mag2db() - Signal Processing

ydb = mag2db(y) expresses
in decibels (dB) the magnitude measurements specified in y.
The relationship between magnitude and decibels is ydb = 20 log10(y).

Syntax

ydb = mag2db(y) example

Example

Magnitude Response of a Highpass FilterOpen This ExampleDesign a 3rd-order highpass Butterworth filter having a normalized 3-dB frequency of 
 rad/sample. Compute its frequency response. Express the magnitude response in decibels and plot it.[b,a] = butter(3,0.5,'high');
[h,w] = freqz(b,a);

dB = mag2db(abs(h));

plot(w/pi,dB)
xlabel('\omega / \pi')
ylabel('Magnitude (dB)')
ylim([-82 5])

Repeat the computation using fvtool.fvtool(b,a)

Output / Return Value

Limitations

Alternatives / See Also

Reference