I need to measure the THD, SNR, and Noise performance of a filter.
It is a low-pass filter with 10MHz cut-off frequency.

My doubts are:
1. how to measure the THD? using Signal Analyzer/Spectrum Analyzer. what input signal level, signal frequency I should use? upto what hormonics the THD should be taken into account?

2. how to measure noise? short the input to ground? or noise source needed? may I use 50Ohm resistor?

3. SNR? may I take the output foundamental to noise floor???

Thanks.