JP2012205003A - Optical receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical receiver capable of improving the stability of an electrical signal level.SOLUTION: The optical receiver 1 receives an optical signal, and converts the optical signal into an RF signal, and outputs the RF signal. The optical receiver 1 includes a PD element 2 for converting an optical signal into an RF signal; an AGO6 for adjusting the level of the RF signal converted by the PD element 2; a detection section 7 for detecting a phenomenon which has occurred inside the optical receiver 1 and affects the level of the RF signal converted by the PD element 2; and a control section 9 which receives the RF signal from the PD element 2, and receives a detected output of the detection section 7, and controls the AGO6 on the based of the level of the received RF signal and the level of the detected output.

Description

  The present invention relates to an optical receiver that receives various signals as optical signals and converts them into electrical signals.

  In recent years, with the progress of optical communication technology, FTTH (Fiber To The Home), which is a data communication service for homes using optical fibers, is becoming popular in ordinary homes. According to this optical transmission system, since repeatless transmission of about several tens of kilometers is possible, the transmission system can be easily widened. This optical transmission system generally includes an optical transmitter and an optical amplifier arranged on the center side, and an optical receiver (V-ONU: Video-Optical Network Unit: video optical subscriber line) arranged on the receiver side. Terminal device) is connected via an optical cable. Then, the optical transmitter converts the RF signal into an optical signal and transmits it, the optical amplifier amplifies the optical signal, and transmits this optical signal to the optical receiver via a long-distance transmission path using an optical cable. In this optical receiver, an optical signal is converted into an electric signal (RF signal) and output to a receiving terminal such as a TV receiver.

  FIG. 6 is a circuit diagram of a conventional optical receiver. As shown in FIG. 6, a conventional optical receiver 100 generally includes a PD (Photo Diode) element 101, amplifiers 102 to 104, an AGC (Auto Gain Controller) 105, a control unit 106, and a branching unit. 107, an output terminal 108, and a monitor output terminal 109. In such a configuration, an optical signal input from the outside is converted into an RF signal by the PD element 101. This RF signal is amplified by the amplifier 102, adjusted in level by the AGC 105, amplified in multiple stages by the amplifiers 103 and 104, and output from the output terminal 108.

  Here, a control voltage characteristic that defines a control voltage Vc output to the AGC 105 is set in the control unit 106 in advance. The control unit 106 performs arithmetic processing on the level of the optical signal received from the PD terminal 101, determines a control voltage Vc corresponding to the level of the optical signal based on the control voltage characteristics, and determines the control voltage Vc as the AGC 105. Output to. Then, the AGC 105 adjusts the level of the RF signal so that the level corresponds to the control voltage Vc (see, for example, Patent Document 1).

JP 2007-31282 A

  By the way, the above-described PD element 101 is easily affected by the installation environment. For example, the level of the RF signal output from the PD element 101 varies depending on the temperature due to the temperature characteristics of the direct current amplification factor hFE of the PD element 101. Specifically, when the temperature of the PD element 101 increases, the level of the RF signal output from the PD element 101 becomes lower than the actual level. Further, when the temperature of the PD element 101 is lowered, the level of the RF signal output from the PD element 101 becomes higher than the actual level. As described above, since the level of the RF signal output from the PD element 101 varies depending on the installation environment, there is room for improvement with respect to the stability of the RF signal level of the optical receiver 100.

  The present invention has been made in view of the above, and an object thereof is to provide an optical receiver capable of improving the stability of the level of an electric signal.

  In order to solve the above-described problems and achieve the object, an optical receiver according to claim 1 is an optical receiver that receives an optical signal, converts the optical signal into an electric signal, and outputs the electric signal. Photoelectric conversion means for converting to a signal; level adjustment means for adjusting the level of the electrical signal converted by the photoelectric conversion means; and a phenomenon occurring inside the optical receiver, the photoelectric conversion means Detecting means for detecting a phenomenon affecting the level of the converted electric signal; receiving the electric signal from the photoelectric converting means; receiving a detection output of the detecting means; and receiving the received electric signal Level adjustment control means for controlling the level adjustment means based on the level of the output and the level of the detection output.

  The optical receiver according to claim 2 is the optical receiver according to claim 1, wherein the detection means is a temperature sensor that detects a temperature of the photoelectric conversion means.

  The optical receiver according to claim 3 is the optical receiver according to claim 1 or 2, wherein the level adjustment control means cannot receive the electrical signal from the photoelectric conversion means, or the detection means. When the detection output cannot be received, the same control as the control immediately before the electric signal or the detection output cannot be received is performed on the level adjusting means.

  An optical receiver according to claim 4 is the optical receiver according to any one of claims 1 to 3, further comprising storage means for storing a predetermined upper limit value, wherein the level adjustment control means comprises: When the level of the detection output received from the detection unit exceeds a threshold value, the predetermined upper limit value is acquired from the storage unit, and the level adjustment unit is controlled based on the acquired upper limit value.

  The optical receiver according to claim 5 is the optical receiver according to any one of claims 1 to 4, wherein the level adjustment control means controls the level adjustment means at a predetermined cycle. In addition, the period when the optical receiver is started up is shorter than the normal period of the optical receiver.

  An optical receiver according to claim 6 is the optical receiver according to any one of claims 1 to 5, further comprising output means for outputting various types of information related to the level adjustment control means. The adjustment control means determines whether or not the photoelectric conversion means is abnormal based on the level of the detection output received from the detection means, and if it is determined that there is an abnormality in the photoelectric conversion means, there is an abnormality. Is output by the output means.

  According to the optical receiver of the first aspect, the level adjustment control means receives the electric signal from the photoelectric conversion means, receives the detection output of the detection means, and determines the level of the received electric signal and the detection output. Since the level adjustment means is controlled based on the level, the level of the electrical signal increased or decreased due to a phenomenon affecting the level of the electrical signal can be adjusted to the original level of the electrical signal, and the stability of the level of the electrical signal Can be improved.

  According to the optical receiver of the second aspect, since the detection means is a temperature sensor that detects the temperature of the photoelectric conversion means, the level of the electric signal increased or decreased due to the fluctuation of the temperature is changed to the level of the original electric signal. And the stability of the level of the electric signal can be further improved.

  According to the optical receiver of claim 3, the level adjustment control means may detect the electric signal or the detection when the electric signal cannot be received from the photoelectric conversion means or when the detection output cannot be received from the detection means. Since the level adjustment means performs the same control as the control immediately before the output can no longer be received, the level adjustment control means becomes unable to receive the optical signal due to a reception failure, etc. Even after the adjustment control means cannot receive the detection output, the optimum state for the electric signal level can be maintained, and the stability of the electric signal level when the optical receiver is abnormal is improved. Can do.

  According to the optical receiver of claim 4, the level adjustment control means adjusts the level based on the upper limit value acquired from the storage means when the level of the detection output received from the detection means exceeds a threshold value. Since the control means controls the erroneous adjustment of the electrical signal level when the detection output level suddenly increases or decreases rapidly due to a failure of the detection means, etc. It is possible to further improve the stability of the electric signal level when the machine is abnormal.

  According to the optical receiver of claim 5, when the level adjustment control unit controls the level adjustment unit at a predetermined cycle, the cycle at the startup of the optical receiver is set to the optical receiver. Therefore, the electric signal level can be effectively adjusted at a timing at which a phenomenon that affects the electric signal level is likely to occur, and the stability of the electric signal level is further improved. Can be improved.

  According to the optical receiver of the sixth aspect, when the level adjustment control unit determines that the photoelectric conversion unit has an abnormality, the output unit outputs information indicating that the abnormality is present. It is possible to notify the user that there is an abnormality in the photoelectric conversion means, and to prompt an appropriate response.

It is a circuit diagram of the optical receiver which concerns on this Embodiment. It is the table | surface which illustrated the content of the information stored in a correction | amendment control voltage table. It is the table | surface which illustrated the content of the information stored in an upper limit table. It is a flowchart of the process which the optical receiver which concerns on this Embodiment performs. It is a flowchart of a control voltage output process. It is a circuit diagram of the conventional optical receiver.

  Hereinafter, an embodiment of an optical receiver according to the present invention will be described in detail with reference to the accompanying drawings. First, the overall configuration of the optical receiver will be described, then the processing executed by the optical receiver will be described, and finally, a modification to the present embodiment will be described. However, the present invention is not limited by this embodiment. In addition, although the installation object and application object of the optical receiver which concerns on this Embodiment are arbitrary, below, it demonstrates as an example the case where it applies to the optical receiver installed in the indoor of a dwelling unit.

Embodiment
(Constitution)
FIG. 1 is a circuit diagram of an optical receiver according to the present embodiment. As shown in FIG. 1, the optical receiver 1 includes a PD element 2, amplifiers 3 to 5, AGC 6, a detection unit 7, a display unit 8, a control unit 9, a storage unit 10, a branching device 11, an output terminal 12, and A monitor output terminal 13 is provided.

  The PD element 2 is a photoelectric conversion unit that converts an optical signal input from the outside into an electric signal (hereinafter referred to as an RF signal). The amplifiers 3 to 5 are amplification means for amplifying the RF signal, the amplifier 3 performs preliminary amplification before reaching the AGC 6, the amplifier 4 performs preliminary amplification of the output from the AGC 6, and the amplifier 5 performs pre-amplification. Perform amplification. The branching device 11 outputs the RF signal amplified by the amplifier 5 to the output terminal 12 and branches a part thereof to the monitor output terminal 13. The output terminal 12 outputs the RF signal output from the branching device 11 to a subsequent device such as a television receiver. The monitor output terminal 13 outputs an RF signal branched by the branching unit 11 and a signal including information on the control unit 9 for monitoring.

  Here, the AGC 6 is level adjusting means for adjusting the level of the RF signal. The AGC 6 can be configured in substantially the same manner as the AGC 6 in the conventional optical receiver 1 and is configured using, for example, a variable ATT that is driven based on the control voltage Vc output from the control unit 9.

  The detection unit 7 is a detection unit that detects a phenomenon that has occurred inside the optical receiver 1 and that affects the level of the RF signal converted by the PD element 2. Here, “a phenomenon occurring inside the optical receiver 1 and affecting the level of the RF signal converted by the PD element 2” includes, for example, the temperature and humidity inside the optical receiver 1. , Atmospheric pressure, magnetism, etc. However, in this embodiment, the temperature inside the optical receiver 1 will be described. This detection part 7 is comprised as a well-known temperature sensor which detects the temperature of PD element 2, for example. Further, the installation position of the detection unit 7 is arbitrary. For example, it is assumed that the temperature inside the optical receiver 1 approximates the temperature of the PD element 2 and may be provided at any position inside the optical receiver 1. Good (for example, near the control unit 9). Alternatively, it may be provided in the vicinity of the PD element 2 in order to detect the temperature of the PD element 2 more accurately.

  The display unit 8 is an output unit that outputs various types of information regarding the control unit 9. The display unit 8 is configured as an LED (Light Emitting Diode), for example.

  The control unit 9 receives the RF signal from the PD element 2, receives the detection output of the detection unit 7, and controls the AGC 6 based on the received RF signal level and the detection output level. It is. For example, the control unit 9 calculates the control voltage Vc based on the received RF signal level and the detection output level, and outputs the calculated control voltage Vc to the AGC 6. Specifically, the control unit 9 includes a CPU, various programs that are interpreted and executed on the CPU (including a basic control program such as an OS and an application program that is activated on the OS and realizes a specific function), and An internal memory such as a RAM for storing programs and various data is provided.

  The storage unit 10 is a storage unit that stores various data necessary for control by the control unit 9. Although the specific configuration of the storage unit 10 is arbitrary, for example, a RAM (Random Access Memory) or a flash memory can be used.

  Further, the storage unit 10 includes a correction control voltage table 10a and an upper limit value table 10b.

  The correction control voltage table 10a is correction control voltage storage means for storing correction control voltage specifying information described later. FIG. 2 is a table illustrating the content of information stored in the correction control voltage table 10a. As shown in FIG. 2, the correction control voltage table 10a stores information corresponding to the table items “temperature” and “correction control voltage” in association with each other. The information stored in correspondence with the item “temperature” is temperature specifying information for specifying the temperature. For example, “10 ° C.-11 ° C.” (indicating 10 ° C. or more and less than 11 ° C.) is stored. The information stored corresponding to the item “correction control voltage” is correction control voltage specifying information for specifying the correction control voltage Va, and for example, “Va10” is stored. Here, the “correction control voltage” includes the temperature characteristic of the direct current amplification factor hFE of the PD element 2 and is for correcting the control voltage Vc calculated by the control unit 9.

  The upper limit table 10b is an upper limit storage unit that stores upper limit specification information described later. FIG. 3 is a table illustrating the contents of information stored in the upper limit table 10b. As shown in FIG. 3, the upper limit table 10b stores information corresponding to the table items “level” and “upper limit” in association with each other. The information stored corresponding to the item “level” is level specifying information for specifying the level of the electrical signal or the detection output level of the detection unit 7, for example, “the level of the electrical signal is equal to or higher than the first threshold”, “Detection output level is greater than or equal to second threshold value” or the like is stored. Information stored in association with the item “upper limit value” is upper limit value specifying information for specifying the upper limit value Vcmax. For example, “Vcmax1”, “Vcmax2”, and the like are stored.

(processing)
Next, processing executed by the optical receiver 1 configured as described above will be described. FIG. 4 is a flowchart of processing executed by the optical receiver 1 according to the present embodiment (steps are abbreviated as “S” in the description of each processing below). This process is activated when, for example, the optical receiver 1 is powered on.

  As shown in FIG. 4, the control unit 9 monitors whether or not a predetermined time has elapsed since the optical receiver 1 was activated (SA1). For example, in the case where the AGC 6 is controlled separately when the optical receiver 1 is started up and at the normal time, the control unit 9 does not elapse for a predetermined time (for example, 5 minutes) after the optical receiver 1 is activated. The AGC 6 is controlled when the optical receiver 1 is started up. On the other hand, when the predetermined time has elapsed, the AGC 6 is controlled as the normal time of the optical receiver 1.

  Here, when the predetermined time has not elapsed since the optical receiver 1 was started (SA1, No), the control unit 9 sets the cycle T for controlling the AGC 6 as the cycle T1 (SA2).

  On the other hand, when a predetermined time has elapsed since the optical receiver 1 was activated (SA1, Yes), the control unit 9 sets the cycle T for controlling the AGC 6 as the cycle T2 (SA3).

  Here, the period T1 and the period T2 may be arbitrarily set, but in the present embodiment, the period T1 is set shorter than the period T2. That is, since it is assumed that temperature fluctuations are likely to occur when the optical receiver 1 is started up, the level of the RF signal is obtained by executing a control voltage output process described later at a relatively short period T1 (for example, 1 minute). Adjust frequently. On the other hand, since it is assumed that the temperature is stable after the start-up of the optical receiver 1, by executing a control voltage output process described later in a relatively long period T2 (for example, 10 minutes), The power consumption due to the control voltage output process is suppressed.

  Next, the control unit 9 monitors whether or not the period T has elapsed since the optical receiver 1 was activated (SA4).

  Here, when the period T has not elapsed since the optical receiver 1 was started (SA4, No), the control unit 9 proceeds to SA1, and thereafter repeats the processes of SA1 to SA4 described above.

  On the other hand, when the period T has elapsed since the optical receiver 1 was started (SA4, Yes), the control unit 9 clears the measurement time of the period T and executes control voltage output processing (SA5). After the end of this control voltage output process, the control unit 9 shifts to SA1, and thereafter repeats the above-described processes SA1 to SA5.

(Processing-Control voltage output processing)
Next, control voltage output processing executed by the optical receiver 1 will be described. FIG. 5 is a flowchart of the control voltage output process.

  As shown in FIG. 5, when the control voltage output process is started, the control unit 9 receives an RF signal from the PD element 2 and monitors whether a detection output is received from the detection unit 7 (SB1). ).

  When the control unit 9 receives an RF signal from the PD element 2 and receives a detection output from the detection unit 7 (SB1, Yes), the control unit 9 determines the level of the RF signal received from the PD element 2. It is determined whether or not has exceeded the first threshold, or whether or not the level of the detection output received from the detection unit 7 has exceeded the second threshold (SB2).

  As a result, it is determined that the level of the RF signal received from the PD element 2 does not exceed the first threshold value, and the level of the detection output received from the detection unit 7 is determined not to exceed the second threshold value. In the case (SB2, No), the control unit 9 calculates the control voltage Vc0 by a known method based on the level of the received RF signal (SB3).

  Next, the control unit 9 refers to the correction control voltage table 10a stored in the storage unit 10 and acquires the correction control voltage Va corresponding to the detection level detected by the detection unit 7 (SB4). For example, when the temperature detected by the detection unit 7 is 30 ° C., the control unit 9 acquires the correction control voltage Va30 with reference to the correction control voltage table 10a.

  Then, the control unit 9 calculates the control voltage Vc by adding the correction control voltage Va to the control voltage Vc0 based on the level of the RF signal (SB5). For example, when the correction control voltage Va is the correction control voltage Va30, the control unit 9 calculates the control voltage Vc as control voltage Vc = control voltage Vc0 + control voltage Va30.

  After the process of SB5, the control unit 9 outputs the control voltage Vc to the AGC 6 (SB6). As a result, the AGC 6 adjusts the level of the RF signal based on the control voltage Vc calculated in the SB 5, so the level of the RF signal increased or decreased due to a phenomenon that affects the level of the RF signal is changed to the level of the original RF signal. Can be adjusted.

  On the other hand, when it is determined that the level of the RF signal received from the PD element 2 exceeds the first threshold, or the level of the detection output received from the detection unit 7 is determined to exceed the second threshold ( The control unit 9 refers to the upper limit value table 10b stored in the storage unit 10 and acquires the upper limit value Vcmax (SB7). For example, when it is determined that the level of the RF signal received from the PD element 2 has exceeded the first threshold value due to the influence of noise or the like, the control unit 9 acquires the corresponding upper limit value Vcmax1 from the upper limit value table 10b. When it is determined that the level of the detection output detected by the detection unit 7 exceeds the second threshold value due to a failure of the detection unit 7 or the like, the control unit 9 determines the corresponding upper limit value Vcmax2 from the upper limit value table 10b. To get.

  Then, the control unit 9 sets the upper limit value Vcmax acquired in SB7 as the control voltage Vc (SB8), and outputs the control voltage Vc to the AGC 6 in the process of SB6 (SB6). As a result, when the RF signal level suddenly increases or decreases rapidly due to the influence of noise or the like, or when the detection output level suddenly increases due to failure of the detection unit 7 or the like, or rapidly decreases. Even in this case, erroneous adjustment of the RF signal level can be suppressed.

  Further, after the processing of SB8, the control unit 9 causes the display unit 8 to output information indicating that the PD element 2 has an abnormality (SB9). For example, the control unit 9 turns on or blinks the display unit 8. Thereby, it can be notified to the user that the PD element 2 is abnormal.

  Further, when the control unit 9 has not received the optical signal from the PD element 2 or has not received the detection output from the detection unit 7 (SB1, No), the control unit 9 is predetermined after the processing of SB1. It is monitored whether time has passed (SB10).

  Here, when the predetermined time has not elapsed since the processing of SB1 (SB10, No), the control unit 9 proceeds to SB1.

  On the other hand, when a predetermined time has elapsed after the processing of SB1 (SB10, Yes), the control unit 9 acquires the control voltage Vcn immediately before the optical signal cannot be received from the PD element 2 from the storage unit 10, or the detection unit 7 The control voltage Vcn immediately before the detection output can no longer be received is acquired (SB11). For example, the control unit 9 sequentially stores the control voltage Vc output to the AGC 6 in the storage unit 10 (for example, stores Vc1, Vc2,..., Vc10, etc. in the storage unit 10). The control unit 9 receives the detection output from the detection unit 7 when the optical signal cannot be received from the PD element 2 due to disconnection of the line connecting the control unit 9 and the PD element 2 or due to a failure of the detection unit 7. If not, the control voltage Vcn stored in the storage unit 10 is acquired immediately before the optical signal or the detection output cannot be received (for example, if the control voltage Vc10 stored immediately before is the control voltage Vc10, this Vc10 is acquired. Note that if the control voltage Vcn is not stored in the storage unit 10, a default value is acquired).

  And the control part 9 makes control voltage Vcn acquired in SB11 the control voltage Vc (SB12), and outputs this control voltage Vc to AGC6 in the process of SB6 (SB6). As a result, after the control unit 9 can no longer receive the RF signal from the disconnection of the line connecting the control unit 9 and the PD element 2, the detection output is received from the detection unit 7 thereafter or due to the failure of the detection unit 7. Even after it becomes impossible, the optimum state for the RF signal level can be maintained.

(effect)
As described above, according to the present embodiment, the control unit 9 receives the optical signal from the PD element 2 and also receives the detection output of the detection unit 7, and determines the level of the received RF signal and the level of the detection output. Since the AGC 6 is controlled based on the above, the level of the RF signal increased or decreased due to a phenomenon affecting the RF signal level can be adjusted to the original RF signal level, and the stability of the RF signal level can be improved. Can do.

  In addition, since the detection unit 7 is a temperature sensor that detects the temperature of the PD element 2, the level of the RF signal increased or decreased due to temperature fluctuation can be adjusted to the original RF signal level. Stability can be further improved.

  The control unit 9 performs the same control as the control immediately before the RF signal or the detection output cannot be received when the RF signal cannot be received from the PD element 2 or the detection output cannot be received from the detection unit 7. Since it is performed on the AGC 6, the control unit 9 cannot receive an optical signal from the disconnection of the line connecting the control unit 9 and the PD element 2, and the detection output from the detection unit 7 thereafter or due to a failure of the detection unit 7 Even after that, the optimum state for the RF signal level can be maintained, and the stability of the RF signal level when the optical receiver 1 is abnormal can be improved.

  In addition, when the level of the detection output received from the detection unit 7 exceeds the second threshold value, the PD element 2 is controlled based on the upper limit value Vcmax2 acquired from the storage unit 10, so When the detection output level suddenly increases or decreases rapidly, erroneous adjustment of the RF signal level can be suppressed, and the stability of the RF signal level when the optical receiver 1 is abnormal. Can be further improved.

  Further, when the control unit 9 controls the AGC 6 at a predetermined period, the period when the optical receiver 1 is started up is shorter than the normal period of the optical receiver 1, so that the level of the RF signal is set. The level of the RF signal can be effectively adjusted at a timing at which an influential phenomenon is likely to occur, and the stability of the level of the RF signal can be further improved.

  When the control unit 9 determines that the PD element 2 is abnormal, the control unit 9 causes the display unit 8 to output information indicating that there is an abnormality. Notification can be made and appropriate responses can be encouraged.

[Modifications to Embodiment]
Although the embodiments of the present invention have been described above, the specific configuration and means of the present invention can be arbitrarily modified and improved within the scope of the technical idea of each invention described in the claims. Can do. Hereinafter, such a modification will be described.

(About problems to be solved and effects of the invention)
First, the problems to be solved by the invention and the effects of the invention are not limited to the above-described contents, and the present invention solves the problems not described above or has the effects not described above. There are also cases where only some of the described problems are solved or only some of the described effects are achieved.

(About distribution and integration)
Each electrical component described above is functionally conceptual and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each part is not limited to the one shown in the figure, and all or a part thereof may be functionally or physically distributed / integrated in arbitrary units according to various loads and usage conditions. Can be configured.

(About the detector)
In the present embodiment described above, the detection unit 7 has been described as detecting the temperature of the PD element 2. However, for example, even if the temperature of a device other than the PD element 2 (for example, AGC 6, amplifiers 3 to 5, etc.) is detected. Good. Specifically, the detection unit 7 is provided in the optical receiver 1 for each device to be detected, and the detection output of each detection unit 7 is output to the control unit 9. In this case, for example, when an abnormality occurs in another device other than the PD element 2, the control unit 9 may cause the display unit 8 to output information indicating that the other device has an abnormality. Specifically, the control unit 9 turns on the display unit 8 when an abnormality is detected in the control unit 9 by diagnosing the control unit 9 using known diagnostic software stored in the storage unit 10. Or blink. Thereby, it can be notified to the user that there is an abnormality in another device.

  Moreover, in this Embodiment mentioned above, although the detection part 7 was demonstrated that it was comprised with the temperature sensor, it is not restricted to this. For example, the detection unit 7 may be any phenomenon that can detect a phenomenon occurring inside the optical receiver 1 and affecting the level of the RF signal converted by the PD element 2. Specifically, the detection unit 7 may be configured as a humidity sensor that measures humidity, an atmospheric pressure sensor that measures atmospheric pressure, a magnetic sensor that measures magnetism, and the like.

  Moreover, the detection part 7 may be comprised by arbitrary combinations of two or more sensors mentioned above. For example, in the present embodiment, the temperature sensor is described. However, for example, a temperature sensor and a humidity sensor may be combined. Thereby, the level fluctuation | variation of RF signal can be suppressed further.

(About the storage unit)
In the present embodiment described above, the storage unit 10 has been described as including the upper limit value table 10b that stores the upper limit value specifying information. However, for example, the lower limit value table that stores the lower limit value specifying information that specifies the lower limit value Vcmin is also included. You may prepare. Specifically, in the lower limit table, information corresponding to the table items “level” and “lower limit” is stored in association with each other. Here, the stored information corresponding to the table item “level” is level specifying information, such as “RF signal level is equal to or lower than third threshold”, “detection output level is equal to or lower than fourth threshold”, or the like. Is stored. The information stored in association with the item “lower limit value” is lower limit value specifying information, and stores, for example, “Vcmin1”, “Vcmin2”, and the like.

(About processing executed by optical receiver)
In the present embodiment described above, the control unit 9 has been described as controlling the AGC 6 at different periods when the predetermined time has elapsed since the optical receiver 1 was activated, but not limited thereto. For example, the control unit 9 may control the AGC 6 according to a change in the control voltage Vc. Specifically, the control unit 9 determines whether or not the absolute value of the difference between the control voltage Vc output from the control unit 9 and the control voltage Vc output immediately before is within a predetermined value (SA1). . Here, when it is determined that the absolute value of these differences is not within the predetermined value due to a rapid temperature rise of the PD element 2 (SA1, No), the controller 9 changes the period T to the period T1 in the process of SA2. (For example, one minute interval). On the other hand, when it is determined that the absolute value of these differences is within a predetermined value (SA1, Yes), the control unit 9 sets the period T to the period T2 in the process of SA3 (for example, one hour interval). Thereby, when the phenomenon which affects the level of the RF signal of the optical receiver 1 occurs, the level of the RF signal can be adjusted more effectively.

(About control voltage output processing)
In the present embodiment described above, in the processing of SB3 to SB5, the control unit 9 calculates the control voltage Vc based on the level of the optical signal received from the PD element 2 and the level of the detection output received from the detection unit 7. Then, although explained, it is not restricted to this. For example, the control unit 9 may be configured to be able to block a control function based on the detection output level as necessary. For this reason, for example, a selection switch for determining whether or not to perform control based on the level of the detection output is provided in the optical receiver 1, and it is selected that the control based on the level of the detection output is not performed via this selection switch. If there is, the controller 9 only monitors whether or not an optical signal has been received from the PD element, and executes only control based on this optical signal. Thereby, control according to a user's various needs can be performed.

DESCRIPTION OF SYMBOLS 1,100 Optical receiver 2,101 PD element 3,4,5,102,103,104 Amplifier 6,105 AGC
DESCRIPTION OF SYMBOLS 7 Detection part 8 Display part 9, 106 Control part 10 Memory | storage part 10a Correction | amendment control voltage table 10b Upper limit table 11, 107 Branch device 12, 108 Output terminal 13, 109 Monitor output terminal

Claims (6)

An optical receiver that receives an optical signal, converts it into an electrical signal, and outputs it.
Photoelectric conversion means for converting an optical signal into an electrical signal;
Level adjusting means for adjusting the level of the electrical signal converted by the photoelectric conversion means;
Detecting means for detecting a phenomenon that occurs inside the optical receiver and affects the level of the electrical signal converted by the photoelectric conversion means;
Level adjustment for receiving the electrical signal from the photoelectric conversion means, receiving the detection output of the detection means, and controlling the level adjustment means based on the level of the received electrical signal and the level of the detection output Control means;
With optical receiver. The detection means is a temperature sensor that detects the temperature of the photoelectric conversion means.
The optical receiver according to claim 1. The level adjustment control means includes:
When the electrical signal cannot be received from the photoelectric conversion means, or when the detection output cannot be received from the detection means, the same control as the control immediately before the electrical signal or the detection output cannot be received is applied to the level adjustment means. Do,
The optical receiver according to claim 1 or 2. Storage means for storing a predetermined upper limit value,
The level adjustment control means includes:
When the level of the detection output received from the detection unit exceeds a threshold, the predetermined upper limit value is acquired from the storage unit, and the level adjustment unit is controlled based on the acquired upper limit value;
The optical receiver as described in any one of Claim 1 to 3. The level adjustment control means includes:
When controlling the level adjusting means at a predetermined period, the period when the optical receiver is started up is shorter than the normal period of the optical receiver,
The optical receiver as described in any one of Claim 1 to 4. Comprising output means for outputting various information relating to the level adjustment control means;
The level adjustment control means includes:
Based on the level of the detection output received from the detection means, determine the presence or absence of abnormality of the photoelectric conversion means,
When it is determined that there is an abnormality in the photoelectric conversion means, the output means outputs information indicating that there is an abnormality,
The optical receiver as described in any one of Claim 1 to 5.

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