This is a demo video of my graphical SWR meter. The device can draw a frequency-SWR graph on a given frequency range. A tuned LRC circuit was connected to the antenna port of the return loss bridge. Frequency is sweeping from 3.5 to 3.8MHz. The resonance point is at 3.7MHz, re real part of the impedance is 50Ohms there.
The display is an old 128x64 dot matrix graphic LCD, a PIC16F877 controls it and a AD9832 DDS generates the sweeping sine wave. There is a LT1253 fast video amplifier which provides enough signal amplitude (20Vpp) to drive the HA8ET-033B return loss bridge. The output DC signal of the bidge is fed into the ADC input of the PIC. There are some DC/DC converters for supplying the LCD and the video amplifier.
