Reader/writer and analog switching circuit

摘要

The reader/writer of this invention includes a high voltage withstanding amplifier, plural resonance circuits and plural high voltage withstanding analog switching circuits. The high voltage withstanding amplifier amplifies an analog signal to be sent to the outside. Each of the resonance circuits sends the analog signal amplified by the high voltage withstanding amplifier to the outside. The high voltage withstanding analog switching circuits are provided between the high voltage withstanding amplifier and the resonance circuits correspondingly to the resonance circuits. Each of the high voltage withstanding analog switching circuits electrically connects/disconnects the high voltage withstanding amplifier to/from the corresponding resonance circuit. Since the reader/writer includes the high voltage withstanding analog switching circuits, there is no need to provide high voltage withstanding amplifiers at the previous stages of the resonance circuits as in a conventional reader/writer. Accordingly, as compared with the conventional reader/writer in which the high voltage withstanding amplifiers are provided correspondingly to the respective resonance circuits, the number of high voltage withstanding amplifiers (the number of components) can be reduced.