| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a reception circuit which can not only achieving a high sensitivity independently of temperature characteristics of an acoustic surface wave filter but also improving responsiveness. <P>SOLUTION: The reception circuit includes: an acoustic surface wave filter 1 which extracts a start signal being in a prescribed frequency band and having a specific pattern, out of received electric signals to output a correlation signal; an envelope detector 2 which extracts and outputs a base band signal corresponding to an envelope of the correlation signal output from the acoustic surface wave filter 1; an amplifier 3 which amplifies the base band signal to output the amplified base band signal; a delay line 4 which delays the amplified base band signal output from the amplifier 3; an adder 5 which adds the base band signal output from the delay line 4 and a base band signal in the next period output from the envelope detector 2; and a start determination part 6 which, when an output value of the base band signal output from the amplifier 3 exceeds a prescribed value, determines that the start signal has been received. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
