I want to understand the initialization settings in the "main.c" software driver, such as the default "AD9361_TXFIRConfig".
1. Does the "tx_inc = 1" specify the programmable FIR filter to operate at 1x mode (no interpolation)?
2. What is the design intent of the default filter coefficients? I copied the non-zero coefficients to Matlab. Then I did "freqz(coef, 1, 2048, 30.72e6), since I noticed the sampling rate on TX chain starts at 30.72MHz. I saw the filter response looks like band-pass filter. I was planning to use the default setup for a 20MHz LTE baseband signal.