[SOLVED] rtl_fm SoX bandpass filter for CTCSS sub-tone

koval · 02-23-2015, 03:18 AM

Hey!

I am using rtl_fm on my computer.

This command work great on my system

Code:

rtl_fm -M fm -f 433.075M -s 12k -g 40 -l 20 | play -r 12k -t raw -e s -b 16 -c 1 -V1 -

For now I need to use lowpass and highpass filter for audio signal. I need to filter CTCSS sub-tone.

When I am trying to run

Code:

rtl_fm -M fm -f 433.075M -s 12k -g 40 -l 20 | play highpass 300 lowpass 3000 -r 12k -t raw -e s -b 16 -c 1 -V1 -

it show me an error

Quote:

"play FAIL sox: Not enough input filenames specified"

Does anybody know how can I use bandpass filter in SoX utility correctly?

Wocky · 02-23-2015, 11:00 PM

Quote:

Originally Posted by koval

Hey!

When I am trying to run

Code:

rtl_fm -M fm -f 433.075M -s 12k -g 40 -l 20 | play highpass 300 lowpass 3000 -r 12k -t raw -e s -b 16 -c 1 -V1 -

it show me an error

highpass and lowpass are effects filters in sox, which must be placed after all filenames. Try this:

Code:

rtl_fm -M fm -f 433.075M -s 12k -g 40 -l 20 | play -r 12k -t raw -e s -b 16 -c 1 -V1 - highpass 300 lowpass 3000

koval · 02-24-2015, 05:53 AM

Oh, thank you so much!
It's working !