void SDRPostThread::initPFBChannelizer() {
// std::cout << "Initializing post-process FIR polyphase filterbank channelizer with " << numChannels << " channels." << std::endl;
if (channelizer) {
firpfbch_crcf_destroy(channelizer);
}
channelizer = firpfbch_crcf_create_kaiser(LIQUID_ANALYZER, numChannels, 4, 60);
chanBw = (sampleRate / numChannels);
chanCenters.resize(numChannels+1);
demodChannelActive.resize(numChannels+1);
// std::cout << "Channel bandwidth spacing: " << (chanBw) << std::endl;
}
void PfbSynthesizerComponent::initialize()
{
// design custom filterbank channelizer
unsigned int m = 7; // prototype filter delay
float As = 60.0f; // stop-band attenuation
channelizer = firpfbch_crcf_create_kaiser(LIQUID_SYNTHESIZER, nChans_x, m, As);
// create NCO to center spectrum
float offset = -0.5f*(float)(nChans_x-1) / (float)nChans_x * 2 * M_PI;
nco = nco_crcf_create(LIQUID_VCO);
nco_crcf_set_frequency(nco, offset);
//Set up our input and output buffers
buf.resize(nChans_x);
bufIt = buf.begin();
outBuf.resize(nChans_x);
}
int main() {
// options
unsigned int num_channels=8; // number of channels
unsigned int m=2; // filter delay
float As=-60; // stop-band attenuation
unsigned int num_frames=25; // number of frames
// create objects
firpfbch_crcf c = firpfbch_crcf_create_kaiser(LIQUID_ANALYZER, num_channels, m, As);
//firpfbch_crcf_print(c);
FILE*fid = fopen(OUTPUT_FILENAME,"w");
fprintf(fid,"%% %s: auto-generated file\n\n", OUTPUT_FILENAME);
fprintf(fid,"clear all;\nclose all;\n\n");
fprintf(fid,"num_channels=%u;\n", num_channels);
fprintf(fid,"num_frames=%u;\n", num_frames);
fprintf(fid,"x = zeros(1,%u);\n", num_channels * num_frames);
fprintf(fid,"y = zeros(%u,%u);\n", num_channels, num_frames);
unsigned int i, j, n=0;
float complex x[num_channels]; // time-domain input
float complex y[num_channels]; // channelized output
// create nco: sweeps entire range of frequencies over the evaluation interval
nco_crcf nco_tx = nco_crcf_create(LIQUID_VCO);
nco_crcf_set_frequency(nco_tx, 0.0f);
float df = 2*M_PI/(num_channels*num_frames);
printf("fr/ch:");
for (j=0; j<num_channels; j++) printf("%3u",j);
printf("\n");
for (i=0; i<num_frames; i++) {
// generate frame of data
for (j=0; j<num_channels; j++) {
nco_crcf_cexpf(nco_tx, &x[j]);
nco_crcf_adjust_frequency(nco_tx, df);
nco_crcf_step(nco_tx);
}
// execute analysis filter bank
firpfbch_crcf_analyzer_execute(c, x, y);
printf("%4u : ", i);
for (j=0; j<num_channels; j++) {
if (cabsf(y[j]) > num_channels / 4)
printf(" x ");
else
printf(" . ");
}
printf("\n");
// write output to file
for (j=0; j<num_channels; j++) {
// frequency data
fprintf(fid,"y(%4u,%4u) = %12.4e + j*%12.4e;\n", j+1, i+1, crealf(y[j]), cimagf(y[j]));
// time data
fprintf(fid,"x(%4u) = %12.4e + j*%12.4e;\n", n+1, crealf(x[j]), cimag(x[j]));
n++;
}
}
// destroy objects
nco_crcf_destroy(nco_tx);
firpfbch_crcf_destroy(c);
// plot results
fprintf(fid,"\n\n");
fprintf(fid,"figure;\n");
fprintf(fid,"subplot(2,1,1);\n");
fprintf(fid," plot(1:length(x),real(x),1:length(x),imag(x));\n");
fprintf(fid," xlabel('time');\n");
fprintf(fid," ylabel('signal');\n");
fprintf(fid,"subplot(2,1,2);\n");
fprintf(fid," plot(20*log10(abs(y.')/num_channels));\n");
fprintf(fid," xlabel('time (decimated)');\n");
fprintf(fid," ylabel('channelized energy [dB]');\n");
fprintf(fid,"n=min(num_channels,8);\n");
fprintf(fid,"figure;\n");
fprintf(fid,"for i=1:n\n");
fprintf(fid," subplot(n,1,i);\n");
fprintf(fid," plot(1:num_frames,real(y(i,:)),1:num_frames,imag(y(i,:)));\n");
fprintf(fid," axis off;\n");
fprintf(fid," ylabel(num2str(i));\n");
fprintf(fid,"end;\n");
fclose(fid);
printf("results written to %s\n", OUTPUT_FILENAME);
printf("done.\n");
return 0;
}
int main() {
// options
unsigned int num_channels = 16; // number of channels
unsigned int m = 5; // filter delay
float As = 60; // stop-band attenuation
unsigned int num_frames = 25; // number of frames
//
unsigned int i;
unsigned int k;
// derived values
unsigned int num_samples = num_frames * num_channels;
// data arrays
float complex x[num_channels][num_frames]; // channelized input
float complex y[num_samples]; // time-domain output [size: num_samples x 1]
// create narrow-band pulse
unsigned int pulse_len = 17; // pulse length [samples]
float bw = 0.30f; // pulse width (bandwidth)
float pulse[pulse_len]; // buffer
liquid_firdes_kaiser(pulse_len, bw, 50.0f, 0.0f, pulse);
// generate input signal(s)
int enabled[num_channels]; // signal enabled?
for (i=0; i<num_channels; i++) {
// pseudo-random channel enabled flag
enabled[i] = ((i*37)%101)%2;
if (enabled[i]) {
// move pulse to input buffer
for (k=0; k<num_frames; k++)
x[i][k] = k < pulse_len ? bw*pulse[k] : 0.0f;
} else {
// channel disabled; set as nearly zero (-100 dB impulse)
for (k=0; k<num_frames; k++)
x[i][k] = (k == 0) ? 1e-5f : 0.0f;
}
}
// create prototype filter
unsigned int h_len = 2*num_channels*m + 1;
float h[h_len];
liquid_firdes_kaiser(h_len, 0.5f/(float)num_channels, As, 0.0f, h);
#if 0
// create filterbank channelizer object using internal method for filter
firpfbch_crcf q = firpfbch_crcf_create_kaiser(LIQUID_SYNTHESIZER, num_channels, m, As);
#else
// create filterbank channelizer object using external filter coefficients
firpfbch_crcf q = firpfbch_crcf_create(LIQUID_SYNTHESIZER, num_channels, 2*m, h);
#endif
// channelize input data
float complex v[num_channels];
for (i=0; i<num_frames; i++) {
// assemble input vector
for (k=0; k<num_channels; k++)
v[k] = x[k][i];
// execute synthesis filter bank
firpfbch_crcf_synthesizer_execute(q, v, &y[i*num_channels]);
}
// destroy channelizer object
firpfbch_crcf_destroy(q);
//
// export results to file
//
FILE * fid = fopen(OUTPUT_FILENAME,"w");
fprintf(fid,"%% %s: auto-generated file\n\n", OUTPUT_FILENAME);
fprintf(fid,"clear all;\n");
fprintf(fid,"close all;\n");
fprintf(fid,"num_channels = %u;\n", num_channels);
fprintf(fid,"m = %u;\n", m);
fprintf(fid,"num_frames = %u;\n", num_frames);
fprintf(fid,"h_len = 2*num_channels*m+1;\n");
fprintf(fid,"num_samples = num_frames*num_channels;\n");
fprintf(fid,"h = zeros(1,h_len);\n");
fprintf(fid,"x = zeros(num_channels, num_frames);\n");
fprintf(fid,"y = zeros(1,num_samples);\n");
// save prototype filter
for (i=0; i<h_len; i++)
fprintf(fid," h(%6u) = %12.4e;\n", i+1, h[i]);
// save channelized input signals
for (i=0; i<num_frames; i++) {
for (k=0; k<num_channels; k++) {
float complex v = x[k][i];
fprintf(fid," x(%3u,%6u) = %12.4e + 1i*%12.4e;\n", k+1, i+1, crealf(v), cimagf(v));
}
}
// save output time signal
for (i=0; i<num_samples; i++)
fprintf(fid," y(%6u) = %12.4e + 1i*%12.4e;\n", i+1, crealf(y[i]), cimagf(y[i]));
// compute the PSD of each input and plot results on a square grid
fprintf(fid,"nfft = 1024;\n"); // TODO: use nextpow2
fprintf(fid,"f = [0:(nfft-1)]/nfft - 0.5;\n");
fprintf(fid,"n = ceil(sqrt(num_channels));\n");
fprintf(fid,"figure;\n");
fprintf(fid,"for i=1:num_channels,\n");
fprintf(fid," X = 20*log10(abs(fftshift(fft(x(i,:),nfft))));\n");
fprintf(fid," subplot(n,n,i);\n");
fprintf(fid," plot(f, X, 'Color', [0.25 0 0.25], 'LineWidth', 1.5);\n");
fprintf(fid," axis([-0.5 0.5 -120 20]);\n");
fprintf(fid," grid on;\n");
fprintf(fid," title(num2str(i-1));\n");
fprintf(fid,"end;\n");
// plot results
fprintf(fid,"\n");
fprintf(fid,"H = 20*log10(abs(fftshift(fft(h/num_channels,nfft))));\n");
fprintf(fid,"Y = 20*log10(abs(fftshift(fft(y/num_channels,nfft))));\n");
fprintf(fid,"figure;\n");
fprintf(fid,"subplot(2,1,1);\n");
fprintf(fid," plot(f, H, 'Color', [0 0.5 0.25], 'LineWidth', 2);\n");
fprintf(fid," axis([-0.5 0.5 -100 10]);\n");
fprintf(fid," grid on;\n");
fprintf(fid," xlabel('Normalized Frequency [f/F_s]');\n");
fprintf(fid," ylabel('Prototype Filter PSD');\n");
fprintf(fid,"subplot(2,1,2);\n");
fprintf(fid," plot(f, Y, 'Color', [0 0.25 0.5], 'LineWidth', 2);\n");
fprintf(fid," axis([-0.5 0.5 -100 0]);\n");
fprintf(fid," grid on;\n");
fprintf(fid," xlabel('Normalized Frequency [f/F_s]');\n");
fprintf(fid," ylabel('Output PSD');\n");
fclose(fid);
printf("results written to %s\n", OUTPUT_FILENAME);
printf("done.\n");
return 0;
}
int main() {
// options
unsigned int num_channels=8; // number of channels
unsigned int m=4; // filter delay
float As=60; // stop-band attenuation
unsigned int num_frames=25; // number of frames
//
unsigned int i;
unsigned int k;
// derived values
unsigned int num_samples = num_frames * num_channels;
// data arrays
float complex x[num_samples]; // time-domain input [size: num_samples x 1 ]
float complex y[num_samples]; // channelized output [size: num_channels x num_frames]
// initialize input with zeros
for (i=0; i<num_samples; i++)
x[i] = 0.0f;
// generate input signal(s)
unsigned int num_signals = 4;
float fc[4] = {0.0f, 0.25f, 0.375f, -0.375f}; // center frequencies
float bw[4] = {0.035f, 0.035f, 0.035f, 0.035f}; // bandwidths
unsigned int pulse_len = 137;
float pulse[pulse_len];
for (i=0; i<num_signals; i++) {
// create pulse
liquid_firdes_kaiser(pulse_len, bw[i], 50.0f, 0.0f, pulse);
// add pulse to input signal with carrier offset
for (k=0; k<pulse_len; k++)
x[k] += pulse[k] * cexpf(_Complex_I*2*M_PI*fc[i]*k) * bw[i];
}
// create prototype filter
unsigned int h_len = 2*num_channels*m + 1;
float h[h_len];
liquid_firdes_kaiser(h_len, 0.5f/(float)num_channels, As, 0.0f, h);
#if 0
// create filterbank channelizer object using internal method for filter
firpfbch_crcf q = firpfbch_crcf_create_kaiser(LIQUID_ANALYZER, num_channels, m, As);
#else
// create filterbank channelizer object using external filter coefficients
firpfbch_crcf q = firpfbch_crcf_create(LIQUID_ANALYZER, num_channels, 2*m, h);
#endif
// channelize input data
for (i=0; i<num_frames; i++) {
// execute analysis filter bank
firpfbch_crcf_analyzer_execute(q, &x[i*num_channels], &y[i*num_channels]);
}
// destroy channelizer object
firpfbch_crcf_destroy(q);
//
// export results to file
//
FILE * fid = fopen(OUTPUT_FILENAME,"w");
fprintf(fid,"%% %s: auto-generated file\n\n", OUTPUT_FILENAME);
fprintf(fid,"clear all;\n");
fprintf(fid,"close all;\n");
fprintf(fid,"num_channels = %u;\n", num_channels);
fprintf(fid,"m = %u;\n", m);
fprintf(fid,"num_frames = %u;\n", num_frames);
fprintf(fid,"h_len = 2*num_channels*m+1;\n");
fprintf(fid,"num_samples = num_frames*num_channels;\n");
fprintf(fid,"h = zeros(1,h_len);\n");
fprintf(fid,"x = zeros(1,num_samples);\n");
fprintf(fid,"y = zeros(num_channels, num_frames);\n");
// save prototype filter
for (i=0; i<h_len; i++)
fprintf(fid," h(%6u) = %12.4e;\n", i+1, h[i]);
// save input signal
for (i=0; i<num_samples; i++)
fprintf(fid," x(%6u) = %12.4e + 1i*%12.4e;\n", i+1, crealf(x[i]), cimagf(x[i]));
// save channelized output signals
for (i=0; i<num_frames; i++) {
for (k=0; k<num_channels; k++) {
float complex v = y[i*num_channels + k];
fprintf(fid," y(%3u,%6u) = %12.4e + 1i*%12.4e;\n", k+1, i+1, crealf(v), cimagf(v));
}
}
// plot results
fprintf(fid,"\n");
fprintf(fid,"nfft = 1024;\n"); // TODO: use nextpow2
fprintf(fid,"f = [0:(nfft-1)]/nfft - 0.5;\n");
fprintf(fid,"H = 20*log10(abs(fftshift(fft(h/num_channels,nfft))));\n");
fprintf(fid,"X = 20*log10(abs(fftshift(fft(x,nfft))));\n");
fprintf(fid,"figure;\n");
fprintf(fid,"subplot(2,1,1);\n");
fprintf(fid," plot(f, H, 'Color', [0 0.5 0.25], 'LineWidth', 2);\n");
fprintf(fid," axis([-0.5 0.5 -100 10]);\n");
fprintf(fid," grid on;\n");
fprintf(fid," xlabel('Normalized Frequency [f/F_s]');\n");
fprintf(fid," ylabel('Prototype Filter PSD');\n");
fprintf(fid,"subplot(2,1,2);\n");
fprintf(fid," plot(f, X, 'Color', [0 0.25 0.5], 'LineWidth', 2);\n");
fprintf(fid," axis([-0.5 0.5 -100 0]);\n");
fprintf(fid," grid on;\n");
fprintf(fid," xlabel('Normalized Frequency [f/F_s]');\n");
fprintf(fid," ylabel('Input PSD');\n");
// compute the PSD of each output and plot results on a square grid
fprintf(fid,"n = ceil(sqrt(num_channels));\n");
fprintf(fid,"figure;\n");
fprintf(fid,"for i=1:num_channels,\n");
fprintf(fid," Y = 20*log10(abs(fftshift(fft(y(i,:),nfft))));\n");
fprintf(fid," subplot(n,n,i);\n");
fprintf(fid," plot(f, Y, 'Color', [0.25 0 0.25], 'LineWidth', 1.5);\n");
fprintf(fid," axis([-0.5 0.5 -120 20]);\n");
fprintf(fid," grid on;\n");
fprintf(fid," title(num2str(i-1));\n");
fprintf(fid,"end;\n");
fclose(fid);
printf("results written to %s\n", OUTPUT_FILENAME);
printf("done.\n");
return 0;
}
