?? rcv_qmf.c
字號:
/******************************* RECIEVE QMF ************************/#include <stdio.h>main (){ int i; /* counter */ int rl, rh; /* low and high band pcm input */ int xout1, xout2; /* even and odd tap accumulators */ FILE *infile; /* input file pointer */ FILE *outfile; /* output file pointer */ static int h[24] = /* qmf tap coefficients */ {3, -11, -11, 53, 12, -156, 32, 362, -210, -805, 951, 3876, 3876, 951, -805, -210, 362, 32, -156, 12, 53, -11, -11, 3} ; static int xd[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} ; static int xs[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} ; infile = fopen("testout.dat", "r"); outfile = fopen("pcmout.dat", "w+");nextpcm: fscanf(infile, "%d%d", &rl, &rh) ; if (rl == 32767) goto finish; for (i=11; i>0; i--) { xd[i] = xd[i-1]; xs[i] = xs[i-1]; }/************************************* RECA ***************************/ xd[0] = rl - rh ; if (xd[0] > 16383) xd[0] = 16383; if (xd[0] < -16384) xd[0] = -16384;/************************************* RECB ***************************/ xs[0] = rl + rh ; if (xs[0] > 16383) xs[0] = 16383; if (xs[0] < -16384) xs[0] = -16384;/************************************* ACCUMC *************************/ xout1 = 0; for (i=0; i<12; i+=1) xout1 += xd[i] * h[2*i]; xout1 = xout1 >> 12 ; if (xout1 > 16383) xout1 = 16383 ; if (xout1 < -16384) xout1 = -16384 ;/************************************* ACCUMD *************************/ xout2 = 0; for (i=0; i<12; i+=1) xout2 += xs[i] * h[2*i+1]; xout2 = xout2 >> 12 ; if (xout2 > 16383) xout2 = 16383 ; if (xout2 < -16384) xout2 = -16384 ;/************************************* SELECT *************************/ fprintf (outfile, "%5d\n%5d\n", xout1, xout2 ) ; goto nextpcm;finish: fprintf (outfile, "32767 32767 \n");}?? 快捷鍵說明
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