We set first_set to false in aie_iir_1b.jl as follows to generate another set of coefficients for an LPF with a passband of 20 MHz.
first_set = false; # true: 1st set; false: 2nd set
...
The frequency response with a 20MHz passband is as follows:
Move the generated *.h (coefficient files) to src and impresponse_b.dat to data.
We use two_freqs.jl to generate an input signal (two_freqs.dat) with two frequencies (f1 = 2 MHz, f2 = 18 MHz) to test the functionality of coefficient switching. The time and frequency domain plots of the signal are as follows:
Move the generated two_freqs.dat to data.
In the testbench (tb.cpp), we uncomment #define RTP_SWITCH to include the second set of coefficients.
Note: A wait() statement is required to allow the specified number of iterations to complete before loading the new set of coefficients.
The output of the AI Engines is as follows (use check2.jl):
The first half of the plot used coefficients for a 10 MHz filter. Thus, only the noisy 2 MHz component passed and the 18 MHz component was significantly attenuated.
In the second half, the coefficients are for a 20 MHz filter. Thus, both 2 MHz and 18 MHz components are seen at the output.
The complete design is included in the data and src directories. Refer to the aie_exp/Part1 tutorial if you are unfamiliar with building an AMD Vitis™ design from scratch.