7189984bbb
C-Netz: At correct timeslot switch channel mode
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Without this, the first BQ(K) message came to early, so that BSA 51
released when receiving ZFZ(K) one frame too early.
2020-10-29 07:35:50 +01:00
c2f14834e5
Rename dbm0 (level) to speech (level)
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In mobile communications we use speech level instead of milliwatts.
The deviation (FM) is always based on speech level, not on 1 milliwatt.
2019-12-08 17:24:36 +01:00
1321f66456
C-Netz: Add option to control voice deviation
2019-01-02 15:58:34 +01:00
76a3484c5c
C-Netz: Make demodulation algorithm (slope or leve) slectable via option
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By default (auto), the algorithm is selected, depending on sound card
or SDR usage. For testing and debugging purpose, the algorithm can be
forced.
2017-05-19 19:11:59 +02:00
ef7ff26793
C-Netz: SDR now uses zero-crossing to detect level changes.
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This does not work with analog radio, but with SDR it works.
The quality should be better and the process is faster.
2017-05-17 20:06:46 +02:00
5f1d7bc970
C-Netz: Improve clock speed measurements.
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Sound card's clock measurements only requires a few minutes to get sub-ppm
accuracy results.
2017-02-18 21:02:46 +01:00
8cb0187133
C-Netz: Remove the obviously useless noise function for unused timeslots
2017-02-18 21:01:17 +01:00
7ea3bc188d
Move samples of int16_t format to sample_t, that is of type double
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This prepares the correction of all levels
2017-02-18 21:01:08 +01:00
c933250685
Add dsp mode change fuction to A and B Netz, fixed NMT
2016-06-12 16:11:20 +02:00
46fa72894e
C-Netz: Calibration/fix processing of tone levels on TX and RX side
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FSK and compander levels are adjusted.
Eliminate offsets between subsequent speech chunks. This is done by
high-pass filter. An offset is not passed to the filter.
Do correct audio processing chain:
time compress -> compressor -> scrambler / pre-emphasis -> TX
RX -> de-scrambler / de-emphasis -> expander -> time expand
2016-05-13 09:37:03 +02:00
e2a9c2c6a5
Automatic FSK polarity selection on TX side
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This is done by simulating two cells with different polarities.
On first message from mobile station, the cell with the correct
polarity is used, the other is disabled.
On RX side the polarity is not selected, since FSK decoder detects
polarity for every frame.
2016-05-13 09:37:01 +02:00
16acdbf59d
Implementation of C-Netz (German mobile telephone system)
2016-04-24 15:19:00 +02:00
Andreas Eversberg