commit 6f4906e375999c242c6e84e1e59cf478490763ed
author Thomas Tsou <tom@tsou.cc> Sat Nov 09 02:40:18 2013 -0500
committer Thomas Tsou <tom@tsou.cc> Fri Nov 15 23:35:07 2013 -0500
tree 8fe5b424f60c41268b95fbc58ca387c06af59124
parent 0a3dc4c21028f36f02528c9a486de229f786b272

Transceiver52M: Dynamically allocate convolution input vectors

This prevents the use of a copy constructor in the downlink
modulator and prevents a secondary memory allocation during
the convolution. Avoid both cases by dynamically allocating
with preloaded head room. The latter provides enough memory
before the first sample in the burst to cover the length
of the filter taps.

Signed-off-by: Thomas Tsou <tom@tsou.cc>

Transceiver52M/sigProcLib.cpp

diff --git a/Transceiver52M/sigProcLib.cpp b/Transceiver52M/sigProcLib.cpp
index ab421b6..23538f3 100644
--- a/Transceiver52M/sigProcLib.cpp
+++ b/Transceiver52M/sigProcLib.cpp
@@ -369,9 +369,11 @@
   switch (spanType) {
   case START_ONLY:
     start = 0;
-    head = h->size();
+    head = h->size() - 1;
     len = x->size();
-    append = true;
+
+    if (x->getStartIndex() < head)
+      append = true;
     break;
   case NO_DELAY:
     start = h->size() / 2;
@@ -681,7 +683,8 @@
 {
   int burst_len;
   float phase;
-  signalVector *c0_pulse, *c1_pulse, c0_burst, c1_burst, *c0_shaped, *c1_shaped;
+  signalVector *c0_pulse, *c1_pulse, *c0_burst;
+  signalVector *c1_burst, *c0_shaped, *c1_shaped;
   signalVector::iterator c0_itr, c1_itr;
 
   /*
@@ -696,13 +699,13 @@
 
   burst_len = sps * (bits.size() + guard_len);
 
-  c0_burst = signalVector(burst_len);
-  c0_burst.isRealOnly(true);
-  c0_itr = c0_burst.begin();
+  c0_burst = new signalVector(burst_len, c0_pulse->size());
+  c0_burst->isRealOnly(true);
+  c0_itr = c0_burst->begin();
 
-  c1_burst = signalVector(burst_len);
-  c1_burst.isRealOnly(true);
-  c1_itr = c1_burst.begin();
+  c1_burst = new signalVector(burst_len, c1_pulse->size());
+  c1_burst->isRealOnly(true);
+  c1_itr = c1_burst->begin();
 
   /* Padded differential start bits */
   *c0_itr = 2.0 * (0x00 & 0x01) - 1.0;
@@ -718,10 +721,10 @@
   *c0_itr = 2.0 * (0x01 & 0x01) - 1.0;
 
   /* Generate C0 phase coefficients */
-  GMSKRotate(c0_burst, sps);
-  c0_burst.isRealOnly(false);
+  GMSKRotate(*c0_burst, sps);
+  c0_burst->isRealOnly(false);
 
-  c0_itr = c0_burst.begin();
+  c0_itr = c0_burst->begin();
   c0_itr += sps * 2;
   c1_itr += sps * 2;
 
@@ -746,8 +749,8 @@
   *c1_itr = *c0_itr * Complex<float>(0, phase);
 
   /* Primary (C0) and secondary (C1) pulse shaping */
-  c0_shaped = convolve(&c0_burst, c0_pulse, NULL, START_ONLY);
-  c1_shaped = convolve(&c1_burst, c1_pulse, NULL, START_ONLY);
+  c0_shaped = convolve(c0_burst, c0_pulse, NULL, START_ONLY);
+  c1_shaped = convolve(c1_burst, c1_pulse, NULL, START_ONLY);
 
   /* Sum shaped outputs into C0 */
   c0_itr = c0_shaped->begin();
@@ -755,6 +758,8 @@
   for (unsigned i = 0; i < c0_shaped->size(); i++ )
     *c0_itr++ += *c1_itr++;
 
+  delete c0_burst;
+  delete c1_burst;
   delete c1_shaped;
 
   return c0_shaped;
@@ -764,7 +769,7 @@
 					int guard_len, int sps)
 {
   int burst_len;
-  signalVector *pulse, burst, *shaped;
+  signalVector *pulse, *burst, *shaped;
   signalVector::iterator burst_itr;
 
   if (sps == 1)
@@ -774,9 +779,9 @@
 
   burst_len = sps * (bits.size() + guard_len);
 
-  burst = signalVector(burst_len);
-  burst.isRealOnly(true);
-  burst_itr = burst.begin();
+  burst = new signalVector(burst_len, pulse->size());
+  burst->isRealOnly(true);
+  burst_itr = burst->begin();
 
   /* Raw bits are not differentially encoded */
   for (unsigned i = 0; i < bits.size(); i++) {
@@ -784,11 +789,13 @@
     burst_itr += sps;
   }
 
-  GMSKRotate(burst, sps);
-  burst.isRealOnly(false);
+  GMSKRotate(*burst, sps);
+  burst->isRealOnly(false);
 
   /* Single Gaussian pulse approximation shaping */
-  shaped = convolve(&burst, pulse, NULL, START_ONLY);
+  shaped = convolve(burst, pulse, NULL, START_ONLY);
+
+  delete burst;
 
   return shaped;
 }

Transceiver52M/sigProcLib.h

diff --git a/Transceiver52M/sigProcLib.h b/Transceiver52M/sigProcLib.h
index 516d352..ebe7519 100644
--- a/Transceiver52M/sigProcLib.h
+++ b/Transceiver52M/sigProcLib.h
@@ -95,6 +95,9 @@
       symmetry = NONE;
     };
 
+  /** start index */
+  int getStartIndex() const { return mStart - mData; };
+
   /** symmetry operators */
   Symmetry getSymmetry() const { return symmetry;};
   void setSymmetry(Symmetry wSymmetry) { symmetry = wSymmetry;};