How to create a Gaussian Chirp signal?

Hi,

I am trying to creat a Gaussian Chirp (bidirectional) signal with these parameters:

f1=29.25MHz , f2=30.75MHz , sweep time=target time=5.376 ms

sample duration=168 microsec , chirps per frame=64

here a code that i write but cant add gaussian envelope:

clear all

clc

hchirp = dsp.Chirp(...

'SweepDirection', 'bidirectional','TargetFrequency', 75,'InitialFrequency', 0, 'TargetTime', 1, ...

'SweepTime', 1, 'SamplesPerFrame', 1344, 'SampleRate', 168);

figure

plot(step(hchirp));

also, i saw a code on this site that made a gaussian chirp but i need time data on x-axis:

clear all

clc

n = (-511:512)'; % Timeline

sigmas = exp(log(2):.3:log(200)); % Scales

w = exp(-.5*(n.^2)*sigmas.^(-2)); % Window Function

c = 279017857; % Chirp rate

% Gaussian Chirp

chirps = w.*cos(n*sigmas.^(-1)*2*pi*5 + (c/2)*(n/sigmas').^2);

plot(chirps(:,15))

axis tight

please help me about this problem?

thanks!