added a matlab demo - surprisingly seamless

mat_sampling.m

@@ -0,0 +1,24 @@
+% this is an example of sampling the ADC from Matlab and then plotting a
+% FFT graph. The ADC unit called 'adc' is configured to use PA1 as Ch. 0
+
+%transport = py.gex.TrxSerialThread(pyargs('port', '/dev/ttyUSB1', 'baud', 57600));
+transport = py.gex.TrxRawUSB();
+client = py.gex.Client(transport);
+adc = py.gex.ADC(client, 'adc');
+
+L=1000;
+Fs=1000;
+
+adc.set_sample_rate(uint32(Fs));
+data = adc.capture(uint32(L));
+data = double(py.array.array('f',data));
+
+Y = fft(data);
+P2 = abs(Y/L);
+P1 = P2(1:L/2+1);
+P1(2:end-1) = 2*P1(2:end-1);
+
+f = Fs*(0:(L/2))/L;
+plot(f,P1)
+
+client.close()