Library

RT-EVENTS Math Operations

Block

Description

The RTE Filter block removes, from the input signal, pulses (pairs of opposite transitions) that are smaller than a fixed width. The block can remove only high pulses (low-to-high and high-to-low transitions), only low pulses (high-to-low and low-to-high transitions) or both kinds of pulses. The following example demonstrates the effect of the filter block.

Typical Example of RTE Filter Block

Limitation

The pulse width limit must be smaller than the inherited sample time of the block. Generally, the filter block can correctly manage the removal of pulses with a width 10 times smaller than the sample time.

When the filter block is set to remove only high pulses or low pulses, the block must delay the first event if the first event of a pulse occurs in the last T seconds of the calculation step, where T is smaller than the pulse width, and the pulse is larger than pulse width limit.

This limitation is caused by the fact that the block cannot predict if a pulse with a transition so close to the end of the step will be larger or smaller than the pulse width limit. The following figure shows this effect on the output signal.

Mask

RTE Filter Mask

Parameters

Pulse Type	Determine the kind of pulse to remove from the input signals.
Pulse Width Limit	Minimum size of the pulse. Below this limit, pulses are removed.
Maximum Number of Events	The maximum number of events or transitions that can occur during a single step. Events above this number are not output.

Input

Input (Double)	RTE Boolean signal to filter

Output

Output (Double)	Filtered RTE Boolean signal

Characteristics

Direct Feedthrough	Yes
Sample Time	Inherited and fixed discrete.
Work offline	Yes
Dimensionalized	Yes

Example

The rte_encoder.mdl model demonstrates how to use RT-EVENTS blocks to simulate an incremental encoder connected to a rotating object. This example also shows how to use blocks of the library to insert fault, to filter noise and to measure some characteristics of RTE Boolean signal. In this example, the RTE Filter block is used to remove noise that occurs on real analog signals.