After a long rest, its get back
One feature on HBRAA3 Antenna analyzer is a filter response plotter.
Its worked based on
*. Si5351 as freq synthesizer
*. AD8307 logarithmic amplifier
by generate some range of frequency , send it to input port of a filter, then let AD8307 amplify the output port, then read the value (25mV /dB) by using micro controller ADC, we can draw the response on LCD. This feature very help for analyze crystal ladder filter, BPF and LPF of any transceiver.
an example 10MHz ladder filter plot response (non scale)