Triggered Delay Line (Obsolete)
Buffer sequence of inputs into frame-based output
Library
dspobslib
Description
Note
The Triggered Delay Line block is still supported but is likely to be obsoleted in a future release. We strongly recommend replacing this block with the Delay Line block.
The Triggered Delay Line block acquires a collection of Mo input samples into a frame, where you specify Mo in the Delay line size parameter. The block buffers a single sample from input 1 whenever it is triggered by the control signal at input 2 (). When the next triggering event occurs, the newly acquired input sample is appended to the output frame so that the new output overlaps the previous output by Mo-1 samples. Between triggering events the block ignores input 1 and holds the output at its last value.
You specify the triggering event at input 2 in the Trigger type pop-up menu:
Rising edge
triggers execution of the block when the trigger input rises from a negative value to zero or a positive value, or from zero to a positive value.Falling edge
triggers execution of the block when the trigger input falls from a positive value to zero or a negative value, or from zero to a negative value.Either edge
triggers execution of the block when either a rising or falling edge (as described above) occurs.
The Triggered Delay Line block has zero latency, so the new input appears at the output in the same simulation time step. The output frame period is the same as the input sample period, Tfo=Tsi.
Sample-Based Operation
In sample-based operation, the Triggered Delay Line block buffers a sequence of sample-based length-N vector inputs (1-D, row, or column) into a sequence of overlapping sample-based Mo-by-N matrix outputs, where you specify Mo in the Delay line size parameter (Mo>1). That is, each input vector becomes a row in the sample-based output matrix. When Mo=1, the input is simply passed through to the output, and retains the same dimension. Sample-based full-dimension matrix inputs are not accepted.
Frame-Based Operation
In frame-based operation, the Triggered Delay Line block rebuffers a sequence of frame-based Mi-by-N matrix inputs into an sequence of overlapping frame-based Mo-by-N matrix outputs, where Mo is the output frame size specified by the Delay line size parameter (that is, the number of consecutive samples from the input frame to rebuffer into the output frame). Mo can be greater or less than the input frame size, Mi. Each of the N input channels is rebuffered independently.
Initial Conditions
The Triggered Delay Line block's buffer is initialized to the value specified by the Initial condition parameter. The block always outputs this buffer at the first simulation step (t=0). When the block's output is a vector, the Initial condition can be a vector of the same size or a scalar value to be repeated across all elements of the initial output. When the block's output is a matrix, the Initial condition can be a matrix of the same size or a scalar to be repeated across all elements of the initial output.
Parameters
- Trigger type
The type of event that triggers the block's execution.
- Delay line size
The length of the output frame (number of rows in output matrix), Mo.
- Initial condition
The value of the block's initial output, a scalar, vector, or matrix.
Supported Data Types
Port | Supported Data Types |
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Input |
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Trigger |
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Output |
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See Also
Buffer | DSP System Toolbox |
Delay Line | DSP System Toolbox |
Unbuffer | DSP System Toolbox |
Version History
Introduced in R2008b