU usage improvement is not significant but the frequency response is better.

Rational resampler filter improvement

Optimize the number of taps per phase in the polyphase filter. This improves the frequency response without increasing CPU usage.

SSE 4.1

Now SSE 4.1 is needed for x86_64 SIMD support. This anticipates further optimizations and is already needed in other parts of the code.

Debian package with BladeRF support

The BladeRF support has been added to the Debian builds.

Other changes and fixes

DV serial support

Fallen back the multi FIFO support as it introduced bugs and it is not possible to effectiely handle two conversations simultaneously on the same dongle.

SDRDaemoFEC plugin

Set SIMD options so that it is effective for FEC processing.

Main window

Fixed device input dock not visible when application is first run. Re-order Window submenu items

Dependencies

Removed useless dependency on QTOpenGL end QTMultimedia where it was not necessary.

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