Abstract: A reader for medical implants includes an antenna and a transceiver chip connected with the antenna. The transceiver chip includes a power amplifier and a resistor. The power amplifier is connected with a reference voltage through the resistor and configured to produce a first communication signal with high frequency and transmit the first communication signal to the medical implants through the antenna. The medical implant receives the first communication signal and produces a second communication signal according to variation of parameters of the medical implant. The antenna is configured to receive the second communication signal. The power amplifier is further configured to vary a DC current which flows through the resistor according to the second communication signal and read signals of the medical implant according to variation of the DC current. The power amplifier is further configured to modulate the second communication signal into a low frequency signal.