GB1436314A - Apparatus for measuring the speed of light - Google Patents
Apparatus for measuring the speed of lightInfo
- Publication number
- GB1436314A GB1436314A GB4455872A GB4455872A GB1436314A GB 1436314 A GB1436314 A GB 1436314A GB 4455872 A GB4455872 A GB 4455872A GB 4455872 A GB4455872 A GB 4455872A GB 1436314 A GB1436314 A GB 1436314A
- Authority
- GB
- United Kingdom
- Prior art keywords
- light
- phase difference
- path length
- oscillator
- velocity
- 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
- 230000003287 optical effect Effects 0.000 abstract 4
- 238000005259 measurement Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 abstract 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J7/00—Measuring velocity of light
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Measuring Phase Differences (AREA)
- Optical Radar Systems And Details Thereof (AREA)
Abstract
1436314 Measuring velocity of light R BARR 27 Dec 1973 [27 Sept 1972] 44558/72 Heading G1A The velocity of light in a medium is measured by modulating a light emitting diode at a frequency in the VHF range, passing the light through the medium to a detector and determining the phase difference between the light emitter modulation signal and the detector signal using a heterodyne technique to convert both these signals to a low frequency. The phase difference is determined for two different values of the optical path length and the values of the change in phase difference, the charge in path length and the modulation frequency are utilized to calculate the velocity of light. As shown, a VHF oscillator 1 operating at 50 MHz modulates the light emission from an LED2, the light (visible or IR) from which passes via reflectors 4 to a detecting diode 3, lenses 5 being included to provide a parallel beam. The optical components are mounted on a conventional optical bench enabling changes in the path length to be measured. The output of the detector and a reference signal from the oscillator 1 are heterodyned with the output of an oscillator 6 operating at 50.02 MHz and the low frequency (20KHz) components are extracted by band pass filters. The phase difference between the high frequency signals is maintained by the heterodyning so that a measurement of its value can be made using a phase meter 8 or by displaying Lissajous figures on a CRO 9. The optical path length is varied and the change in phase difference measured, or, in the case of Lissajous figures the path length is varied between two known phase difference displays. The frequency of the oscillator 1 is determined for example by using digital circuits to divide it down to such an extent that it can be measured by a stop clock and mechanical counter. The mirrors 4 may be omitted and an in-line arrangement used. The velocity of light in transparent media such as water can also be determined.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB4455872A GB1436314A (en) | 1972-09-27 | 1972-09-27 | Apparatus for measuring the speed of light |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB4455872A GB1436314A (en) | 1972-09-27 | 1972-09-27 | Apparatus for measuring the speed of light |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1436314A true GB1436314A (en) | 1976-05-19 |
Family
ID=10433855
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB4455872A Expired GB1436314A (en) | 1972-09-27 | 1972-09-27 | Apparatus for measuring the speed of light |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1436314A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107093539A (en) * | 2016-12-26 | 2017-08-25 | 中国工程物理研究院应用电子学研究所 | A kind of Terahertz phase velocity gradual change folded waveguide oscillator |
| CN107845317A (en) * | 2017-09-19 | 2018-03-27 | 鲁东大学 | A kind of experimental method of the single channel photo-beat phase method measurement light velocity |
| CN111256846A (en) * | 2020-01-16 | 2020-06-09 | 山东超越数控电子股份有限公司 | Method and equipment for measuring light velocity by using phase-locked amplifier |
-
1972
- 1972-09-27 GB GB4455872A patent/GB1436314A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107093539A (en) * | 2016-12-26 | 2017-08-25 | 中国工程物理研究院应用电子学研究所 | A kind of Terahertz phase velocity gradual change folded waveguide oscillator |
| CN107845317A (en) * | 2017-09-19 | 2018-03-27 | 鲁东大学 | A kind of experimental method of the single channel photo-beat phase method measurement light velocity |
| CN107845317B (en) * | 2017-09-19 | 2020-04-10 | 鲁东大学 | Experimental method for measuring light velocity by single-path light beat phase method |
| CN111256846A (en) * | 2020-01-16 | 2020-06-09 | 山东超越数控电子股份有限公司 | Method and equipment for measuring light velocity by using phase-locked amplifier |
| CN111256846B (en) * | 2020-01-16 | 2022-09-16 | 超越科技股份有限公司 | Method and equipment for measuring light velocity by using phase-locked amplifier |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3619058A (en) | Distance measuring apparatus | |
| US4171908A (en) | Automatic two wavelength photoelasticimeter | |
| US2586540A (en) | Torsion meter | |
| KR900002117B1 (en) | Method and apparatus for measuring distance by laser beam | |
| US3522992A (en) | Geodetic survey system and digital phase-meter therefor | |
| SE333697B (en) | ||
| GB1459928A (en) | Visibility meter | |
| US3424531A (en) | Distance measuring instrument using a pair of modulated light waves | |
| GB1231431A (en) | ||
| GB1436314A (en) | Apparatus for measuring the speed of light | |
| US3472598A (en) | Apparatus for determining the relative index of refraction of light permeable substances | |
| US3687517A (en) | Doppler effect frequency monitoring system | |
| US3838924A (en) | Vector velocimeter (direction indicating velocimeter) | |
| GB1274241A (en) | Apparatus for measuring the refraction index of a medium along a light path | |
| US3864041A (en) | Doppler-shift velocity measurement system using a two-frequency laser | |
| US3740152A (en) | Device for detecting the boundary between different brightness regions of an object | |
| US3434785A (en) | Beam sweeping optical distance meter | |
| SU1179103A1 (en) | Interferometer for distance measurement | |
| GB1222177A (en) | Improvements in or relating to fluid flow measurements | |
| JPS5866881A (en) | Surveying equipment by light wave | |
| US2968736A (en) | Cycling mechanism for photoelectrical devices | |
| GB1019540A (en) | A method and apparatus for determining the difference in area of an article from an article of known area | |
| SU720298A1 (en) | Device for measuring distance | |
| JPS57192833A (en) | Method of detecting vibration of object to be measured using coherent light | |
| SU1672217A1 (en) | Electro-optical light range finder |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |