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path: root/src/cnetz/dsp.c
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2017-05-17minor cleanupsAndreas Eversberg1-15/+25
2017-05-17C-Netz: SDR now uses zero-crossing to detect level changes.Andreas Eversberg1-2/+2
This does not work with analog radio, but with SDR it works. The quality should be better and the process is faster.
2017-05-17C-Netz: Improved transmission of speechAndreas Eversberg1-17/+46
The speech is now correctly ramped up and down during pause bits.
2017-05-15Rename filter -> iir_filter (file name and instance name)Andreas Eversberg1-3/+3
This is useful when using fir_filter in the future.
2017-03-04samplerate.c: Allow transcoding to lower sample rate other than 8000 HzAndreas Eversberg1-1/+1
2017-02-18C-Netz: Remove useless -V optionAndreas Eversberg1-9/+1
2017-02-18C-Netz: Add low pass filter to eliminate high frequency noiseAndreas Eversberg1-2/+7
This improves the FSK decoding quite allot, especially with SDR.
2017-02-18C-Netz: Improve clock speed measurements.Andreas Eversberg1-36/+24
Sound card's clock measurements only requires a few minutes to get sub-ppm accuracy results.
2017-02-18C-Netz: Make average to clock measurements for a quicker resultAndreas Eversberg1-6/+25
2017-02-18C-Netz: Remove the obviously useless noise function for unused timeslotsAndreas Eversberg1-22/+9
2017-02-18Correcting all levels and move all remaining integer samples to sample_tAndreas Eversberg1-21/+17
The leves are based on the standards of each mobile network. They are adjusted to the specified frequency deviation now.
2017-02-18Add global DC-Filter and remove all individual DC-FiltersAndreas Eversberg1-0/+2
2017-02-18Move samples of int16_t format to sample_t, that is of type doubleAndreas Eversberg1-23/+18
This prepares the correction of all levels
2017-02-18Indexing tables by casting index to unsigned integer onlyAndreas Eversberg1-14/+14
2017-02-18Prepare for SDR: Add bandwidth and deviation info to sender instanceAndreas Eversberg1-0/+5
2017-02-18Rework on audio interfaceAndreas Eversberg1-3/+3
Sound instance is now called audio instance and uses funcation pointers. This gives a clean interface to be exchanged with other technologies, linke SDR.
2017-01-07prepare audio handling for multi carrier SDRAndreas Eversberg1-3/+2
2017-01-07C-Netz: Make demodulation buffer size dynamicAndreas Eversberg1-0/+2
2017-01-07C-Netz: Fixed double free bugAndreas Eversberg1-2/+6
2016-12-09Add function to change dsp state, more debug with channel infoAndreas Eversberg1-9/+30
2016-11-30C-Netz: Simplifying TX signal clock sync between two channelsAndreas Eversberg1-36/+14
2016-11-22C-Netz: Minor coding style changes, no changes to processAndreas Eversberg1-1/+1
2016-10-23C-Netz: Adjusting compandor response levelAndreas Eversberg1-1/+1
2016-10-07C-Netz: Reset FSK decoder when switching channel modeAndreas Eversberg1-0/+2
This prevents corrupt frames, as well as clear pending frames that were received during the old mode, but may not be received during the new mode.
2016-10-07C-Netz: Don't access transaction after destroying itAndreas Eversberg1-0/+7
2016-10-07Add check if fromat at PDEBUG() is consistent (like printf)Andreas Eversberg1-2/+2
The bugs it found are fixed too.
2016-10-02C-Netz: callref is moved completely to transaction objectAndreas Eversberg1-1/+1
2016-10-02callref: Move callref from 'sender' to individual implementation of a, b, c-netzAndreas Eversberg1-1/+1
Cellular networks use transaction instances, so callref is now member of transaction object.
2016-08-03C-Netz: Add hack to increase voice deviation for some newer phoneAndreas Eversberg1-1/+16
2016-08-02C-Netz: Use cosine-square ramp for better signal generationAndreas Eversberg1-2/+2
2016-07-31C-Netz: Fixed multi-transceiver mode and show channel in various logsAndreas Eversberg1-3/+5
2016-06-20Rename 'compander' to 'compandor'Andreas Eversberg1-3/+3
2016-06-12Add dsp mode change fuction to A and B Netz, fixed NMTAndreas Eversberg1-1/+14
2016-05-15Move amplitude (level) debugging to debug.cAndreas Eversberg1-12/+0
2016-05-13C-Netz: Calibration/fix processing of tone levels on TX and RX sideAndreas Eversberg1-12/+76
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
2016-05-13C-Netz: Send 5280 Hz test tone on idle speech channelAndreas Eversberg1-1/+34
2016-05-13Automatic FSK polarity selection on TX sideAndreas Eversberg1-8/+16
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.
2016-05-08Multi transceiver supportAndreas Eversberg1-6/+52
This can be multiple transceivers on multiple sound cards. Two transceivers can be bundled on one sound device as well, using both channels.
2016-05-08C-Netz: Minor fix on clock speed indicationAndreas Eversberg1-1/+1
2016-04-24Implementation of C-Netz (German mobile telephone system)Andreas Eversberg1-0/+690
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