Merge pull request #661 from happycube/efmfilter-test

Improved EFM filter parameters

lddecode/core.py

@@ -378,16 +378,17 @@ def computeefmfilter(self):
 
         This improved EFM filter was devised by Adam Sampson (@atsampson)
         """
+
         # Frequency bands
-        freqs = np.linspace(0.0e6, 2.0e6, num=11)
+        freqs = np.linspace(0.0e6, 1.9e6, num=11)
         freq_per_bin = self.freq_hz / self.blocklen
         # Amplitude and phase adjustments for each band.
         # These values were adjusted empirically based on a selection of NTSC and PAL samples.
-        amp = np.array([0.0, 0.2, 0.41, 0.73, 0.98, 1.03, 0.99, 0.81, 0.59, 0.42, 0.0])
+        amp = np.array([0.0, 0.215, 0.41, 0.73, 0.98, 1.03, 0.99, 0.81, 0.59, 0.42, 0.0])
         phase = np.array(
-            [0.0, -0.95, -1.05, -1.05, -1.2, -1.2, -1.2, -1.2, -1.2, -1.2, -1.2]
+            [0.0, -0.92, -1.03, -1.11, -1.2, -1.2, -1.2, -1.2, -1.05, -0.95, -0.8]
         )
-        coeffs = None
+        phase = [p * 1.25 for p in phase]
 
         """Compute filter coefficients for the given FFTFilter."""
         # Anything above the highest frequency is left as zero.

lddecode/efm_pll.py

@@ -49,11 +49,11 @@ def computeefmfilter(freq_hz = 40000000, blocklen = 65536):
     freq_per_bin = freq_hz / blocklen
     # Amplitude and phase adjustments for each band.
     # These values were adjusted empirically based on a selection of NTSC and PAL samples.
-    amp = np.array([0.0, 0.2, 0.41, 0.73, 0.98, 1.03, 0.99, 0.81, 0.59, 0.42, 0.0])
+    amp = np.array([0.0, 0.215, 0.41, 0.73, 0.98, 1.03, 0.99, 0.81, 0.59, 0.42, 0.0])
     phase = np.array(
-        [0.0, -0.95, -1.05, -1.05, -1.2, -1.2, -1.2, -1.2, -1.2, -1.2, -1.2]
+        [0.0, -0.92, -1.03, -1.11, -1.2, -1.2, -1.2, -1.2, -1.05, -0.95, -0.8]
     )
-    coeffs = None
+    phase = [p * 1.25 for p in phase]
 
     """Compute filter coefficients for the given FFTFilter."""
     # Anything above the highest frequency is left as zero.