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Editing the jtms3.txt file. 

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/jtms3@2487 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Joe Taylor 2012-07-04 21:30:56 +00:00
parent a199729efb
commit 5a551b3435
3 changed files with 12 additions and 21 deletions
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30
jtms3.txt
View File

@ -5,32 +5,22 @@
Type 1 messages are 72 user-information bits, source encoded as in Type 1 messages are 72 user-information bits, source encoded as in
JT65. Convolutional FEC (K=32, r=1/2) increases the number of bits to JT65. Convolutional FEC (K=32, r=1/2) increases the number of bits to
(72+31)*2 = 206. Nine bits are sent twice, extending the array to 215 (72+31)*2 = 206; nine bits are sent twice, extending the array to 215
bits. These are interleaved by bit-reversal of index values. Then 43 bits. These are interleaved by bit-reversal of index values. Then 43
sync bits are inserted, spread evenly so as to fall at positions 1, 7, sync bits are inserted, spread evenly so as to fall at positions 1, 7,
13, ... 253. Frame size is 258 bits: 215 information-carrying bits 13, ... 253. Frame size is 258 bits: 215 information-carrying bits
and 43 sync bits. Frame duration is 129 ms. and 43 sync bits. Frame duration is 129 ms.
[Optional: Type 2 messages convey 4 user information bits (report, Type 2 messages convey 4 user information bits (report, R+report, RRR,
R+report, RRR, 73) encoded with a (15,4,8) block code, plus a 12-bit 73) encoded with a (15,4,8) block code, plus a 12-bit CRC for each
CRC for each callsign encoded with the Golay (23,12) code. This callsign, encoded with the Golay (23,12) code. This makes for 15 +
makes for 15 + 2*23 = 61 information-carrying bits. One dummy bit is 2*23 = 61 information-carrying bits. One dummy bit is added, and the
added, and the 62 bits are interspersed with 31 sync bits, making a 62 bits are interspersed with 31 sync bits, making a frame of 93 bits
frams of 93 bits and frame time 46.5 ms.] and frame time 46.5 ms.
2. Modulation is BPSK at 2000 baud. For sample rate 48000 Hz, this 2. Modulation is BPSK at 2000 baud, 24 samples per symbol at 48000 Hz
means nsps = 48000/2000 = 24 samples per symbol. The baseband asmple rate. The baseband waveform is built by inserting a tapered
waveform is built as follows: sinc function for each bit, then multiplying by a 1500 Hz sine wave.
a. Replicate each bit nsps times into array y(npts=30*48000),
substituting -1 for 0. Repeat the whole message enough times
to fill npts, then pad with zeros to length 2*npts.
b. Compute real-to-complex FFT of y(2*nsym*nsps). Roll off the complex
spectrum at f=1000 Hz. Translate the half-band 0-1000 upward to
1500-2500 Hz, and insert conjugate values at 1500 down to 500 Hz.
c. The inverse (complex-to-real) FFT yields the Tx audio waveform.
3. Receiving 3. Receiving

1
libm65/genjtms3.f90
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@ -20,6 +20,7 @@ subroutine genjtms3(msg,msgsent,iwave,nwave)
call scr258(isync,datsym,1,chansym) !Insert sync and data into chansym(258) call scr258(isync,datsym,1,chansym) !Insert sync and data into chansym(258)
if(msg(1:1).eq.'@') chansym=0
twopi=8.0*atan(1.0) twopi=8.0*atan(1.0)
f0=1500.0 f0=1500.0
dphi=twopi*f0/48000.0 dphi=twopi*f0/48000.0

2
mainwindow.cpp
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@ -1,4 +1,4 @@
//-------------------------------------------------------------- MainWindow //--------------------------------------------------------------- MainWindow
#include "mainwindow.h" #include "mainwindow.h"
#include "ui_mainwindow.h" #include "ui_mainwindow.h"
#include "devsetup.h" #include "devsetup.h"