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>

1 files changed, 34 insertions, 0 deletions

diff --git a/Transceiver52M/Channelizer.h b/Transceiver52M/Channelizer.h
new file mode 100644
index 0000000..fdd6779
--- /dev/null
+++ b/Transceiver52M/Channelizer.h
@@ -0,0 +1,34 @@
+#ifndef _CHANNELIZER_RX_H_
+#define _CHANNELIZER_RX_H_
+
+#include "ChannelizerBase.h"
+
+class Channelizer : public ChannelizerBase {
+public:
+	/** Constructor for channelizing filter bank
+	    @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
+	*/
+	Channelizer(size_t m, size_t blockLen, size_t hLen = 16);
+	~Channelizer();
+
+	/* Return required input and output buffer lengths */
+	size_t inputLen() const;
+	size_t outputLen() const;
+
+	/** Rotate "input commutator" and drive samples through filterbank
+	    @param in complex input vector 
+	    @param iLen number of samples in buffer (must match block length)
+	    @return false on error and true otherwise
+	*/
+	bool rotate(const float *in, size_t iLen);
+
+	/** Get buffer for an output path
+	    @param chan channel number of filterbank
+            @return NULL on error and pointer to buffer otherwise
+	*/
+	float *outputBuffer(size_t chan) const;
+};
+
+#endif /* _CHANNELIZER_RX_H_ */