A dual-mode signal transceiver includes a first transmitter circuit, a second transmitter circuit, and a receiver circuit. The first transmitter circuit is configured to operate in a first mode and configured to process a first input signal according to a first oscillating signal, in order to output a first output signal. The second transmitter circuit is configured to operate in a second mode and configured to process a second input signal according to a second oscillating signal, in order to output a second output signal, wherein a frequency of the second oscillating signal is not an integral multiple of a frequency of the first oscillating signal. The receiver circuit is configured to process an external signal associated with one of the first mode and the second mode according to the first oscillating signal, in order to read data associated with the external signal.