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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 nth 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

expand all

### Decrease Sampling Rates

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

```

## See Also

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