From 519642b75f323bacb16e54e5ffd3b6a2f0004808 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A1s=20Retzler?= Date: Sun, 8 Nov 2015 15:49:09 +0100 Subject: [PATCH] Update README.md --- README.md | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/README.md b/README.md index 540c7e7..4987e9a 100644 --- a/README.md +++ b/README.md @@ -51,3 +51,18 @@ We will play these files in a loop, you can stop it with Ctrl+C. (while true; do cat music48000.raw; done) | csdr convert_i16_f | csdr gain_ff 70000 | csdr convert_f_samplerf 20833 | sudo rpitx -i- -m RF -f 28400 * Frequency deviation is set much higher with `csdr gain_ff 70000`, that's the only difference between this and NFM. + +### Modulate from microphone input source +Use this if you have a microphone connected to the Raspberry Pi via external USB audio device.
+You will have to get the correct ALSA device ID via `arecord -L`, it will be something like `plughw:CARD=Device,DEV=0`. You should enter as the argument of the `-D` switch of `arecord`. + + #AM: + arecord -c1 -r48000 -D plughw:CARD=Device,DEV=0 -fS16_LE - | csdr convert_i16_f | csdr gain_ff 1.0 | csdr dsb_fc | csdr add_dcoffset_cc | sudo rpitx -i- -m IQFLOAT -f 28400 + #USB: + arecord -c1 -r48000 -D plughw:CARD=Device,DEV=0 -fS16_LE - | csdr convert_i16_f | csdr dsb_fc | csdr bandpass_fir_fft_cc 0 0.1 0.01 | csdr gain_ff 2.0 | csdr shift_addition_cc 0.2 | sudo rpitx -i- -m IQFLOAT -f 28400 + #LSB: + arecord -c1 -r48000 -D plughw:CARD=Device,DEV=0 -fS16_LE - | csdr convert_i16_f | csdr dsb_fc | csdr bandpass_fir_fft_cc -0.1 0 0.01 | csdr gain_ff 2.0 | csdr shift_addition_cc 0.2 | sudo rpitx -i- -m IQFLOAT -f 28400 + #NFM: + arecord -c1 -r48000 -D plughw:CARD=Device,DEV=0 -fS16_LE - | csdr convert_i16_f | csdr gain_ff 7000 | csdr convert_f_samplerf 20833 | sudo rpitx -i- -m RF -f 28400 + #WFM: + arecord -c1 -r48000 -D plughw:CARD=Device,DEV=0 -fS16_LE - | csdr convert_i16_f | csdr gain_ff 70000 | csdr convert_f_samplerf 20833 | sudo rpitx -i- -m RF -f 28400