RF Blockset / Simulink: Perform a frequency sweep of a mixer model

Question

Nicholas Molinski 2022-7-27

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1769310-rf-blockset-simulink-perform-a-frequency-sweep-of-a-mixer-model

example_model.slx

Hello Matlab Team,

I am having trouble configuring an RF Blockset Simulink model. I have a system that features a filter and a mixer. I would like to put in a frequency agile signal (chirp) and see the realtime response on the Spectrum Analyzer. I've attached the model an included an image below.

I am sweeping a 100-200MHz@4dBm signal through the model with a Mixer with a 50MHz LO. For simplicity, I am using a unity gain s-parameter file for the 'filter' model and the CPWG is 50Ohms (when using just these two blocks I can observe signal output). When I run my full model, I would expect to to see the modulation products from the mixer and the fundamental tone from the output signal while the simulation is running.

For example, I expect to see 150MHz and 250MHz mixing products when the frequency sweeps to 200MHz. I would also expect to see in my spectrum a 50MHz LO at around -14dBm (10dB LO to IF isolation).

Instead, I see no the output which makes me believe I have a configuration parameter incorrect. I used the model_IQdemod example as a starting point and normally do modelling with the rfckt objects.