.TH "rtl_adsb" 1 "0.5.0" RTL-SDR "User Commands"
  .SH NAME
  rtl_fm \- a simple FM demodulator for RTL2832 based DVB-T receivers
  .SH DESCRIPTION
  Uses a re-purposed DVB-T receiver as a software defined
  radio to receive narrow band FM signals and demodulate
  to audio. Written for and incorporated in the osmocom rtl-sdr project.
  .LP
  Narrowband FM is commonly used by public service agencies and
  commercial dispatch operations in the VHF and UHF bands.
  Also can demodulate Wideband FM, as found in the 88-108 MHz FM
  broadcast band.
  Experimental options include AM, LSB, USB and DSB demodulation.
  .LP
  Much software is available for the RTL2832. Most of the user-level
  packages rely on the librtlsdr library which comes as part of the
  rtl-sdr codebase. This codebase contains both the library itself and
  also a number of command line tools such as rtl_test, rtl_sdr,
  rtl_tcp, and rtl_fm. These command line tools use the library to test
  for the existence of RTL2832 devices and to perform basic data
  transfer functions to and from the device.
  .LP
  Because most of the RTL2832 devices are connected using USB, the
  librtlsdr library depends on the libusb library to communicate with
  the device.
  .SH USAGE
  With a suitable antenna for receiving the signal attached
  to the rtl-sdr supported device, this program will output the
  digital audio data decoded from that signal. The data can be
  listened to by piping to Sox or aplay applications to play the
  stream on the computer sound card.
  .SH SYNOPSIS
  .B  rtl_fm [-f freq] [-options] [filename]
  .SH OPTIONS
  .IP "-f frequency_to_tune_to [Hz]"
   use multiple -f for scanning, (requires squelch)
   ranges supported, -f 118M:137M:25k
  .IP "[-M modulation (default: fm)]"
   fm, wbfm, raw, am, usb, lsb
   wbfm == -M fm -s 170k -o 4 -A fast -r 32k -l 0 -E deemp
   raw mode outputs 2x16 bit IQ pairs
  .IP "-s sample_rate (default: 24k)"
  .IP "-d device_index (default: 0)"
  .IP "-g tuner_gain (default: automatic)"
  .IP "-l squelch_level (default: 0/off)"
  .IP "-o oversampling (default: 1, 4 recommended)"
   for fm squelch is inverted
  .IP "[-o oversampling (default: 1, 4 recommended)]"
  .IP "-p ppm_error (default: 0)"
  .IP "[-E enable_option (default: none)]"
   use multiple -E to enable multiple options
      edge:   enable lower edge tuning
      dc:     enable dc blocking filter
      deemp:  enable de-emphasis filter
      direct: enable direct sampling
      offset: enable offset tuning
  .IP "filename ('-' means stdout)"
   omitting the filename also uses stdout
  .SH Experimental options
  .IP "[-r resample_rate (default: none / same as -s)]"
  .IP "[-t squelch_delay (default: 10)]"
    +values will mute/scan, -values will exit
  .IP "[-F fir_size (default: off)]"
      enables low-leakage downsample filter
      size can be 0 or 9.  0 has bad roll off
  .IP "-A std/fast/lut choose atan math (default: std)"
  .IP filename
   (a '-' dumps samples to stdout)
   (omitting the filename also uses stdout)
  .SH EXAMPLES
  Produces signed 16 bit ints, use Sox or aplay to hear them.
  .IP "rtl_fm ... - | play -t raw -r 24k -es -b 16 -c 1 -V1 -"
                    | aplay -r 24k -f S16_LE -t raw -c 1
           -M wbfm  | play -r 32k ...
  .IP "rtl_fm ...  -s 22050 - | multimon -t raw /dev/stdin"
  .SH SEE ALSO
  RTL-SDR wiki documentation:
  .B http://sdr.osmocom.org/trac/wiki/rtl-sdr
  .LP
  Rtl_fm Guide:
  .B http://kmkeen.com/rtl-demod-guide/
  .LP
  .sp
  sox(1), play(1), aplay(1)
  .LP
  Other rtl-sdr programs:
  .sp
  rtl_adsb(1), rtl_eeprom(1), rtl_sdr(1), rtl_tcp(1), rtl_test(1)
  .SH AUTHOR
  This manual page was written by Maitland Bottoms
  for the Debian project (but may be used by others).
  .SH COPYRIGHT
  Copyright (c) 2013 A. Maitland Bottoms <bottoms@debian.org>
  .LP
  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 2 of the License, or
  (at your option) any later version.
  .LP
  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.