Add subsample delay compensation (untested)

1 files changed, 12 insertions, 5 deletions

diff --git a/AlignSample.hpp b/AlignSample.hpp
index d027823..9529792 100644
--- a/AlignSample.hpp
+++ b/AlignSample.hpp
@@ -1,5 +1,5 @@
 /*
-   Copyright (C) 2015
+   Copyright (C) 2017
    Matthias P. Braendli, matthias.braendli@mpb.li
 
     http://opendigitalradio.org
@@ -33,7 +33,8 @@
 #define FFT_TYPE fftwf_complex
 
 
-typedef std::complex<float> complexf;
+using complexf = std::complex<float>;
+using vec_cf = std::vector<complexf>;
 
 struct CorrelationResult {
     CorrelationResult(size_t len) :
@@ -43,7 +44,7 @@ struct CorrelationResult {
         rx_timestamp(0),
         tx_timestamp(0) {}
 
-    std::vector<complexf> correlation;
+    vec_cf correlation;
     float rx_power;
     float tx_power;
 
@@ -85,8 +86,14 @@ class AlignSample {
 
         CorrelationResult crosscorrelate(size_t len);
 
-        std::pair<std::vector<complexf>, std::vector<complexf> > get_samples(
-                size_t len, size_t rx_delay);
+        /* Drop delay samples from the rx_samples */
+        void delay_rx_samples(size_t delay);
+
+        /* Calculate and compensate for subsample delay, assuming that the
+         * RX and TX samples are already aligned
+         */
+        std::pair<vec_cf, vec_cf> get_samples(
+                size_t len);
 
         void consume(size_t samples);