Tapped Delay

Delay scalar signal multiple sample periods and output all delayed versions

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Libraries:
Simulink / Discrete
HDL Coder / Discrete

Description

The Tapped Delay block delays an input by the specified number of sample periods and provides an output signal for each delay. For example, when you specify 4 for Number of delays and Order output starting with is Oldest, the block provides four outputs — the first delayed by four sample periods, the second delayed by three, and so on. Use this block to discretize a signal in time or resample a signal at a different rate.

The block accepts one scalar input and generates an output vector that contains data for each incremental delay. Specify the order of the delayed signals in the output vector with the Order output vector starting with parameter:

• Oldest orders the output vector starting with the oldest delay version and ending with the newest delay version.

• Newest orders the output vector starting with the newest delay version and ending with the oldest delay version.

Specify the output vector for the first sampling period with the Initial condition parameter. Careful selection of this parameter can mitigate unwanted output behavior.

Specify the time between samples with the Sample time parameter. Specify the number of delays with the Number of delays parameter. A value of -1 instructs the block to inherit the number of delays by backpropagation. Each delay is equivalent to the z^-1 discrete-time operator, which the Unit Delay block represents.

Examples

Internet Low Bitrate Codec (iLBC) for VoIP

Implements the Internet Low Bitrate Codec (iLBC) and illustrates its use. iLBC is designed for encoding and decoding speech for transmission via VoIP (Voice Over Internet Protocol).

Ports

Input

Port_1 — Input signal

scalar

Input signal to delay.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point
Complex Number Support: Yes

Output

Port_1 — Delayed versions of input signal

scalar | vector

All versions of the delayed input signal. Use the Order output vector starting with parameter to specify the order of delayed signals in the output vector.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Parameters

Initial condition — Initial output

0.0 (default) | scalar

Specify the initial output of the simulation. The Initial condition parameter is converted from a double to the input data type offline using round-to-nearest and saturation.

Limitations

The initial condition of this block cannot be inf or NaN.

Programmatic Use

Block Parameter: vinit

Type: character vector

Values: scalar

Default: '0.0'

Sample time — Time between samples

-1 (default) | scalar | vector

Specify the time interval between samples. To inherit the sample time, set this parameter to -1. For more information, see Specify Sample Time.

Programmatic Use

Block Parameter: samptime

Type: character vector

Values: scalar | vector

Default: '-1'

Number of delays — Number of discrete-time operators

4 (default) | positive scalar | -1 (for inherited)

Specify the number of discrete-time operators as a positive scalar, or -1 for inherited.

Programmatic Use

Block Parameter: NumDelays

Type: character vector

Values: positive scalar | -1 (inherited)

Default: '4'

Order output vector starting with — Order of output

Oldest (default) | Newest

Specify whether to output the oldest delay version first, or the newest delay version first.

Programmatic Use

Block Parameter: DelayOrder

Type: character vector

Values: 'Oldest' | 'Newest'

Default: 'Oldest'

Include current input in output vector — Include current input in output vector

off (default) | on

Select this check box to include the current input in the output vector.

Programmatic Use

Block Parameter: includeCurrent

Type: character vector

Values: 'off' | 'on'

Default: 'off'

Block Characteristics

Data Types	Boolean | double | fixed point | integer | single
Direct Feedthrough	no
Multidimensional Signals	no
Variable-Size Signals	no
Zero-Crossing Detection	no

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

HDL Code Generation

Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.

HDL Coder™ provides additional configuration options that affect HDL implementation and synthesized logic.

HDL Architecture

This block has one default HDL architecture.

HDL Block Properties

ConstrainedOutputPipeline	Number of registers to place at the outputs by moving existing delays within your design. Distributed pipelining does not redistribute these registers. The default is 0. For more details, see ConstrainedOutputPipeline (HDL Coder).
InputPipeline	Number of input pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see InputPipeline (HDL Coder).
OutputPipeline	Number of output pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see OutputPipeline (HDL Coder).
ResetType	Suppress reset logic generation. The default is default, which generates reset logic. See also ResetType (HDL Coder).

Complex Data Support

This block supports code generation for complex signals.

PLC Code Generation
Generate Structured Text code using Simulink® PLC Coder™.

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.

Version History

Introduced before R2006a