| 摘要 |
PURPOSE:To improve the reception sensitivity and to widen the reception band by making a change in a voltage caused in a circuit element equal to a voltage change of a 2nd wiring pattern formed on a rear side of the circuit component. CONSTITUTION:A ground pattern 22 is set to a reference potential of a carrier chip 24 and an IC chip 25 of an optical reception circuit mounted on a board 21. Moreover, an island isolated pattern 23 is formed from the ground pattern 22 while being isolated electrically. When an optical signal is received by a photodiode 26, the optical output current is converted into a voltage signal, demodulated via a capacitor Cc, a buffer amplifier 27 and an amplifier 28 and sent to a prescribed receiver. Moreover, a reception signal voltage from the amplifier 27 is given to the pattern 23. Thus, a voltage change in an anode and a cathode of the diode 26 is nearly equal to a reception signal voltage change of the pattern 23. |
