peak2rms

Peak-magnitude-to-RMS ratio

Syntax

y = peak2rms(x)

y = peak2rms(x,dim)

Description

y = peak2rms(x) returns the ratio of the largest absolute value in x to the root-mean-square (RMS) value of x.

y = peak2rms(x,dim) computes the peak-magnitude-to-RMS ratio of x along dimension dim.

Examples

Peak-Magnitude-to-RMS Ratio of Sinusoid

Compute the peak-magnitude-to-RMS ratio of a 100 Hz sinusoid sampled at 1 kHz.

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

y = peak2rms(x)

y = 
1.4142

Peak-Magnitude-to-RMS Ratio of Complex Exponential

Create a complex exponential with a frequency of $$\pi /4$$ rad/sample. Find the peak-magnitude-to-RMS ratio.

n = 0:99;
x = exp(1j*pi/4*n);

y = peak2rms(x)

y = 
1

Peak-Magnitude-to-RMS Ratios of 2-D Matrix

Create a matrix in which 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 peak-magnitude-to-RMS ratios of the columns.

t = 0:0.001:1-0.001;
x = cos(2*pi*100*t)'*(1:4);

y = peak2rms(x)

y = 1×4

    1.4142    1.4142    1.4142    1.4142

Peak-Magnitude-to-RMS Ratios of 2-D Matrix Along Specified Dimension

Create a matrix in which 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 RMS levels of the rows, specifying the dimension equal to 2 with the dim argument.

t = 0:0.001:1-0.001;
x = (1:4)'*cos(2*pi*100*t);

y = peak2rms(x,2)

y = 4×1

    1.4142
    1.4142
    1.4142
    1.4142

Input Arguments

x — Input array

vector | matrix | N-D array

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

Data Types: double | single
Complex Number Support: Yes

dim — Dimension to operate along

positive integer scalar

Dimension to operate along, specified as a positive integer scalar. By default, peak2rms operates along the first array dimension of x with size greater than 1. For example, if x is a row or column vector, y is a real-valued scalar. If x is an N-by-M matrix with N > 1, y is a 1-by-M row vector containing the peak-magnitude-to-RMS levels of the columns of y.

Data Types: double | single

Output Arguments

y — Peak-magnitude-to-RMS ratio

scalar | matrix | N-D array

Peak-magnitude-to-RMS ratio, specified as a real-valued scalar, matrix, or N-D array.

More About

Peak-Magnitude-to-RMS Ratio

The peak-magnitude-to-RMS ratio is

$$\frac{{\Vert X\Vert }_{\infty }}{\sqrt{\frac{1}{N}{\displaystyle \sum _{n=1}^N{\left|X_n\right|}^2}}},$$

where the infinity-norm and RMS values are computed along the specified dimension.

References

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

Extended Capabilities

Tall Arrays

Calculate with arrays that have more rows than fit in memory.

The peak2rms function fully supports tall arrays. For more information, see Tall Arrays.

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

This function fully supports GPU arrays. For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Version History

Introduced in R2012a