CSDR-AM script added to the examples folder

docs/examples/csdr/README.md

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+# CSDR-AM
+
+The purpose of this shell script is to record multiple AM frequencies from a single RTL-SDR and creates individual audio files per conversation.
+
+## Requirements
+
+Tested on a linux box.
+
+* [csdr](https://github.com/ha7ilm/csdr)
+* [sox](http://sox.sourceforge.net/)
+
+## Configurations
+
+### Within the script itself
+
+Change the the values to you needs. Make sure the `centered_freq` and `sampling_rate` covers the `freqs`.
+
+Note the syntax for `freqs` and `filenames`, they are arrays.
+
+Each filename template use sox multiple output mode syntax for file numbering (`%6n`). The static part is reused by `dirWatch` to distinguish which `talkgroup` to import to.
+
+```bash
+audio_dir=./audio_files/air
+device_id=00000001
+center_freq=119.4e6
+gain=38.6
+sampling_rate=2400000
+squelch=2e-4
+
+freqs=(118.9e6 119.1e6 119.9e6)
+
+filenames=(118900000-%6n 119100000-%6n 119900000-%6n)
+```
+
+## Rdio Scanner
+
+Whenever a new file is being created by the `CSDR-AM` script, `Rdio Scanner` will pick it up and load it.
+
+Since the script create a file for each frequency which will have a size of `0` until the next conversation, we have to tell the `dirWatch` entry to delay the import for `4000` milliseconds.
+
+The system also needs to be defined.
+
+> For simplicy, talkgroup ids are defined with the same value as for the frequency. It makes it easier to change things afterwards.
+
+```json
+"rdioScanner": {
+    "dirWatch": [
+		{
+			"delay": 4000,
+			"deleteAfter": true,
+			"directory": "/home/radio/csdr/audio_files/air",
+			"extension": "wav",
+			"system": 61,
+			"talkgroup": ".*\\/(\\d+)-.*"
+		}
+    ],
+    "systems": [
+        {
+            "id": 61,
+            "label": "AIRCRAFT",
+            "led": "cyan",
+            "talkgroups": [
+                {
+                    "id": 119100000,
+                    "label": "YMX TOWER",
+                    "name": "YMX Tower",
+                    "tag": "Aircraft",
+                    "group": "AIRCRAFT",
+                    "frequency": 119100000
+                },
+                {
+                    "id": 119900000,
+                    "label": "YUL TOWER",
+                    "name": "YUL Tower",
+                    "tag": "Aircraft",
+                    "group": "AIRCRAFT",
+                    "frequency": 119900000
+                },
+                {
+                    "id": 118900000,
+                    "label": "YUL DA_SE",
+                    "name": "YUL Dep/Arr S/E",
+                    "tag": "Aircraft",
+                    "group": "AIRCRAFT",
+                    "frequency": 118900000
+                }
+            ]
+        }
+    ]
+}
+```

docs/examples/csdr/csdr-am

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+#!/bin/bash
+
+##
+## #############################################################################
+##  Copyright (C) 2019-2020 Chrystian Huot
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <http://www.gnu.org/licenses/>
+## #############################################################################
+##
+
+##
+## Begin of configurable values
+##
+
+audio_dir=./audio_files/air
+device_id=00000001
+center_freq=119.4e6
+gain=38.6
+sampling_rate=2400000
+squelch=2e-4
+
+## List of frequencies covered by your RTL
+
+freqs=(118.9e6 119.1e6 119.9e6)
+
+## Filename tempaltes for each frequencies
+## See sox documentation for multiple files output
+
+filenames=(118900000-%6n 119100000-%6n 119900000-%6n)
+
+##
+## End of configurable values
+##
+
+for i in ${!freqs[@]}; do
+	mkfifo /tmp/csdr_${device_id}_${freqs[i]}_iq.fifo
+
+	mkfifo /tmp/csdr_${device_id}_${freqs[i]}_squelch.fifo
+done
+
+trap cleanup EXIT
+
+test -d ${audio_dir} || mkdir -p ${audio_dir} || exit 1
+
+trap "rm -f /tmp/csdr_${device_id}_*.fifo" EXIT
+
+for i in ${!freqs[@]}; do
+	cat /tmp/csdr_${device_id}_${freqs[i]}_iq.fifo |
+		csdr convert_u8_f |
+		csdr shift_addition_cc $(csdr =\(${center_freq}-${freqs[i]}\)/${sampling_rate}) |
+		csdr fir_decimate_cc 50 0.005 HAMMING |
+		csdr squelch_and_smeter_cc --fifo /tmp/csdr_${device_id}_${freqs[i]}_squelch.fifo --outfifo /dev/null 6e-5 600 |
+		csdr amdemod_cf |
+		csdr agc_ff |
+		csdr limit_ff |
+		csdr convert_f_s16 |
+		sox -c 1 -r 44100 -t s16 - "${audio_dir}/${filenames[i]}.wav" silence 1 0.50 0.1% 1 2.0 0.1% : newfile : restart &
+done
+
+for i in ${!freqs[@]}; do
+	echo ${squelch} >/tmp/csdr_${device_id}_${freqs[i]}_squelch.fifo
+done
+
+server="rtl_sdr -d ${device_id} -f ${center_freq} -g ${gain} -s ${sampling_rate} -"
+
+for i in ${!freqs[@]}; do
+	if [ $i == $((${#freqs[@]} - 1)) ]; then
+		server+=" > /tmp/csdr_${device_id}_${freqs[i]}_iq.fifo"
+	else
+		server+=" | tee /tmp/csdr_${device_id}_${freqs[i]}_iq.fifo"
+	fi
+done
+
+eval ${server}