# MATLAB Programming/Loglog

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## Introduction[edit]

The *loglog* command plots both x and y data sets on a log scale while the *plot* command plots both axes on linear scales and the *semilogx/y* command plots 1 axis on a linear scale and the other axis on a log scale. Other than the scale of the axes, the 3 plotting commands are identical in most ways.

## Basic Usage[edit]

The basic usage of the *plot*, *semilogx/y*, and *loglog* command are identical. Below is an example of how a PSD would be plotted

>> Fs = 1000; % Sample Rate of 1 kHz >> t = 0:(1/Fs):1000; % Time vector >> x = sin(pi*t); % Sine wave based on time vector >> [Pxx, f] = pwelch(x, [], [], [], Fs); >> loglog(f, Pxx) >> grid on >> xlabel('Frequency (Hz)') >> ylabel('Magnitude (units^2/Hz)') >> title('PSD of Sine Wave')