Hi,
I have given a project in which I need to design an ADC for GNSS (Global Navigation Satellite System). Here are some of specifications of the ADC.
input frequency fin = 20MHz
Bandwidth = 20MHz
Power consumption P <= 1mW
ENOB >= 3.7
Resolution: 4 bits

I am confused which sampling frequency should I choose?
I know it has to be larger than two times highest frequency component but I don't know which frequency optimistic, 40MHz, 60MHz, 80MHz, 100MHz, or larger.
And what type of ADC is more appropriate for this application?