JPS5696376A - Mark reading circuit - Google Patents

Mark reading circuit

Info

Publication number
JPS5696376A
JPS5696376A JP17105279A JP17105279A JPS5696376A JP S5696376 A JPS5696376 A JP S5696376A JP 17105279 A JP17105279 A JP 17105279A JP 17105279 A JP17105279 A JP 17105279A JP S5696376 A JPS5696376 A JP S5696376A
Authority
JP
Japan
Prior art keywords
threshold voltage
mark
ignored
amplifier
ideal rectifier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP17105279A
Other languages
Japanese (ja)
Other versions
JPS6223910B2 (en
Inventor
Tetsuro Suma
Yuji Isobe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujitsu Ltd
Original Assignee
Fujitsu Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP17105279A priority Critical patent/JPS5696376A/en
Publication of JPS5696376A publication Critical patent/JPS5696376A/en
Publication of JPS6223910B2 publication Critical patent/JPS6223910B2/ja
Granted legal-status Critical Current

Links

Abstract

PURPOSE: To discriminate always a mark accurately even if the illumination intensity is changed, by using an ideal rectifier, where forward voltage drop can be ignored, as the threshold voltage holding circuit.
CONSTITUTION: The output of photodiode 11 is given to operational amplifier 13 and diode 15, which form an ideal rectifier, through amplifier 12. The output is applied to threshold setting resistances 23 and 24 through capacitor 18, buffer amplifier 21, and so on. Thus, since forward voltage drop can be ignored by the ideal rectifier, the threshold voltage obtained from the connection point between resistances 23 and 24 is proportional to the white level voltage completely. Consequently, the threshold voltage is changed according to the change of the illumination intensity of the object by applying the threshold voltage to one input of comparator 14, and thus, the mark is always discriminated accurately.
COPYRIGHT: (C)1981,JPO&Japio
JP17105279A 1979-12-28 1979-12-28 Mark reading circuit Granted JPS5696376A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP17105279A JPS5696376A (en) 1979-12-28 1979-12-28 Mark reading circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP17105279A JPS5696376A (en) 1979-12-28 1979-12-28 Mark reading circuit

Publications (2)

Publication Number Publication Date
JPS5696376A true JPS5696376A (en) 1981-08-04
JPS6223910B2 JPS6223910B2 (en) 1987-05-26

Family

ID=15916180

Family Applications (1)

Application Number Title Priority Date Filing Date
JP17105279A Granted JPS5696376A (en) 1979-12-28 1979-12-28 Mark reading circuit

Country Status (1)

Country Link
JP (1) JPS5696376A (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55115168A (en) * 1979-02-21 1980-09-04 Ibm Signal transfer detector

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55115168A (en) * 1979-02-21 1980-09-04 Ibm Signal transfer detector

Also Published As

Publication number Publication date
JPS6223910B2 (en) 1987-05-26

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