# spectrogram

Spectrogram.

## Syntax

sp = spectrogram(x)

sp = spectrogram(x,fs)

sp = spectrogram(x,fs,window)

sp = spectrogram(x,fs,window,overlap)

sp = spectrogram(x,fs,window,overlap,nfft)

sp = spectrogram(x,fs,window,overlap,nfft)

sp = spectrogram(x,fs,window,overlap,nfft,range)

[sp,t,f] = spectrogram(...)

## Inputs

`x`- The signal to be analyzed power spectrum content.
`window`- The window size, or the window column vector.
`overlap`- The number of overlapping points in adjacent windows.
`nfft`- The size of the fft.
`fs`- The sampling frequency.
`range`- The spectrum type. The options are as follows:
- 'onesided' (default)
- 'onesided_dB'
- 'twosided'

## Outputs

`sp`- The spectogram power density output, with segments stored by column.
- t
- The vector of times corresponding to the start of each column of
`sp`. - f
- The vector of frequencies corresponding to each row of
`sp`.

## Example

spectrogram of a linear chirp signal.

```
f0 = 0;
f1 = 5;
T = 10;
c = (f1 - f0) / T;
t = [0:0.1:T-0.1];
x = sin(2 * pi * ((c/2)*t.^2 + f0*t));
spectrogram(x, 10, 20, 14, 32, 'onesided');
```

## Comments

Default values are assigned to arguments with a [] input.

The function produces power spectral density values with no compensation for the window bias. It may be useful
to normalize `sp` by sum(win.^2), where win is the window vector.

The 'onesided' and 'onesided_dB'outputs have a length of `nfft/2+1`
if `nfft` is even, or `(nfft+1)/2` if `nfft` is odd.

It is often recommended to remove the trend line prior to calling spectrogram. The function does not automatically call detrend.