github f4exb/sdrangel v3.3.3
ATV narrow band modes

latest releases: v7.19.1, v7.19.0, v7.18.1...
6 years ago

ATV Narrowband modes

ATV modulator and demodulator plugins now support lower FPS and less number of lines. We now have:

  • 640, 625, 525, 480, 405, 360, 343, 240, 180, 120, 90, 60 and 32 lines
  • 30, 25, 20, 16, 12, 10, 8, 5, 2 and 1 FPS

This will allow transmission of animated images in narrow bandwidths. This is known as NBTV.

There are new vertical synchronization schemes that consume less number of lines: One long sync pulse followed by a high level line in interleaved and not interleaved half image modes (ShI and ShNI) and horizontal sync pulse skip (HSkip).

This implements ticket #13

See the plugins folders for details:

In addition the horizontal sync has been redesigned so that resynchronization is done for a complete image and not line by line. This removes tearing effect but the image may flicker a bit. You will also need to set a sample rate that yields an integer number of samples (points) per line.

Note on the ATV demodulator

There is a bug that causes a segfault if the sample source is running while the ATV Demodulator is added. A workaround is to stop the sample source, add the demod and start the sample source.

Continuous sample rate setting

To better support any sample rate from the source or sink plugins for all devices that support arbitrary sample rate the samle rate can be set continuously within the ADC/DAC range using a value dial similar to the frequency dial. This applies to the following plugins:

This implements ticket #19

Builds

This version had a nasty bug (issue #22) see v3.3.4 for the builds.

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