#
# Copyright 2005, 2006 Free Software Foundation, Inc.
# 
# This file is part of GNU Radio
# 
# GNU Radio 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, or (at your option)
# any later version.
# 
# GNU Radio 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.
# 
# You should have received a copy of the GNU General Public License
# along with GNU Radio; see the file COPYING.  If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
# 


What is this?
--------------------

This gnuradio module is a simple DCF77 transmitter or to be more precise
it is a generator for a time signal, that is usually transmitted by the
DCF77 station.

To learn more about the DCF77 station, please read this wikipedia page:
https://secure.wikimedia.org/wikipedia/en/wiki/DCF77

The time signal generated by this gnuradio module can be used to set the
time of radio controlled clocks. In two of three cases you can set the time
for a powered up clock in three to five minutes. If your clock is already
synced with a time signal, it highly depends on the clock, when it tries
to synchronise again. Some clocks will only sync once a day.

Installation
--------------------

This package requires that gnuradio-core is already installed. It
also depends on some GNU Radio prerequisites, such as boost.

To build the code from the tarball use the normal recipe:

  $ ./configure
  $ make
  $ make check

If you're building from CVS, you'll need to use this sequence, since
CVS doesn't contain configure or the generated Makefiles.

  $ ./bootstrap
  $ ./configure
  $ make
  $ make check


The doc directory is not built by default.  This is to avoid spurious
build problems on systems that don't have xmlto installed.  If you
have xmlto and its dependencies installed, you can build the html
version of the howto article by cd'ing to doc and invoking make.

Usage
--------------------

Just have a look into start.sh and dcf77_tx_test.py prepare your USRP
and run start.sh.

Plug in the LFTX module in order to prepare your USRP. For testing
you can connect the LFTX to a coil and place the clock in the
center of the coil. You don't need any amplifier for this setup.


Legal aspects
--------------------

Obviously there are legal aspects. Transmitting time signals outside
of special radio test rooms is not allowed in most cases.


Author
--------------------

Martin Schobert <martin@weltregierung.de>