update l5

Makefile

@@ -11,8 +11,8 @@ FILES = l00_diode \
 	l02_esd \
 	l03_refbias \
 	l04_afe \
-#	l05_sc \
-	l06_adc \
+	l05_sc \
+#	l06_adc \
 	l07_vreg \
 	l08_pll \
 	l09_osc \

ex/dt.py

@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+#
+import numpy as np
+import matplotlib.pyplot as plt
+
+Hann = True
+
+#- Create a time vector
+N = 2**13
+t = np.linspace(0,N,N)
+
+#- Create the "continuous time" signal with multiple sinusoidal signals and some noise
+f1 = 233/N
+fd = 1/N*119
+x_s = np.sin(2*np.pi*f1*t) + 1/1024*np.random.randn(N) +   0.5*np.sin(2*np.pi*(f1-fd)*t) + 0.5*np.sin(2*np.pi*(f1+fd)*t)
+
+#- Create the sampling vector, and the sampled signal
+t_s_unit = [1,1,0,0,0,0,0,0]
+t_s = np.tile(t_s_unit,int(N/len(t_s_unit)))
+x_sn = x_s*t_s
+
+#- Convert to frequency domain with a hanning window to avoid FFT bin
+#- energy spread
+if(Hann):
+    w = np.hanning(N+1)
+else:
+    w = np.ones(N+1)
+X_s = np.fft.fftshift(np.fft.fft(np.multiply(w[0:N],x_s)))
+X_sn = np.fft.fftshift(np.fft.fft(np.multiply(w[0:N],x_sn)))
+
+
+
+plt.subplot(2,2,1)
+plt.ylabel("Time Domain")
+plt.plot(x_s)
+plt.xlabel("Continuous time, continuous value")
+plt.subplot(2,2,2)
+plt.plot(x_sn)
+plt.ylabel("Frequency Domain")
+plt.xlabel("Discrete time, continuous value")
+plt.subplot(2,2,3)
+plt.plot(20*np.log10(np.abs(X_s)))
+plt.subplot(2,2,4)
+plt.plot(20*np.log10(np.abs(X_sn)))
+
+fig = plt.gcf()
+fig.set_size_inches(12, 7)
+plt.tight_layout()
+plt.savefig(f"l5_dt.pdf")
+plt.show()