# N-Sample Switch

Switch between two inputs after specified number of sample periods

Libraries:
DSP System Toolbox / Signal Management / Switches and Counters

## Description

The N-Sample Switch block outputs the signal connected to the top input port during the first N sample times after the simulation begins or the block is reset, where you specify N in the Switch count parameter. Beginning with output sample N+1, the block outputs the signal connected to the bottom input until the next reset event or the end of the simulation.

## Ports

### Input

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Specify the first input signal as a scalar, vector, or a matrix.

Both inputs must have the same dimension, except in the following two cases:

• When one input is a scalar, the block expands the scalar input to match the size of the other input.

• When one input is an unoriented vector and the other input is a row or column vector with the same number of elements, the block reshapes the unoriented vector to match the dimension of the other input.

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

Specify the second input signal as a scalar, vector, or a matrix.

Both inputs must have the same dimension, except in the following two cases:

• When one input is a scalar, the block expands the scalar input to match the size of the other input.

• When one input is an unoriented vector and the other input is a row or column vector with the same number of elements, the block reshapes the unoriented vector to match the dimension of the other input.

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

Specify the reset signal as a scalar. At any time during the count, a trigger event at the Rst port resets the counter to zero. The reset sample time must be a positive integer multiple of the input sample time.

For more information on the reset trigger type, see the description for the Trigger type parameter.

#### Dependencies

To enable this port, select the Reset input check box.

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

### Output

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Output of the switch, returned as a scalar, vector, or a matrix. The block switches between two inputs after specified number of sample periods N.

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

## Parameters

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Specify the number of sample periods, N, for which the output is connected to the top input before switching to the bottom input as a nonnegative integer.

Tunable: Yes

Select this check box to enable the Rst input port. The rate of the reset signal must be a positive integer that is a multiple of the rate of the data signal input.

This block supports triggered subsystems when you select the Reset input check box.

Reset the block's counter with the type of event at the Rst port.

You specify the triggering event in the Trigger type pop-up menu, and can be one of the following:

• `Rising edge` — Triggers a reset operation when the Rst input does one of the following:

• Rises from a negative value to a positive value or zero

• Rises from zero to a positive value, where the rise is not a continuation of a rise from a negative value to zero (see the following figure)

• `Falling edge` — Triggers a reset operation when the `Rst` input does one of the following:

• Falls from a positive value to a negative value or zero

• Falls from zero to a negative value, where the fall is not a continuation of a fall from a positive value to zero (see the following figure)

• `Either edge` — Triggers a reset operation when the `Rst` input is a `Rising edge` or ```Falling edge``` (as described above).

• `Non-zero sample` — Triggers a reset operation at each sample time that the `Rst` input is not zero.

Tunable: Yes

#### Dependencies

To enable this parameter, select the Reset input check box.

Specify the sample period Ts for the block's counter as a positive scalar. The block switches inputs at t = Ts×(N+1).

You specify the sample period of the output in the Sample time parameter, that is, the output sample period is not inherited from the sample period of either input.

The block applies a zero-order hold at the input ports, so the value the block reads from a given port between input sample times is the value of the most recent input to that port.

## Block Characteristics

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

## Version History

Introduced before R2006a