JPH03296309A - Optical reception circuit - Google Patents
Optical reception circuitInfo
- Publication number
- JPH03296309A JPH03296309A JP9806190A JP9806190A JPH03296309A JP H03296309 A JPH03296309 A JP H03296309A JP 9806190 A JP9806190 A JP 9806190A JP 9806190 A JP9806190 A JP 9806190A JP H03296309 A JPH03296309 A JP H03296309A
- Authority
- JP
- Japan
- Prior art keywords
- amplifier
- noise level
- avalanche photodiode
- bias voltage
- signal
- 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.)
- Pending
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 26
- 238000001514 detection method Methods 0.000 claims abstract description 7
- 238000000098 azimuthal photoelectron diffraction Methods 0.000 description 29
- 238000010586 diagram Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Landscapes
- Optical Radar Systems And Details Thereof (AREA)
- Amplifiers (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は、レーザ測距装置等の光受信回路に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical receiving circuit for a laser distance measuring device or the like.
レーザ測距装置等においては、光受信回路の受光素子と
してその高感度、高速応答性により、アバランシェ・フ
ォトダイオード（以下ＡＰＤと称す）が多く用いられて
いる。ＡＰＤはバイアス電圧に依存する増倍率を有して
いる。In laser ranging devices and the like, avalanche photodiodes (hereinafter referred to as APDs) are often used as light receiving elements in optical receiving circuits due to their high sensitivity and high speed response. APD has a multiplication factor that depends on the bias voltage.
ところで、レーザ測距装置等に応用される。受光素子と
してＡＰＤを使用した光受信回路における主な雑音源は
、背景光によるショット雑音、ＡＰＤの暗電流及び増幅
器入力抵抗による熱雑音である。By the way, it is applied to laser distance measuring devices and the like. The main noise sources in an optical receiving circuit using an APD as a light receiving element are shot noise due to background light, dark current of the APD, and thermal noise due to amplifier input resistance.
この場合の、受信信号の信号対雑音比（以下Ｓ／Ｎ比と
いう）は次式のように表わされる。In this case, the signal-to-noise ratio (hereinafter referred to as S/N ratio) of the received signal is expressed by the following equation.
ここでＰ、は信号光電力、 Ｐｓは背景光電力、■、は
ＡＰＤの暗電流１ＭはＡＰＤの増倍率、ηは量子効率。Here, P is the signal optical power, Ps is the background optical power, ■, the APD dark current 1M is the APD multiplication factor, and η is the quantum efficiency.
ｅは電荷、ｈνは光子エネルギ、２はＡＰＤの過剰雑音
指数、Ｂは帯域幅、ＲＬは負荷抵抗（増幅器入力抵抗１
ｈはボルツマン定数、Ｔは絶対温度、Ｆは増幅器の雑
音指数である。e is the charge, hν is the photon energy, 2 is the excess noise figure of the APD, B is the bandwidth, RL is the load resistance (amplifier input resistance 1
h is the Boltzmann constant, T is the absolute temperature, and F is the noise figure of the amplifier.
式（１）かられかるように、 ＡＰＤの増倍率Ｍの値
には、Ｓ／Ｎ比を最大にする最適値Ｍ、５、があり。As can be seen from equation (1), the value of the APD multiplication factor M has an optimal value M, 5, which maximizes the S/N ratio.
次式で表わされる。It is expressed by the following formula.
式（２）でわかるように最適増倍率は、ＡＰＤに入射す
る背景光電力のレベルによって変化する。As can be seen from equation (2), the optimal multiplication factor changes depending on the level of background light power incident on the APD.
また、ＡＰＤの増倍率Ｍはバイアス電圧Ｖによって変化
し、これらの関係は次式で与えられる。Further, the multiplication factor M of the APD changes depending on the bias voltage V, and the relationship between them is given by the following equation.
ここでＶ、はブレークダウン電圧、ｍは定数である。Here, V is a breakdown voltage and m is a constant.
第３図は、従来の光受信回路の構成例を示す図であり９
図において、（１）は直流電源、（２）はＡＰＤ、（３
）は受信光、（４）は増幅器、（５）は基準電源、（６
）は比較器である。FIG. 3 is a diagram showing an example of the configuration of a conventional optical receiving circuit.
In the figure, (1) is a DC power supply, (2) is an APD, and (3
) is the received light, (4) is the amplifier, (5) is the reference power supply, (6
) is a comparator.
直流電源（１）は、ＡＰＤ（２）に固定のバイアス電圧
を印加する。Ａ Ｐ Ｄ （２）は入射した受信光（３
）の強さに比例した出力電流を発生する。増幅器（４）
は前記Ａ Ｐ Ｄ （２）からの出力電流を電圧に変換
して増幅し、比較器（６）に出力する。また、基準電源
（５）は２光受信回路の雑音を考慮した所定のレベルの
閾値電圧を比較器（６）へ出力する。比較器（６）は、
前記増幅器（４）からの出力信号レベルと前記基準電源
（５）からの閾値電圧レベルと比較し閾値レベルを越え
る信号を２値レベルに変換し。A DC power supply (1) applies a fixed bias voltage to the APD (2). A P D (2) is the incident received light (3
) generates an output current proportional to the strength of the Amplifier (4)
converts the output current from the A P D (2) into a voltage, amplifies it, and outputs it to the comparator (6). Further, the reference power source (5) outputs a threshold voltage of a predetermined level considering the noise of the two-light receiver circuit to the comparator (6). The comparator (6) is
The output signal level from the amplifier (4) is compared with a threshold voltage level from the reference power supply (5), and a signal exceeding the threshold level is converted into a binary level.
受信信号として次段の信号処理回路（囲路）に送出する
。It is sent as a received signal to the next stage signal processing circuit (circuit).
以上のように、従来の光受信回路では、ＡＰＤに固定の
バイアス電圧を印加、すなわち固定の増倍率に設定され
ているため、ＡＰＤへ入射する背景光電力が大きくなっ
た場合、ショット雑音が増大し、Ｓ／Ｎ比が低下あるい
は雑音レベルが比較器の閾値レベルを越え受信信号とし
て誤って検出する誤警報率が増大するという問題点があ
った。As described above, in conventional optical receiving circuits, a fixed bias voltage is applied to the APD, that is, the multiplication factor is set to a fixed value, so when the background light power incident on the APD increases, shot noise increases. However, there is a problem in that the S/N ratio decreases or the noise level exceeds the threshold level of the comparator, increasing the false alarm rate where it is erroneously detected as a received signal.
この発明は、上記のような問題点を解消するためになさ
れたもので、ＡＰＤの増倍率が、ＡＰＤに入射する背景
光電力のレベルに応じて変化しＳ／Ｎ比を最適値に保つ
ことができまた背景光電力のレベルが増大しても誤警報
率を一定値以下に維持できる光受信回路を得ることを目
的とする。This invention was made to solve the above-mentioned problems, and the multiplication factor of the APD changes according to the level of background light power incident on the APD to maintain the S/N ratio at an optimal value. It is an object of the present invention to provide an optical receiving circuit that can maintain a false alarm rate below a certain value even when the level of background optical power increases.
この発明に係る光受信回路は、増幅器からの出力信号の
雑音レベルを検出し、ＡＰＤに入射した背景光によって
生じる雑音レベルが所定の値を越えないように、ＡＰＤ
のバイアス電圧を制御してＡＰＤの増倍率を制御するよ
うにしたものである。The optical receiving circuit according to the present invention detects the noise level of the output signal from the amplifier, and controls the APD so that the noise level caused by background light incident on the APD does not exceed a predetermined value.
The bias voltage of the APD is controlled to control the multiplication factor of the APD.
この発明における光受信回路は、ＡＰＤの増倍率がＡＰ
Ｄに入射する背景光電力のレベルに応じて変化し、Ｓ／
Ｎ比が最適値となる値に自動的に制御され、Ｓ／Ｎ比を
最適値に保つとともに誤警報率を一定値以下に維持する
。In the optical receiving circuit according to the present invention, the multiplication factor of APD is AP
varies depending on the level of background light power incident on D, and S/
The N ratio is automatically controlled to the optimum value, and the S/N ratio is kept at the optimum value, and the false alarm rate is maintained below a certain value.
以下、この発明の実施例を図を用いて説明する。 Embodiments of the present invention will be described below with reference to the drawings.
第１図は、この発明による光受信回路の一実施例を示す
構成図である。FIG. 1 is a block diagram showing an embodiment of an optical receiving circuit according to the present invention.
同図において、（７）はＡＰＤにバイアス電圧を印加す
るとともに、このバイアス電圧をバイアス制御信号（８
）により可変できる直流電源、（９）は増幅器（４）か
らの出力信号の雑音レベルを検出する雑音レベル検出回
路、 （１０）は雑音レベル検出回路（９）で検出した
雑音レベルが所定の値を越えないようにＡＰＤのバイア
ス電圧を制御するよう直流電源（７）へバイアス制御信
号（８）を出力するノくイアスミ圧制御回路である。In the same figure, (7) applies a bias voltage to the APD and also applies this bias voltage to the bias control signal (8).
), (9) is a noise level detection circuit that detects the noise level of the output signal from the amplifier (4), and (10) is a noise level detection circuit that detects the noise level detected by the noise level detection circuit (9) at a predetermined value. This is a bias pressure control circuit that outputs a bias control signal (8) to a DC power supply (7) so as to control the bias voltage of the APD so that it does not exceed .
第１図において、第３図と同一部分又は相当部には同一
符号が付しである。In FIG. 1, the same or equivalent parts as in FIG. 3 are given the same reference numerals.
ＡＰＤ（２）、増幅器（４）、基準電源（５）及び比較
器（６）の動作は、第３図と同様である。The operations of the APD (2), amplifier (4), reference power supply (5), and comparator (6) are the same as in FIG.
ところで、受信信号の雑音レベルは式（１）より次式で
表わされる。By the way, the noise level of the received signal is expressed by the following equation from equation (1).
また前述のようにＡＰＤの像倍率Ｍには、受信信号のＳ
／Ｎ比を最良に保つために、背景光電力のレベルに応じ
た最適値Ｍ６１１１があり１式（２）で与えられる。Furthermore, as mentioned above, the image magnification M of the APD includes the S of the received signal.
In order to maintain the best /N ratio, there is an optimum value M6111 depending on the level of background light power, which is given by Equation 1 (2).
ＡＰＤのバイアス電圧を制御して、背景光電力のレベル
に応じて最適増倍率Ｍａｓｔとなるようにした場合の雑
音レベルＮｏｏｋは７式（２）と式（４）からとなり、
増幅器の入力抵抗による熱雑音で決まり。The noise level Nook when the bias voltage of the APD is controlled to achieve the optimum multiplication factor Mas according to the level of background optical power is obtained from Equation 7 (2) and Equation (4),
Determined by the thermal noise caused by the input resistance of the amplifier.
背景光電力のレベルに依存せず、一定となる。It does not depend on the background light power level and remains constant.
このとき増幅器（４）の出力信号の雑音レベルは次式で
表わされる。At this time, the noise level of the output signal of the amplifier (4) is expressed by the following equation.
２ ＲＬ
ここでＧは増幅器（４）の利得である。従って、増幅器
（４）の出力の雑音レベルを雑音レベル検出回路（９）
で検出して１バイアス制御回路（１０）及び直流電源°
（７）で、前記雑音レベルの上限を式（６）で表わされ
る値に制御するようＡ Ｐ Ｄ （２）のバイアス電圧
を制御すれば、ＡＰＤ（２）は入射する背景光電力のレ
ベルに応じて最適増倍率となるよう制御される。2 RL where G is the gain of the amplifier (4). Therefore, the noise level detection circuit (9) detects the noise level of the output of the amplifier (4).
1 bias control circuit (10) and DC power supply
In (7), if the bias voltage of APD (2) is controlled so that the upper limit of the noise level is controlled to the value expressed by equation (6), APD (2) will be adjusted to the level of the incident background light power. Accordingly, the multiplication factor is controlled to be the optimum multiplication factor.
また、上述のように制御した場合、受信信号の誤警報率
は、背景光電力のレベルが増大しても雑音レベルが所定
の値に制限されるため、一定値以下に維持されることに
なる。Furthermore, when controlled as described above, the false alarm rate of the received signal will be maintained below a certain value because the noise level will be limited to a predetermined value even if the background optical power level increases. .
また９式（８）かられかるようにＹｓａｐ、は増幅器（
４）の温度Ｔに依存するので、雑音レベルの上限を制限
する値も増幅器（４）の温度に対応して変化させること
が望ましい。Also, as seen from Equation 9 (8), Ysap is the amplifier (
4), it is desirable to change the value that limits the upper limit of the noise level in accordance with the temperature of the amplifier (4).
第２図は、この場合の光受信回路の一実施例を示す構成
図である。第２図において、第１図と同一部分又は相当
部分には同一符号が付しである。FIG. 2 is a configuration diagram showing an embodiment of the optical receiving circuit in this case. In FIG. 2, the same or equivalent parts as in FIG. 1 are given the same reference numerals.
温度検出器（１１）を増幅器（４）に近接して配置して
、増幅器（４）の温度を検出し、バイアス電圧制御回路
（１０）は、この増幅器（４）の温度変化に対応して、
雑音レベルの上限を制限する値を変化させることにより
、温度変動に対しても常に最適な状態に維持することが
できる。A temperature detector (11) is placed close to the amplifier (4) to detect the temperature of the amplifier (4), and a bias voltage control circuit (10) is configured to adjust the temperature in response to the temperature change of the amplifier (4). ,
By changing the value that limits the upper limit of the noise level, it is possible to always maintain an optimal state even with temperature fluctuations.
以上のように、この発明によれば、ＡＰＤの増倍率がＡ
ＰＤに入射する背景光電力のレベルに応じて変化し、Ｓ
Ｎ比が最適値となる値に自動的に制御されるので、ＡＰ
Ｄに入射する背景光電力のレベルが変わっても光受信回
路のＳＮ比を最適値に保つとともに、誤警報率を一定値
以下にてきレーザ測距装置等の性能改善に大きく寄与す
ることができる。As described above, according to the present invention, the multiplication factor of APD is A
It changes depending on the level of background light power incident on the PD, and S
Since the N ratio is automatically controlled to the optimum value, the AP
Even if the level of background light power incident on D changes, the S/N ratio of the optical receiver circuit can be maintained at an optimal value, and the false alarm rate can be kept below a certain value, greatly contributing to improving the performance of laser distance measuring devices, etc. .
第１図はこの発明による光受信回路の一実施例の構成を
示す図、第２図はこの発明による光受信回路の他の実施
例の構成を示す図、第３図は従来の光受信回路の構成を
示す図である。
図において、（１）は直流電源、（２）はアバランシェ
・フォトダイオード、（３）は受信光、（４）は増幅器
、（５）は基準電源、（６）は比較器、（７）は直流電
源、（８）はバイアス制御信号、（９）は雑音レベル検
出回路、 （１０）はバイアス電圧制御回路（１１）は
温度検出器である。
なお２図中、同一符号は同一、又は相当部分を示す。
Ｌ。FIG. 1 is a diagram showing the configuration of one embodiment of the optical receiving circuit according to the present invention, FIG. 2 is a diagram showing the configuration of another embodiment of the optical receiving circuit according to the present invention, and FIG. 3 is a diagram showing the configuration of a conventional optical receiving circuit. FIG. In the figure, (1) is a DC power supply, (2) is an avalanche photodiode, (3) is a received light, (4) is an amplifier, (5) is a reference power supply, (6) is a comparator, and (7) is a (8) is a bias control signal; (9) is a noise level detection circuit; (10) is a bias voltage control circuit; (11) is a temperature detector. Note that in the two figures, the same reference numerals indicate the same or equivalent parts. L.
Claims (4)
オードと、このアバランシェ・フォトダイオードにバイ
アス電圧を印加するとともにこのバイアス電圧をバイア
ス制御信号により可変できる直流電源と、前記アバラン
シェ・フォトダイオードからの出力電流を電圧信号に変
換して増幅する増幅器と、この増幅器からの出力信号の
雑音レベルを検出する雑音レベル検出回路と、前記アバ
ランシェ・フォトダイオードに入射した背景光によつて
生じる前記増幅器からの出力信号の雑音レベルが所定の
値を越えないように前記アバランシェ・フォトダイオー
ドのバイアス電圧を制御して前記アバランシェ・フォト
ダイオードの増倍率を制御するように前記直流電源へバ
イアス制御信号を出力するバイアス電圧制御回路を、基
準電圧を発生する基準電源と、この基準電源の出力電圧
と、前記増幅器からの出力信号電圧との差を２値信号に
変換する比較器とを備えた光受信回路。(1) An avalanche photodiode that photoelectrically converts received light, a DC power supply that applies a bias voltage to the avalanche photodiode and can vary this bias voltage using a bias control signal, and an output current from the avalanche photodiode. an amplifier for converting and amplifying the voltage signal into a voltage signal; a noise level detection circuit for detecting the noise level of the output signal from the amplifier; and an output signal from the amplifier caused by background light incident on the avalanche photodiode. bias voltage control for outputting a bias control signal to the DC power supply so as to control the bias voltage of the avalanche photodiode so that the noise level of the avalanche photodiode does not exceed a predetermined value, and to control the multiplication factor of the avalanche photodiode; An optical receiving circuit comprising: a reference power source that generates a reference voltage; and a comparator that converts the difference between the output voltage of the reference power source and the output signal voltage from the amplifier into a binary signal.
出力信号の雑音レベルの上限を制限する値を、受信信号
の信号対雑音比が実質的に最適値となる前記アバランシ
ェ・フォトダイオードの増倍率が得られるバイアス電圧
を前記アバランシェ・フォトダイオードに印加した場合
に発生する前記増幅器の出力信号の雑音レベルとしたこ
とを特徴とする特許請求の範囲第（１）項記載の光受信
回路。(2) The bias voltage control circuit sets a value that limits the upper limit of the noise level of the output signal from the amplifier to the multiplication factor of the avalanche photodiode at which the signal-to-noise ratio of the received signal becomes a substantially optimal value. 2. The optical receiver circuit according to claim 1, wherein the noise level of the output signal of the amplifier that is generated when a bias voltage that obtains the above is applied to the avalanche photodiode.
出力信号の雑音レベルの上限を制御する値を、実質的に
次式により求められる値としたことを特徴とする特許請
求の範囲第（１）項記載の光受信回路。 Ｖ＿ｎ＝（ｘ＋２／ｘ）＾１＾／＾２（４ｋＴＢＦ／Ｒ
＿Ｌ）＾１＾／２・Ｒ＿Ｌ・ＧここでＶ＿ｎは前記増幅
器からの出力信号の雑音レベル、ｘは前記アバランシェ
・フォトダイオードの過剰雑音指数、ｋはボルツマン定
数、Ｔは増幅器の温度、Ｂは増幅器の帯域幅、Ｆは増幅
器の雑音指数、Ｒ＿Ｌは増幅器の入力抵抗、Ｇは増幅器
の利得である。(3) The bias voltage control circuit is characterized in that the value for controlling the upper limit of the noise level of the output signal from the amplifier is substantially determined by the following equation. ) The optical receiving circuit described in section 2. V_n=(x+2/x)^1^/^2(4kTBF/R
_L)^1^/2・R_L・G where V_n is the noise level of the output signal from the amplifier, x is the excess noise figure of the avalanche photodiode, k is the Boltzmann constant, T is the temperature of the amplifier, and B is the The bandwidth of the amplifier, F is the noise figure of the amplifier, R_L is the input resistance of the amplifier, and G is the gain of the amplifier.
変化に対応して、前記増幅器からの出力信号の雑音レベ
ルの上限を制御する値を変化させるようにしたことを特
徴とする特許請求の範囲第（１）項記載の光受信回路。(4) The bias voltage control circuit is configured to change a value for controlling an upper limit of the noise level of the output signal from the amplifier in response to a temperature change in the amplifier. The optical receiving circuit according to paragraph (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9806190A JPH03296309A (en) | 1990-04-13 | 1990-04-13 | Optical reception circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9806190A JPH03296309A (en) | 1990-04-13 | 1990-04-13 | Optical reception circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03296309A true JPH03296309A (en) | 1991-12-27 |
Family
ID=14209815
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9806190A Pending JPH03296309A (en) | 1990-04-13 | 1990-04-13 | Optical reception circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03296309A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008215878A (en) * | 2007-02-28 | 2008-09-18 | Yamaha Motor Co Ltd | Light receiving device, laser radar device, and vehicle |
| JP2008286669A (en) * | 2007-05-18 | 2008-11-27 | Sokkia Topcon Co Ltd | Light wave range finder |
| WO2019004144A1 (en) * | 2017-06-27 | 2019-01-03 | パイオニア株式会社 | Receiving device, control method, program and storage medium |
| WO2019004146A1 (en) * | 2017-06-27 | 2019-01-03 | パイオニア株式会社 | Information processing device, control method, program and recording medium |
| WO2019065490A1 (en) * | 2017-09-26 | 2019-04-04 | パイオニア株式会社 | Control device, detection device, method for controlling avalanche diode, program and storage medium |
| CN113646663A (en) * | 2019-03-27 | 2021-11-12 | 松下知识产权经营株式会社 | Distance measuring device, distance measuring system, distance measuring method, and program |
-
1990
- 1990-04-13 JP JP9806190A patent/JPH03296309A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008215878A (en) * | 2007-02-28 | 2008-09-18 | Yamaha Motor Co Ltd | Light receiving device, laser radar device, and vehicle |
| JP2008286669A (en) * | 2007-05-18 | 2008-11-27 | Sokkia Topcon Co Ltd | Light wave range finder |
| WO2019004144A1 (en) * | 2017-06-27 | 2019-01-03 | パイオニア株式会社 | Receiving device, control method, program and storage medium |
| WO2019004146A1 (en) * | 2017-06-27 | 2019-01-03 | パイオニア株式会社 | Information processing device, control method, program and recording medium |
| JPWO2019004146A1 (en) * | 2017-06-27 | 2020-04-30 | パイオニア株式会社 | Information processing apparatus, control method, program, and storage medium |
| JPWO2019004144A1 (en) * | 2017-06-27 | 2020-04-30 | パイオニア株式会社 | Receiver, control method, program and storage medium |
| EP3647812A4 (en) * | 2017-06-27 | 2021-03-17 | Pioneer Corporation | Receiving device, control method, program and storage medium |
| WO2019065490A1 (en) * | 2017-09-26 | 2019-04-04 | パイオニア株式会社 | Control device, detection device, method for controlling avalanche diode, program and storage medium |
| JPWO2019065490A1 (en) * | 2017-09-26 | 2020-11-05 | パイオニア株式会社 | Controls, detectors, methods for controlling avalanche diodes, programs and storage media |
| JP2022091847A (en) * | 2017-09-26 | 2022-06-21 | パイオニア株式会社 | Control device, detection device, method for controlling avalanche diode, program, and storage media |
| CN113646663A (en) * | 2019-03-27 | 2021-11-12 | 松下知识产权经营株式会社 | Distance measuring device, distance measuring system, distance measuring method, and program |
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