What's new in rtty-2.1
----------------------
DSP CORE:
- Two cascaded resonators for mark & space filters. This gives a much higher
  out of band attenuation than a single resonator.
- DPLL routine now integrates the signal during bit time.
  This routine now returns after a whole bit is received.
- Tree modes supported: CW, RTTY and AX25.
- CW:
  - Still experimental code.
  - Keying times adjusted automatically or manually. 
- RTTY:
  - Corrections in Baudot character tables.
  - CR characters ignored.
  - A long space tone is now detected as a "BREAK" condition.
  - A lot of changes in the STOP bit detection due to the new DPLL.
- AX25 (HDLC):
  - Hexadecimal dump of AX25 packets.
  - Address field decoded.

GRAPHICS:
- There are major changes in the graphics code internals, but they are not
  reflected in the program look. The XOR-drawing mode is no longer used.
- The "eye-plot" has been added again.
- The inferface window includes more controls for the new supported modes.
- The mark and space frequencies can be swapped clicking on "SWAP" button.
- The current setup can be saved to the "rtty.cfg" file clicking on "SAVE".

TEST PROGRAMS:
- A program wich generates an FSK output is included (fsk). This program
  is in fact two narrow-band ASK modulators. The carrier amplitudes are
  cosine shapped, giving a very low out-of-band spurs. The supported formats
  are RTTY, with 8 or 7 bits, optional parity, and AX25. AX25 packets have
  no internal structute except for the address field and CRC.
- A morse keyer/training program is also included (morse).

What's new in rtty-2.0
----------------------

rtty version 2.0 is a major revision of the previous rtty package. Most of
the code has been rewriten in order to implement a more efficient
algorithms or just to simplify some stupid parts of the previous version.
Some funtionality, that i think is rarely used, has been removed. The
following is a list of the main changes:

DSP CORE:
- Filter routines are no longer those provided by "mkfilter". I'm now using
  my own filter routines. Filters are divided into "biquad sections".
- Filter coefficients are calculated during execution time instead of
  tabulated. This saves some hundreds Kb of RAM.
- Band-pass filters are now simple resonators instead of more sophisticated
  filters (Butterworth or Bessel). The resonator Q is adjusted depending on
  the selected data rate.
- DPLL routine is now much simpler. No floating point is used at all.
- UART emulation includes some fixes/improvements:
  - repeated START bit waiting under gitches.
  - waiting until valid STOP bit(s).
- HDLC decoding has been removed.
- Errors are now marked using color ANSI escapes.

GRAPHICS:
- New graphical interface.
- Smaller form.
- Only one scope window for both spectrum and time-base signals.
- Eye plot has been removed.
- Radio buttons for an easy data format setup.
- The scope window is a form canvas. Plotting is done using a raw X11
  interface for higher speed.
- The filter bandwidths are shown in the spectrum window togheter with the
  input signal spectrum.
- The graphic interface can be disabled with the "-x" command line option.

PROCESS COMMUNICATIONS:
- All the comunications are done using POSIX Threads. The messy system-V IPC
  are no longer used. A big inter-process comunication simplification is
  achieved.
- The program can start three threads. One thread is the main decoding loop.
  The second thread is the form interface. The third thread does the
  plotting of the scope signals.
- If the program is called with the "-x" command line option no other
  threads are started.

OTHER:
- The decoding SETUP can be retrieved from the "rtty.cfg" file.
- Source code comments are now written in english.
- Some documentation about the algorithms and the program itself has been
  written in english.
