initial commit

Makefile

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+RM=rm
+MKDIR=mkdir
+CC=gcc
+STRIP=strip
+
+OUTDIR=build
+OUTFILE="$(OUTDIR)/rtl_wmbus"
+CFLAGS=-Iinclude -std=gnu99
+CFLAGS_WARNINGS=-Wall -W -Waggregate-return -Wbad-function-cast -Wcast-align -Wcast-qual -Wchar-subscripts -Wcomment -Wfloat-equal -Winline -Wmain -Wmissing-noreturn -Wmissing-prototypes -Wparentheses -Wpointer-arith -Wredundant-decls -Wreturn-type -Wshadow -Wsign-compare -Wstrict-prototypes -Wswitch -Wunreachable-code -Wunused -Wuninitialized
+LIB=-lm 
+SRC=rtl_wmbus.c
+
+all: $(OUTDIR) release
+
+$(OUTDIR):
+	$(MKDIR) -p "$(OUTDIR)"
+
+release: $(OUTDIR)
+	$(CC) -msse4.2 -DNDEBUG -O3                  $(CFLAGS) $(CFLAGS_WARNINGS) -o $(OUTFILE) $(SRC) $(LIB)
+
+debug: $(OUTDIR)
+	$(CC) -msse4.2 -DDEBUG  -O0 -g3 -ggdb -p -pg $(CFLAGS) $(CFLAGS_WARNINGS) -o $(OUTFILE) $(SRC) $(LIB)
+
+# Will build on Raspberry Pi 1 only
+pi1:
+	$(CC) -DNDEBUG -O3 -march=armv6 -mtune=arm1176jzf-s -mfloat-abi=hard -mfpu=vfp -ffast-math $(CFLAGS) $(CFLAGS_WARNINGS) -o $(OUTFILE) $(SRC) $(LIB)
+
+rebuild: clean all
+
+clean:
+	$(RM) -rf "$(OUTDIR)"

README.md

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+
+  rtl-wmbus - Software Decoder for Wireless-M-Bus with RTL-SDR
+  ------------------------------------------------------------
+
+rtl-wmbus is a software-defined radio receiver for Wireless-M-Bus. It is
+written in plain C and uses RTL-SDR to interface with RTL2832-based hardware.
+
+Wireless-M-Bus is the wireless version of M-Bus ("Meter-Bus", http://www.m-bus.com),
+which is an European standard for remote reading of smart meters.
+
+The primary purpose of rtl-wmbus is experimenting with digital signal
+processing and software radio. rtl-wmbus can be used on resource constrained
+devices such Raspberry Pi Zero or Raspberry PI B+ overclocked to 1GHz.
+Any Android based tablet will do the same too.
+
+rtl-wmbus provides:
+ * FSK demodulating
+ * clock recovery
+ * mode T1 and mode C1 packet decoding
+
+rtl-wmbus requires:
+ * Linux or Android
+ * C99
+ * supported DVB-T receiver
+ * RTL-SDR library for Linux: http://sdr.osmocom.org/trac/wiki/rtl-sdr or
+ * (optional, only for android builds) RTL-SDR library port for Android: https://github.com/martinmarinov/rtl_tcp_andro-
+
+For the latest version, see https://github.com/xaelsouth/rtl-wmbus
+
+
+  Installing
+  ----------
+
+The Osmocom RTL-SDR library must be installed before you can build
+rtl-wmbus. See http://sdr.osmocom.org/trac/wiki/rtl-sdr for more
+information. RTL-SDR library for Android would be installed via
+Google Play.
+
+To install rtl-wmbus, download, unpack the source code and go to the
+top level directory. Then use one of these three options:
+
+ $ make debug # (no optimization at all, with debug options)
+
+ $ make release # (-O3 optimized version, without any debugging options)
+
+ $ make pi1 # (Raspberry Pi optimized version, without any debugging options,
+               will build on RasPi1) only
+
+Before building Android version the SDK and NDK have to be installed.
+See androidbuild.bat for how to build.
+
+   Usage
+   -----
+Shown using "release"-version:
+
+ To save IQ-stream on disk and decode them off-line:
+
+ $ rtl_sdr samples.bin -f 868.9M -s 1600000
+
+ $ cat samples.bin | build/rtl_wmbus
+
+ To run continuously:
+
+ $ rtl_sdr -f 868.9M -s 1600000 - 2>/dev/null | build/rtl_wmbus
+
+ To count "good" (no 3 out of 6 errors, no checksum errors) packets:
+
+ $ cat samples.bin | build/rtl_wmbus 2>/dev/null | grep "[T,C]1;1;1" | wc -l
+
+Carrier-frequency given at "-f" must be set properly. With my DVB-T-
+Receiver I had to choose carrier 50kHz under the standard of 868.95MHz. 
+Sample rate at 1.6Ms/s is hardcoded and cannot be changed.
+
+samples2.bin is a "life" example with two devices received.
+
+On Android first the driver must be started with options given above.
+IQ-data goes to a port which is would be already set by driver settings.
+Use get_net to get IQ-data into rtl_wmbus.
+
+  License
+  -------
+
+Copyright (c) 2017 <[email protected]>
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGE.

androidbuild.bat

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+@echo off
+
+rem SETTINGS
+set SDK_ROOT=c:\Android\sdk
+set NDK_ROOT=c:\Android\android-ndk-r10e
+set SYSROOT=%NDK_ROOT%\platforms\android-21\arch-arm
+set CC=%NDK_ROOT%\toolchains\arm-linux-androideabi-4.9\prebuilt\windows-x86_64\bin\arm-linux-androideabi-gcc --sysroot=%SYSROOT%
+
+rem BUILD
+rd /S /Q Android
+md Android
+%CC% -o Android/rtl_wmbus rtl_wmbus.c -std=gnu99 -Iinclude -Wall -O3 -g0 -lm
+
+rem INSTALL
+%SDK_ROOT%\platform-tools\adb push Android\rtl_wmbus /mnt/sdcard/wmbus
+

atan2.h

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+#ifndef ATAN2_H
+#define ATAN2_H
+
+#include <math.h>
+
+
+static inline float atan2_libm(float complex y)
+{
+    return carg(y) * (float)M_1_PI;
+}
+
+
+/** https://gist.github.com/volkansalma/2972237 */
+static inline float atan2_approximation(float complex s)
+{
+    static const float ONEQTR_PI = M_PI / 4.0;
+    static const float THRQTR_PI = 3.0 * M_PI / 4.0;
+
+    float y = cimagf(s), x = crealf(s);
+    float r, angle;
+    float abs_y = fabs(y) + 1e-10f;      // kludge to prevent 0/0 condition
+
+    if (x < 0.0f)
+    {
+        r = (x + abs_y) / (abs_y - x);
+        angle = THRQTR_PI;
+    }
+    else
+    {
+        r = (x - abs_y) / (x + abs_y);
+        angle = ONEQTR_PI;
+    }
+
+    angle += (0.1963f*(float)M_1_PI * r * r - 0.9817f*(float)M_1_PI) * r;
+
+    if (y < 0.0f)
+        angle = -angle;     // negate if in quad III or IV
+
+    return angle;
+}
+
+
+/** https://gist.github.com/volkansalma/2972237 */
+static inline float atan2_approximation2(float complex s)
+{
+    float y = cimagf(s), x = crealf(s);
+
+    if (x == 0.0f)
+    {
+        if (y > 0.0f) return 0.5f;
+        if (y == 0.0f) return 0.0f;
+        return -0.5f;
+    }
+
+    float atan;
+    const float z = y / x;
+
+    if (fabs(z) < 1.0f)
+    {
+        atan = z / (1.0f*(float)M_PI + 0.28086f*(float)M_PI*z*z);
+        if (x < 0.0f)
+        {
+            if (y < 0.0f) return atan - 1.0f;
+            return atan + 1.0f;
+        }
+    }
+    else
+    {
+        atan = 0.5f - z / (z*z + 0.28086f) * (float)M_1_PI;
+        if ( y < 0.0f ) return atan - 1.0f;
+    }
+
+    return atan;
+}
+
+
+#endif /* ATAN2_H */

filter/bp_iir_cheb1_1600kHz_90kHz_98kHz_102kHz_110kHz.m

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+clear all;
+
+samplerate = 1600e3;
+nyqistrate = samplerate/2;
+
+Ws1 = 90e3/nyqistrate;
+Wp1 = 98e3/nyqistrate;
+Wp2 = 102e3/nyqistrate;
+Ws2 = 110e3/nyqistrate;
+Rp = 1;
+Rs = 40;
+
+% seems to be the best
+[n, Wc] = cheb1ord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+[b, a] = cheby1(n, Rp, Wc);
+
+% does not work at all
+%[n, Wc] = cheb2ord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+%[b, a] = cheby2(n, Rp, Wc);
+
+% performs badly
+%[n, Wc] = ellipord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+%[b, a] = ellip(n, Rp, Rs, Wc);
+
+% big filter order - unpracticable
+%[n, Wc] = buttord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+%[b, a] = butter(n, Wc);
+
+print_iir_filter_coef(b ,a);

filter/bp_iir_cheb1_400kHz_90kHz_98kHz_102kHz_110kHz.m

@@ -0,0 +1,29 @@
+clear all;
+
+samplerate = 400e3;
+nyqistrate = samplerate/2;
+
+Ws1 = 90e3/nyqistrate;
+Wp1 = 98e3/nyqistrate;
+Wp2 = 102e3/nyqistrate;
+Ws2 = 110e3/nyqistrate;
+Rp = 1;
+Rs = 40;
+
+% seems to be the best
+[n, Wc] = cheb1ord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+[b, a] = cheby1(n, Rp, Wc);
+
+% does not work at all
+%[n, Wc] = cheb2ord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+%[b, a] = cheby2(n, Rp, Wc);
+
+% performs badly
+%[n, Wc] = ellipord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+%[b, a] = ellip(n, Rp, Rs, Wc);
+
+% big filter order - unpracticable
+%[n, Wc] = buttord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+%[b, a] = butter(n, Wc);
+
+print_iir_filter_coef(b ,a);

filter/bp_iir_cheb1_800kHz_90kHz_98Hz_102kHz_110kHz.m

@@ -0,0 +1,29 @@
+clear all;
+
+samplerate = 800e3;
+nyqistrate = samplerate/2;
+
+Ws1 = 90e3/nyqistrate;
+Wp1 = 98e3/nyqistrate;
+Wp2 = 102e3/nyqistrate;
+Ws2 = 110e3/nyqistrate;
+Rp = 1;
+Rs = 40;
+
+% seems to be the best
+[n, Wc] = cheb1ord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+[b, a] = cheby1(n, Rp, Wc);
+
+% does not work at all
+%[n, Wc] = cheb2ord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+%[b, a] = cheby2(n, Rp, Wc);
+
+% performs badly
+%[n, Wc] = ellipord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+%[b, a] = ellip(n, Rp, Rs, Wc);
+
+% big filter order - unpracticable
+%[n, Wc] = buttord([Wp1, Wp2], [Ws1, Ws2], Rp, Rs);
+%[b, a] = butter(n, Wc);
+
+print_iir_filter_coef(b ,a);

filter/lp_fir_butter_1600kHz_160kHz_200kHz.m

@@ -0,0 +1,15 @@
+clear all;
+
+samplerate = 1600e3;
+nyqistrate = samplerate/2;
+
+Wp1 = 160e3/nyqistrate;
+Ws1 = 200e3/nyqistrate;
+Rp = 1;
+Rs = 40;
+
+[n, Wc] = buttord(Wp1, Ws1, Rp, Rs);
+[b] = fir1(n, Wc);
+
+print_fir_filter_coef(b);
+

filter/lp_fir_butter_800kHz_100kHz_10kHz.m

@@ -0,0 +1,15 @@
+clear all;
+
+samplerate = 800e3;
+nyqistrate = samplerate/2;
+
+Wp1 = 100e3/nyqistrate;
+Ws1 = 10e3/nyqistrate;
+Rp = 1;
+Rs = 40;
+
+[n, Wc] = buttord(Wp1, Ws1, Rp, Rs);
+[b] = fir1(n, Wc);
+
+print_fir_filter_coef(b);
+

filter/lp_ppf_butter_1600kHz_160kHz_200kHz.m

@@ -0,0 +1,27 @@
+clear all;
+
+samplerate = 1600e3;
+nyqistrate = samplerate/2;
+
+Wp1 = 160e3/nyqistrate;
+Ws1 = 200e3/nyqistrate;
+Rp = 1;
+Rs = 40;
+
+[n, Wc] = buttord(Wp1, Ws1, Rp, Rs);
+[b] = fir1(n, Wc);
+
+x = 1:22;
+y = filter(b,1,x);
+y = y(2:2:end);
+
+phase_channels = 2;
+b_poly = buffer(b, phase_channels);
+y1 = filter(b_poly(2,:), 1, x(1:2:end));
+y2 = filter(b_poly(1,:), 1, x(2:2:end));
+
+y_poly = y1 + y2;
+
+y_err = y - y_poly;
+
+print_ppf_filter_coef(b, phase_channels);

filter/print_fir_filter_coef.m

@@ -0,0 +1,14 @@
+function [] = print_fir_filter_coef(b);
+
+[R, C] = size(b);
+
+fprintf(stdout, "#define COEFFS %u\n", C);
+
+fprintf(stdout, "static const float b[COEFFS] = {");
+for c = 1:C,
+    fprintf(stdout, "%.10g, ", b(c));
+end
+fprintf(stdout, "};\n");
+
+fprintf(stdout, "#undef COEFFS\n");
+