CN108964784B - Optical noise elimination device - Google Patents
Optical noise elimination device Download PDFInfo
- Publication number
- CN108964784B CN108964784B CN201710347065.7A CN201710347065A CN108964784B CN 108964784 B CN108964784 B CN 108964784B CN 201710347065 A CN201710347065 A CN 201710347065A CN 108964784 B CN108964784 B CN 108964784B
- Authority
- CN
- China
- Prior art keywords
- resistor
- optical
- noise
- signal
- light
- 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 - Fee Related
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 162
- 230000008030 elimination Effects 0.000 title claims abstract description 6
- 238000003379 elimination reaction Methods 0.000 title claims abstract description 6
- 238000005286 illumination Methods 0.000 abstract description 24
- 238000006243 chemical reaction Methods 0.000 abstract description 5
- 238000010586 diagram Methods 0.000 description 5
- 230000006698 induction Effects 0.000 description 5
- 238000004891 communication Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
- H04B10/66—Non-coherent receivers, e.g. using direct detection
- H04B10/69—Electrical arrangements in the receiver
- H04B10/697—Arrangements for reducing noise and distortion
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
- H04B10/66—Non-coherent receivers, e.g. using direct detection
- H04B10/69—Electrical arrangements in the receiver
- H04B10/697—Arrangements for reducing noise and distortion
- H04B10/6972—Arrangements for reducing noise and distortion using passive filtering
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Optical Communication System (AREA)
Abstract
一种光杂讯消除装置包括第一和第二光滤波器、光电转换器及运算单元，第一和第二光滤波器分别允许应用光信号的波长的光和不同于应用光信号的波长的光通过而产生第一光信号和第二背景光杂讯，第一光信号包括应用光信号及相同于应用光信号的波长的第一背景光杂讯，光电转换器侦测第一光信号与第二背景光杂讯，而进行光电转换产生正比于第一光信号的照度的第一电信号及正比于第二背景光杂讯的照度的第二电信号，运算单元将第一电信号和第二电信号分别根据一第一比例与一第二比例进行调整后，再运算得到正比于应用光信号的照度的输出信号，能消除与该应用光信号波长相同的该第一背景光杂讯。
An optical noise elimination device includes first and second optical filters, a photoelectric converter and a computing unit. The first and second optical filters allow light of a wavelength of an applied optical signal and light of a wavelength different from the applied optical signal to pass through respectively to generate a first optical signal and a second background optical noise. The first optical signal includes the applied optical signal and a first background optical noise of the same wavelength as the applied optical signal. The photoelectric converter detects the first optical signal and the second background optical noise and performs photoelectric conversion to generate a first electrical signal proportional to the illumination of the first optical signal and a second electrical signal proportional to the illumination of the second background optical noise. The computing unit adjusts the first electrical signal and the second electrical signal according to a first ratio and a second ratio respectively, and then calculates to obtain an output signal proportional to the illumination of the applied optical signal, so as to eliminate the first background optical noise of the same wavelength as the applied optical signal.
Description
Technical Field
The present invention relates to an optical noise cancellation apparatus, and more particularly to an optical noise cancellation apparatus.
Background
With the development of science and technology, optical applications and technology become more and more widespread, for example, the invention patent "infrared receiver" disclosed in publication TW I240501 uses a single filter to filter out noise outside the infrared band of sunlight noise to increase the sensitivity of the infrared receiver, but it cannot remove the sunlight noise in the infrared band, so that the infrared receiver receives the illuminance of the sunlight noise when receiving the illuminance of infrared, and the infrared receiver is interfered by the influence of sunlight intensity, resulting in inaccurate performance.
Furthermore, the invention of TW I467937 discloses a light emitting diode communication device capable of reducing background light noise, which applies manchester encoding to the light emitting diode communication device to generate manchester electrical signals to improve signal quality and reduce signal noise, but when sunlight noise is strong to a certain degree, the limit of manchester encoding is exceeded.
Disclosure of Invention
The invention aims to provide an optical noise elimination device which can eliminate the sunlight noise with the same frequency as the applied optical signal.
The invention relates to an optical noise elimination device which is suitable for receiving an application optical signal and eliminating background optical noise with the same wavelength as the application optical signal.
The first optical filter only allows light of the wavelength of the application optical signal to pass through to generate a first optical signal, which includes the application optical signal and a first background optical noise identical to the wavelength of the application optical signal.
The second optical filter only allows light of a wavelength different from the application light signal to pass through to generate a second background light noise.
The photoelectric converter detects the first optical signal and the second background light noise respectively, and performs photoelectric conversion to generate a first electrical signal proportional to the illuminance of the first optical signal and a second electrical signal proportional to the illuminance of the second background light noise.
The operation unit is electrically connected with the photoelectric converter to receive the first electric signal and the second electric signal, and after the first electric signal and the second electric signal are respectively adjusted according to a first proportion and a second proportion, an output signal which is in direct proportion to the illumination of the application optical signal is obtained through operation, and the first proportion and the second proportion are related to the increase and decrease of the illumination of background light noise in different wave bands.
In the optical noise cancellation apparatus of the present invention, the first ratio × the illuminance of the first background optical noise is equal to the second ratio × the illuminance of the second background optical noise.
The optical noise cancellation apparatus of the present invention comprises: a first resistor having a first end and a second end, the first end being electrically connected to the photoelectric converter for receiving the second electrical signal; the second resistor is provided with a first end and a second end, and the first end is electrically connected with the second end of the first resistor; a third resistor having a first end and a second end, the first end being electrically connected to the photoelectric converter for receiving the first electrical signal; a fourth resistor having a first end and a grounded second end, the first end being electrically connected to the second end of the third resistor; and the operational amplifier is provided with an inverting input end, a non-inverting input end and an output end, the inverting input end is electrically connected with the second end of the first resistor, the non-inverting input end is electrically connected with the second end of the third resistor, the output end is electrically connected with the second end of the second resistor, and the operational amplifier carries out subtraction operation according to the first electric signal and the second electric signal to generate the output signal.
In the optical noise cancellation device of the present invention, the impedance values of the first resistor and the second resistor are related to the first ratio, and the impedance values of the first resistor, the second resistor, the third resistor and the fourth resistor are related to the second ratio.
The optical noise cancellation device of the present invention,
r1, r2, r3 and r4 are resistance values of the first resistor, the second resistor, the third resistor and the fourth resistor, respectively.
According to the optical noise cancellation device of the present invention, when the illuminance of the background optical noise at different bands is the same, an impedance value of the first resistor, the second resistor, the third resistor and the fourth resistor is the same.
The optical-to-electrical converter of the present invention comprises: the first light meter is used for detecting the first light signal and generating a first induction current which is in direct proportion to the illumination of the first light signal according to the illumination of the first light signal; the first operational amplifier is provided with an inverting input end, a non-inverting input end and an output end, the inverting input end is electrically connected with the first light meter to receive the first induction current, the non-inverting input end is grounded, and the first operational amplifier generates the first electric signal according to the magnitude of the first induction current; a first feedback resistor electrically connected between the inverting input terminal and the output terminal of the first operational amplifier; a second light meter for detecting the second background light noise and generating a second induced current proportional to the illumination of the second background light noise according to the illumination of the second background light noise; the second operational amplifier is provided with an inverting input end, a non-inverting input end and an output end, the inverting input end is electrically connected with the second light meter to receive the second induction current, the non-inverting input end is grounded, the second operational amplifier generates the second electric signal according to the magnitude of the second induction current, and a second feedback resistor is electrically connected between the inverting input end and the output end of the second operational amplifier.
In the optical noise cancellation device of the present invention, the first optical filter and the second optical filter are optical filters.
The optical noise cancellation apparatus of the present invention operates at a low frequency using the optical signal and the background optical noise.
The wavelength of the background light noise of the optical noise cancellation device of the present invention is between 300 nm and 900 nm.
The invention has the beneficial effects that: the optical noise eliminating device of the invention utilizes the photoelectric converter to detect the first optical signal and the second background optical noise, and carries out photoelectric conversion to generate the first electric signal and the second electric signal, the arithmetic unit receives the first electric signal and the second electric signal, and carries out adjustment according to the first proportion and the second proportion, and then carries out operation to obtain an output signal which is in direct proportion to the illumination of the application optical signal, thereby eliminating the first background optical noise.
Drawings
Other features and effects of the present invention will be clearly apparent from the embodiments with reference to the drawings:
FIG. 1 is a circuit diagram illustrating a first embodiment of an optical noise cancellation device according to the present invention;
FIG. 2 is a waveform diagram illustrating an illuminance-wavelength waveform diagram of the first embodiment of the optical noise cancellation device according to the present invention; and
fig. 3 is a waveform diagram illustrating an illuminance-wavelength waveform diagram of a second embodiment of the optical noise cancellation device according to the present invention.
Detailed Description
Before the present invention is described in detail, it should be noted that in the following description, like elements are represented by like reference numerals.
Referring to fig. 1, the optical noise cancellation apparatus of the present invention is adapted to receive an application optical signal and cancel a background optical noise having a wavelength identical to that of the application optical signal to avoid affecting performance of optical applications such as laser ranging or optical communication, and includes a first optical filter 1, a second optical filter 2, a photoelectric converter 3, and an operation unit 4.
The first optical filter 1 only allows light of the wavelength of the application optical signal to pass through to generate a first optical signal, which includes the application optical signal and a first background optical noise identical to the wavelength of the application optical signal.
The second optical filter 2 only allows light with a wavelength different from that of the application optical signal to pass through, so as to generate a second background light noise, and the first optical filter 1 and the second optical filter 2 of the present embodiment are optical filters.
The photoelectric converter 3 detects the first optical signal and the second background optical noise respectively, and performs photoelectric conversion to generate a first electrical signal proportional to the illuminance of the first optical signal and a second electrical signal proportional to the illuminance of the second background optical noise.
The photoelectric converter 3 includes a first light meter 31, a first operational amplifier 33, a first feedback resistor Rf1, a second light meter 32, a second operational amplifier 34, and a second feedback resistor Rf 2.
The first light meter 31 detects the first light signal and generates a first induced current proportional to the illuminance of the first light signal according to the illuminance of the first light signal.
The first operational amplifier 33 has an inverting input terminal electrically connected to the first light meter 31 for receiving the first sensing current, a non-inverting input terminal grounded, and an output terminal, and the first operational amplifier 33 generates the first electrical signal according to the magnitude of the first sensing current.
The first feedback resistor Rf1 is electrically connected between the inverting input terminal and the output terminal of the first operational amplifier 33.
The second light meter 32 detects the second background light noise, and generates a second induced current proportional to the illuminance of the second background light noise according to the illuminance of the second background light noise, and the first light meter 31 and the second light meter 32 may be photodiodes (photo diodes).
The second operational amplifier 34 has an inverting input terminal electrically connected to the second light meter 32 for receiving the second sensing current, a non-inverting input terminal grounded, and an output terminal, and the second operational amplifier 34 generates the second electrical signal according to the second sensing current.
The second feedback resistor Rf2 is electrically connected between the inverting input terminal and the output terminal of the second operational amplifier 34.
The operation unit 4 is electrically connected to the photoelectric converter 3 to receive the first electrical signal and the second electrical signal, and adjusts the first electrical signal and the second electrical signal according to a first ratio and a second ratio, and then calculates to obtain an output signal Vout proportional to the illuminance of the application optical signal, where the first ratio and the second ratio are related to the increase and decrease of the illuminance of the background optical noise in different bands, and the first ratio × the illuminance of the first background optical noise is equal to the second ratio × the illuminance of the second background optical noise.
The operation unit 4 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and an operational amplifier 41.
The first resistor R1 has a first end and a second end, and the first end is electrically connected to the photoelectric converter 3 for receiving the second electrical signal.
The second resistor R2 has a first end and a second end, and the first end is electrically connected to the second end of the first resistor R1.
The third resistor R3 has a first end and a second end, and the first end is electrically connected to the photoelectric converter 3 for receiving the first electrical signal.
The fourth resistor R4 has a first end electrically connected to the second end of the third resistor R3 and a second end connected to ground.
The operational amplifier 41 has an inverting input terminal electrically connected to the second terminal of the first resistor R1, a non-inverting input terminal electrically connected to the second terminal of the third resistor R3, and an output terminal electrically connected to the second terminal of the second resistor R2, wherein the operational amplifier 41 performs a subtraction operation according to the first electrical signal and the second electrical signal to generate the output signal Vout.
And the output signal Vout is-a first proportion × v1+ a second proportion × v2, v1 and v2 are voltage values of the first electrical signal and the second electrical signal, respectively.
It should be noted that the application optical signal and the background optical noise of the embodiment operate at low frequencies, and the wavelength of the background optical noise is between 300 nm and 900 nm.
For convenience of explanation, referring to fig. 2 for a theoretical preliminary explanation, it is assumed that the illuminations of the sunlight in all the wavelength bands are consistent, and as shown in fig. 2, the illuminations of the background light noise are all 50000 lux (lux), when the application light signal is generated, the application light signal is defined to operate at 650 nm wavelength and the illumination at the time of generation is 10 lux, at this time, one optical filter allows 650 nm wavelength light to pass through and takes out the illumination energy of 50010 lux (the illumination of the background light noise is 50000 lux + the illumination of the application light signal is 10 lux), at the same time, another optical filter allows 750 nm wavelength light to pass through and takes out 50000 lux, and finally, the illumination at 650 nm wavelength is subtracted by the illumination at 750 nm wavelength (50010 lux-50000 lux) to obtain the illumination of the application light signal.
Referring to fig. 3, assuming that the illuminance of the sunlight is not uniform in all bands, as shown in fig. 3, the illuminance of the background noise is linear, when the application optical signal is generated at 650 nm wavelength and the generated illuminance is 10 lux, the optical filter allows 650 nm wavelength light to pass through and extracts 50010 lux illuminance energy, and at the same time, the two other optical filters respectively allowing 750 nm and 850 nm wavelength light to pass through measure 50000 lux at 750 nm wavelength and 60000 lux at 850 nm wavelength illuminance, and then calculate the illuminance of the application optical signal according to the following formula.
The parameters L650, L750 and L850 are illumination at a wavelength of 650 nm, 750 nm and 850 nm, respectively.
The following will be further described with reference to a first embodiment in which the illuminance of the sunlight in all bands is assumed to be uniform, and a second embodiment in which the illuminance of the sunlight in all bands is assumed not to be uniform.
In describing the first embodiment, the application light signal is defined to operate at a wavelength of 650 nanometers (nm) and the illumination at the time of occurrence is 10 lux, and the first optical filter 1 and the second optical filter 2 allow light of 650 nanometers and 750 nanometers to pass, respectively.
Referring to fig. 2, when the illuminance of the background light noise in different bands is 50000 lux (that is, the first background light noise is equal to the second background light noise), the impedance values of the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 of the arithmetic unit 4 are all the same, so that the first ratio and the second ratio are all 1, the first optical filter 1 allows the application optical signal operating at 650 nm and the first background light noise to pass through to generate the first optical signal, the first light quantity meter 31 detects the first optical signal and generates the first induced current proportional to the illuminance of the first optical signal according to the illuminance of the first optical signal, the first operational amplifier 33 receives the first induced current and generates the first electrical signal according to the magnitude of the first induced current, the second optical filter 2 allows the second background light noise operating at 750 nm to pass through, the second light meter 32 detects the second background light noise and generates a second induced current proportional to the illuminance of the second background light noise according to the illuminance of the second background light noise, and the second operational amplifier 34 receives the second induced current and generates the second electrical signal according to the magnitude of the second induced current.
The arithmetic unit 4 receives the first electrical signal and the second electrical signal, and since the first ratio and the second ratio are both 1, the output signal Vout is-v 1+ v 2.
The second embodiment of the optical noise cancellation device of the present invention is similar to the first embodiment, except that: when the illuminance of the background light noise in different bands is different and is in a linear state, the values of the first ratio and the second ratio are adjusted by changing the impedance ratio of the first resistor R1 and the second resistor R2 and the impedance ratio of the third resistor R3 and the fourth resistor R4, so that the background light noise in the linear state can be eliminated.
Further, the present invention is also explained by the following (formula 1), wherein the wavelength of the application optical signal is 650 nanometers (nm), the illuminance of the application optical signal at the time of occurrence is 10 lux, the illuminance of the first background optical noise, the second background optical noise and a third background optical noise is linear with respect to the wavelength, the third background optical noise is operated at 850 nm, the illuminance of the second background optical noise and the third background optical noise is detected by a measuring device, and the slope of the illuminance of the background optical noise with respect to the wavelength is calculated according to the illuminance of the second background optical noise and the third background optical noise.
Wherein, L λ 2 is the illumination of the third background optical noise, L λ 1 is the illumination of the second background optical noise, λ 2 is the wavelength of the third background optical noise, and λ 1 is the wavelength of the second background optical noise.
Referring to fig. 3, it can be clearly seen that the illuminance of the third background light noise is 60000 lux, the illuminance of the second background light noise is 50000 lux, and the slope is obtained by substituting the above equation 1, and then the ratios of the resistance values of the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are set to be 3: 2 such that the first ratio is 2/3 and the second ratio is 1, and thus, the output signal Vout is- (2/3) v1+ v 2. The ratio of the impedance values of the first resistor, the second resistor, the third resistor and the fourth resistor is set to match the values of the first background light noise and the third background light noise, for example, the illuminance of the third background light noise is 60000 lux, the illuminance of the first background light noise is 40000 lux, and the ratio of the two is 3: 2.
in summary, the optical noise cancellation apparatus of the present invention can cancel the first background optical noise with the same wavelength as the application optical signal: the optical noise cancellation device of the present invention utilizes the photoelectric converter 3 to detect the first optical signal and the second background optical noise, and performs photoelectric conversion to generate the first electrical signal and the second electrical signal, the operation unit 4 receives the first electrical signal and the second electrical signal, and performs adjustment according to the first ratio and the second ratio, and then performs operation to obtain an output signal proportional to the illumination of the application optical signal, thereby eliminating the first background optical noise, and thus the object of the present invention can be achieved.
The above description is only a preferred embodiment of the present invention, and the scope of the present invention should not be limited thereby, and all the simple equivalent changes and modifications made by the claims and the contents of the specification should be included in the scope of the present invention.
Claims (9)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710347065.7A CN108964784B (en) | 2017-05-17 | 2017-05-17 | Optical noise elimination device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710347065.7A CN108964784B (en) | 2017-05-17 | 2017-05-17 | Optical noise elimination device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108964784A CN108964784A (en) | 2018-12-07 |
| CN108964784B true CN108964784B (en) | 2021-01-05 |
Family
ID=64461408
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710347065.7A Expired - Fee Related CN108964784B (en) | 2017-05-17 | 2017-05-17 | Optical noise elimination device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108964784B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5192978A (en) * | 1991-09-17 | 1993-03-09 | Kaman Aerospace Corporation | Apparatus and method for reducing solar noise in imaging lidar, underwater communications and lidar bathymetry systems |
| CN1534865A (en) * | 2003-04-01 | 2004-10-06 | �����ɷ� | Low noise light receiver |
| CN1629940A (en) * | 2003-12-17 | 2005-06-22 | 索尼株式会社 | Laser noise elimination circuit and optical disc device |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6812466B2 (en) * | 2002-09-25 | 2004-11-02 | Prospects, Corp. | Infrared obstacle detection in the presence of sunlight |
| CN201707755U (en) * | 2010-06-30 | 2011-01-12 | 天津市协力自动化工程有限公司 | Triple-band infrared flame detector |
| TW201251350A (en) * | 2011-06-08 | 2012-12-16 | Delta Networks Inc | Detector and method thereof |
| CN202459187U (en) * | 2011-12-02 | 2012-10-03 | 中国计量学院 | A blind person guide device prompting pedestrians about making way for the blind |
| CN204859151U (en) * | 2015-08-04 | 2015-12-09 | 深圳市华科瑞科技有限公司 | Processing circuit for anti-strong light interference of infrared sensor of medical equipment |
-
2017
- 2017-05-17 CN CN201710347065.7A patent/CN108964784B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5192978A (en) * | 1991-09-17 | 1993-03-09 | Kaman Aerospace Corporation | Apparatus and method for reducing solar noise in imaging lidar, underwater communications and lidar bathymetry systems |
| CN1534865A (en) * | 2003-04-01 | 2004-10-06 | �����ɷ� | Low noise light receiver |
| CN1629940A (en) * | 2003-12-17 | 2005-06-22 | 索尼株式会社 | Laser noise elimination circuit and optical disc device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108964784A (en) | 2018-12-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101701560B1 (en) | Circuit architecture for photodiodes | |
| JP2005265846A (en) | Color sensor that cancels dark current | |
| KR20220013059A (en) | Laser detector based reflector and method for reducing disturbance light noise thereof | |
| JP2015137924A (en) | Charge amp built-in type combustion pressure sensor | |
| JP2008251770A (en) | Photoelectric conversion circuit | |
| US20110248150A1 (en) | Device for quantifying and locating a light signal modulated at a predetermined frequency | |
| CN108964784B (en) | Optical noise elimination device | |
| JP2004357276A (en) | Low noise optical receiver | |
| CN106941340A (en) | A kind of collection for improving photosignal signal to noise ratio and process circuit | |
| TWI627837B (en) | Optical noise canceling device | |
| JP4006985B2 (en) | Pyroelectric infrared detector | |
| CN113465637A (en) | Photoelectric receiving and detecting circuit | |
| GB2202624A (en) | Optimum biasing system for electronic devices | |
| CN215639499U (en) | Photoelectric receiving and detecting circuit | |
| JPS6388871A (en) | Optical hybrid integrated circuit device | |
| JP2000216425A (en) | Photoelectric mixer | |
| JP2928616B2 (en) | Photodetector | |
| CN119197762B (en) | Photoelectric detector circuit capable of adaptively eliminating direct current bias influence of photodiode | |
| CN213186050U (en) | Weak light signal amplifying circuit | |
| CN115494287B (en) | An analog front-end circuit and integrated circuit for AC/DC current separation | |
| SU1714387A1 (en) | Light-detecting device | |
| CN214583654U (en) | Device for improving dynamic range of photodiode | |
| JPH0983452A (en) | Light receiving circuit | |
| CN110440780B (en) | A Large Bandwidth, Miniaturized Laser Gyro Preamplifier System | |
| KR101756922B1 (en) | Direct current potential transformer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20210105 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |