DSP Blockset

Zero Pad

Alter the input size by zero-padding or truncating rows and/or columns.

Library

Signal Operations

Description

The Zero Pad block changes the size of the input matrix from M_i-by-N_i to M_o-by-N_o by zero-padding or truncating along the rows, the columns, or both dimensions. The dimensions of the output, M_o and N_o, are specified by the Number of output rows and Number of output columns parameters, respectively.

The Zero pad along parameter specifies how the input should be altered. The options are:

• Columns

When Columns is selected, the Number of output rows parameter (M_o) is enabled, and the block pads or truncates each input column by an equal amount. If M_o>M_i, the block pads by adding M_o-M_i rows of zeros to the bottom of the matrix. If M_o<M_i, the block truncates by deleting M_i-M_o rows from the bottom of the matrix. In both cases, the number of columns is unchanged (N_o=N_i). A 1-D vector input is zero padded or truncated at the "bottom," and the output is a 1-D vector.

• Rows

When Rows is selected, the Number of output columns parameter (N_o) is enabled, and the block pads or truncates each input row by an equal amount. If N_o>N_i, the block pads by adding N_o-N_i columns of zeros to the right side of the matrix. If N_o<N_i, the block truncates by deleting N_i-N_o columns from the right side of the matrix. In both cases, the number of rows is unchanged (M_o=M_i). A 1-D vector input is zero padded or truncated at the "bottom," and the output is a 1-D vector.

• Columns and rows

When Columns and rows is selected, both the Number of output rows parameter (M_o) and the Number of output columns parameter (N_o) are enabled, and the block pads or truncates rows and columns as specified. A length-M_i 1-D vector input is treated as an M_i-by-1 matrix and the output is an M_o-by-N_o matrix.

• None

When None is selected, the input is passed through to the output without padding or truncation.

Example

In the model below, the 3-by-3 input is zero-padded along the column dimension to 5-by-3. The parameter settings in the Zero Pad block are:

• Zero pad along = Columns
• Number of output rows = 5

Dialog Box

Zero pad along

The direction along which to pad or truncate. Columns specifies that the row dimension should be changed to M_o; Rows specifies that the column dimension should be changed to N_o; Columns and rows specifies that both column and row dimensions should be changed; None disables padding and truncation and passes the input through to the output unchanged.

Number of output rows

The desired number of rows in the output, M_o. This parameter is enabled when Columns or Columns and rows is selected in the Zero pad along menu.

Number of output columns

The desired number of columns in the output, N_o. This parameter is enabled when Rows or Columns and rows is selected in the Zero pad along menu.

See Also

Matrix Concatenation	Simulink
Pad	DSP Blockset
Repeat	DSP Blockset
Submatrix	DSP Blockset
Upsample	DSP Blockset
Variable Selector	DSP Blockset

Yule-Walker Method

DSP Function Reference