config: allow command line modem configuration

amodem/config.py

@@ -1,17 +1,27 @@
 import numpy as np
 
-Fs = 32e3
+## Parameters
+Fs = 32000.0 # sampling frequency [Hz]
+Nfreq = 8 # number of frequencies used
+Tsym = 0.001 # symbol duration [seconds]
+Nx = 8
+Ny = 8
+
 Ts = 1.0 / Fs
 
-frequencies = (1 + np.arange(8)) * 1e3
+frequencies = (1 + np.arange(Nfreq)) * 1e3
 carrier_index = 0
 Fc = frequencies[carrier_index]
 Tc = 1.0 / Fc
 
-symbols = np.array([complex(x, y)
-                   for x in np.linspace(-1, 1, 8)
-                   for y in np.linspace(-1, 1, 8)]) / np.sqrt(2)
+assert Nx == 2 ** round(np.log2(Nx))
+assert Ny == 2 ** round(np.log2(Ny))
+
+xs = np.linspace(-1, 1, Nx) if Nx > 1 else 0.0
+ys = np.linspace(-1, 1, Ny) if Ny > 1 else 0.0
+symbols = np.array([complex(x, y) for x in xs for y in ys])
+symbols = symbols / np.max(np.abs(symbols))
 
-Tsym = 1e-3
 Nsym = int(Tsym / Ts)
 baud = int(1/Tsym)
+

amodem/configure.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+template = '''import numpy as np
+
+## Parameters
+Fs = {Fs} # sampling frequency [Hz]
+Nfreq = {Nfreq} # number of frequencies used
+Tsym = {Tsym} # symbol duration [seconds]
+Nx = {Nx}
+Ny = {Ny}
+
+Ts = 1.0 / Fs
+
+frequencies = (1 + np.arange(Nfreq)) * 1e3
+carrier_index = 0
+Fc = frequencies[carrier_index]
+Tc = 1.0 / Fc
+
+assert Nx == 2 ** round(np.log2(Nx))
+assert Ny == 2 ** round(np.log2(Ny))
+
+xs = np.linspace(-1, 1, Nx) if Nx > 1 else 0.0
+ys = np.linspace(-1, 1, Ny) if Ny > 1 else 0.0
+symbols = np.array([complex(x, y) for x in xs for y in ys])
+symbols = symbols / np.max(np.abs(symbols))
+
+Nsym = int(Tsym / Ts)
+baud = int(1/Tsym)
+'''
+
+defaults = dict(Fs=32e3, Nx=8, Ny=8, Tsym=1e-3, Nfreq=8)
+
+import sys
+args = sys.argv[1:]
+for arg in args:
+    name, value = arg.split('=')
+    if name in defaults:
+        T = type(defaults[name])
+        defaults[name] = T(value)
+
+content = template.format(**defaults)
+print(content)