User`s guide

Sample and Hold
5-383
5Sample and Hold
Purpose Sample and hold an input signal.
Library Signal Operations
Description The Sample and Hold block acquires the input at the signal port whenever it
receives a trigger event at the trigger port (marked by ). The block then holds
the output at the acquired input value until the next triggering event occurs. If
the acquired input is frame-based, the output is frame-based; otherwise, the
output is sample-based.
The trigger input must be a sample-based scalar with sample rate equal to the
input frame rate at the signal port. The trigger event is specified by the
Trigger type pop-up menu, and can be one of the following:
•
Rising edge triggers the block to acquire the signal input when the trigger
input rises from zero to a positive value.
•
Falling edge triggers the block to acquire the signal input when the trigger
input falls from zero to a negative value.
•
Either edge triggers the block to acquire the signal input when the trigger
input either rises from zero to a positive value or falls from zero to a negative
value.
The block’s output prior to the first trigger event is specified by the
Initial
condition
parameter. If the acquired input is an M-by-N matrix, the Initial
condition
can be an M-by-N matrix, or a scalar to be repeated across all
elements of the matrix. If the input is a length-M 1-D vector, the
Initial
condition
can be a length-M row or column vector, or a scalar to be repeated
across all elements of the vector.
Dialog Box
Trigger type
The type of event that triggers the block to acquire the input signal.