From 4135c8f5adc5f9c5b1c51919b1d3c9532b9c3d17 Mon Sep 17 00:00:00 2001
From: John Greb <hexameron@spam.no>
Date: Mon, 22 Dec 2014 20:23:55 +0000
Subject: [PATCH] Bandpass FFT.

---
 include-gpl/dsp/fftfilt.h         |  3 ++-
 plugins/channel/ssb/ssbdemod.cpp  |  2 +-
 plugins/channel/tcpsrc/tcpsrc.cpp |  2 +-
 plugins/channel/usb/usbdemod.cpp  |  6 +++---
 sdrbase/dsp/fftfilt.cxx           | 26 +++++++++++++++++++++++++-
 5 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/include-gpl/dsp/fftfilt.h b/include-gpl/dsp/fftfilt.h
index e135fcdfd..0f76d683a 100644
--- a/include-gpl/dsp/fftfilt.h
+++ b/include-gpl/dsp/fftfilt.h
@@ -48,7 +48,8 @@ public:
 	void create_filter(float f1, float f2);
 	void rtty_filter(float);
 
-	int run(const cmplx& in, cmplx **out, bool usb);
+	int runFilt(const cmplx& in, cmplx **out);
+	int runSSB(const cmplx& in, cmplx **out, bool usb);
 };
 
 #endif
diff --git a/plugins/channel/ssb/ssbdemod.cpp b/plugins/channel/ssb/ssbdemod.cpp
index 91d2721bd..6b53a33af 100644
--- a/plugins/channel/ssb/ssbdemod.cpp
+++ b/plugins/channel/ssb/ssbdemod.cpp
@@ -67,7 +67,7 @@ void SSBDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iter
 		c *= m_nco.nextIQ();
 
 		if(m_interpolator.interpolate(&m_sampleDistanceRemain, c, &ci)) {
-			n_out = SSBFilter->run(ci, &sideband, m_usb);
+			n_out = SSBFilter->runSSB(ci, &sideband, m_usb);
 			m_sampleDistanceRemain += (Real)m_sampleRate / 48000.0;
 		} else
 			n_out = 0;
diff --git a/plugins/channel/tcpsrc/tcpsrc.cpp b/plugins/channel/tcpsrc/tcpsrc.cpp
index 2240214bb..574663298 100644
--- a/plugins/channel/tcpsrc/tcpsrc.cpp
+++ b/plugins/channel/tcpsrc/tcpsrc.cpp
@@ -73,7 +73,7 @@ void TCPSrc::feed(SampleVector::const_iterator begin, SampleVector::const_iterat
 	if(m_ssbSockets.count() > 0) {
 		for(SampleVector::const_iterator it = m_sampleBuffer.begin(); it != m_sampleBuffer.end(); ++it) {
 			Complex cj(it->real() / 20000.0, it->imag() / 20000.0);
-			int n_out = TCPFilter->run(cj, &sideband, true);
+			int n_out = TCPFilter->runSSB(cj, &sideband, true);
 			if (n_out) {
 				for (int i = 0; i < n_out; i+=2) {
 					Real one = (sideband[i].real() + sideband[i].imag()) * 0.7 * 32000.0;
diff --git a/plugins/channel/usb/usbdemod.cpp b/plugins/channel/usb/usbdemod.cpp
index 5a7656cc5..0733480f2 100644
--- a/plugins/channel/usb/usbdemod.cpp
+++ b/plugins/channel/usb/usbdemod.cpp
@@ -89,11 +89,11 @@ void USBDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iter
 		b = it->imag();
 		c = Complex(a / 65536.0, b / 65536.0);
 
-		n_out = USBFilter->run(c, &sideband, true);
+		n_out = USBFilter->runSSB(c, &sideband, true);
 		if (m_sampleRate <= 72000)
-			n_out += USBFilter->run(c, &sideband, true);
+			n_out += USBFilter->runSSB(c, &sideband, true);
 		if (m_sampleRate == 64000)
-			n_out += USBFilter->run(c, &sideband, true);
+			n_out += USBFilter->runSSB(c, &sideband, true);
 		for (i = m_i ; i < n_out; i += samplestep) {
 			Real demod = (sideband[i].real() + sideband[i].imag()) * 32768.0;
 
diff --git a/sdrbase/dsp/fftfilt.cxx b/sdrbase/dsp/fftfilt.cxx
index 1c4acf9d8..c856ee27d 100644
--- a/sdrbase/dsp/fftfilt.cxx
+++ b/sdrbase/dsp/fftfilt.cxx
@@ -144,7 +144,31 @@ void fftfilt::create_filter(float f1, float f2)
 }
 
 // Filter with fast convolution (overlap-add algorithm).
-int fftfilt::run(const cmplx & in, cmplx **out, bool usb)
+int fftfilt::runFilt(const cmplx & in, cmplx **out)
+{
+	timedata[inptr++] = in;
+	if (inptr < flen2)
+		return 0;
+	inptr = 0;
+
+	memcpy(freqdata, timedata, flen * sizeof(cmplx));
+	fft->ComplexFFT(freqdata);
+	for (int i = 0; i < flen; i++)
+		freqdata[i] *= filter[i];
+
+	fft->InverseComplexFFT(freqdata);
+
+	for (int i = 0; i < flen2; i++) {
+		output[i] = ovlbuf[i] + freqdata[i];
+		ovlbuf[i] = freqdata[flen2 + i];
+	}
+
+	*out = output;
+	return flen2;
+}
+
+// Second version for single sideband
+int fftfilt::runSSB(const cmplx & in, cmplx **out, bool usb)
 {
 	timedata[inptr++] = in;