| 摘要 |
<P>PROBLEM TO BE SOLVED: To make one infrared receiver antenna adaptible to three or more infrared wireless microphones while suppressing the increase of a cost to the minimum. <P>SOLUTION: The infrared receiver antenna includes: a photo-diode 11 for receiving infrared signals transmitted from infrared wireless microphones; a tuner circuit composed of junction capacitance C of the photo-diode 11 and inductance L of a coil 12; and an amplifier circuit 14 for amplifying received signals detected in the tuner circuit, and is provided with three or more infrared wireless microphones on a transmitting side each of which is assigned with different transmission frequencies. In the infrared receiver antenna, the inductance L is adjusted to locate a resonant frequency of the tuner circuit approximately in the center of each transmission frequency, and a resistor 13 for reducing sharpness Q in the resonance of the resonant frequency is connected in parallel to the coil 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
