kopia lustrzana https://github.com/projecthorus/radiosonde_auto_rx
27 wiersze
1.7 KiB
Markdown
27 wiersze
1.7 KiB
Markdown
# 2019-03-02 auto_rx Performance Baseline
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Mark Jessop - 2019-03-02
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The scripts in the `auto_rx/test` directory provide the ability to measure the various decoders performance with a set of radiosonde signal samples, with calibrated [Eb/N0](https://en.wikipedia.org/wiki/Eb/N0) (SNR-per-bit) values.
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A few notes:
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* All measurements have been performed using the demodulator (rtl_fm, filtering) settings as per the 2019-02-27 auto_rx release.
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* All decoders (rs41, rs92, etc...) have any available error-correction options enabled.
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* Packet Error Rates have been calculated based on a comparison with the known number of packets in the high-SNR source file.
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FM Demodulation is performed with the following rtl_fm sample rates:
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* RS41: 15 kHz
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* RS92: 12 kHz
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* DFM09: 20 kHz
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* M10: 22 kHz
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The traces for the error-corrected decoders (RS41, RS92, DFM), exhibit the typical 'cliff' response, with the PER going from 1.0 to 0 in only a few dB.
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A few things to look into:
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* This is a plot of *packet*-error-rate. Can we get a measure of the number of bits in a 'packet' (whatever that may be for each sonde; it may mean multiple frames) to be able to estimate a *bit*-error-rate? How does this compare to theoretical FSK modem performance?
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* Why is ths RS92 'cliff' offset from the others? Are the packets bigger? Is there something sub-optimal in the demodulation chain?
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* Further investigation into what the rtl_fm samples rates mean for pre-FM-demod filter bandwidth is required, to ensure they are set optimally.
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* Double and triple-checking of the Eb/N0 calculations in `generate_lowsnr.py`, to be sure we're generating our low-Eb/N0 samples correctly. |