GB1340813A – Interpolative readout apparatus
– Google Patents
GB1340813A – Interpolative readout apparatus
– Google Patents
Interpolative readout apparatus
Info
Publication number
GB1340813A
GB1340813A
GB75172A
GB75172A
GB1340813A
GB 1340813 A
GB1340813 A
GB 1340813A
GB 75172 A
GB75172 A
GB 75172A
GB 75172 A
GB75172 A
GB 75172A
GB 1340813 A
GB1340813 A
GB 1340813A
Authority
GB
United Kingdom
Prior art keywords
voltage
transducer
voltages
calibration
measurement
Prior art date
1971-01-12
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
GB75172A
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.)
Damon Corp
Original Assignee
Damon Corp
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.)
1971-01-12
Filing date
1972-01-07
Publication date
1973-12-19
1972-01-07
Application filed by Damon Corp
filed
Critical
Damon Corp
1973-12-19
Publication of GB1340813A
publication
Critical
patent/GB1340813A/en
Status
Expired
legal-status
Critical
Current
Links
Espacenet
Global Dossier
Discuss
Classifications
G—PHYSICS
G01—MEASURING; TESTING
G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
G01R17/00—Measuring arrangements involving comparison with a reference value, e.g. bridge
Abstract
1340813 Evaluating functions by interpolations DAMON CORP 7 Jan 1972 [12 Jan 1971 23 Aug 1971] 751/72 Headings G4G and G4H [Also in Division G1] A non-linear voltage measuring system paticularly for receiving a transducer voltage which varies non-linearly with a parameter being measured and for producing a corrected output voltage which varies linearly with the parameter being measured, has two modes of operation-a calibration mode in which transducer voltages A, B, C, D and E, Fig. 1, corresponding to known values of the parameter (assumed to be a concentration) being measured are entered and stored in the system together with voltages K, L, M, N and O, which are the desired corrected output voltages for the known values of the parameter, and a measurement mode in which firstly an unknown value of the parameter is sensed producing a transducer voltage P, say, secondly the two calibration transducer voltages C, D, which are respectively below and above the transducer voltage P are determined, thirdly the ratio in which the transducer voltage P divides the interval between the voltages C and D is determined, and fourthly a voltage Q which divides the corrected calibration output voltages M, N in the same ratio is produced. This voltage may be digitized or otherwise displayed as desired. As described the system comprises five analogue storage devices 15, 16, 17, 18, 19, Fig. 2, to which transducer signals A, B, C, D, E, Fig. 1, are applied sequentially during the calibration mode, and five potentiometers R1, R2, R3, R4, R5, on which the corresponding corrected output voltages K, L, M, N, O are set manually. Entry of the calibration transducer voltages is as follows. A shift register 27 is cleared and reset to mark its first lead A. This energizes reed-contact drive windings 31 and 41 closing, in particular, contacts 21 and 51. The first calibration transducer voltage A is then applied to an input differential amplifier 11 where it is compared with the exist. ing contents of store 15 via a loop including contact 51, a contact 57, an amplifier 58 and a filter 59. Any difference produces an error signal which progressively modifies the value in store 15 until it equals the value A from the transducer. A manual advance key 52 is then depressed causing the shift register to advance to its B stage and the above process is repeated until all the transducer calibration voltages A, B, C, D, E, have been stored. The measure. ment mode proceeds automatically once a switch S3 is set in its left-hand position and the shift register is reset. The first phase of the measurement mode, that is the determination of the pair of transducer calibration voltages that straddle the measurement signal, is effected by comparing the measurement signal P, Fig. 1, sequentially with the transducer calibration voltages starting with voltage B. Thus, with the shift register marking its first output lead A the measurement signal P, Fig. 1, on lead 12, Fig. 2, is compared in the differential amplifier 11 with the value B from store 16 via a contact 61, a resistor R7, amplifier 58 and filter 59. If the measurement value P is larger than the value B from store 16, as detected by a polarity threshold detector 93, a gate 92 is opened to allow a clock pulse from an oscillator 78 to advance the shift register to its second stage. This results in the value C from store 17 being compared with the measurement voltage P, and the process continues until the shift register reaches a stage at which the measurement value P is less than the value from the selected store. When this occurs, which in the example given is when the shift register marks its C outputs lead and the value D is compared with the measurement voltage P, the threshold circuit 93 closes gate 92 and energizes the drive winding 94 of a readcontact 76, which initiates the next phase of the measurement cycle. In this phase, with the measurement voltage P still present on lead 12, the stored transducer calibration voltages C and D which straddle the measurement voltage are effectively applied alternately via contacts 53 and 57, and contact 63 and resistor R7, to the amplifier 58 under the control of a duty cycle modulator 77 which, by repeatedly closing contact 57 at the clock frequency of 20 c./s., but with a variable mark/space ratio, ensures that the signal resulting from the filter 59 is a linear combination of the transducer calibration voltages C and D. This linear combination, e.g. the mark/space ratio, is adjusted by the output signal from the differential amplifier 11 until it equals the measurement voltage P, and simultaneously the same linear combination of the stored corrected output voltages M and N is formed by an amplifier 86 and a filter 87. Hence a voltage Q, Fig. 1, is produced by filter 87 which is the desired corrected output voltage. The system described has the intrinsic error that the measurement voltage P is located not on the curve extending between the transducer calibration voltages C and D, Fig. 1, but on the straight line. This error is however said to be small. A mark/space ratio modulation circuit is outlined in connection with a second embodiment (Figs. 3, 4A and 4B, not shown) in which only two calibration points can be preset, and a modification (Fig. 5, not shown) is described enabling extrapolation outside the range set by the calibration points to be effected.
GB75172A
1971-01-12
1972-01-07
Interpolative readout apparatus
Expired
GB1340813A
(en)
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
US10587871A
1971-01-12
1971-01-12
Publications (1)
Publication Number
Publication Date
GB1340813A
true
GB1340813A
(en)
1973-12-19
Family
ID=22308272
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB75172A
Expired
GB1340813A
(en)
1971-01-12
1972-01-07
Interpolative readout apparatus
Country Status (2)
Country
Link
GB
(1)
GB1340813A
(en)
IT
(1)
IT948835B
(en)
1972
1972-01-07
GB
GB75172A
patent/GB1340813A/en
not_active
Expired
1972-01-11
IT
IT6707772A
patent/IT948835B/en
active
Also Published As
Publication number
Publication date
IT948835B
(en)
1973-06-11
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Legal Events
Date
Code
Title
Description
1974-05-01
PS
Patent sealed
1976-08-04
PLNP
Patent lapsed through nonpayment of renewal fees