set the sample rate to ratio 10

.vscode/.server-controller-port.log

@@ -1,5 +1,5 @@
 {
   "port": 13452,
-  "time": 1741953769473,
+  "time": 1742112482618,
   "version": "0.0.3"
 }

gen_wave.py

@@ -6,7 +6,7 @@ import io, os
 if PLOT: import matplotlib.pyplot as plt
 if FFT: import numpy as np  # Import numpy for FFT
 
-sample_rate = 9500
+sample_rate = 11875
 
 # this is modified from ChristopheJacquet's pydemod
 def rrcosfilter(NumSamples):
@@ -57,9 +57,9 @@ outc.write(header)
 outh.write(header)
 
 def generate():
-    offset = int(sample_rate*0.004)  # 190 khz = 760
-    count = int(offset / 10**(len(str(offset)) - 1))  # 760 / 100 = 7
-    l = int(sample_rate / 1187.5) // 2  # 16/2 = 8
+    offset = int(sample_rate*0.004)
+    count = int(offset / 10**(len(str(offset)) - 1))
+    l = int(sample_rate / 1187.5) // 2
     if count*l > l*16: raise Exception("Sample rate too small")
     print(f"{offset=} {count=} {l=}")
 
@@ -67,13 +67,11 @@ def generate():
     sample[l] = 1
     sample[2*l] = -1
 
-    # Apply the data-shaping filter
     sf = rrcosfilter(l*16)
     shapedSamples = convolve(sample, sf)
 
-    # Slice the array like numpy would
     out = shapedSamples[offset-l*count:offset+l*count]
-    out = [i/(max(out)) for i in out]
+    out = [2 * (i - min(out)) / (max(out) - min(out)) - 1 for i in out]
     if max(out) > 1 or min(out) < -1: raise Exception("Clipped")
 
     if PLOT:
@@ -92,6 +90,7 @@ def generate():
         # Plot the magnitude of the FFT
         plt.figure(figsize=(10, 6))
         plt.plot(fft_freqs[:N//2], np.abs(fft_out)[:N//2])  # Plot only the positive frequencies
+        plt.xlim(0,1187.5*3)
         plt.title("FFT of the waveform")
         plt.xlabel("Frequency (Hz)")
         plt.ylabel("Magnitude")

gen_wave_original.py

@@ -0,0 +1,109 @@
+PLOT = True
+FFT = PLOT and True
+
+import math
+import io, os
+if PLOT: import matplotlib.pyplot as plt
+if FFT: import numpy as np  # Import numpy for FFT
+
+sample_rate = 190000
+
+# this is modified from ChristopheJacquet's pydemod
+def rrcosfilter(NumSamples):
+    T_delta = 1/float(sample_rate)
+    sample_num = list(range(NumSamples))
+    h_rrc = [0.0] * NumSamples
+    SymbolPeriod = 1/(2*1187.5)
+
+    for x in sample_num:
+        t = (x-NumSamples/2)*T_delta
+        if t == 0.0:
+            h_rrc[x] = 1.0 - 1 + (4/math.pi)
+        elif t == SymbolPeriod/4:
+            h_rrc[x] = (1/math.sqrt(2))*(((1+2/math.pi)* \
+                    (math.sin(math.pi/4))) + ((1-2/math.pi)*(math.cos(math.pi/4))))
+        elif t == -SymbolPeriod/4:
+            h_rrc[x] = (1/math.sqrt(2))*(((1+2/math.pi)* \
+                    (math.sin(math.pi/4))) + ((1-2/math.pi)*(math.cos(math.pi/4))))
+        else:
+            h_rrc[x] = (4*(t/SymbolPeriod)*math.cos(math.pi*t*2/SymbolPeriod))/ \
+                    (math.pi*t*(1-(4*t/SymbolPeriod)*(4*t/SymbolPeriod))/SymbolPeriod)
+
+    return h_rrc
+
+def convolve(a, b):
+    out = [0] * (len(a) + len(b) - 1)
+    for i in range(len(a)):
+        for j in range(len(b)):
+            out[i+j] += a[i] * b[j]
+    return out
+
+PATH = os.path.dirname(os.path.abspath(__file__))
+
+outc = io.open(f"{PATH}/src/waveforms.c", mode="w", encoding="utf8")
+outh = io.open(f"{PATH}/src/waveforms.h", mode="w", encoding="utf8")
+
+header = u"""
+/* This file was automatically generated by "gen_wave.py".
+   (C) 2014 Christophe Jacquet.
+   (C) 2023 Anthony96922.
+   (C) 2025 kuba201.
+   Released under the GNU GPL v3 license.
+*/
+
+"""
+
+outc.write(header)
+outh.write(header)
+
+def generate():
+    offset = 760
+    count = 7
+    l = int(sample_rate / 1187.5) // 2
+    if count*l > l*16: raise Exception("Sample rate too small")
+    print(f"{offset=} {count=} {l=}")
+
+    sample = [0.0] * (count*l)
+    sample[l] = 1
+    sample[2*l] = -1
+
+    sf = rrcosfilter(l*16)
+    shapedSamples = convolve(sample, sf)
+
+    out = shapedSamples[offset-l*count:offset+l*count]
+    out = [2 * (i - min(out)) / (max(out) - min(out)) - 1 for i in out]
+    if max(out) > 1 or min(out) < -1: raise Exception("Clipped")
+
+    if PLOT:
+        # Plot the waveform
+        plt.plot(out, label="out")
+        plt.legend()
+        plt.grid(True)
+        plt.show()
+
+    if FFT:
+        # Compute the FFT of the waveform
+        N = len(out)
+        fft_out = np.fft.fft(out)
+        fft_freqs = np.fft.fftfreq(N, d=1/sample_rate)
+
+        # Plot the magnitude of the FFT
+        plt.figure(figsize=(10, 6))
+        plt.plot(fft_freqs[:N//2], np.abs(fft_out)[:N//2])  # Plot only the positive frequencies
+        plt.xlim(0,1187.5*3)
+        plt.title("FFT of the waveform")
+        plt.xlabel("Frequency (Hz)")
+        plt.ylabel("Magnitude")
+        plt.grid(True)
+        plt.show()
+
+    # outc.write(u"float waveform_biphase[{size}] = {{{values}}};\n\n".format(
+        # values = u", ".join(map(str, out)),
+        # size = len(out)))
+
+    # outh.write(u"extern float waveform_biphase[{size}];\n".format(size=len(out)))
+
+generate()
+
+outc.close()
+outh.close()

src/rds.h

@@ -10,9 +10,10 @@
 
 #define GROUP_LENGTH		4
 #define BITS_PER_GROUP		(GROUP_LENGTH * (BLOCK_SIZE + POLY_DEG))
-#define RDS_SAMPLE_RATE		9500
-#define SAMPLES_PER_BIT     8 // (1/1187.5)*RDS_SAMPLE_RATE
-#define FILTER_SIZE	 24
+// when i say ratio 10, i mean 1187.5*10
+#define RDS_SAMPLE_RATE		11875 // pira's m32 works at 361 khz, which is a ratio of 304, but this does a ratio of 10, while the m232 does a ratio of about 500
+#define SAMPLES_PER_BIT     10 // (1/1187.5)*RDS_SAMPLE_RATE or RDS_SAMPLE_RATE/1187.5, to check you can do (1187.5*SAMPLES_PER_BIT)=(RDS_SAMPLE_RATE)
+#define FILTER_SIZE	 40
 #define SAMPLE_BUFFER_SIZE	(SAMPLES_PER_BIT + FILTER_SIZE)
 
 #define RT_LENGTH	64

src/waveforms.c

@@ -6,5 +6,5 @@
    Released under the GNU GPL v3 license.
 */
 
-float waveform_biphase[24] = {0.004662004662004664, -1.192872569837455e-17, -0.008325008325008324, 5.168171209081069e-17, 0.017316017316017313, -4.0195812562580885e-17, -0.04761904761904761, -2.153908398182045e-17, 0.2857142857142856, 0.7363107781851077, 1.0, 0.7363107781851077, 0.0, -0.7363107781851077, -1.0, -0.7363107781851077, -0.2857142857142856, 2.153908398182045e-17, 0.04761904761904761, 4.0195812562580885e-17, -0.017316017316017313, -5.168171209081069e-17, 0.008325008325008324, 1.192872569837455e-17};
+float waveform_biphase[40] = {0.001428519781289772, 0.0016664760371696286, -0.0007489747210579489, -0.002879473467708782, -0.00106869603307147, 0.003402376491623338, 0.004197098675717825, -0.0020108774820242203, -0.008325008325008265, -0.003370279435959911, 0.011902549863605172, 0.016661972622002308, -0.009354493372215611, -0.04761904761904756, -0.02565484871607826, 0.14035864022832323, 0.4612061004721879, 0.817876195033512, 1.0, 0.8360849414906586, 0.3268491412309902, -0.3268491412309902, -0.8360849414906588, -1.0, -0.817876195033512, -0.461206100472188, -0.14035864022832323, 0.02565484871607837, 0.04761904761904745, 0.009354493372215611, -0.016661972622002308, -0.011902549863605172, 0.0033702794359598, 0.008325008325008376, 0.0020108774820242203, -0.004197098675717825, -0.003402376491623449, 0.00106869603307147, 0.002879473467708893, 0.00074897472105806};
 

src/waveforms.h

@@ -6,4 +6,4 @@
    Released under the GNU GPL v3 license.
 */
 
-extern float waveform_biphase[24];
+extern float waveform_biphase[40];