#########################################################################################
##
## COMPARATOR BLOCK
## (blocks/mixed/comparator.py)
##
## Milan Rother 2024
##
#########################################################################################
# IMPORTS ===============================================================================
import numpy as np
from .._block import Block
from ...events.zerocrossing import ZeroCrossing
# MIXED SIGNAL BLOCKS ===================================================================
[docs]
class Comparator(Block):
"""Comparator block that sets the output to '1' it the input
signal crosses a predefined threshold and to '-1' if it
crosses in the reverse direction.
This is realized by the block spawning a zero-crossing
event detector that watches the input of the block and
locates the transition up to a tolerance.
The block output is determined by a simple sign check in
the 'update' method.
Parameters
----------
threshold : float
threshold value for the comparator
tolerance : float
tolerance for zero crossing detection
Attributes
----------
events : list[ZeroCrossing]
internal zero crossing event
"""
def __init__(self, threshold=0, tolerance=1e-4):
super().__init__()
self.threshold = threshold
self.tolerance = tolerance
def func_evt(t):
return self.inputs[0] - self.threshold
#internal event for transition detection
self.events = [
ZeroCrossing(
func_evt=func_evt,
tolerance=tolerance
)
]
[docs]
def update(self, t):
self.outputs[0] = np.sign(self.inputs[0] - self.threshold)
return 0.0