mirror of https://github.com/saitohirga/WSJT-X.git
92 lines
4.0 KiB
Plaintext
92 lines
4.0 KiB
Plaintext
To: Users of WSJT
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From: Joe Taylor, K1JT
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Subject: WSJT 5.9.0
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Date: November 14, 2005
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I am pleased to announce that WSJT 5.9.0 is available for free
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download from the WSJT Home Page,
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http://pulsar.princeton.edu/~joe/K1JT. It should appear soon
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on the European mirror site, http://www.dk5ya.de, as well.
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I believe that all reported bugs found in beta-release version 5.8.6
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have been fixed. In addition, new enhancements have taken the program
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well beyond the capabilities of the baseline comparison versions,
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4.9.8 and 5.8.6.
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The new WSJT 5.9.0 is faster and better than previous versions in a
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number of ways. A brief description of the enhancements since version
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5.8.6 can be found at
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http://pulsar.princeton.edu/~joe/K1JT/UpdateHistory.txt. There are
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many program changes, so be sure to read this information carefully
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before trying to use WSJT 5.9.0!
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Of course there may be some new bugs, and perhaps I have overlooked an
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existing problem that you already know about. Please let me know if
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you find shortcomings in version 5.9.0, or if you have suggestions for
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further improvements.
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Sorry, I have not yet found time to implement EME Echo mode. When
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that is done, and when I have finished some further enhancements to
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the decoders, WSJT 6.0 will be born. With some luck, there may also
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be a new User's Guide at about that time.
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With best wishes,
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-- 73, Joe, K1JT
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Additional Information for Programmers
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-----------------------------------------------------------------------
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WSJT versions 5.8+ are the result of a complete re-write of the user
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interface, timing control, and audio I/O portions of WSJT 4.9.8. My
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principal motivation was to make the program multi-threaded, both for
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real-time operational convenience and for performance reasons.
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Another strong motivation was a desire to move the program away from
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its dependence on a proprietary compiler (Microsoft Visual Basic) and
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a single computer platform (Windows).
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The user interface of WSJT 5.8+ is written in Python -- an elegant,
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open, cross-platform language that has been a pleasure for me to
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learn. The remainder of the program is written mostly in Fortran,
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with some routines coded in C; much of that code has been carried over
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directly from WSJT 4.9.8.
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I hope soon to release the source code for WSJT under the GNU General
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Public License (GPL). To this end, I have separated out the one piece
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of proprietary code formerly in the program -- the soft-decision Reed
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Solomon decoder licensed from CodeVector Technologies (CVT). A driver
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for this decoder, optimized for JT65, has been compiled into a
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stand-alone executable that is now distributed as part of the WSJT
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installation package, but not part of the program itself. With this
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approach I can honor all provisions of the CVT license, and at the
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same time release everything else as an open source program under the
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GPL.
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WSJT 5.9.0 now includes an open source hard-decision Reed Solomon
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decoder based on code written by Phil Karn, KA9Q . WSJT uses this
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decoder automatically if the proprietary CVT decoder is unavailable.
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In such instances the "deep search" decodes retain their full
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sensitivity, but fully general decoding independent of the callsign
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database will be less sensitive by 2 or more dB, depending on signal
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fading characteristics. Separation of the program into two executable
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units is transparent to the user.
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WSJT 5.9.0 uses the following open source libraries, which are also
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available under the GPL:
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1. FFTW, by Matteo Frigo and Steven Johnson, for computing Fourier
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transforms
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2. "Secret Rabbit Code" or "libsamplerate", by Erik de Castro, for
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accomplishing band-limited resampling of data
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3. RS, by Phil Karn, KA9Q, for Reed Solomon encoding and
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hard-decision decoding.
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I hope that the open release of WSJT source code will encourage others
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to read and understand the code, get involved in improving WSJT, and
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perhaps porting it to other platforms. Versions of the CVT
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soft-decision decoder for Linux or Macintosh will be easy to compile
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and distribute, if there is demand for them.
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