---
name: "fdmdv_demod"
section: "1"
platform: "linux"
package: "codec2"
version: "1.2.0-3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/fdmdv_demod"
---

# fdmdv\_demod(1)

a diagnostic tool for the codec2 library to create a codec2 bit file from a series of FDMDV modem samples.

## NAME

fdmdv\_demod - a diagnostic tool for the codec2 library to create a codec2 bit file from a series of FDMDV modem samples.

## SYNOPSIS

**fdmdv\_demod usage:** *InputModemRawFile* *OutputBitFile* *\[Nc\]* *\[OctaveDumpFile\]*

## DESCRIPTION

Given an input raw file (8kHz, 16 bit shorts) of FDMDV modem samples outputs a file of bits.  The output file is assumed to be arranged as codec frames of 56 bits (7 bytes) which are received as two 28 bit modem frames.

Demod states can be optionally logged to an Octave file for display using the Octave script fdmdv\_demod\_c.m.  This is useful for checking demod performance.

## EXAMPLE

 fdmdv\_dmod hts1a\_fdmdv.raw hts1a.c2

## OPTIONS

The first argument, *InputModemRawFile* is the file name of a file with FDMDV modem samples. If "-" is given the input is taken from stdin.

The second argument,  *OutputBitFile* is the file name of a file to be created with codec2 bits. If "-" is given the output is sent to stdout.

The optional third argument, *\[Nc\]* is the number of carriers to use in the modem. The default is 14. The minimum is 2 and the maximum is 20.

The optional fourth argument, *\[OctaveDumpFile\]* is the name of to Octave data file to create.

## SEE ALSO

[**c2dec**(1)](/c2dec/1.md), [**c2enc**(1)](/c2enc/1.md), [**fdmdv\_mod**(1)](/fdmdv_mod/1.md), [**fdmdv\_get\_test\_bits**(1)](/fdmdv_get_test_bits/1.md) [**fdmdv\_put\_test\_bits**(1)](/fdmdv_put_test_bits/1.md)