Hello Alex,
If you are using the GUI there are a couple of places where you can adjust the frequency. Under Device Settings-> General
As well as under Device Settings -> Block Diagram
If you are not using the GUI then you can change the transmit and receive frequency by writing to the FREQ register (address = 0x1C) by using this formula Frequency = 0.2 * FREQ + 30 [kHz] where FREQ is a value from 0 to 250. This will help you program from 30-80kHz.
If your application requires a higher frequency then the FREQ_SHIFT bit will have to be set which will give you a range of 180-480kHz. The FREQ_SHIFT essentially just multiplies whatever your frequency result was by 6. I hope this helps!
I will be linking a Texas Instruments Precision Labs video series that will help you get familiar with the PGA460 and its various settings, regardless if you are working with the GUI or not this video series is extremely helpful to visualize how some of the settings work on the device.: https://training.ti.com/pga460-ultrasonic-sensing-how-set-and-install-evm?context=1128182-1128152
Best,
Isaac
