FGFS-4.1/gr-air-modes
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Default int & dump to "no", use center sampling instead.

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A learning experience I guess. If the pulse isn't REALLY square,
and instead is bandlimited in any way, integrate & dump doesn't work
as well as center sampling.

At any rate, the completely rewritten decoder should be both faster
and more sensitive than before.
This commit is contained in:
Nick Foster
2011-06-12 01:14:49 -07:00
parent 3421598b7c
commit 72acc5e3c1
2 changed files with 5 additions and 9 deletions
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2
src/lib/air_modes_preamble.cc
View File

@@ -138,7 +138,7 @@ int air_modes_preamble::general_work(int noutput_items,
//all right i'm prepared to call this a preamble
//let's integrate and dump the output
//FIXME: disable and use center sample
bool life_sucks = false;
bool life_sucks = true;
if(life_sucks) {
for(int j=0; j<240; j++) {
out[j] = in[i+j*d_samples_per_chip];

12
src/lib/air_modes_slicer.cc
View File

@@ -129,7 +129,6 @@ int air_modes_slicer::work(int noutput_items,
int size = noutput_items - d_check_width; //since it's a sync block, i assume that it runs with ninput_items = noutput_items
int i;
static int n_ok=0, n_badcrc=0, n_loconf=0, n_zeroes=0;
std::vector<pmt::pmt_t> tags;
uint64_t abs_sample_cnt = nitems_read(0);
@@ -208,19 +207,19 @@ int air_modes_slicer::work(int noutput_items,
for(int m = 0; m < 14; m++) {
if(rx_packet.data[m]) zeroes = 0;
}
if(zeroes) {n_zeroes++; continue;} //toss it
if(zeroes) {continue;} //toss it
rx_packet.message_type = (rx_packet.data[0] >> 3) & 0x1F; //get the message type for the parser to conveniently use, and to make decisions on ECC methods
if(rx_packet.type == Short_Packet && rx_packet.message_type != 11 && rx_packet.numlowconf > 0) {n_loconf++; continue;}
if(rx_packet.message_type == 11 && rx_packet.numlowconf >= 10) {n_loconf++; continue;}
if(rx_packet.type == Short_Packet && rx_packet.message_type != 11 && rx_packet.numlowconf > 0) {continue;}
if(rx_packet.message_type == 11 && rx_packet.numlowconf >= 10) {continue;}
rx_packet.parity = modes_check_parity(rx_packet.data, packet_length);
//parity for packets that aren't type 11 or type 17 is encoded with the transponder ID, which we don't know
//therefore we toss 'em if there's syndrome
//parity for the other short packets is usually nonzero, so they can't really be trusted that far
if(rx_packet.parity && (rx_packet.message_type == 11 || rx_packet.message_type == 17)) {n_badcrc++; continue;}
if(rx_packet.parity && (rx_packet.message_type == 11 || rx_packet.message_type == 17)) {continue;}
//we no longer attempt to brute force error correct via syndrome. it really only gets you 1% additional returns,
//at the expense of a lot of CPU time and complexity
@@ -256,9 +255,6 @@ int air_modes_slicer::work(int noutput_items,
<< " " << std::setprecision(10) << std::setw(10) << rx_packet.timestamp;
gr_message_sptr msg = gr_make_message_from_string(std::string(d_payload.str()));
d_queue->handle(msg);
n_ok++;
std::cout << "n_ok: " << n_ok << " n_loconf: " << n_loconf << " n_badcrc: " << n_badcrc << " n_zeroes: " << n_zeroes << std::endl;
}
return size;