mirror of
https://github.com/DigitalDevices/dddvb.git
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101 lines
2.2 KiB
Plaintext
101 lines
2.2 KiB
Plaintext
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Modulator channels will automatically be enabled if you redirect data
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from a demodulator to it.
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E.g._:
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first demod on bridge 0 TAB1, modulator on bridge 1.
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echo "00 10" > /sys/class/ddbridge/ddbridge0/redirect
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Currently it is fixed to QAM256. Controls will be added later.
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Rate control is experimental and PCR correction also not
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implemented yet. So, depending on the reception device
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there can be disturbances in playback.
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It is now also possible to chain redirects.
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E.g., demod and modulator as above, CI on bridge 0 TAB 2:
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echo "00 01" > /sys/class/ddbridge/ddbridge0/redirect
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echo "02 10" > /sys/class/ddbridge/ddbridge0/redirect
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The stream is also still available at the demux device
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belonging to the demod devices.
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Now write and start an application (not provided) that
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talks to the CI to decrypt the desired services.
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For testing one can use a standard application that
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supports decryption. Additionally to seeing the
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decoded service on the PC it will then also be streamed
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into cable by the modulator.
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The modulator device can be controlled with the
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following properties:
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MODULATOR_FREQUENCY:
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Set the frequency on Version 2 (FSM) cards
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units - Hz
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range - 114000000-874000000
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allowed values - 114 + 8000000*X
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For older cards you have to use the
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DVB_MOD_SET ioctl.
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MODULATOR_SYMBOLRATE:
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Set the symbol rate
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units - Hz
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range - Version 1 cards: only 6900000
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Version 2 cards(FSM): X-7100000
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MODULATOR_MODULATION:
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Set the modulation type
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range: QAM_16 .. QAM_256
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MODULATOR_ATTENUATION:
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range - 0-31
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unit - 1 dB
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MODULATOR_GAIN:
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range - 0-255
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unit - 0.125 dB
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The MODULATOR_ATTENUATOR is based on a switched resistor network,
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also it is backward compatible to our old modulator.
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the MODULATOR_GAIN is based on a variable gain amplifier, so it is less
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accurate then the attenuator.
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High gain values will drive the output amplifier into clipping. The
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limit depends on # of channels active.
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MODULATOR_INPUT_BITRATE:
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The modulator will ALWAY insert null packets if it
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does not get enough data.
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If you specify the input bitrate it will insert additional
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null packets according to the difference between input
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and output bit rate.
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The latter is determined by symbol rte and modulation.
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So, this property should be set last.
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unit - 2^-32 Hz
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