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authorTom Rondeau <tom@trondeau.com>2015-05-08 13:17:02 -0400
committerTom Rondeau <tom@trondeau.com>2015-12-29 11:29:46 -0500
commita55dbd4a69eebb2c44c586593e09d067d235c921 (patch)
treeaae5e8a807c78d3ad133ae240bc0cf6950a02827 /gr-dtv/lib/atsc
parent8e54c0201cb10c974460122cf4db6df13a00caf0 (diff)
dtv: atsc: add ControlPort hooks into Viterbi decoder.
Produces the best metric for each decoder used.
Diffstat (limited to 'gr-dtv/lib/atsc')
-rw-r--r--gr-dtv/lib/atsc/atsc_single_viterbi.cc65
-rw-r--r--gr-dtv/lib/atsc/atsc_single_viterbi.h17
-rw-r--r--gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.cc25
-rw-r--r--gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.h4
4 files changed, 77 insertions, 34 deletions
diff --git a/gr-dtv/lib/atsc/atsc_single_viterbi.cc b/gr-dtv/lib/atsc/atsc_single_viterbi.cc
index 385940e453..011cc0fe96 100644
--- a/gr-dtv/lib/atsc/atsc_single_viterbi.cc
+++ b/gr-dtv/lib/atsc/atsc_single_viterbi.cc
@@ -28,7 +28,7 @@ namespace gr {
/* was_sent is a table of what symbol we get given what bit pair
was sent and what state we where in [state][pair] */
- const int atsc_single_viterbi::was_sent[4][4] = {
+ const int atsc_single_viterbi::d_was_sent[4][4] = {
{0,2,4,6},
{0,2,4,6},
{1,3,5,7},
@@ -37,7 +37,7 @@ namespace gr {
/* transition_table is a table of what state we were in
given current state and bit pair sent [state][pair] */
- const int atsc_single_viterbi::transition_table[4][4] = {
+ const int atsc_single_viterbi::d_transition_table[4][4] = {
{0,2,0,2},
{2,0,2,0},
{1,3,1,3},
@@ -49,11 +49,12 @@ namespace gr {
{
for (unsigned int i = 0; i<2; i++)
for (unsigned int j = 0; j<4; j++) {
- path_metrics[i][j] = 0;
- traceback[i][j] = 0;
+ d_path_metrics[i][j] = 0;
+ d_traceback[i][j] = 0;
}
- post_coder_state = 0;
- phase = 0;
+ d_post_coder_state = 0;
+ d_phase = 0;
+ d_best_state_metric = 100000;
}
atsc_single_viterbi::atsc_single_viterbi()
@@ -61,17 +62,24 @@ namespace gr {
reset();
}
+ float
+ atsc_single_viterbi::best_state_metric() const
+ {
+ return d_best_state_metric;
+ }
+
char
atsc_single_viterbi::decode(float input)
{
unsigned int best_state = 0;
- float best_state_metric = 100000;
+ //float best_state_metric = 100000;
+ d_best_state_metric = 100000;
/* Precompute distances from input to each possible symbol */
- float distances[8] = { (float)fabs( input + 7 ), (float)fabs( input + 5 ),
- (float)fabs( input + 3 ), (float)fabs( input + 1 ),
- (float)fabs( input - 1 ), (float)fabs( input - 3 ),
- (float)fabs( input - 5 ), (float)fabs( input - 7 ) };
+ float distances[8] = { fabsf( input + 7 ), fabsf( input + 5 ),
+ fabsf( input + 3 ), fabsf( input + 1 ),
+ fabsf( input - 1 ), fabsf( input - 3 ),
+ fabsf( input - 5 ), fabsf( input - 7 ) };
/* We start by iterating over all possible states */
for (unsigned int state = 0; state < 4; state++) {
@@ -79,15 +87,20 @@ namespace gr {
states to the state we are testing, we only need to look at
the 4 paths that can be taken given the 2-bit input */
int min_metric_symb = 0;
- float min_metric = distances[was_sent[state][0]] + path_metrics[phase][transition_table[state][0]];
+ float min_metric = distances[d_was_sent[state][0]] +
+ d_path_metrics[d_phase][d_transition_table[state][0]];
+
for (unsigned int symbol_sent = 1; symbol_sent < 4; symbol_sent++)
- if( (distances[was_sent[state][symbol_sent]] + path_metrics[phase][transition_table[state][symbol_sent]]) < min_metric) {
- min_metric = distances[was_sent[state][symbol_sent]] + path_metrics[phase][transition_table[state][symbol_sent]];
+ if( (distances[d_was_sent[state][symbol_sent]] +
+ d_path_metrics[d_phase][d_transition_table[state][symbol_sent]]) < min_metric) {
+ min_metric = distances[d_was_sent[state][symbol_sent]] +
+ d_path_metrics[d_phase][d_transition_table[state][symbol_sent]];
min_metric_symb = symbol_sent;
}
- path_metrics[phase^1][state] = min_metric;
- traceback[phase^1][state] = (((unsigned long long)min_metric_symb) << 62) | (traceback[phase][transition_table[state][min_metric_symb]] >> 2);
+ d_path_metrics[d_phase^1][state] = min_metric;
+ d_traceback[d_phase^1][state] = (((unsigned long long)min_metric_symb) << 62) |
+ (d_traceback[d_phase][d_transition_table[state][min_metric_symb]] >> 2);
/* If this is the most probable state so far remember it, this
only needs to be checked when we are about to output a path
@@ -98,26 +111,24 @@ namespace gr {
head state path will tend towards the optimal path with a
probability approaching 1 in just 8 or so transitions
*/
- if(min_metric <= best_state_metric) {
- best_state_metric = min_metric;
+ if(min_metric <= d_best_state_metric) {
+ d_best_state_metric = min_metric;
best_state = state;
}
}
- if(best_state_metric > 10000) {
+ if(d_best_state_metric > 10000) {
for(unsigned int state = 0; state < 4; state++)
- path_metrics[phase^1][state] -= best_state_metric;
+ d_path_metrics[d_phase^1][state] -= d_best_state_metric;
}
- phase ^= 1;
+ d_phase ^= 1;
- int y2 = (0x2 & traceback[phase][best_state]) >> 1;
- int x2 = y2 ^ post_coder_state;
- post_coder_state = y2;
+ int y2 = (0x2 & d_traceback[d_phase][best_state]) >> 1;
+ int x2 = y2 ^ d_post_coder_state;
+ d_post_coder_state = y2;
- return ( x2 << 1 ) | (0x1 & traceback[phase][best_state]);
+ return ( x2 << 1 ) | (0x1 & d_traceback[d_phase][best_state]);
}
} /* namespace dtv */
} /* namespace gr */
-
-
diff --git a/gr-dtv/lib/atsc/atsc_single_viterbi.h b/gr-dtv/lib/atsc/atsc_single_viterbi.h
index 3c756c7690..9522e2eb1b 100644
--- a/gr-dtv/lib/atsc/atsc_single_viterbi.h
+++ b/gr-dtv/lib/atsc/atsc_single_viterbi.h
@@ -44,14 +44,17 @@ namespace gr {
//! internal delay of decoder
static int delay () { return TB_LEN - 1; }
- protected:
- static const int transition_table[4][4];
- static const int was_sent[4][4];
+ float best_state_metric() const;
- float path_metrics [2][4];
- unsigned long long traceback [2][4];
- unsigned char phase;
- int post_coder_state;
+ protected:
+ static const int d_transition_table[4][4];
+ static const int d_was_sent[4][4];
+
+ float d_path_metrics [2][4];
+ unsigned long long d_traceback [2][4];
+ unsigned char d_phase;
+ int d_post_coder_state;
+ float d_best_state_metric;
};
} /* namespace dtv */
diff --git a/gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.cc b/gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.cc
index 430eb55a17..2284372dfb 100644
--- a/gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.cc
+++ b/gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.cc
@@ -77,6 +77,15 @@ namespace gr {
fifo[i]->reset();
}
+ std::vector<float>
+ atsc_viterbi_decoder_impl::decoder_metrics() const
+ {
+ std::vector<float> metrics(NCODERS);
+ for (int i = 0; i < NCODERS; i++)
+ metrics[i] = viterbi[i].best_state_metric();
+ return metrics;
+ }
+
int
atsc_viterbi_decoder_impl::work(int noutput_items,
gr_vector_const_void_star &input_items,
@@ -135,5 +144,21 @@ namespace gr {
return noutput_items;
}
+ void
+ atsc_viterbi_decoder_impl::setup_rpc()
+ {
+#ifdef GR_CTRLPORT
+ add_rpc_variable(
+ rpcbasic_sptr(new rpcbasic_register_get<atsc_viterbi_decoder, std::vector<float> >(
+ alias(), "decoder_metrics",
+ &atsc_viterbi_decoder::decoder_metrics,
+ pmt::make_f32vector(1,0),
+ pmt::make_f32vector(1,100000),
+ pmt::make_f32vector(1,0),
+ "", "Viterbi decoder metrics", RPC_PRIVLVL_MIN,
+ DISPTIME)));
+#endif /* GR_CTRLPORT */
+ }
+
} /* namespace dtv */
} /* namespace gr */
diff --git a/gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.h b/gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.h
index b4fbbd1033..ef4faab313 100644
--- a/gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.h
+++ b/gr-dtv/lib/atsc/atsc_viterbi_decoder_impl.h
@@ -63,8 +63,12 @@ namespace gr {
atsc_viterbi_decoder_impl();
~atsc_viterbi_decoder_impl();
+ void setup_rpc();
+
void reset();
+ std::vector<float> decoder_metrics() const;
+
virtual int work(int noutput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items);
generated by cgit v1.2.3 (git 2.39.1) at 2025-03-23 09:57:32 +0000