Initial

zerocross_meas.py

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+import numpy as np
+
+import matplotlib.pyplot as plt
+import fft
+import IIR_filter
+
+class zerocross_meas(object):
+	"""docstring for fft_meas"""
+	def __init__(self, fs=50e3, tn=1):
+		self.fs = fs
+		self.ts = 1/self.fs
+		self.tn = tn
+		self.time = 0
+		self.freq = 0
+		self.freq_ts = 0
+		self.y = 0 
+		self.y_old = 0
+		self.idx = 0
+		self.LPfilter = IIR_filter.IIR_1_Order_LP(fs=self.fs, fc=200)
+
+	def step(self, x, time):
+
+		if time - self.time > self.ts:
+			self.time = time	
+			self.y = self.LPfilter.step(x)
+
+			if self.y_old < 0 and self.y > 0:
+				self.idx += 1
+
+
+			if time - self.freq_ts > self.tn:
+				self.freq = self.idx / self.tn
+				self.freq_ts = time
+				self.idx = 0
+
+
+			self.y_old = self.y
+
+			
+	def print(self):
+		print(self.freq)