JPH0323345U

JPH0323345U -

Info

Publication number: JPH0323345U
Application number: JP8310589U
Authority: JP
Priority date: 1989-07-17
Filing date: 1989-07-17
Publication date: 1991-03-11

Description

[Brief explanation of the drawing]

第１図は本考案の実施例を示す光電式煙検知器
の全体構成図、第２図は本考案のパルス幅検波回
路図、第３図はそのパルス幅検波回路の動作説明
図、第４図は本考案の他の実施例を示すパルス幅
検波回路図、第５図はそのパルス幅検波回路の動
作説明図、第６図は本考案の実施例を示す副搬送
波式投光器出力パルスを示す図、第７図は従来の
光電式煙検知器の構成図、第８図は従来の投光器
出力パルスを示す図である。１０，３０……コンパレータ、１１……副搬送
波発生回路、１２……変調器、１３……タイミン
グパルス回路、１４……出力増幅器、１５……投
光器、１６……ＬＥＤ、１７……受光器、１８…
…受光ダイオード、１９……副搬送波増幅器、２
０……整流回路、２１……パルス幅検波回路、４
０……副搬送波式投光器出力パルス。 Fig. 1 is an overall configuration diagram of a photoelectric smoke detector showing an embodiment of the present invention, Fig. 2 is a pulse width detection circuit diagram of the invention, Fig. 3 is an explanatory diagram of the operation of the pulse width detection circuit, and Fig. 4 is an illustration of the operation of the pulse width detection circuit. The figure is a pulse width detection circuit diagram showing another embodiment of the present invention, Fig. 5 is an explanatory diagram of the operation of the pulse width detection circuit, and Fig. 6 shows the output pulse of a subcarrier type floodlight showing an embodiment of the present invention. 7 is a block diagram of a conventional photoelectric smoke detector, and FIG. 8 is a diagram showing output pulses of a conventional floodlight. 10, 30... Comparator, 11... Subcarrier generation circuit, 12... Modulator, 13... Timing pulse circuit, 14... Output amplifier, 15... Emitter, 16... LED, 17... Light receiver, 18...
...Photodetector diode, 19...Subcarrier amplifier, 2
0... Rectifier circuit, 21... Pulse width detection circuit, 4
0...Subcarrier type projector output pulse.

Claims

[Scope of Claim for Utility Model Registration] (1) (a) A light projector that emits pulses with a wide pulse width, (b) A light receiver that receives reflected light based on the pulses, and (c) Output from the light receiver. (d) a rectifier circuit that rectifies the output from the amplifier; and (e) a pulse width detection circuit that detects the pulse width of the pulse output from the rectifier circuit. Photoelectric smoke detector. (2) The photoelectric smoke detector according to claim 1, wherein the pulse width detection circuit includes an integrating circuit and a circuit for determining a threshold value of its output. (3) (a) The pulse width detection circuit includes a first integrating circuit having a first capacitance; (b) a first transistor that is turned on by the output of the first integrating circuit; (c) a second integrating circuit having a second capacitance that is charged when the first transistor is turned on; (d) turned on by the output of the second integrating circuit;
and a second transistor that discharges the charge of the first capacitance.
Photoelectric smoke detector as described. (4) (a) A light projector that emits a wide pulse including a subcarrier, (b) a light receiver that receives reflected light based on the pulse, and (c) an amplifier that amplifies the output from the light receiver. (d) a rectifier circuit that rectifies the output from the amplifier; and (e) a pulse width detection circuit that detects the pulse width of the pulse output from the rectifier circuit. Detector. (5) The photoelectric smoke detector according to claim 4, wherein the pulse width detection circuit includes an integrating circuit and a circuit for determining a threshold value of its output. (6) (a) The pulse width detection circuit includes a first integrating circuit having a first capacitance; (b) a first transistor that is turned on by the output of the first integrating circuit; (c) a second integrating circuit having a second capacitance that is charged when the first transistor is turned on; (d) turned on by the output of the second integrating circuit;
and a second transistor that discharges the charge of the first capacitance.
Photoelectric smoke detector as described.