loopback test

xfer_tracer/script.py

@@ -27,69 +27,30 @@ def audio_callback(in_data, frame_count, time_info, status):
 	return (outbytes, pa.paContinue)
 
 paudio = pa.PyAudio()
-stream = paudio.open(format=pa.paFloat32,
+output_strm = paudio.open(format=pa.paFloat32,
 	channels=1,
 	rate=48000,
 	output=True,
 	stream_callback=audio_callback)
+output_strm.start_stream()
 
-def do_frequency(scaled_f, osci, hscale):
+input_strm = paudio.open(format=pa.paFloat32,
+    channels=1,
+    rate=48000,
+    input=True)
+input_strm.stop_stream()
+
+def do_frequency(scaled_f):
     scaled_frequency = scaled_f
-	time.sleep(0.1)
-	osci.write("acquire:state run") # Restart acquisition sequence
-	time.sleep(10 * hscale)
+    time.sleep(0.2) # Stall for latency/transitory behavior
+    input_strm.start_stream()
+    L = input_strm.read(int(48000 * 0.1)) # We get 1/sqrt(n) noise rejection and 1/n spurious tone rejection
+    input_strm.stop_stream()
+    return np.frombuffer(L, dtype=np.float32)
 
-	osci.write("data:source CH1")
-	A_samps = osci.query_binary_values("curve?",datatype='b',container=numpy.array)
-	A_samps = A_samps.astype(np.float64)
+import matplotlib.pyplot as plt
+L = do_frequency(440.0/48000)
+print(L)
+plt.plot(L)
+plt.show()
 
-	osci.write("data:source CH2") # For now, do not adjust for zeros in the resp.
-	B_samps = osci.query_binary_values("curve?",datatype='b',container=numpy.array)
-	B_samps = B_samps.astype(np.float64)
-
-	A_samps = np.rfft(A_samps) # No window, because of the precise frequency
-	B_samps = np.rfft(B_samps)
-
-	# We have (10 * hscale)/Tcurv periods
-	return B_samps[np.round((10 * hscale) * (scaled_f * 4800))]
-        /A_samps[np.round((10 * hscale) * (scaled_f * 4800))]
-
-def find_oscillo():
-	rm = pyvisa.ResourceManager()
-	R = rm.list_resources("USB?*")
-	if R.empty():
-		print("No device found")
-		exit(1)
-	return rm.open_resource(R[0])
-
-osci = find_oscillo()
-print(osci.query("*IDN?"))
-
-osci.write("*RST")
-time.sleep(5)
-osci.write("horizontal:main:scale 5.0e-4")
-
-osci.write("ch1:scale 1.0e-1")
-osci.write("ch1:bandwidth ON")
-osci.write("ch1:coupling AC")
-osci.write("select:ch1 1")
-
-osci.write("ch2:scale 5.0e-2")
-osci.write("ch2:bandwidth ON")
-osci.write("ch2:coupling AC")
-osci.write("select:ch2 1")
-
-# 8-bit data
-osci.write("data:source CH1")
-osci.write("data:encdg ascii")
-
-osci.write("trigger:main:edge:source CH1")
-osci.write("trigger:main:mode NORMAL")
-osci.write("trigger:main:type EDGE")
-
-osci.write("acquire:mode average")
-osci.write("acquire:numavg 128")
-osci.write("acquire:stopafter sequence")
-osci.write("acquire:state RUN")
-
-print(osci.query("curve?"))

xfer_tracer/shell.nix

@@ -10,6 +10,7 @@ pkgs.mkShell {
 			ps.psutil
 			ps.pyusb
 			ps.numpy
-			ps.pyaudio]))
+			ps.pyaudio
+			ps.matplotlib]))
 	];
 }