FastDDC code added, and now it builds!

This commit is contained in:
ha7ilm 2015-11-07 19:21:08 +01:00
parent cb1b6ac8e2
commit edc2c21e43
4 changed files with 254 additions and 1 deletions

102
csdr.c
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@ -48,6 +48,8 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "ima_adpcm.h"
#include <sched.h>
#include <math.h>
#include <strings.h>
#include "fastddc.h"
char usage[]=
"csdr - a simple commandline tool for Software Defined Radio receiver DSP.\n\n"
@ -1269,7 +1271,6 @@ int main(int argc, char *argv[])
float high_cut;
float transition_bw;
window_t window = WINDOW_DEFAULT;
char window_string[256]; //TODO: nice buffer overflow opportunity
int fd;
if(fd=init_fifo(argc,argv))
@ -1646,6 +1647,105 @@ int main(int argc, char *argv[])
}
}
if( !strcmp(argv[1],"fastddc_fwd_cc") ) //<decimation> [transition_bw [window]]
{
int decimation;
if(argc<=2) return badsyntax("need required parameter (decimation)");
sscanf(argv[2],"%d",&decimation);
float transition_bw = 0.05;
if(argc>=3) sscanf(argv[3],"%g",&transition_bw);
window_t window = WINDOW_DEFAULT;
if(argc>=4) window=firdes_get_window_from_string(argv[5]);
else fprintf(stderr,"fastddc_fwd_cc: window = %s\n",firdes_get_string_from_window(window));
fastddc_t ddc;
if(fastddc_init(&ddc, transition_bw, decimation, 0)) { badsyntax("error in fastddc_init()"); return 1; }
fastddc_print(&ddc);
if(!initialize_buffers()) return -2;
sendbufsize(ddc.fft_size);
//make FFT plan
complexf* input = (complexf*)fft_malloc(sizeof(complexf)*ddc.fft_size);
complexf* windowed = (complexf*)fft_malloc(sizeof(complexf)*ddc.fft_size);
complexf* output = (complexf*)fft_malloc(sizeof(complexf)*ddc.fft_size);
for(int i=0;i<ddc.fft_size;i++) iof(input,i)=qof(input,i)=0; //null the input buffer
int benchmark = 1;
if(benchmark) fprintf(stderr,"fastddc_fwd_cc: benchmarking FFT...");
FFT_PLAN_T* plan=make_fft_c2c(ddc.fft_size, windowed, output, 1, benchmark);
if(benchmark) fprintf(stderr," done\n");
for(;;)
{
FEOF_CHECK;
//overlapped FFT
for(int i=0;i<ddc.overlap_length;i++) input[i]=input[i+ddc.input_size];
fread(input+ddc.overlap_length, sizeof(complexf), ddc.input_size, stdin);
apply_window_c(input,windowed,ddc.fft_size,window);
fft_execute(plan);
fwrite(output, sizeof(complexf), ddc.fft_size, stdout);
TRY_YIELD;
}
}
if( !strcmp(argv[1],"fastddc_apply_cc") ) //<decimation> <shift_rate> [transition_bw [window]]
{
int decimation;
if(argc<=2) return badsyntax("need required parameter (decimation)");
sscanf(argv[2],"%d",&decimation);
float shift_rate;
if(argc>=3) sscanf(argv[3],"%g",&shift_rate);
float transition_bw = 0.05;
if(argc>=4) sscanf(argv[4],"%g",&transition_bw);
window_t window = WINDOW_DEFAULT;
if(argc>=5) window=firdes_get_window_from_string(argv[5]);
else fprintf(stderr,"fastddc_apply_cc: window = %s\n",firdes_get_string_from_window(window));
fastddc_t ddc;
if(fastddc_init(&ddc, transition_bw, decimation, shift_rate)) { badsyntax("error in fastddc_init()"); return 1; }
fastddc_print(&ddc);
if(!initialize_buffers()) return -2;
sendbufsize(ddc.output_size);
//prepare making the filter and doing FFT on it
complexf* taps=(complexf*)calloc(sizeof(complexf),ddc.fft_size); //initialize to zero
complexf* taps_fft=(complexf*)malloc(sizeof(complexf)*ddc.fft_size);
FFT_PLAN_T* plan_taps = make_fft_c2c(ddc.fft_size, taps, taps_fft, 1, 0); //forward, don't benchmark (we need this only once)
//make the filter
float filter_half_bw = 0.5/decimation;
firdes_bandpass_c(taps, ddc.taps_real_length, shift_rate-filter_half_bw, shift_rate+filter_half_bw, window);
fft_execute(plan_taps);
//make FFT plan
complexf* input = (complexf*)fft_malloc(sizeof(complexf)*ddc.fft_size);
complexf* output = (complexf*)fft_malloc(sizeof(complexf)*ddc.output_size);
int benchmark = 1;
if(benchmark) fprintf(stderr,"fastddc_apply_cc: benchmarking FFT...");
FFT_PLAN_T* plan_inverse = make_fft_c2c(ddc.fft_size, input, output, 0, 1); //inverse, do benchmark
if(benchmark) fprintf(stderr," done\n");
decimating_shift_addition_status_t shift_stat;
bzero(&shift_stat, sizeof(shift_stat));
for(;;)
{
FEOF_CHECK;
fread(input, sizeof(complexf), ddc.fft_size, stdin);
shift_stat = fastddc_apply_cc(input, output, &ddc, plan_inverse, taps_fft, shift_stat);
fwrite(output, sizeof(complexf), ddc.output_size, stdout);
TRY_YIELD;
}
}
if(!strcmp(argv[1],"none"))
{
return 0;

125
fastddc.c Normal file
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@ -0,0 +1,125 @@
/*
This software is part of libcsdr, a set of simple DSP routines for
Software Defined Radio.
Copyright (c) 2014, Andras Retzler <randras@sdr.hu>
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of the copyright holder nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL ANDRAS RETZLER BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "fastddc.h"
//DDC implementation based on:
//http://www.3db-labs.com/01598092_MultibandFilterbank.pdf
inline int is_integer(float a) { return floorf(a) == a; }
int fastddc_init(fastddc_t* ddc, float transition_bw, int decimation, float shift_rate)
{
ddc->pre_decimation = 1; //this will be done in the frequency domain
ddc->post_decimation = decimation; //this will be done in the time domain
while( is_integer((float)ddc->post_decimation/2) && ddc->post_decimation/2 != 1)
{
ddc->post_decimation/=2;
ddc->pre_decimation*=2;
}
ddc->taps_real_length = firdes_filter_len(transition_bw); //the number of non-zero taps
ddc->taps_length = ceil(ddc->taps_real_length/(float)ddc->pre_decimation) * ddc->pre_decimation; //the number of taps must be a multiple of the decimation factor
ddc->fft_size = next_pow2(ddc->taps_length * 4); //it is a good rule of thumb for performance (based on the article), but we should do benchmarks
while (ddc->fft_size<ddc->pre_decimation) ddc->fft_size*=2; //fft_size should be a multiple of pre_decimation
ddc->overlap_length = ddc->taps_length - 1;
ddc->input_size = ddc->fft_size - ddc->overlap_length;
ddc->fft_inv_size = ddc->fft_size / ddc->pre_decimation;
//Shift operation in the frequency domain: we can shift by a multiple of v.
ddc->v = ddc->fft_size/ddc->overlap_length; //+-1 ? (or maybe ceil() this?) //TODO: why?
int middlebin=ddc->fft_size / 2;
ddc->startbin = middlebin + middlebin * shift_rate * 2;
ddc->startbin = ddc->v * round( ddc->startbin / (float)ddc->v );
ddc->offsetbin = ddc->startbin - middlebin;
ddc->post_shift = ((float)ddc->offsetbin/ddc->fft_size) - shift_rate;
ddc->pre_shift = ddc->offsetbin * ddc->v;
//Overlap is scraped, not added
ddc->scrape=ddc->overlap_length/ddc->pre_decimation;
ddc->output_size=ddc->fft_inv_size-ddc->scrape;
return ddc->fft_size<=2; //returns true on error
}
void fastddc_print(fastddc_t* ddc)
{
fprintf(stderr,
"fastddc_print_sizes(): (fft_size = %d) = (taps_length = %d) + (input_size = %d) - 1\n"
"\t(overlap_length = %d) = taps_length - 1, taps_real_length = %d\n"
"\tdecimation = (pre_decimation = %d) * (post_decimation = %d), fft_inv_size = %d\n"
"\tstartbin = %d, offsetbin = %d, v = %d, pre_shift = %g, post_shift = %g\n"
,
ddc->fft_size, ddc->taps_length, ddc->input_size,
ddc->overlap_length, ddc->taps_real_length,
ddc->pre_decimation, ddc->post_decimation, ddc->fft_inv_size,
ddc->startbin, ddc->offsetbin, ddc->v, ddc->pre_shift, ddc->post_shift );
}
decimating_shift_addition_status_t fastddc_apply_cc(complexf* input, complexf* output, fastddc_t* ddc, FFT_PLAN_T* plan_inverse, complexf* taps_fft, decimating_shift_addition_status_t shift_stat)
{
//implements DDC by using the overlap & scrape method
//TODO: +/-1s on overlap_size et al
//input shoud have ddc->fft_size number of elements
complexf* inv_input = plan_inverse->input;
complexf* inv_output = plan_inverse->output;
//Initialize buffers for inverse FFT to zero
for(int i=0;i<plan_inverse->size;i++)
{
iof(inv_input,i)=0;
qof(inv_input,i)=0;
}
//Alias & shift & filter at once
// * no, we won't break this algorithm to parts that are easier to understand: now we go for speed
for(int i=0;i<ddc->fft_size;i++)
{
int output_index = (ddc->startbin+i)%plan_inverse->size;
int tap_index = (ddc->fft_size+i-ddc->offsetbin)%ddc->fft_size;
cmultadd(inv_input+output_index, input+i, taps_fft+tap_index); //cmultadd(output, input1, input2): complex output += complex input1 * complex input 2
}
fft_execute(plan_inverse);
//Normalize data
for(int i=0;i<plan_inverse->size;i++) //@apply_ddc_fft_cc: normalize by size
{
iof(inv_output,i)/=plan_inverse->size;
qof(inv_output,i)/=plan_inverse->size;
}
//Overlap is scraped, not added
//Shift correction
shift_addition_data_t dsadata=decimating_shift_addition_init(ddc->post_shift, ddc->post_decimation); //this could be optimized (passed as parameter), but we would not win too much at all
shift_stat=decimating_shift_addition_cc(plan_inverse->output+ddc->scrape, output, ddc->output_size, dsadata, ddc->post_decimation, shift_stat);
return shift_stat;
}

27
fastddc.h Normal file
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@ -0,0 +1,27 @@
#include <math.h>
#include "libcsdr.h"
#include "libcsdr_gpl.h"
typedef struct fastddc_s
{
int pre_decimation;
int post_decimation;
int taps_length;
int taps_real_length;
int overlap_length; //it is taps_length - 1
int fft_size;
int fft_inv_size;
int input_size;
int output_size;
float pre_shift;
int startbin; //for pre_shift
int v; //step for pre_shift
int offsetbin;
float post_shift;
int output_scrape;
int scrape;
} fastddc_t;
int fastddc_init(fastddc_t* ddc, float transition_bw, int decimation, float shift_rate);
decimating_shift_addition_status_t fastddc_apply_cc(complexf* input, complexf* output, fastddc_t* ddc, FFT_PLAN_T* plan_inverse, complexf* taps_fft, decimating_shift_addition_status_t shift_stat);
void fastddc_print(fastddc_t* ddc);

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@ -1,4 +1,5 @@
#include "libcsdr.c"
#include "libcsdr_gpl.c"
#include "ima_adpcm.c"
#include "fastddc.c"
//this wrapper helps parsevect.py to generate better output