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PTT / Transmit Squelch function
Hello !
Great work with LibRpiTx.... NBFM working really well with DEVIATION set to 2.5 !
I am testing an application which use LibRpiTx to transmit samples, and was hoping to have control over the transmit. Either as a PTT flag (through control pipe?) or as a Transmit Squelch capability, where the TX (carrier) will be on only when the audio level rises above a set level.
What would be the best approach to go about it ?
Cheers
As I understand, your application need to control Tx On/Off. You can use clkgpio::disableclk(4) and clkgpio::enableclk(4) to disable/enable the signal on GIPIO4. Method to (pipe, audio level) has to be done from your application. Have you a github link to your application ?
Hello Evariste...
Just upped the code into github repo.... mmdvm-sdr and PiNBFm ... so basically mmdvm-sdr will provide audio file in wave format, that needs to be tx'd with PiNBFm (stripped version of PiFMRDS/LibRPiTx without RDS/stereo processing)...
The offline tx is working fine... I tried to do pipe out from mmdvm-sdr to PiNBFm (direct, thru sox and also through netcat), but there is no carrier or modulation on pipe opening... It would be great if we can detect audio signal and enable TX only on signal... mmdvm-sdr provides PTT signal, which can be used if clkgpio::disableclk()/enableclk() is exposed..
Kindly suggest how these can be integrated...
Nice project ! I follow install instructions.All seems OK with mmdvm and MMDVMHost. RxSample.wav is growing but there is only silence inside.
On your side : can you add gpu_freq=250 on /boot/config.txt , seems that modulation stops if this parameter is not there (still investigate on the cause)
Thanks for trying !
Did you connect successfully to any of the networks and manage to see network packets in the MMDVM Debug Log (set Debug=1 in [Modem] section) ?
something like this: M: 2018-05-16 15:21:57.454 DMR Slot 2, received network voice header from W0TSM to TG 310 M: 2018-05-16 15:21:58.145 DMR Talker Alias (Data Format 1, Received 6/21 char): 'W0TSM ' M: 2018-05-16 15:21:58.881 DMR Talker Alias (Data Format 1, Received 13/21 char): 'W0TSM DMR ID:' M: 2018-05-16 15:21:59.587 DMR Talker Alias (Data Format 1, Received 20/21 char): 'W0TSM DMR ID: 312960' M: 2018-05-16 15:22:00.303 DMR Talker Alias (Data Format 1, Received 21/21 char): 'W0TSM DMR ID: 3129603' M: 2018-05-16 15:23:01.549 DMR Slot 2, received network end of voice transmission, 65.2 seconds, 3% packet loss, BER: 0.1%
Can you attach the log file / screenshots of both the process ?
I have added an sample test capture for testing TX output. https://github.com/r4d10n/mmdvm-sdr/blob/master/RXSample-test.wav
I will try the the gpu_freq parameter.
Cheers