GB1400565A - Analogue-to-digital converters - Google Patents

Analogue-to-digital converters

Info

Publication number
GB1400565A
GB1400565A GB3776172A GB3776172A GB1400565A GB 1400565 A GB1400565 A GB 1400565A GB 3776172 A GB3776172 A GB 3776172A GB 3776172 A GB3776172 A GB 3776172A GB 1400565 A GB1400565 A GB 1400565A
Authority
GB
United Kingdom
Prior art keywords
switches
earth
voltage
zener diode
zener
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.)
Expired
Application number
GB3776172A
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.)
Schlumberger Instruments et Systemes SA
Original Assignee
Schlumberger Instruments et Systemes SA
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 Schlumberger Instruments et Systemes SA filed Critical Schlumberger Instruments et Systemes SA
Publication of GB1400565A publication Critical patent/GB1400565A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
    • G01R19/255—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques using analogue/digital converters of the type with counting of pulses during a period of time proportional to voltage or current, delivered by a pulse generator with fixed frequency
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/12—Analogue/digital converters
    • H03M1/50—Analogue/digital converters with intermediate conversion to time interval

Abstract

1400565 Dual ramp converter SCHLUMBERGER INSTRUMENTS et SYSTMES 14 Aug 1972 [12 Aug 1971] 37761/72 Heading H3H A dual ramp analogue to digital converter having an operational amplifier with integrating capacitor and input resistance has a voltage reference circuit comprising two branches connected to the amplifier input, two series resistances in each branch connecting the branches to two voltage sources of opposite polarity, a Zener diode inverse connected between the resistor junctions in each branch and two switches connected respectively between the two ends of the Zener diode and earth. As shown each branch comprises resistors 25, 22 (or 25<SP>1</SP>, 22<SP>1</SP>) connected at their junctions E, E<SP>1</SP> by reversed biased Zener diode 21. Switches 24, 24<SP>1</SP> which are preferably complementary switching transistors connect points E, E<SP>1</SP> to earth. In operation, after the unknown voltage has been integrated for a predetermined time, one of switches 24<SP>1</SP>, 24 is closed to apply the Zener voltage of opposite polarity to the unknown to the integrator. In another embodiment (Fig. 5) resistors 25, 25<SP>1</SP> may be split into two (26, 27 and 26<SP>1</SP>, 27<SP>1</SP>) with the junction connected to earth by further switches 28, 28<SP>1</SP>. Both switches 24, 28 or 241, 281 are operated together and if R 2 (27)=R 3 (26) the current through the Zener is the same as when all switches are open which improves stability. The potentials of the points E, E<SP>1</SP> may be stabilized during operation by current generators 31, 31<SP>1</SP> which reduce the current through switches 24, 24<SP>1</SP> effectively to zero.
GB3776172A 1971-08-12 1972-08-14 Analogue-to-digital converters Expired GB1400565A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7129508A FR2148376B1 (en) 1971-08-12 1971-08-12

Publications (1)

Publication Number Publication Date
GB1400565A true GB1400565A (en) 1975-07-16

Family

ID=9081799

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3776172A Expired GB1400565A (en) 1971-08-12 1972-08-14 Analogue-to-digital converters

Country Status (2)

Country Link
FR (1) FR2148376B1 (en)
GB (1) GB1400565A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0148296A1 (en) * 1984-01-09 1985-07-17 Leybold Aktiengesellschaft Method and circuit for converting a measuring current into an impulse rate proportional to the measuring current
US4939519A (en) * 1986-02-03 1990-07-03 Thaler Corporation Apparatus for method and a high precision analog-to-digital converter

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4549149A (en) * 1983-04-08 1985-10-22 Warner-Lambert Technologies, Inc. Current to frequency converter switched to increased frequency when current input low

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0148296A1 (en) * 1984-01-09 1985-07-17 Leybold Aktiengesellschaft Method and circuit for converting a measuring current into an impulse rate proportional to the measuring current
US4939519A (en) * 1986-02-03 1990-07-03 Thaler Corporation Apparatus for method and a high precision analog-to-digital converter

Also Published As

Publication number Publication date
FR2148376B1 (en) 1975-04-18
FR2148376A1 (en) 1973-03-23

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee