From 3a59a54107f01ae33c12b41ae2bb8b931ec23008 Mon Sep 17 00:00:00 2001
From: Roman Zeyde <roman.zeyde@gmail.com>
Date: Tue, 21 Oct 2014 10:42:13 +0300
Subject: [PATCH] refactor calibration `recv` script

---
 amodem/calib.py     | 69 ++++++++++++++++++++++++++++++---------------
 scripts/amodem      |  4 +--
 tests/test_calib.py |  2 +-
 3 files changed, 50 insertions(+), 25 deletions(-)

diff --git a/amodem/calib.py b/amodem/calib.py
index 9ef3c0c..2f0bf6d 100644
--- a/amodem/calib.py
+++ b/amodem/calib.py
@@ -12,7 +12,7 @@ CALIBRATION_SYMBOLS = int(1.0 * config.Fs)
 ALLOWED_EXCEPTIONS = (IOError, KeyboardInterrupt)
 
 
-def send(wave_play=wave.play):
+def send(wave_play=wave.play, verbose=False):
     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))
@@ -28,41 +28,66 @@ def send(wave_play=wave.play):
         p.kill()
 
 
-FRAME_LENGTH = 100 * config.Nsym
+FRAME_LENGTH = 200 * config.Nsym
 
 
 def recorder(process):
+    t = np.arange(0, FRAME_LENGTH) * config.Ts
+    scaling_factor = 0.5 * len(t)
+    carriers = [np.exp(2j * np.pi * f * t) for f in config.frequencies]
+    carriers = np.array(carriers) / scaling_factor
+
     frame_size = int(wave.bytes_per_sample * FRAME_LENGTH)
     fd = process.stdout
+
+    states = [True]
+    errors = ['weak', 'strong', 'noisy']
     try:
         while True:
             data = fd.read(frame_size)
             if len(data) < frame_size:
                 return
             data = common.loads(data)
-            data = data - np.mean(data)
-            yield data
+            frame = data - np.mean(data)
+
+            coeffs = np.dot(carriers, frame)
+            peak = np.max(np.abs(frame))
+            total = np.sqrt(np.dot(frame, frame) / scaling_factor)
+
+            max_index = np.argmax(np.abs(coeffs))
+            freq = config.frequencies[max_index]
+            rms = abs(coeffs[max_index])
+            coherency = rms / total
+            flags = [rms > 0.1, peak < 1.0, coherency > 0.9999]
+
+            states.append(all(flags))
+            states = states[-2:]
+
+            message = 'good signal'
+            error = not any(states)
+            if error:
+                error_index = flags.index(False)
+                message = 'too {} signal'.format(errors[error_index])
+
+            yield dict(
+                freq=freq, rms=rms, peak=peak, coherency=coherency,
+                total=total, error=error, message=message
+            )
     except ALLOWED_EXCEPTIONS:
         pass
     finally:
         process.kill()
 
+fmt = '{freq:6.0f} Hz: {message:s}{extra:s}'
+fields = ['peak', 'total', 'rms', 'coherency']
 
-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))
-
-    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'
+def recv(wave_record=wave.record, printer=sys.stdout.write, verbose=False):
+    extra = ''
+    if verbose:
+        extra = ''.join(', {0}={{{0}:.4f}}'.format(f) for f in fields)
+    for r in recorder(wave_record(stdout=wave.sp.PIPE)):
+        msg = fmt.format(extra=extra.format(**r), **r)
+        if not r['error']:
+            log.info(msg)
+        else:
+            log.error(msg)
diff --git a/scripts/amodem b/scripts/amodem
index 5ce5791..5ffb541 100755
--- a/scripts/amodem
+++ b/scripts/amodem
@@ -148,7 +148,7 @@ def run_modem(args, func):
 
 def run_send(args):
     if args.calibrate:
-        calib.send()
+        calib.send(verbose=args.verbose)
     elif args.wave:
         join_process(wave.play(fname=args.input))
     else:
@@ -157,7 +157,7 @@ def run_send(args):
 
 def run_recv(args):
     if args.calibrate:
-        calib.recv()
+        calib.recv(verbose=args.verbose)
     elif args.wave:
         join_process(wave.record(fname=args.output))
     else:
diff --git a/tests/test_calib.py b/tests/test_calib.py
index 97bf248..6adc712 100644
--- a/tests/test_calib.py
+++ b/tests/test_calib.py
@@ -43,5 +43,5 @@ def test_errors():
     def _read(data):
         raise KeyboardInterrupt()
     p.read = _read
-    calib.recv(p)
+    calib.recv(p, verbose=True)
     assert p.buf.tell() == 0