I have a simple question about a function generator.
I am testing a Phase locked loop circuit on PCB using TLC2934.
A reference signal from the function generator is provided to the circuit.
The initial condition of the signal Was 3V of high level, 0V of low level, and 20Mhz.
To test PLL, the frequency is changing. However, as the frequency increases (up to 80Mhz), the Vpp decreases, and the offset voltage is increasing.
I have no idea why Vpp is varying with the increasing frequency.