Commit Graph

79 Commits

Author SHA1 Message Date
Andreas Eversberg 534411d660 New common FSK implementation, replaces all individual implementations 2017-08-09 17:27:13 +02:00
Andreas Eversberg 8ce3ff455d Add incoming answer to call control, also allow to send recall tone 2017-08-09 17:27:08 +02:00
Andreas Eversberg 0cbd9657d2 Move Hagelbarger error correction code from NMT to common code
It will be used by Radiocom 2000 also.
Some minor fixes and improvements apply.
2017-08-08 12:53:48 +02:00
Andreas Eversberg 6c64025717 Move FFSK modem from NMT to common code, so it can be used by other networks 2017-08-08 12:53:34 +02:00
Andreas Eversberg 0c9de251be NMT: Implement Hagelbarger Code
This will correct burst errors of received messages. If the message
is too corrupted, it will be ignored, because some element may not
match then. The digits and line signals are checked for consistency,
since they are repeated serveral times in a message.
2017-08-08 12:52:29 +02:00
Andreas Eversberg 085ceb9173 Minor fixes to compandor 2017-07-15 07:38:12 +02:00
Andreas Eversberg ca10048e5c Rename filter -> iir_filter (file name and instance name)
This is useful when using fir_filter in the future.
2017-05-15 21:46:32 +02:00
Andreas Eversberg 438ce08add SoapySDR support
There is no time stamp handling. It is just TX'ing in advance and
synchronous to received RX rate.
2017-02-18 21:02:55 +01:00
Andreas Eversberg 58ebc15292 Add test to measure performance of FM modulation and filtering 2017-02-18 21:02:53 +01:00
Andreas Eversberg 7e45f556ce Correcting all levels and move all remaining integer samples to sample_t
The leves are based on the standards of each mobile network. They
are adjusted to the specified frequency deviation now.
2017-02-18 21:01:13 +01:00
Andreas Eversberg bd7ccc5fa0 Add global DC-Filter and remove all individual DC-Filters 2017-02-18 21:01:12 +01:00
Andreas Eversberg 71e556e7ff Work on emphasis filter: Neutral @ 1000 Hz; Use filter before de-emphasis 2017-02-18 21:01:11 +01:00
Andreas Eversberg b3fd53b165 Test filter uses a dB graph to show the response graphically 2017-02-18 21:01:10 +01:00
Andreas Eversberg 7ea3bc188d Move samples of int16_t format to sample_t, that is of type double
This prepares the correction of all levels
2017-02-18 21:01:08 +01:00
Andreas Eversberg ac0da3f76e Filter improvement: LP and HP filters, added test function
The -3 dB level at cut-off frequency is now maintained for multiple
iterations.
2017-02-18 21:01:04 +01:00
Andreas Eversberg 57993e3e48 Support for UHD SDR interface 2017-02-18 21:00:49 +01:00
Andreas Eversberg d447be5e26 NMT: Rework on FSK process, no more requirement for special sample rates 2017-01-07 06:28:20 +01:00
Andreas Eversberg 1ea95de120 C-Netz: Use emphasis with 200 uS time constant 2016-10-23 08:46:05 +02:00
Andreas Eversberg 038ce9d1b7 Add info key 'i' to show some states.
Currently showing C-Netz attached subscribers
2016-08-03 12:03:49 +02:00
Andreas Eversberg c273bbc5ff Remove console line before printing debugging and on exit 2016-07-24 12:31:08 +02:00
Andreas Eversberg b3b42e8bc4 Cleanup warnings at autoconfig files 2016-07-24 12:31:06 +02:00
Andreas Eversberg a6bd841247 NMT: Various fixes for SMS support 2016-07-24 12:31:05 +02:00
Andreas Eversberg e7fa08b6df NMT / SMS: Short Message Service support 2016-07-09 15:16:16 +02:00
Andreas Eversberg 64c829909b NMT / DMS: User data facility support (required for SMS) 2016-07-09 11:27:24 +02:00
Andreas Eversberg 2ee51022f4 Rename 'compander' to 'compandor' 2016-06-20 19:37:56 +02:00
Andreas Eversberg 42eefe90bf common code: Fixed de-emphasis by adding high pass filter
This high-pass filter filters out DC and frequencies below 300 Hz.
Now de-emphases will not cause low frequencies to saturate audio level
range or cause too high levels on low frequencies.
2016-05-13 09:37:02 +02:00
Andreas Eversberg 0c99848120 common code: Make preemphasis 0 dB @ 1000 Hz 2016-05-01 15:14:57 +02:00
Andreas Eversberg 4356c93afa common: Add pre and de emphasis, if the radio does not support it
Connect to the oscillator of the transmitter - good girl!
You need to enable pre emphasis in this case.

Connect to the discriminator of the receiver - good boy!
You need to enable de emphasis in this case.
2016-04-24 15:14:56 +02:00
Andreas Eversberg 2a092b8cf7 Fixing compander 2016-04-24 15:10:25 +02:00