rtl_fm options

rtl_fm, a simple narrow band FM demodulator for RTL2832 based DVB-T receivers

Use:	rtl_fm -f freq [-options] [filename]
	-f frequency_to_tune_to [Hz]
	    use multiple -f for scanning (requires squelch)
	    ranges supported, -f 118M:137M:25k
	[-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
	[-s sample_rate (default: 24k)]
	[-d device_index (default: 0)]
	[-g tuner_gain (default: automatic)]
	[-l squelch_level (default: 0/off)]
	[-p ppm_error (default: 0)]
	[-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
	filename ('-' means stdout)
	    omitting the filename also uses stdout

Experimental options:
	[-r resample_rate (default: none / same as -s)]
	[-t squelch_delay (default: 10)]
	    +values will mute/scan, -values will exit
	[-F fir_size (default: off)]
	    enables low-leakage downsample filter
	    size can be 0 or 9.  0 has bad roll off
	[-A std/fast/lut choose atan math (default: std)]

Produces signed 16 bit ints, use Sox or aplay to hear them.
	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 ...
	  -s 22050 | multimon -t raw /dev/stdin