48<->8 short resampler working again, including test

Author: drowe67

CMakeLists.txt

@@ -379,6 +379,14 @@ if(UNITTEST)
              set_tests_properties(test_fdmdv_16to8_short PROPERTIES PASS_REGULAR_EXPRESSION "PASS")
 
     # 48<->8 kHz float resamplers
+    add_test(NAME test_fdmdv_48to8_short
+             COMMAND sh -c "cd ${CMAKE_CURRENT_SOURCE_DIR}/octave;
+                            ${CMAKE_CURRENT_BINARY_DIR}/unittest/t48_8_short;
+                            DISPLAY=\"\" echo \"diff_fft_mag('in8.raw','out8.raw'); quit;\" | octave-cli -qf
+                            ")
+             set_tests_properties(test_fdmdv_48to8_short PROPERTIES PASS_REGULAR_EXPRESSION "PASS")
+
+    # 48<->8 kHz short resamplers
     add_test(NAME test_fdmdv_48to8
              COMMAND sh -c "cd ${CMAKE_CURRENT_SOURCE_DIR}/octave;
                             ${CMAKE_CURRENT_BINARY_DIR}/unittest/t48_8;

src/fdmdv.c

@@ -1922,9 +1922,8 @@ void fdmdv_8_to_48_short(short out48k[], short in8k[], int n)
 	for(j=0; j<FDMDV_OS_48; j++) {
 	    acc = 0.0;
 	    for(k=0,l=0; k<FDMDV_OS_TAPS_48K; k+=FDMDV_OS_48,l++)
-		out48k[i*FDMDV_OS_48+j] += fdmdv_os_filter48[k+j]*in8k[i-l];
-	    out48k[i*FDMDV_OS_48+j] = acc*FDMDV_OS_48;
-	    
+		acc += fdmdv_os_filter48[k+j]*in8k[i-l];
+	    out48k[i*FDMDV_OS_48+j] = acc*FDMDV_OS_48;	    
 	}
     }	
 

unittest/CMakeLists.txt

@@ -92,3 +92,6 @@ target_link_libraries(t16_8_short codec2)
 
 add_executable(t48_8 t48_8.c ../src/fdmdv.c ../src/kiss_fft.c)
 target_link_libraries(t48_8 codec2)
+
+add_executable(t48_8_short t48_8_short.c ../src/fdmdv.c ../src/kiss_fft.c)
+target_link_libraries(t48_8_short codec2)

unittest/t48_8_short.c

@@ -0,0 +1,84 @@
+/*
+   t48_8_short.c
+   David Rowe
+   Dec 2021
+*/
+
+#include <assert.h>
+#include <math.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "codec2_fdmdv.h"
+
+#define N8         180        /* processing buffer size at 8 kHz */
+#define N48        (N8*FDMDV_OS_48)
+#define MEM8       FDMDV_OS_TAPS_48_8K
+#define FRAMES     50
+#define TWO_PI     6.283185307
+#define FS         48000
+
+#define SINE
+
+int main() {
+    short in8k[MEM8+N8];
+    short out48k[N48];
+    FILE *f48;
+
+    short in48k[FDMDV_OS_TAPS_48K + N48];
+    short out8k[N48];
+    FILE *f8, *f8in;
+
+    int i,f,t,t1;
+    float freq = 800.0;
+
+    f48 = fopen("out48.raw", "wb");
+    assert(f48 != NULL);
+    f8 = fopen("out8.raw", "wb");
+    assert(f8 != NULL);
+    f8in = fopen("in8.raw", "wb");
+    assert(f8in != NULL);
+
+    /* clear filter memories */
+
+    for(i=0; i<MEM8; i++)
+	in8k[i] = 0.0;
+    for(i=0; i<FDMDV_OS_TAPS_48K; i++)
+	in48k[i] = 0.0;
+
+    t = t1 = 0;
+    for(f=0; f<FRAMES; f++) {
+
+#ifdef DC
+	for(i=0; i<N8; i++)
+	    in8k[MEM8+i] = 16000.0;
+#endif
+#ifdef SINE
+	for(i=0; i<N8; i++,t++)
+	    in8k[MEM8+i] = 16000.0*cos(TWO_PI*t*freq/(FS/FDMDV_OS_48));
+#endif
+	fwrite(&in8k[MEM8], sizeof(short), N8, f8in);
+
+	/* upsample  */
+	fdmdv_8_to_48_short(out48k, &in8k[MEM8], N8);
+
+	/* save 48k to disk for plotting and check out */
+	fwrite(out48k, sizeof(short), N48, f48);
+
+	/* add a 10 kHz spurious signal for fun, we want down sampler to
+	   knock this out */
+	for(i=0; i<N48; i++,t1++)
+	    in48k[i+FDMDV_OS_TAPS_48K] = out48k[i] + 16000.0*cos(TWO_PI*t1*1E4/FS);
+
+	/* downsample */
+	fdmdv_48_to_8_short(out8k, &in48k[FDMDV_OS_TAPS_48K], N8);
+
+	/* save 8k to disk for plotting and check out */
+	fwrite(out8k, sizeof(short), N8, f8);
+    }
+
+    fclose(f48);
+    fclose(f8);
+    fclose(f8in);
+    return 0;
+
+}