How to plot power spectrum whose RF frequency is much higher than the signal sampling frequency?

I want to up-convert a baseband signal bb to RF signal that has much higher carrier frequency fc, I used the equations:

t =0:1 / fs : N / fs;

RF= bb.*exp(j * 2 * pi *fc.* t / fs)

The RF freq fc is 20 times bigger than the sample rate fs,

How can I use RF toolbox to build a upconverter that allow me to see the frequency spectrum?

Thanks

Answer 1

[Pooja Kumari]

Dear Daniel,

I understand that you are facing issues with the RF Toolbox while trying to build an upconverter to visualize the frequency spectrum.

You can use RF Budget Analysis app which analyses the gain, noise figure, and nonlinearity of your RF system architecture. This app allows you to perform a comprehensive analysis of your RF system. You can refer to the below documentation for more information on RF Budget Analysis app which is available in RF Toolbox:

RF Budget Analysis - MATLAB & Simulink - MathWorks India

If you are designing an RF system using the RF Budget Analyzer app and need to model an IMT(Intermediate Frequency to Modulated Frequency) mixer, you can utilize the mixerIMT object. This object allows you to add the IMT mixer to your RF system model. You can refer to below documentation for more information on mixerIMT:

Create IMT mixer element - MATLAB - MathWorks India

You can use “rplot” for plotting the amplifier power characteristics at the operating frequency. You can refer to the below documentation for more information on rplot:

Plot cumulative RF budget result verses cascade input frequency, and amplifier power characteristics - MATLAB rfplot - MathWorks India

I hope this helps!