GB1248904A – Improvements in or relating to digital instruments
– Google Patents
GB1248904A – Improvements in or relating to digital instruments
– Google Patents
Improvements in or relating to digital instruments
Info
Publication number
GB1248904A
GB1248904A
GB4708567A
GB4708567A
GB1248904A
GB 1248904 A
GB1248904 A
GB 1248904A
GB 4708567 A
GB4708567 A
GB 4708567A
GB 4708567 A
GB4708567 A
GB 4708567A
GB 1248904 A
GB1248904 A
GB 1248904A
Authority
GB
United Kingdom
Prior art keywords
gate
display
counter
hold circuits
display devices
Prior art date
1967-10-16
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
GB4708567A
Inventor
John Antony Clements
Bernard Frederick Fellerman
Brian Shepherd
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.)
Smiths Group PLC
Original Assignee
Smiths Group PLC
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.)
1967-10-16
Filing date
1967-10-16
Publication date
1971-10-06
1967-10-16
Application filed by Smiths Group PLC
filed
Critical
Smiths Group PLC
1967-10-16
Priority to GB4708567A
priority
Critical
patent/GB1248904A/en
1971-10-06
Publication of GB1248904A
publication
Critical
patent/GB1248904A/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
G01R17/02—Arrangements in which the value to be measured is automatically compared with a reference value
G01R17/04—Arrangements in which the value to be measured is automatically compared with a reference value in which the reference value is continuously or periodically swept over the range of values to be measured
G—PHYSICS
G01—MEASURING; TESTING
G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
G01P1/00—Details of instruments
G01P1/07—Indicating devices, e.g. for remote indication
G01P1/08—Arrangements of scales, pointers, lamps or acoustic indicators, e.g. in automobile speedometers
G—PHYSICS
G01—MEASURING; TESTING
G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
G01P3/42—Devices characterised by the use of electric or magnetic means
G01P3/44—Devices characterised by the use of electric or magnetic means for measuring angular speed
G01P3/48—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage
G01P3/481—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals
G01P3/489—Digital circuits therefor
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
G—PHYSICS
G01—MEASURING; TESTING
G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
G01R23/02—Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
G01R23/10—Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage by converting frequency into a train of pulses, which are then counted, i.e. converting the signal into a square wave
H—ELECTRICITY
H03—ELECTRONIC CIRCUITRY
H03K—PULSE TECHNIQUE
H03K21/00—Details of pulse counters or frequency dividers
H03K21/08—Output circuits
Abstract
1,248,904. Digital display arrangements. SMITHS INDUSTRIES Ltd. 16 Oct., 1968 [16 Oct., 1967], No. 47085/67. Heading G4H. The output of a measuring device is applied to a number of digital display devices 30-32, having an astable oscillator within unit 10 arranged to switch the display devices on and off at such a rate as to be undiscernable to the eye and means are provided for varying the mark/space ratio of the oscillator to vary the brightness of the display. The anodes of the display devices are connected to the 200v. supply through resistors 34 and via diodes 35 to the multivibrator. When the multivibrator is in one state it acts as a short circuit across the display devices to extinguish them. The mark/space ratio is variable by an adjustable potentiometer 37. The cathodes of the displace devices are connected to a speed measuring circuit for a road vehicle. In one form a generator driven from the output shaft of the gear-box generates a frequency signal which is squared to produce pulses at a frequency indicating the speed. A sampling gate opened for a set period passes the pulses to a three decade binary counter providing signals for the display device. In another form hold circuits are interposed between the counter and the display to hold the signals during the sampling period. In a modification of this form the sampling gate is omitted, the sampling period being established by resetting the counters at the start and, at the end of the period enabling the hold circuits to store the value counted. In a variant of this form the timing circuit may be triggered by a gate detecting a zero condition in the counter, which counts continuously, the gate enabling the hold circuits after the elapsed sampling period. An independent timing circuit resets the hold circuits to zero if the interval between two successive enabling pulses exceeds a set value. In another form the frequency signal is converted to an amplitude signal and compared with a step signal to obtain a timed pulse. This is used to close a gate which, since the beginning of the cycle, has been passing clock pulses to the counter.
GB4708567A
1967-10-16
1967-10-16
Improvements in or relating to digital instruments
Expired
GB1248904A
(en)
Priority Applications (1)
Application Number
Priority Date
Filing Date
Title
GB4708567A
GB1248904A
(en)
1967-10-16
1967-10-16
Improvements in or relating to digital instruments
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
GB4708567A
GB1248904A
(en)
1967-10-16
1967-10-16
Improvements in or relating to digital instruments
Publications (1)
Publication Number
Publication Date
GB1248904A
true
GB1248904A
(en)
1971-10-06
Family
ID=10443664
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB4708567A
Expired
GB1248904A
(en)
1967-10-16
1967-10-16
Improvements in or relating to digital instruments
Country Status (1)
Country
Link
GB
(1)
GB1248904A
(en)
Cited By (2)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
DE2255056A1
(en)
*
1971-11-10
1973-05-17
Philips Nv
SPEED MEASURING AND DISPLAYING DEVICE
FR2159455A1
(en)
*
1971-11-10
1973-06-22
Philips Nv
1967
1967-10-16
GB
GB4708567A
patent/GB1248904A/en
not_active
Expired
Cited By (2)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
DE2255056A1
(en)
*
1971-11-10
1973-05-17
Philips Nv
SPEED MEASURING AND DISPLAYING DEVICE
FR2159455A1
(en)
*
1971-11-10
1973-06-22
Philips Nv
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