rpitx/csdr
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Added matched filter

Browse source
This commit is contained in:
ha7ilm 2017-04-30 17:51:35 +02:00
parent 0878d3bd43
commit d1af45a588
3 changed files with 152 additions and 31 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

66
csdr.c
View file

@ -3030,26 +3030,76 @@ int main(int argc, char *argv[])
fwrite(zeros, sizeof(float), n_zero_samples, stdout);
clone_(the_bufsize);
}
/*
if(!strcmp(argv[1], "matched_filter_cc")) //<matched_filter_type> <samples_per_symbol> <num_taps>
int matched_filter_which = 0;
if(
(!strcmp(argv[1], "firdes_matched_filter_f") && (matched_filter_which = 1)) ||
(!strcmp(argv[1], "matched_filter_cc") && (matched_filter_which = 2))
) //(RRC <samples_per_symbol> <num_taps> <beta> | COSINE <samples_per_symbol>)
{
if(argc<=2) return badsyntax("required parameter <matched_filter_type> is missing.");
matched_filter_type_t type = matched_filter_get_type_from_string(argv[2]);
int samples_per_symbol = 0;
if(argc<=2) return badsyntax("required parameter <samples_per_symbol> is missing.");
sscanf(argv[2],"%d",&samples_per_symbol);
if(argc<=3) return badsyntax("required parameter <samples_per_symbol> is missing.");
sscanf(argv[3],"%d",&samples_per_symbol);
int num_taps = 0;
if(argc<=2) return badsyntax("required parameter <num_taps> is missing.");
sscanf(argv[2],"%d",&num_taps);
if(argc<=4 && type!=MATCHED_FILTER_COSINE)
return badsyntax("required parameter <num_taps> is missing.");
sscanf(argv[4],"%d",&num_taps);
float beta = 0;
if(argc<=5 && type==MATCHED_FILTER_RRC)
return badsyntax("required parameter <beta> is missing.");
sscanf(argv[5],"%f",&beta);
if(type==MATCHED_FILTER_COSINE) num_taps = (2*samples_per_symbol)+1;
float* taps = (float*)malloc(sizeof(float)*num_taps);
switch(type)
{
case MATCHED_FILTER_RRC:
firdes_rrc_f(taps, num_taps, samples_per_symbol, beta);
break;
case MATCHED_FILTER_COSINE:
firdes_cosine_f(taps, num_taps, samples_per_symbol);
break;
}
if(!sendbufsize(initialize_buffers())) return -2;
if(matched_filter_which==1)
{
for(int i=0;i<num_taps;i++) printf("%f ", taps[i]);
return 0;
}
for(;;)
{
FEOF_CHECK;
FREAD_C;
apply_real_fir_cc((complexf*)input_buffer, (complexf*)output_buffer, the_bufsize, taps, num_taps);
FWRITE_C;
TRY_YIELD;
}
}
*/
if(!strcmp(argv[1], "generic_slicer_f_u8")) //<n_symbols>
{
int n_symbols = 0;
if(argc<=2) return badsyntax("required parameter <n_symbols> is missing.");
sscanf(argv[2],"%d",&n_symbols);
if(!sendbufsize(initialize_buffers())) return -2;
for(;;)
{
FEOF_CHECK;
if(!FREAD_R) break;
generic_slicer_f_u8(input_buffer, (unsigned char*)output_buffer, the_bufsize, n_symbols);
FWRITE_U8;
TRY_YIELD;
}
return 0;
}
if(!strcmp(argv[1],"none"))
{

99
libcsdr.c
View file

@ -1721,6 +1721,33 @@ void serial_line_decoder_f_u8(serial_line_t* s, float* input, unsigned char* out
DEBUG_SERIAL_LINE_DECODER && fprintf(stderr, "sld: >> output_size = %d (+%d)\n", s->output_size, s->input_used);
}
void generic_slicer_f_u8(float* input, unsigned char* output, int input_size, int n_symbols)
{
float symbol_distance = 2.0/(n_symbols+1);
for(int i=0;i<input_size;i++)
for(int j=0;j<n_symbols;i++)
{
float symbol_center = -1+j*symbol_distance;
float symbol_low_limit = symbol_center-(symbol_distance/2);
float symbol_high_limit = symbol_center+(symbol_distance/2);
if(j==0)
{
if(input[i]<symbol_high_limit) output[i]=j;
break;
}
else if (j==n_symbols-1)
{
if(input[i]>=symbol_low_limit) output[i]=j;
break;
}
else
{
if(input[i]>=symbol_low_limit && input[i]<symbol_high_limit) output[i]=j;
break;
}
}
}
void binary_slicer_f_u8(float* input, unsigned char* output, int input_size)
{
for(int i=0;i<input_size;i++) output[i] = input[i] > 0;
@ -2169,6 +2196,24 @@ int apply_fir_cc(complexf* input, complexf* output, int input_size, complexf* ta
return i;
}
int apply_real_fir_cc(complexf* input, complexf* output, int input_size, float* taps, int taps_length)
{
int i;
for(i=0; i<input_size-taps_length+1; i++)
{
float acci = 0, accq = 0;
for(int ti=0;ti<taps_length;ti++)
{
acci += iof(input,i)*taps[ti];
accq += qof(input,i)*taps[ti];
}
iof(output,i)=acci;
qof(output,i)=accq;
}
return i;
}
float normalized_timing_variance_u32_f(unsigned* input, float* temp, int input_size, int samples_per_symbol, int initial_sample_offset, int debug_print)
{
float *ndiff_rad = temp;
@ -2310,32 +2355,44 @@ void get_random_gaussian_samples_c(complexf* output, int output_size, FILE* stat
}
}
/*
void get_awgn_samples_c(complexf* output, int output_size, FILE* status)
{
int* pioutput = (int*)output;
int cnt = 0;
for(int i=0;i<output_size;i++)
{
do
{
fread(pioutput+2*i, sizeof(complexf), 2, status);
iof(output, i)=((float)pioutput[2*i])/((float)INT_MAX);
qof(output, i)=((float)pioutput[2*i+1])/((float)INT_MAX);
}
while(sqrt(iof(output, i)*iof(output, i)+qof(output, i)*qof(output, i))>1);
iof(output, i)=(1/0.82)*iof(output, i);
qof(output, i)=(1/0.82)*qof(output, i);
}
}
*/
int deinit_get_random_samples_f(FILE* status)
{
return fclose(status);
}
int firdes_cosine_f(float* taps, int taps_length, int samples_per_symbol)
{
//needs a taps_length 2 × samples_per_symbol + 1
int middle_i=taps_length/2;
for(int i=0;i<samples_per_symbol;i++) taps[middle_i+i]=taps[middle_i-i]=(1+cos(PI*i/(float)samples_per_symbol))/2;
}
int firdes_rrc_f(float* taps, int taps_length, int samples_per_symbol, float beta)
{
//needs an odd taps_length
int middle_i=taps_length/2;
taps[middle_i]=(1/samples_per_symbol)*(1+beta*(4/PI-1));
for(int i=1;i<taps_length/2;i++)
{
if(i==samples_per_symbol/(4*beta))
taps[middle_i+i]=taps[middle_i-i]=(beta/(samples_per_symbol*sqrt(2)))*((1+(2/PI))*sin(PI/(4*beta))+(1-(2/PI)*cos(PI/(4*beta))));
else
taps[middle_i+i]=taps[middle_i-i]=(1/samples_per_symbol)*
(sin(PI*(i/(float)samples_per_symbol)*(1-beta)) + 4*beta*(i/(float)samples_per_symbol)*cos(PI*(i/(float)samples_per_symbol)*(1+beta)))/
(PI*(i/(float)samples_per_symbol)*(1-powf(4*beta*(i/(float)samples_per_symbol),2)));
}
}
#define MMATCHEDFILT_GAS(NAME) \
if(!strcmp( #NAME , input )) return MATCHED_FILTER_ ## NAME;
matched_filter_type_t matched_filter_get_type_from_string(char* input)
{
MMATCHEDFILT_GAS(RRC);
MMATCHEDFILT_GAS(COSINE);
return MATCHED_FILTER_DEFAULT;
}
float* add_ff(float* input1, float* input2, float* output, int input_size)
{
for(int i=0;i<input_size;i++) output[i]=input1[i]+input2[i];

14
libcsdr.h
View file

@ -370,3 +370,17 @@ int deinit_get_random_samples_f(FILE* status);
float* add_ff(float* input1, float* input2, float* output, int input_size);
float total_logpower_cf(complexf* input, int input_size);
float normalized_timing_variance_u32_f(unsigned* input, float* temp, int input_size, int samples_per_symbol, int initial_sample_offset, int debug_print);
typedef enum matched_filter_type_e
{
MATCHED_FILTER_RRC,
MATCHED_FILTER_COSINE
} matched_filter_type_t;
#define MATCHED_FILTER_DEFAULT MATCHED_FILTER_RRC
int firdes_cosine_f(float* taps, int taps_length, int samples_per_symbol);
int firdes_rrc_f(float* taps, int taps_length, int samples_per_symbol, float beta);
matched_filter_type_t matched_filter_get_type_from_string(char* input);
int apply_real_fir_cc(complexf* input, complexf* output, int input_size, float* taps, int taps_length);
void generic_slicer_f_u8(float* input, unsigned char* output, int input_size, int n_symbols);