After a period of testing, I found that when receiving high-frequency signals via the API and performing FFT with window normalization, the measured power is correct. However, when receiving signals below 120 MHz, the power decreases as the frequency decreases, behaving like a high-pass filter.
We are using the SM200B IQ segment mode with the following settings: center frequency = 100 MHz, time_duration = 15.36e-3, ref_level = -10, trigger_type = “immediate”, and ext_trig_timeout = 1. Could it be that these parameter settings cause the received signal go through high pass filter(the preselector in user manual 3.2.4)? If so, is there a way to solve this problem?
p.s. I also tried to use smSetPreselector() and set False to it, but still didn’t work
