Block

Mask

Description

This block measure the duration of one period of a periodic signal. The input signal can be provided using any fixed-point numerical format.

Parameters

This block has no parameter.

Inputs

Signal	Should be fed with the input signal, on which the frequency measurement is to be applied.
RMS	Should be connected to the input signal RMS value. It is used to position the trigger for the frequency measurement.
Average	Should be connected to the input signal average value. It is used to position the trigger for the frequency measurement.

Outputs

Period	The period of the input periodic signal expressed in the number of 10-ns clock cycles.

Characteristics and Limitations

This block calculates the period of most periodic signals. To compute the frequency, it measures the number of clock cycles between two consecutive threshold crossing, after a hysteresis loop.

Periodic signals with many local extrema, such as the hysteresis loop cycles more than once in a period, may mot give correct period values. Good input waveforms include sinusoidal, square, triangular and saw-toothed waveforms. A modulated sine wave is not an appropriate waveform.

The tresholds of the hysteresis loop corresponds to (s(t) - Average > RMS - Average) and (s(t) - Average < -(RMS - Average)).

Direct Feedthrough	N/A
Discrete sample time	N/A
XHP support	N/A
Work offline	YES

RT-XSG Documentation

Frequency Measurement