Merge pull request #1555 from albayenes/num-fft-bins-is-more-appropriate-name-for-fftSize
Replace fftSize with more meaningful name for num_fft_bins
This commit is contained in:
Michael Ossmann
@ -192,7 +192,7 @@ bool one_shot = false;
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bool finite_mode = false;
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volatile bool sweep_started = false;
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int fftSize = 20;
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int num_fft_bins = 20;
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double fft_bin_width;
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fftwf_complex* fftwIn = NULL;
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fftwf_complex* fftwOut = NULL;
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@ -242,7 +242,7 @@ int rx_callback(hackrf_transfer* transfer)
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byte_count += transfer->valid_length;
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buf = (int8_t*) transfer->buffer;
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ifft_bins = fftSize * step_count;
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ifft_bins = num_fft_bins * step_count;
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for (j = 0; j < BLOCKS_PER_TRANSFER; j++) {
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ubuf = (uint8_t*) buf;
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if (ubuf[0] == 0x7F && ubuf[1] == 0x7F) {
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@ -301,28 +301,28 @@ int rx_callback(hackrf_transfer* transfer)
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continue;
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}
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/* copy to fftwIn as floats */
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buf += BYTES_PER_BLOCK - (fftSize * 2);
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for (i = 0; i < fftSize; i++) {
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buf += BYTES_PER_BLOCK - (num_fft_bins * 2);
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for (i = 0; i < num_fft_bins; i++) {
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fftwIn[i][0] = buf[i * 2] * window[i] * 1.0f / 128.0f;
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fftwIn[i][1] = buf[i * 2 + 1] * window[i] * 1.0f / 128.0f;
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}
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buf += fftSize * 2;
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buf += num_fft_bins * 2;
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fftwf_execute(fftwPlan);
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for (i = 0; i < fftSize; i++) {
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pwr[i] = logPower(fftwOut[i], 1.0f / fftSize);
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for (i = 0; i < num_fft_bins; i++) {
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pwr[i] = logPower(fftwOut[i], 1.0f / num_fft_bins);
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}
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if (binary_output) {
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record_length =
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2 * sizeof(band_edge) + (fftSize / 4) * sizeof(float);
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2 * sizeof(band_edge) + (num_fft_bins / 4) * sizeof(float);
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fwrite(&record_length, sizeof(record_length), 1, outfile);
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band_edge = frequency;
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fwrite(&band_edge, sizeof(band_edge), 1, outfile);
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band_edge = frequency + DEFAULT_SAMPLE_RATE_HZ / 4;
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fwrite(&band_edge, sizeof(band_edge), 1, outfile);
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fwrite(&pwr[1 + (fftSize * 5) / 8],
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fwrite(&pwr[1 + (num_fft_bins * 5) / 8],
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sizeof(float),
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fftSize / 4,
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num_fft_bins / 4,
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outfile);
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fwrite(&record_length, sizeof(record_length), 1, outfile);
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@ -330,25 +330,25 @@ int rx_callback(hackrf_transfer* transfer)
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fwrite(&band_edge, sizeof(band_edge), 1, outfile);
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band_edge = frequency + (DEFAULT_SAMPLE_RATE_HZ * 3) / 4;
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fwrite(&band_edge, sizeof(band_edge), 1, outfile);
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fwrite(&pwr[1 + fftSize / 8], sizeof(float), fftSize / 4, outfile);
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fwrite(&pwr[1 + num_fft_bins / 8], sizeof(float), num_fft_bins / 4, outfile);
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} else if (ifft_output) {
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ifft_idx = (uint32_t) round(
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(frequency - (uint64_t) (FREQ_ONE_MHZ * frequencies[0])) /
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fft_bin_width);
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ifft_idx = (ifft_idx + ifft_bins / 2) % ifft_bins;
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for (i = 0; (fftSize / 4) > i; i++) {
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for (i = 0; (num_fft_bins / 4) > i; i++) {
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ifftwIn[ifft_idx + i][0] =
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fftwOut[i + 1 + (fftSize * 5) / 8][0];
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fftwOut[i + 1 + (num_fft_bins * 5) / 8][0];
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ifftwIn[ifft_idx + i][1] =
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fftwOut[i + 1 + (fftSize * 5) / 8][1];
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fftwOut[i + 1 + (num_fft_bins * 5) / 8][1];
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}
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ifft_idx += fftSize / 2;
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ifft_idx += num_fft_bins / 2;
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ifft_idx %= ifft_bins;
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for (i = 0; (fftSize / 4) > i; i++) {
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for (i = 0; (num_fft_bins / 4) > i; i++) {
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ifftwIn[ifft_idx + i][0] =
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fftwOut[i + 1 + (fftSize / 8)][0];
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fftwOut[i + 1 + (num_fft_bins / 8)][0];
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ifftwIn[ifft_idx + i][1] =
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fftwOut[i + 1 + (fftSize / 8)][1];
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fftwOut[i + 1 + (num_fft_bins / 8)][1];
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}
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} else {
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time_t time_stamp_seconds = usb_transfer_time.tv_sec;
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@ -361,11 +361,11 @@ int rx_callback(hackrf_transfer* transfer)
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(uint64_t) (frequency),
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(uint64_t) (frequency + DEFAULT_SAMPLE_RATE_HZ / 4),
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fft_bin_width,
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fftSize);
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for (i = 0; (fftSize / 4) > i; i++) {
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num_fft_bins);
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for (i = 0; (num_fft_bins / 4) > i; i++) {
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fprintf(outfile,
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", %.2f",
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pwr[i + 1 + (fftSize * 5) / 8]);
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pwr[i + 1 + (num_fft_bins * 5) / 8]);
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}
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fprintf(outfile, "\n");
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fprintf(outfile,
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@ -375,9 +375,9 @@ int rx_callback(hackrf_transfer* transfer)
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(uint64_t) (frequency + (DEFAULT_SAMPLE_RATE_HZ / 2)),
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(uint64_t) (frequency + ((DEFAULT_SAMPLE_RATE_HZ * 3) / 4)),
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fft_bin_width,
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fftSize);
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for (i = 0; (fftSize / 4) > i; i++) {
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fprintf(outfile, ", %.2f", pwr[i + 1 + (fftSize / 8)]);
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num_fft_bins);
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for (i = 0; (num_fft_bins / 4) > i; i++) {
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fprintf(outfile, ", %.2f", pwr[i + 1 + (num_fft_bins / 8)]);
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}
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fprintf(outfile, "\n");
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}
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@ -536,7 +536,7 @@ int main(int argc, char** argv)
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case 'w':
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result = parse_u32(optarg, &requested_fft_bin_width);
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fftSize = DEFAULT_SAMPLE_RATE_HZ / requested_fft_bin_width;
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num_fft_bins = DEFAULT_SAMPLE_RATE_HZ / requested_fft_bin_width;
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break;
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case 'W':
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@ -657,7 +657,7 @@ int main(int argc, char** argv)
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* for interleaved mode. With our fixed sample rate of 20 Msps, that
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* results in a maximum bin width of 5000000 Hz.
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*/
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if (4 > fftSize) {
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if (4 > num_fft_bins) {
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fprintf(stderr,
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"argument error: FFT bin width (-w) must be no more than 5000000\n");
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return EXIT_FAILURE;
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@ -667,11 +667,11 @@ int main(int argc, char** argv)
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* The maximum number of FFT bins we support is equal to the number of
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* samples in a block. Each block consists of 16384 bytes minus 10
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* bytes for the frequency header, leaving room for 8187 two-byte
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* samples. As we pad fftSize up to the next odd multiple of four, this
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* makes our maximum supported fftSize 8180. With our fixed sample
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* samples. As we pad num_fft_bins up to the next odd multiple of four, this
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* makes our maximum supported num_fft_bins 8180. With our fixed sample
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* rate of 20 Msps, that results in a minimum bin width of 2445 Hz.
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*/
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if (8180 < fftSize) {
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if (8180 < num_fft_bins) {
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fprintf(stderr,
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"argument error: FFT bin width (-w) must be no less than 2445\n");
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return EXIT_FAILURE;
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@ -681,19 +681,19 @@ int main(int argc, char** argv)
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* number of FFT bins is equal to an odd multiple of four.
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* (e.g. 4, 12, 20, 28, 36, . . .)
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*/
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while ((fftSize + 4) % 8) {
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fftSize++;
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while ((num_fft_bins + 4) % 8) {
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num_fft_bins++;
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}
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fft_bin_width = (double) DEFAULT_SAMPLE_RATE_HZ / fftSize;
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fftwIn = (fftwf_complex*) fftwf_malloc(sizeof(fftwf_complex) * fftSize);
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fftwOut = (fftwf_complex*) fftwf_malloc(sizeof(fftwf_complex) * fftSize);
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fft_bin_width = (double) DEFAULT_SAMPLE_RATE_HZ / num_fft_bins;
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fftwIn = (fftwf_complex*) fftwf_malloc(sizeof(fftwf_complex) * num_fft_bins);
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fftwOut = (fftwf_complex*) fftwf_malloc(sizeof(fftwf_complex) * num_fft_bins);
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fftwPlan =
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fftwf_plan_dft_1d(fftSize, fftwIn, fftwOut, FFTW_FORWARD, fftw_plan_type);
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pwr = (float*) fftwf_malloc(sizeof(float) * fftSize);
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window = (float*) fftwf_malloc(sizeof(float) * fftSize);
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for (i = 0; i < fftSize; i++) {
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window[i] = (float) (0.5f * (1.0f - cos(2 * M_PI * i / (fftSize - 1))));
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fftwf_plan_dft_1d(num_fft_bins, fftwIn, fftwOut, FFTW_FORWARD, fftw_plan_type);
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pwr = (float*) fftwf_malloc(sizeof(float) * num_fft_bins);
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window = (float*) fftwf_malloc(sizeof(float) * num_fft_bins);
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for (i = 0; i < num_fft_bins; i++) {
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window[i] = (float) (0.5f * (1.0f - cos(2 * M_PI * i / (num_fft_bins - 1))));
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}
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/* Execute the plan once to make sure it's ready to go when real
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@ -807,11 +807,11 @@ int main(int argc, char** argv)
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if (ifft_output) {
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ifftwIn = (fftwf_complex*) fftwf_malloc(
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sizeof(fftwf_complex) * fftSize * step_count);
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sizeof(fftwf_complex) * num_fft_bins * step_count);
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ifftwOut = (fftwf_complex*) fftwf_malloc(
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sizeof(fftwf_complex) * fftSize * step_count);
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sizeof(fftwf_complex) * num_fft_bins * step_count);
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ifftwPlan = fftwf_plan_dft_1d(
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fftSize * step_count,
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num_fft_bins * step_count,
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ifftwIn,
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ifftwOut,
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FFTW_BACKWARD,
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