Why standard Waveform from audio out gets distorted when i reduce the amplitude?

Question

shyam 2015-7-28

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/231489-why-standard-waveform-from-audio-out-gets-distorted-when-i-reduce-the-amplitude

评论： Dinesh Iyer 2015-7-28

In my attempt to generate a standard sine wave out of a sound card, i started using matlab which has a function soundsc for scaling the output

 t = 0:1/48000:10;
 y = sin(1000*2*pi*t);
 soundsc(y,48000,[a b]);

its ok when my a and b are -1 and 1 respectively, when i try to make them even -0.9 and 0.9 respectively the standard sine wave of 1Khz gets distorted why so ?

are our sound cards will not be able to handle standard sounds ??

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Dinesh Iyer 2015-7-28

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/231489-why-standard-waveform-from-audio-out-gets-distorted-when-i-reduce-the-amplitude#answer_187466

Shyam,

The reason for this distortion is that some of the signal values are being clipped. When you specify [a, b], it is assumed that signal you are attempting to playback has values in the range [a, b] and it allows you to scale it to the the range [-1, 1].

In your case, the signal "y" has values in the range [-1, 1] and by specifying [a, b] t be [-0.9 0.9], the values between [-0.9 0.9] in "y" are being scaled to [-1 1]. Values greater than 0.9 are scaled out of range and hence clipped.

The help for the soundsc function makes this clear.

Dinesh

2 个评论
显示无隐藏无

shyam 2015-7-28

thanks i understood,but i have tried with some other experiment like replacing the y=sin(..) line with y = 0.5 sine(..) but the output was not halved but its response was not linear what may be the problem ?

Dinesh Iyer 2015-7-28