From 7aed8ef4d2bc11124ac30c1cdfffd697fe6770bf Mon Sep 17 00:00:00 2001
From: Roman Zeyde <roman.zeyde@gmail.com>
Date: Thu, 9 Oct 2014 19:18:57 +0300
Subject: [PATCH] calib: test all frequencies

---
 amodem/calib.py | 75 +++++++++++++++++++++++++++++++------------------
 1 file changed, 47 insertions(+), 28 deletions(-)

diff --git a/amodem/calib.py b/amodem/calib.py
index bbf93f3..6be38fc 100644
--- a/amodem/calib.py
+++ b/amodem/calib.py
@@ -1,47 +1,66 @@
-import sys
 import numpy as np
+import logging
+import sys
+
+log = logging.getLogger(__name__)
 
 from . import common
 from . import config
-from . import dsp
 from . import wave
 
-Tsample = 1
-t = np.arange(int(Tsample * config.Fs)) * config.Ts
-sig = np.exp(2j * np.pi * config.Fc * t)
-sig_dump = common.dumps(sig)
-fmt = 'coherence={:.3f} amplitude={:.3f} phase={:+.1f} peak={:.3f}\n'
+CALIBRATION_SYMBOLS = int(1.0 * config.Fs)
 
+ALLOWED_EXCEPTIONS = (IOError, KeyboardInterrupt)
 
 def send(wave_play=wave.play):
-    p = wave_play(stdin=wave.sp.PIPE, stderr=open('/dev/null'))
+    t = np.arange(0, CALIBRATION_SYMBOLS) * config.Ts
+    signal = [np.sin(2 * np.pi * f * t) for f in config.frequencies]
+    signal = common.dumps(np.concatenate(signal))
+
+    p = wave_play(stdin=wave.sp.PIPE)
+    fd = p.stdin
     try:
         while True:
-            try:
-                p.stdin.write(sig_dump)
-            except IOError:
-                return
-    except KeyboardInterrupt:
+            fd.write(signal)
+    except ALLOWED_EXCEPTIONS:
+        pass
+    finally:
         p.kill()
 
 
-def recv(wave_record=wave.record, reporter=sys.stdout.write):
-    p = wave_record(stdout=wave.sp.PIPE)
+FRAME_LENGTH = 100 * config.Nsym
+
+def recorder(process):
+    frame_size = int(wave.bytes_per_sample * FRAME_LENGTH)
+    fd = process.stdout
     try:
         while True:
-            data = p.stdout.read(len(sig_dump))
-            if len(data) < len(sig_dump):
+            data = fd.read(frame_size)
+            if len(data) < frame_size:
                 return
-            x = common.loads(data)
-            x = x - np.mean(x)
+            data = common.loads(data)
+            data = data - np.mean(data)
+            yield data
+    except ALLOWED_EXCEPTIONS:
+        pass
+    finally:
+        process.kill()
 
-            normalization_factor = np.sqrt(0.5 * len(x)) * dsp.norm(x)
-            coherence = np.abs(np.dot(x, sig)) / normalization_factor
-            z = np.dot(x, sig.conj()) / (0.5 * len(x))
-            amplitude = np.abs(z)
-            phase = np.angle(z)
-            peak = np.max(np.abs(x))
+def recv(wave_record=wave.record, log=sys.stdout.write):
+    t = np.arange(0, FRAME_LENGTH) * config.Ts
+    carriers = [np.exp(2j * np.pi * f * t) for f in config.frequencies]
+    carriers = np.array(carriers) / (0.5 * len(t))
 
-            reporter(fmt.format(coherence, amplitude, phase * 180/np.pi, peak))
-    except KeyboardInterrupt:
-        p.kill()
+    for frame in recorder(wave_record(stdout=wave.sp.PIPE)):
+        peak = np.max(np.abs(frame))
+        coeffs = np.dot(carriers, frame)
+        max_index = np.argmax(np.abs(coeffs))
+        max_coeff = coeffs[max_index]
+
+        freq = config.frequencies[max_index]
+        rms = abs(max_coeff)
+        total = np.sqrt(np.dot(frame, frame) / (0.5 * len(t)))
+        coherency = rms / total
+        log(fmt.format(freq / 1e3, 100 * coherency, rms, total, peak))
+
+fmt = '{:4.0f} kHz @ {:6.2f}% : RMS = {:.4f}, Total = {:.4f}, Peak = {:.4f}\n'