Signal acquisition circuit and analog-to-digital conversion system

The invention provides a signal acquisition circuit and an analog-to-digital conversion system. The signal acquisition circuit comprises at least two sampling modules, an output selection module and at least one phase shifter, the sampling module is used for collecting an input signal, the output selection module comprises at least two input ends, the input ends of the output selection module are connected with the output ends of the sampling module in a one-to-one correspondence manner, and the output selection module is used for selecting a sampling signal in one of the at least two sampling modules and outputting the sampling signal through the output end; an input signal end of the sampling module is used for inputting an input signal, and a clock input signal end of the sampling module is used for inputting a clock signal; the at least one phase shifter is connected in series between the clock input signal ends of the at least two sampling modules, and the at least one phase shifter is used for performin