peak-detector.py

class PeakDetector:
    def __init__(self,
                 threshold: int, hysteresis: int):
        self.threshold = threshold
        self.hysteresis = hysteresis

        self.previous_peak_maximum = 0
        self.current_maximum = 0

    def __call__(self, value: int):
        if self.current_maximum > 0:
            if value >= self.current_maximum:
                self.current_maximum = value

            elif self.threshold - value > self.hysteresis:
                self.previous_peak_maximum = self.current_maximum
                self.current_maximum = 0

        elif value >= self.threshold:
            self.current_maximum = value

        return self.previous_peak_maximum

if __name__ == '__main__':
    import numpy as np
    from matplotlib import pyplot as plt

    # Generate a test signal
    n = np.arange(0, 4096)
    signal = (511-128) * np.sin(2 * np.pi * n / 512) + 511
    signal += 63 * np.sin(2 * np.pi * n / 4096) + 63
    signal = np.round(signal).astype(np.int)

    # Apply the peak detector
    pkdetector = PeakDetector(800, 32)
    peak_signal = list(map(lambda x: pkdetector(x), signal))

    # Plot the results
    plt.figure(figsize=(10, 6))
    plt.plot(signal)
    plt.plot(peak_signal)
    plt.show()