[AD9364] Tx filter config using Linux IIO

MatBr said:

I am setting out_voltage_rf_bandwidth to 200 kHz. Are there any indication of what is actually configured?

It is setting the analog filter BW.

you can change the filter bandwidths by using the filter wizard tool and generating coefficients as per the configuration. Download from the below link:

https://wiki.analog.com/resources/eval/user-guides/ad-fmcomms2-ebz/software/filters 

According to UG-673, there are two analog filters with corner frequencies ranging from 625 kHz to 32 MHz for the first one, and 2.7 MHz to 100MHz for the second. So 200 kHz is not be achievable, is it?

The filter design tool is to compute the coefficients of the digital FIR filter, right? So it is not related to out_voltage_rf_bandwidth?

MatBr said:

The filter design tool is to compute the coefficients of the digital FIR filter, right?

Based on the input sampling rate and BW, the filter wizard tool will design for design for all the filters in the chain,and give you the overall response at the output. You can use the fvconverter tool to plot the overall response in the filter wizard, you will be able to see the analog filter and the digital filters response.

Ok I will look into it.

But do you have an idea about my first question: According to https://wiki.analog.com/resources/tools-software/linux-drivers/iio-transceiver/ad9361#tx_rf_bandwidth_control, the out_voltage_rf_bandwidth entry sets the two analog filters. I do not understand what it does, since it accepts my writing of 200 kHz, but I cannot see this corner frequency in tests. What's more, the spec reads that the analog filters' corner frequencies do not go below 625 kHz.

RF Bandwidth will be derived from the FIR filter wizard and as explained in the previous reply use the fvconverter tool to view the combined response of analog and digital.