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https://github.com/saitohirga/WSJT-X.git
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111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
// q65_subs.c
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/* Fortran interface for Q65 codec
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To encode a Q65 message:
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integer x(13) !Message payload, 78 bits as 13 six-bit integers
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integer y(63) !Codeword, 63 six-bit integers
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call q65_enc(imsg,icodeword)
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To decode a Q65 message:
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parameter (LL=64,NN=63)
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real s3(LL,NN) !Received energies
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real s3prob(LL,NN) !Symbol-value probabilities
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integer APmask(13)
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integer APsymbols(13)
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real snr2500
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integer xdec(13) !Decoded 78-bit message as 13 six-bit integers
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integer irc !Return code from q65_decode()
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call q65_dec(s3,APmask,APsymbols,s3prob,snr2500,xdec,irc)
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*/
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#include "qra15_65_64_irr_e23.h" // QRA code used by Q65
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#include "q65.h"
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#include <stdio.h>
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#include <stdlib.h>
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static q65_codec_ds codec;
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void q65_enc_(int x[], int y[])
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{
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static int first=1;
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if (first) {
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// Set the QRA code, allocate memory, and initialize
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int rc = q65_init(&codec,&qra15_65_64_irr_e23);
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if (rc<0) {
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printf("error in q65_init()\n");
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exit(0);
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}
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first=0;
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}
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// Encode message x[13], producing codeword y[63]
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q65_encode(&codec,y,x);
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}
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void q65_intrinsics_ff_(float s3[], int* submode, float* B90,
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int* fadingModel, float s3prob[])
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{
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/* Input: s3[LL,NN] Received energies
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* submode 0=A, 4=E
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* B90 Spread bandwidth, 90% fractional energy
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* fadingModel 0=Gaussian, 1=Lorentzian
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* Output: s3prob[LL,NN] Symbol-value intrinsic probabilities
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*/
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int rc;
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static int first=1;
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if (first) {
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// Set the QRA code, allocate memory, and initialize
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int rc = q65_init(&codec,&qra15_65_64_irr_e23);
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if (rc<0) {
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printf("error in q65_init()\n");
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exit(0);
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}
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first=0;
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}
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rc = q65_intrinsics_fastfading(&codec,s3prob,s3,*submode,*B90,*fadingModel);
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if(rc<0) {
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printf("error in q65_intrinsics()\n");
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exit(0);
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}
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}
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void q65_dec_(float s3[], float s3prob[], int APmask[], int APsymbols[],
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float* snr2500, int xdec[], int* rc0)
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{
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/* Input: s3prob[LL,NN] Symbol-value intrinsic probabilities
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* APmask[13] AP information to be used in decoding
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* APsymbols[13] Available AP informtion
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* Output:
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* snr2500 SNR_2500 of decoded signal, or lower limit
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* xdec[13] Decoded 78-bit message as 13 six-bit integers
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* rc0 Return code from q65_decode()
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*/
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int rc;
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int ydec[63];
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float esnodb;
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rc = q65_decode(&codec,ydec,xdec,s3prob,APmask,APsymbols);
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*rc0=rc;
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// rc = -1: Invalid params
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// rc = -2: Decode failed
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// rc = -3: CRC mismatch
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*snr2500 = -31.0;
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if(rc<0) return;
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rc = q65_esnodb_fastfading(&codec,&esnodb,ydec,s3);
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if(rc<0) {
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printf("error in q65_esnodb_fastfading()\n");
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exit(0);
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}
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*snr2500 = esnodb - 31.0;
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}
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