Mablab中fmlin()函数有什么作用？

产生线性调频信号的，需要下载时频分析工具箱才能用的。

function [y,iflaw]=fmlin(N,fnormi,fnormf,t0);
%FMLINSignal with linear frequency modulation.
%[Y,IFLAW]=FMLIN(N,FNORMI,FNORMF,T0) generates a linear frequency
%modulation.
%The phase of this modulation is such that Y(T0)=1.
%
%N : number of points
%FNORMI : initial normalized frequency (default: 0.0)
%FNORMF : final normalized frequency (default: 0.5)
%T0 : time reference for the phase (default: N/2).
%Y : signal
%IFLAW : instantaneous frequency law (optional).