How to draw smooth power spectrum curve like this?

Hello,I want to know how to draw a smooth power spectrum curve like this?I try to draw it by using Welch Method but failed.I need some help!!!!thx!!!

Answer 1

[LEKIREDDY BHARADHWAJ REDDY]

type this equation in matlab you will get it.

[Yujia Mi]

Thx!I will try it,but what value should 'a' take?

[LEKIREDDY BHARADHWAJ REDDY]

let 'a' be any integer

[Yujia Mi]

okkkkk,thx!!!