mcbts: Add multi-ARFCN channelizing filters
Introduce polyphase channelizer (Rx) and synthesis (Tx) filterbanks,
which serve as the signal processing backend for multi-carrier GSM.
Fast Fourier Transform (FFT) is used internally. FFTW is added as
a new build dependency.
Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
diff --git a/Transceiver52M/Synthesis.h b/Transceiver52M/Synthesis.h
new file mode 100644
index 0000000..4100283
--- /dev/null
+++ b/Transceiver52M/Synthesis.h
@@ -0,0 +1,35 @@
+#ifndef _SYNTHESIS_H_
+#define _SYNTHESIS_H_
+
+#include "ChannelizerBase.h"
+
+class Synthesis : public ChannelizerBase {
+public:
+ /** Constructor for synthesis filterbank
+ @param m number of physical channels
+ @param blockLen number of samples per output of each iteration
+ @param hLen number of taps in each constituent filter path
+ */
+ Synthesis(size_t m, size_t blockLen, size_t hLen = 16);
+ ~Synthesis();
+
+ /* Return required input and output buffer lengths */
+ size_t inputLen() const;
+ size_t outputLen() const;
+
+ /** Rotate "output commutator" and drive samples through filterbank
+ @param out complex output vector
+ @param oLen number of samples in buffer (must match block length * m)
+ @return false on error and true otherwise
+ */
+ bool rotate(float *out, size_t oLen);
+
+ /** Get buffer for an input path
+ @param chan channel number of filterbank
+ @return NULL on error and pointer to buffer otherwise
+ */
+ float *inputBuffer(size_t chan) const;
+ bool resetBuffer(size_t chan);
+};
+
+#endif /* _SYNTHESIS_H_ */