Pulse Delay

Purpose

Delay discrete-value input signal by fixed time

Library

Control / Delays

Description

The Pulse Delay applies a fixed time delay to an input signal that changes at discrete instants and is otherwise constant. The signal can be a scalar or vector.

Whenever a change of an input signal is detected at a simulation time \(t\), the Pulse Delay records the new signal value in an internal buffer and schedules an event that forces the solver to make a step exactly at the simulation time \(t+T_{D}\) in order to output the delayed input value.

A typical application of the Pulse Delay is to delay the pulses of a modulator.

Note

• The Pulse Delay should not be used to delay continuous signals as this will lead to excessive memory consumption. Besides, the output of the Pulse Delay is always piece-wise constant. To delay continuously changing signals, use the continuous Transport Delay

• The Pulse Delay should also not be used to delay signals that have a fixed sample time. To delay such signals, use a Zero Order Hold or a Delay depending on the duration of the delay with respect to the sample time of the input signal. Suppose that the input signal has a sample time \(T_{s}\) and you want to delay it by a time \(T_{D}\). Calculate the delay order \(O = \lfloor\frac{T_{D}}{T_{s}}\rfloor\) (i.e. the integer part of the division) and an offset time \(T_{o} = \text{mod}(T_{D}, T_{s})\). If \(O\) is zero, use a Zero Order Hold with the sample time \([T_{s}, T_{o}]\). If \(O\) is greater than zero, use a Delay with the sample time \([T_{s}, T_{o}]\) and the delay order \(O\). For more information regarding sample times, see Sample Times.

Example Model

• See the example model “Pulse Delay”.

• Find it in PLECS under Help > PLECS Documentation > List of Example Models.

Parameters

Time delay \(T_{\mathrm{d}}\)

The time by which the input signal is delayed, in seconds \((\mathrm{s})\).

Initial output

The output value after simulation start before the input values appear at the output.