 Let's increase the sampling frequency. Open a monitor for INTPL(U_0).
This is an interpolator that inserts three "zeros" between each
input data. As a result, the sampling frequency is increased to 4kHz. (M
= 4)
Please see how the data changed by choosing "Open a Monitor"
for TXTOUT(U_6).
Zeros are inserted and the sampling frequency was increased by x4.
Open a monitor for FFTMON(U_4) to see the spectrum.
You may see 400Hz, 600Hz, 1400Hz and 1600Hz. Since we need only 400Hz,
let's remove other frequencies.
|