d_dec_rate = (unsigned int)floor(d_int_rate/rate);
d_flt_rate = (d_int_rate/rate) - d_dec_rate;
- // The accumulator keeps track of overflow to increment the stride correctly.
- d_acc = 0;
-
// Store the last filter between calls to work
d_last_filter = 0;
d_start_index = 0;
d_filters = std::vector<gr_fir_ccf*>(d_int_rate);
+ d_diff_filters = std::vector<gr_fir_ccf*>(d_int_rate);
// Create an FIR filter for each channel and zero out the taps
std::vector<float> vtaps(0, d_int_rate);
- for(unsigned int i = 0; i < d_int_rate; i++) {
+ for(int i = 0; i < d_int_rate; i++) {
d_filters[i] = gr_fir_util::create_gr_fir_ccf(vtaps);
+ d_diff_filters[i] = gr_fir_util::create_gr_fir_ccf(vtaps);
}
// Now, actually set the filters' taps
- set_taps(taps);
+ std::vector<float> dtaps;
+ create_diff_taps(taps, dtaps);
+ set_taps(taps, d_taps, d_filters);
+ set_taps(dtaps, d_dtaps, d_diff_filters);
}
gr_pfb_arb_resampler_ccf::~gr_pfb_arb_resampler_ccf ()
}
void
-gr_pfb_arb_resampler_ccf::set_taps (const std::vector<float> &taps)
+gr_pfb_arb_resampler_ccf::set_taps (const std::vector<float> &newtaps,
+ std::vector< std::vector<float> > &ourtaps,
+ std::vector<gr_fir_ccf*> &ourfilter)
{
- unsigned int i,j;
+ int i,j;
- unsigned int ntaps = taps.size();
+ unsigned int ntaps = newtaps.size();
d_taps_per_filter = (unsigned int)ceil((double)ntaps/(double)d_int_rate);
// Create d_numchan vectors to store each channel's taps
- d_taps.resize(d_int_rate);
-
+ ourtaps.resize(d_int_rate);
+
// Make a vector of the taps plus fill it out with 0's to fill
// each polyphase filter with exactly d_taps_per_filter
std::vector<float> tmp_taps;
- tmp_taps = taps;
+ tmp_taps = newtaps;
while((float)(tmp_taps.size()) < d_int_rate*d_taps_per_filter) {
tmp_taps.push_back(0.0);
}
// Partition the filter
for(i = 0; i < d_int_rate; i++) {
// Each channel uses all d_taps_per_filter with 0's if not enough taps to fill out
- d_taps[i] = std::vector<float>(d_taps_per_filter, 0);
+ ourtaps[d_int_rate-1-i] = std::vector<float>(d_taps_per_filter, 0);
for(j = 0; j < d_taps_per_filter; j++) {
- d_taps[i][j] = tmp_taps[i + j*d_int_rate]; // add taps to channels in reverse order
+ ourtaps[d_int_rate - 1 - i][j] = tmp_taps[i + j*d_int_rate];
}
// Build a filter for each channel and add it's taps to it
- d_filters[i]->set_taps(d_taps[i]);
+ ourfilter[i]->set_taps(ourtaps[d_int_rate-1-i]);
}
// Set the history to ensure enough input items for each filter
- set_history (d_taps_per_filter);
+ set_history (d_taps_per_filter + 1);
d_updated = true;
}
+void
+gr_pfb_arb_resampler_ccf::create_diff_taps(const std::vector<float> &newtaps,
+ std::vector<float> &difftaps)
+{
+ float maxtap = 1e-20;
+ difftaps.clear();
+ difftaps.push_back(0); //newtaps[0]);
+ for(unsigned int i = 1; i < newtaps.size()-1; i++) {
+ float tap = newtaps[i+1] - newtaps[i-1];
+ difftaps.push_back(tap);
+ if(tap > maxtap) {
+ maxtap = tap;
+ }
+ }
+ difftaps.push_back(0);//-newtaps[newtaps.size()-1]);
+
+ // Scale the differential taps; helps scale error term to better update state
+ // FIXME: should this be scaled this way or use the same gain as the taps?
+ for(unsigned int i = 0; i < difftaps.size(); i++) {
+ difftaps[i] /= maxtap;
+ }
+}
+
void
gr_pfb_arb_resampler_ccf::print_taps()
{
while((j < d_int_rate) && (i < noutput_items)) {
// Take the current filter output
o0 = d_filters[j]->filter(&in[count]);
+ o1 = d_diff_filters[j]->filter(&in[count]);
- // Take the next filter output; wrap around to 0 if necessary
- if(j+1 == d_int_rate)
- // Use the sample of the next input item through the first filter
- o1 = d_filters[0]->filter(&in[count+1]);
- else {
- // Use the sample from the current input item through the nex filter
- o1 = d_filters[j+1]->filter(&in[count]);
- }
-
- //out[i] = o0; // nearest-neighbor approach
- out[i] = o0 + (o1 - o0)*d_acc; // linearly interpolate between samples
+ out[i] = o0 + o1*d_flt_rate; // linearly interpolate between samples
i++;
- // Accumulate the position in the stream for the interpolated point.
- // If it goes above 1, roll around to zero and increment the stride
- // length this time by the decimation rate plus 1 for the increment
- // due to the acculated position.
- d_acc += d_flt_rate;
- j += d_dec_rate + (int)floor(d_acc);
- d_acc = fmodf(d_acc, 1.0);
+ j += d_dec_rate;
}
if(i < noutput_items) { // keep state for next entry
float ss = (int)(j / d_int_rate); // number of items to skip ahead by
unsigned int filter_size);
std::vector<gr_fir_ccf*> d_filters;
+ std::vector<gr_fir_ccf*> d_diff_filters;
std::vector< std::vector<float> > d_taps;
+ std::vector< std::vector<float> > d_dtaps;
unsigned int d_int_rate; // the number of filters (interpolation rate)
unsigned int d_dec_rate; // the stride through the filters (decimation rate)
float d_flt_rate; // residual rate for the linear interpolation
- float d_acc;
unsigned int d_last_filter;
int d_start_index;
unsigned int d_taps_per_filter;
gr_pfb_arb_resampler_ccf (float rate,
const std::vector<float> &taps,
unsigned int filter_size);
+
+ void create_diff_taps(const std::vector<float> &newtaps,
+ std::vector<float> &difftaps);
public:
~gr_pfb_arb_resampler_ccf ();
-
+
/*!
* Resets the filterbank's filter taps with the new prototype filter
* \param taps (vector/list of floats) The prototype filter to populate the filterbank. The taps
* should be generated at the interpolated sampling rate.
*/
- void set_taps (const std::vector<float> &taps);
+ void set_taps (const std::vector<float> &newtaps,
+ std::vector< std::vector<float> > &ourtaps,
+ std::vector<gr_fir_ccf*> &ourfilter);
/*!
* Print all of the filterbank taps to screen.
projects / debian / gnuradio / commitdiff