# Documentation

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# downsample

Decrease sampling rate by integer factor

## Syntax

```y = downsample(x,n) y = downsample(x,n,phase) ```

## Description

`y = downsample(x,n)` decreases the sampling rate of `x` by keeping every `n`th sample starting with the first sample. `x` can be a vector or a matrix. If `x` is a matrix, each column is considered a separate sequence.

`y = downsample(x,n,phase)` specifies the number of samples by which to offset the downsampled sequence. `phase` must be an integer from 0 to `n` – 1.

## Examples

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Decrease the sampling rate of a sequence by 3.

```x = [1 2 3 4 5 6 7 8 9 10]; y = downsample(x,3)```
```y = 1 4 7 10 ```

Decrease the sampling rate of the sequence by 3 and add a phase offset of 2.

`y = downsample(x,3,2)`
```y = 3 6 9 ```

Decrease the sampling rate of a matrix by 3.

```x = [1 2 3; 4 5 6; 7 8 9; 10 11 12]; y = downsample(x,3)```
```y = 1 2 3 10 11 12 ```