spectrum and signal for chirp signal

Hi, I have post this question to matlab but no one answer . Hope someone help me in here.
I have tried to plot the chirp signal from 20MHz to 70MHz in time domain and frequency domain. The target time and sweep time is set to 3 ms. Normally I see slew rate =1s, dont know why?. Sampling time = 140 us and samples per frame = 4096. The output of chirp block connects to time vector scope and to magnitude fft and then frequency vector scope. The magnitude fft block ticks to "inherit fft length from input dimensions". I run simulation at 1s (normal mode). The time and frequency vector scope gives me a strange output event it shows the waveform and spectrum. But in different scale I think. I have searched to try understanding " Sample- and Frame-Based Concepts". However, dont quite know how to apply to this signal. I think I miss some thing here. Please help me: 1. How can I show this signal to those scope? 2. What is the right sample per frame for this case? 2. How should I choose the slew rate?

I do not know Simulink use but you can do time or frequency domain plot through MATLAB commands(chirp and fft) easily.

Hi von Moltke, I can write this with code too and as you said easily. However, I would like to study to Simulink and use for my further design. It seems confusing with simulink.