dcf77rx1
Soundcard dcf77 (and hbg) beacon receiver
Usage
dcf77rx [-a
audio
device]
[-s]
[-n]
[-v
verboselevel
(1
or
2)]
[-g]
[-p]
[-l]
[-u]
[-t]
Overview
dcf77rx is a soundcard demodulator for time reference signals transmitted by the transmitters DCF77 and HBG on LF frequencies. The program expects the transmitter signal downconverted to an audio passband frequency of 1kHz by an LSB or USB receiver. A circuit for home-brewing such a transverter is included in the docs of the hf package.
The decoded time information is used to derive correction factors for the sampling rate, the gettimeofday clock and to measure the exact CPU clock frequency. These clock sources are used for calibration in my AMTOR/Pactor1 package (hf) as reference clocks. This program is part of the package.
Options
-
-a -
specify the path to the sound driver (default: /dev/dsp on Linux, /dev/audio on Solaris).
-
-s -
use standard input instead of audio input. Format is 8kHz 16bit words 1 channel in the endianness of the CPU.
-
-n -
do not use the `mmap()` way of approaching the soundcard, which means, do not read directly from the soundcard dma buffer. Some soundcards do not support mmap mode. This option is experimental, it is not yet tested how good the results will be!
-
-v -
Set the verbosity level (1 or 2, default 0). The higher the number, the more debugging information is written to standard error. At first use, try level 2 to get familiar with how it works.
-
-g -
HBG mode.
-
-p -
DCF77 phase mode. DCF77 transmits the time information amplitude modulated and phase modulated with a pseudorandom code. This option uses the latter to decode the time. This is strongly recommended, as the PN code is more robust and allows much more exact determination of the second pulses.
-
-l -
Receiver uses LSB (lower sideband) mode.
-
-u -
Receiver uses USB (upper sideband) mode.
-
-t -
Set the system time to the received MEZ btw MESZ (CET btw CEST) from DCF77.
Credits
Hans-Guenter DF4OX/DL0PTB sent me printed documentation about the DCF77 transmission format which helped me a lot.
Releases
3 releases since Debian 3.1 (Sarge); the text changed 2 times.