GB1248904A - Improvements in or relating to digital instruments - Google Patents
Improvements in or relating to digital instrumentsInfo
- 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
- 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
Links
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
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Frequencies, Analyzing Spectra (AREA)
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.
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)
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)
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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