Root-sum-of-squares level

## Syntax

``y = rssq(x)``
``y = rssq(x,dim)``

## Description

example

````y = rssq(x)` returns the root-sum-of-squares (RSS) level, `y`, of the input array `x`. If `x` is a row or column vector, `y` is a real-valued scalar. If `x` has more than one dimension, then `rssq` operates along the first array dimension with size greater than 1.```

example

````y = rssq(x,dim)` computes the RSS level of `x` along dimension `dim`.```

## Examples

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Compute the RSS level of a 100 Hz sinusoid sampled at 1 kHz.

```t = 0:0.001:1-0.001; x = cos(2*pi*100*t); y = rssq(x)```
```y = 22.3607 ```

Create a matrix where each column is a 100 Hz sinusoid sampled at 1 kHz with a different amplitude. The amplitude is equal to the column index.

Compute the RSS levels of the columns.

```t = 0:0.001:1-0.001; x = cos(2*pi*100*t)'*(1:4); y = rssq(x)```
```y = 1×4 22.3607 44.7214 67.0820 89.4427 ```

Create a matrix where each row is a 100 Hz sinusoid sampled at 1 kHz with a different amplitude. The amplitude is equal to the row index.

Compute the RSS levels of the rows by specifying the dimension with the `dim` argument.

```t = 0:0.001:1-0.001; x = (1:4)'*cos(2*pi*100*t); y = rssq(x,2)```
```y = 4×1 22.3607 44.7214 67.0820 89.4427 ```

## Input Arguments

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Input array, specified as a vector, matrix, or N-D array.

Example: `cos(2*pi*100*(0:0.001:1-0.001))` specifies a sinusoid sampled at 1 kHz for 1 second.

Data Types: `single` | `double`
Complex Number Support: Yes

Dimension to operate along, specified as a positive integer scalar.

Data Types: `single` | `double`

## Output Arguments

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Root-sum-of-squares level, returned as a scalar, vector, matrix, or N-D array.

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### Root-Sum-of-Squares Level

The root-sum-of-squares (RSS) level of a vector, x, is

`${x}_{\text{RSS}}=\sqrt{\sum _{n=1}^{N}{|{x}_{n}|}^{2}},$`

with the summation performed along the specified dimension. The RSS level is also referred to as the 2-norm.

## References

[1] IEEE® Standard on Transitions, Pulses, and Related Waveforms, IEEE Standard 181, 2003.