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Bitrates
dudmuck edited this page Nov 7, 2013
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Example configurations:
desired bitrate | sample rate | samples per symbol | modulator sensitivity h=1 | h=0.5 |
---|---|---|---|---|
50kbps | 200k | 4 | 0.8 | n/a |
50kbps | 250k | 5 | 0.62 | n/a |
50kbps | 400k | 8 | 0.4 | n/a |
50kbps | 500k | 10 | 0.4 | n/a |
50kbps | 800k | 16 | 0.2 | n/a |
50kbps | 1000k | 20 | 0.15 | n/a |
50kbps | 1.6M | 32 | 0.15 | n/a |
100kbps | 400k | 4 | 0.8 | 0.4 |
100kbps | 800k | 8 | 0.4 | 0.2 |
100kbps | 1000k | 10 | 0.312 | 0.156 |
100kbps | 1.6M | 16 | 0.2 | 0.1 |
100kbps | 2.0M | 20 | 0.156 | 0.078 |
100kbps | 3.2M | 32 | todo | todo |
200kbps | 800k | 4 | 0.8 | 0.4 |
200kbps | 1000k | 5 | 0.62 | 0.312 |
200kbps | 1.6M | 8 | 0.4 | 0.2 |
200kbps | 2.0M | 10 | 0.312 | 0.156 |
200kbps | 3.2M | 16 | 0.2 | 0.1 |
200kbps | 4.0M | 20 | 0.156 | 0.0.78 |
Modulator sensitivity is only concern for transmitter deviation.
h
is modulation index, the ratio of (FM) frequency deviation to bit rate.
Different combinations of sample rate and samples per symbol is given because different RF bandwidths may be desired, or radio hardware is only capable of certain sample rates. Yet the newer SDR hardware has more flexible PLL clocking and should be more capable than this table.
Because bit rate is fixed to sample rate, its critical to ensure that the desired clock rate is actually selected on hardware, especially with older hardware without PLL clocking.
When using modulator sensitivty >= 0.8, take care of drive level into radio sink device (IQ baseband complex).