MATLAB Answers

How do I present an audio signal in a time domain plot using MATLAB, such that the y-axis is in decibel (dB) instead of of a linear scale?

50 ビュー (過去 30 日間)
Kwaku Owusu
Kwaku Owusu 2021 年 1 月 14 日
コメント済み: Kwaku Owusu 2021 年 1 月 16 日
Please, I have a recorded audio signal from experimental work. I have been able to plot the time domain graph (see attached) using Matlab software. By default, the y-axis values are present in a linear scale (Amplitude). I would like to plot the time domain graph such that the y-axis scale is is in decibel. I understand that using 20*log10(signal/ref. signal) should provide the decibel scale on the y-axis, however, this does not seem to work after several attempts.
** My code**
Let say the signa name is TD, so I use the code plot(20*log10(TD/20*10^-6)), the 20*10^-6 is my reference air pressure. The problem is that the entire signal is distorted.
Please, I would be glad if someone can assist me (specifically with a code in matlab to visualise the signal). I might not be doing something right. Thank you.
Thank you.

  6 件のコメント

表示 3 件の古いコメント
Mathieu NOE
Mathieu NOE 2021 年 1 月 15 日
do not forget to take the abs of your time data before doing the 20*log10 action
spl = 20*log10(abs(TD/20*10^-6))
maybe some smoothing may be needed (=> movmean)
make sure that TD signal unit is Pascals



dpb 2021 年 1 月 15 日
編集済み: dpb 2021 年 1 月 15 日
In particular, note that "Signal intensity, power, and energy are always proportional to the square of the signal amplitude.power". When you just use a zero-mean time trace, the log10 is undefined for values <=0 which is what is happening with what you've tried so far.

その他の回答 (0 件)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by