An electronic device includes a communication module, an external module and a signal integration circuit. The signal integration circuit includes a first input port, a second input port, a third input port and an output port. The first input port is for inputting an input signal. The second input port is for selectively inputting a first L1 band signal. The third input port is for selectively inputting a second L1 band signal. The output port selectively outputs a first output signal or a second output signal. When the third input port is coupled to an external module, the third input port is for inputting the second L1 band signal, and the output port outputs the second output signal. When the third input port is not coupled to the external module, the second input port is for inputting the first L1 band signal, and the output port outputs the first output signal.