C-Netz: Use raised cosine to shape data signal
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@@ -87,13 +87,8 @@ static void dsp_init_ramp(cnetz_t *cnetz)
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LOGP(DDSP, LOGL_DEBUG, "Generating smooth ramp table.\n");
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LOGP(DDSP, LOGL_DEBUG, "Generating smooth ramp table.\n");
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for (i = 0; i < 256; i++) {
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for (i = 0; i < 256; i++) {
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/* use square-root of cosine ramp. tests showed that phones are more
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/* Use raised cosine ramp. */
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* happy with that. (This is not correct pulse shaping!) */
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c = cos((double)i / 256.0 * PI);
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c = cos((double)i / 256.0 * PI);
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if (c < 0)
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c = -sqrt(-c);
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else
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c = sqrt(c);
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cnetz->fsk_ramp_down[i] = c * (double)cnetz->fsk_deviation;
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cnetz->fsk_ramp_down[i] = c * (double)cnetz->fsk_deviation;
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cnetz->fsk_ramp_up[i] = -cnetz->fsk_ramp_down[i];
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cnetz->fsk_ramp_up[i] = -cnetz->fsk_ramp_down[i];
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}
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}
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