JP2010028438A - Detecting apparatus and detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detecting apparatus and a detecting method for detecting connecting condition of the wired link and power source supplying condition of the apparatuses connected in the latter-half stages when a plurality of apparatuses for transmitting image signals and audio signals or the like are connected and also transmitting situations of the apparatuses in the latter-half stages to the apparatuses connected in the former-half stages. <P>SOLUTION: The detecting apparatus transmits electrical signals transmitted from the apparatuses in the former-half stage to the apparatuses in the latter-half stage, detects situations of the apparatuses in the latter-half stage, and transmits the detected situations to the apparatuses in the former-half stage. The detecting apparatus includes a voltage superimposing part for superimposing a DC voltage to the electrical signal to be transmitted to the apparatuses in the latter-half stage by respectively connecting the apparatuses in the former-half stage and the latter-half stage via the wired link, an inverse voltage superimposing part for superimposing a voltage having the inverted polarity of the DC voltage to the electrical signal transmitted from the apparatuses in the former-half stage, and a control part for controlling operation of the inverse voltage superimposing part in accordance with the result of detection of the voltage at the connecting end part of the wired link in the side of the apparatuses in the latter-half stage. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is capable of detecting a wired line connection status and a power-on status of a device connected in a subsequent stage when a plurality of devices that transmit video signals, audio signals, etc. via a wired line are connected, and The present invention relates to a detection device and a detection method capable of transmitting the detected status of the subsequent device to a device connected to the previous device.

  When transmitting video and audio signals via a wired line such as a LAN cable or coaxial cable, if the cable length exceeds a certain length, the signal will be attenuated and the signal waveform will be distorted. Normal signal output is not possible. In order to eliminate such attenuation and distortion of the signal, a cable extension device that amplifies the transmitted signal and corrects the distortion is used.

  The cable extension device is installed on the transmitting device side (hereinafter referred to as “transmitting device”) that is the source of the transmitted signal, and is installed on the receiving device side that outputs the transmitted signal (hereinafter referred to as “transmission device”). Since each device is installed at a distance, the cable connection status and operation status (for example, power-on status, etc.) of the receiving device are visually recognized from the vicinity of the transmitting device. I can't.

  Therefore, in the installation work of the cable extension device, personnel corresponding to the number of devices are required, and preparations are made so that the situation can be checked using a communication means such as a transceiver between each other, or for signal transmission. It is necessary to lay a communication cable different from the cable between the devices and to provide another communication means for communication via the communication cable. However, it is inefficient to arrange a large number of personnel, and providing a separate communication means is complicated and difficult to manage.

  In order to solve the above problem, a system is known that can detect a cable connection status in a counterpart device using only a cable used for signal transmission (see Patent Document 1). The AV system described in Patent Document 1 is included in a video signal to be transmitted by synchronization signal detection means provided in the device when a cable is connected to the device on one side (for example, a transmission device). The presence or absence of cable connection in the opposite apparatus can be determined based on the result of extracting the synchronization signal and evaluating the synchronization signal.

JP-A-5-83748

  However, the AV system cannot be used when transmitting a signal (for example, an analog signal) that does not include a synchronization signal. Further, the means for extracting the synchronization signal from the video signal and the means for evaluating the synchronization signal have complicated structures. Furthermore, even with such an AV system, it is only possible to detect the presence or absence of a cable connection in the opposing device, and it is not possible to detect the operation status such as whether or not the opposing device is powered on.

  As described above, a conventionally known device can detect whether or not a cable is connected to a remote device, but it cannot be used for a signal that does not include a synchronization signal, so is less versatile and has a complicated configuration. In addition, there are still problems such as arranging a large number of personnel or using another communication means to detect the operation status of the opposing device.

  In addition, when a plurality of conventional devices are connected in a daisy chain and the signal transmission distance is further extended, the status of the device several steps ahead cannot be detected in the device at hand.

  Therefore, the present invention can detect a wired line connection status and a power-on status of a device connected at a subsequent stage when a plurality of devices that transmit video signals, audio signals, etc. via a wired line are connected. And it aims at providing the detection apparatus which can transmit the condition of the back | latter stage apparatus detected to the apparatus connected to the front | former stage.

  A detection apparatus according to the present invention is an apparatus that transmits an electrical signal transmitted from a preceding apparatus to a subsequent apparatus, detects a situation of the subsequent apparatus, and transmits the detected state to the preceding apparatus, The device and each of the subsequent devices are connected via a wired line, and a voltage superimposing unit for superimposing a DC voltage on the electric signal transmitted to the subsequent device, and the electric signal transmitted from the previous device. Controls the operation of the reverse voltage superimposing unit according to the detection result of the wire voltage connection terminal voltage on the device side in the subsequent stage and the reverse voltage superimposing unit that superimposes the voltage having the opposite polarity to the DC voltage on the signal. And a control unit.

  Further, in the detection device according to the present invention, the control unit detects a wired line connection end voltage on the downstream device side, and determines the status of the downstream device according to a detection result of the detection unit. An oscillating unit that oscillates according to a determination result of the determining unit, a reverse voltage control unit that operates the reverse voltage superimposing unit intermittently according to the determination result of the determining unit and the output of the oscillating unit, It is characterized by having.

  In the detection device according to the present invention, the reverse voltage control unit intermittently operates the reverse voltage superimposing unit in synchronization with an operation cycle of the reverse voltage superimposing unit of the subsequent device. .

  In the detection device according to the present invention, the detection unit detects a wired line connection status and a power-on status in the subsequent device, and the determination unit outputs an exclusive OR using the detection result of the detection unit. The oscillation unit oscillates only when the output of the exclusive OR is “H”, and the reverse voltage control unit outputs a negative logical product using the output of the determination unit and the output of the oscillation unit, The reverse voltage superimposing unit is operated by a switch that opens and closes in response to the output.

  The detection method according to the present invention is executed by a detection device that transmits an electrical signal transmitted from a preceding device to a succeeding device, detects the status of the succeeding device, and transmits the detected state to the preceding device. In the method, the detection device is connected to each of the upstream device and the downstream device via a wired line, and the detection device transmits a DC voltage to an electrical signal transmitted to the downstream device. A step of superimposing a reverse voltage having a polarity opposite to that of the direct current voltage on the electrical signal transmitted from the upstream device, and the detection device is connected to the downstream device side. And a step of controlling the reverse voltage superposition according to the detection result.

  According to the present invention, when a plurality of devices are connected in multiple stages, the status of any device installed between the transmission device and the reception device can be detected even by the device installed on the transmission device side. Therefore, the installation work can be performed efficiently. In addition, when any device fails, it is possible to detect an abnormality in all the devices connected to the previous stage of this device, so that the failed device can be easily identified, and maintenance is easy. Become.

  Hereinafter, embodiments of a detection apparatus and a detection method according to the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram illustrating an example of a detection apparatus according to the present embodiment. In FIG. 1, the detection apparatus 1 includes a transmission block 10, a reception block 20, and a situation detection block 30. In front of the detection device 1 (on the left side in FIG. 1), there is a transmission device 3 that is a transmission source of a signal to be transmitted, or a detection device having the same configuration as the detection device 1 (hereinafter referred to as “previous device”). Are connected via an extension cable 5. Further, in the subsequent stage (right side in FIG. 1) of the detection apparatus 1, the reception apparatus 4 that is an output apparatus of the signal transmitted from the transmission apparatus 3 or the previous stage apparatus, or a detection apparatus (hereinafter referred to as the detection apparatus 1). Are connected via an extension cable 5.

  The transmission block 10 has a function of superimposing a direct current voltage on a signal input from the transmission device 3 or a signal transmitted from the preceding device and outputting it to the subsequent device. The reception block 20 has a function of outputting a signal transmitted from the preceding device to the transmitting block 10 or the receiving device 4 and the above-described direct current at the wired line connection end on the side where the preceding device is connected via the extension cable 5. The voltage has a function of superimposing a reverse DC voltage having a polarity opposite to that of the voltage. The status detection block 30 detects the connection status of the extension cable 5 and the power-on status in the previous stage device, notifies the result, and intermittently superimposes the reverse DC voltage according to the detection result. Has the function to perform.

  The transmission device 3 is, for example, a personal computer or a video recorder that outputs a video signal. Further, the transmission device 3 may output a transmission signal from another signal source (not shown) to the detection device 1. In this case, the transmission device 3 is a device that can process signals such as an amplifier and an equalizer connected to a personal computer, a video recorder, and a music playback device that are signal sources.

  The receiving device 4 is, for example, a video output device such as a display or a projector, an audio output device configured with an audio equalizer, a decoder, an amplifier, a speaker, or the like. In the description of the present embodiment, the extension cable 5 is a LAN cable including, for example, four lines of twisted pairs, and performs signal transmission using one signal line (one line) therein.

  Next, further detailed functional blocks of the detection apparatus 1 will be described with reference to FIG. As shown in FIG. 2, the transmission block 10 includes a voltage superimposing unit 11 and a signal output unit 12. The reception block 20 includes a signal receiving unit 21, a process amplifier unit 22, and a reverse voltage superimposing unit 23. The situation detection block 30 includes a detection unit 31, a detection notification unit 32, a determination unit 33, an oscillation unit 34, a reverse voltage control unit 35, a detection unit 36, and a detection notification unit 37.

  The voltage superimposing unit 11 is configured by a circuit that biases a DC voltage with respect to the electrical signal input from the transmission device 3 or the electrical signal transmitted from the preceding device input from the reception block 20. The signal output unit 12 is configured by a circuit including an amplifier that converts a DC biased electric signal into a balanced signal and an impedance matching resistor that maintains matching with the characteristic impedance of the extension cable 5.

  The signal receiving unit 21 is configured by a circuit including an impedance matching resistor that maintains matching with the characteristic impedance of the extension cable 5 and a receiving differential amplifier that performs balanced / unbalanced conversion of the received signal and outputs the signal. The process amplifier unit 22 is an equalizer and an amplifier that amplifies the signal that has been balanced / unbalanced converted by the signal receiving unit 21 to the original signal level and outputs the amplified signal to the receiving device 4 or the transmission block 10. The circuit operates in accordance with 36 outputs. The reverse voltage superimposing unit 23 is controlled by a reverse voltage control unit 35 to be described later, and is configured by a circuit that superimposes on the extension cable 5 a DC voltage having a polarity opposite to the voltage superimposed in the voltage superimposing unit 11.

  The detection unit 31 is configured by a circuit that outputs the signal output unit 12 according to the voltage level of the DC component of the signal output to the extension cable 5. The detection notification unit 32 is configured by a circuit that notifies the outside of the detection device 1 based on the output of the detection unit 31. The determination unit 33 is configured by a circuit that determines a cable connection state and a power-on state of a subsequent apparatus according to the output of the detection unit 31. The oscillating unit 34 is configured by a circuit that outputs a signal that determines an operation interval of a reverse voltage control unit 35 to be described later according to the determination result of the determination unit 33. The reverse voltage control unit 35 is configured by a circuit that controls superimposition of the reverse bias in the reverse voltage superimposing unit 23 based on the signal oscillated from the oscillating unit 34. The detection unit 36 is configured by a circuit that outputs in accordance with the voltage level of the DC component of the signal received via the extension cable 5. The notification unit 37 is configured by a circuit that notifies the output of the detection unit 35 to the outside of the detection device 1.

  Next, an example of the circuit configuration in each of the above portions and the operation thereof will be described with reference to FIGS. The signal used for the following description is a digital audio signal of 1 Vp-p. FIG. 3 is a circuit example of the voltage superimposing unit 11 and the signal output unit 12 constituting the transmission block 10. In FIG. 3, a signal input from the transmission device 3 (see FIG. 2) or the process amplifier unit 22 is biased to +0.5 Vdc by the capacitor C <b> 1, the resistor R <b> 1, and the resistor R <b> 2 constituting the voltage superimposing unit 11. The biased signal is input to the plus terminal of the differential balanced output amplifier AMP1 which is a transmission output driver of the signal output unit 12, and is converted into a differential balanced signal. A signal biased to 5 Vdc is output, and a signal biased to −0.5 Vdc is output from the minus output terminal.

  A resistor R3 and a resistor R4 for impedance matching with the characteristic impedance of the extension cable 5 are connected to the positive output terminal and the negative output terminal of the AMP1, respectively. The signal is transmitted to the subsequent device by connecting to the extension cable 5 through the resistors R3 and R4.

  Next, a circuit example of the signal receiving unit 21, the process amplifier unit 22, and the reverse voltage superimposing unit 23 that configure the receiving block 20 in FIG. 4 is shown. In FIG. 4, the signal received via the extension cable 5 is terminated by the impedance matching resistors R11 and R12 of the signal receiving unit 21, amplified to the original signal level by the AMP 11, and processed by the process amplifier via the capacitor C3. Is output to the unit 22. The process amplifier unit 22 outputs the level-adjusted signal to the reception device 4 or the voltage superimposing unit 11 of the transmission block 10 by the output of the detection unit 36 described later. The reverse voltage superimposing unit 23 applies a reverse voltage of −0.5 Vdc to the input terminal plus side of the extension cable 5 and +0.5 Vdc to the input cable minus side of the extension cable 5 by the reverse voltage control unit 35 described later. R13 and R14 are configured as described above.

  Next, in FIG. 5, a circuit example of the detection unit 31 and the detection notification unit 32 constituting the situation detection block 30 is shown, and the operation will be described. In FIG. 5, the detection unit 31 takes out a signal (a signal biased to +0.5 Vdc) from the extension cable 5 side of the resistor R3 (FIG. 3) via the resistor R5, and integrates R5 and the capacitor C2. Thus, the DC voltage of the electric signal from which the digital component is removed is applied to the negative terminals of AMP2 and AMP3. Here, R5 can be considered so as not to affect the transmission signal by using a resistor having a higher resistance value than R3.

  AMP2 and AMP3 are comparison circuits whose outputs are switched depending on the magnitude relationship between the voltage applied to the minus terminal and the voltage applied to the plus terminal. Outputs if the voltage applied to the negative terminals of AMP2 and AMP3 (DC voltage superimposed on the above signal) is greater than or equal to a predetermined value (output is “H”), and does not output if the voltage is lower than the predetermined value (Output is “L”). R6, R7, and R8 divide the power supply voltage and apply a voltage serving as a threshold for comparison determination to the plus terminal so that AMP2 and AMP3 can perform the comparison operation as described above. For example, when the extension cable 5 is connected to the detection device 1 at the subsequent stage, the output CN of the AMP2 becomes “H” and the output PWR of the AMP3 becomes “L”. In this state, when the detection device 1 at the subsequent stage is turned on, the output PWR of the AMP 3 becomes “H”. That is, the output CN is “H” indicating a connected state (Connected), and the output PWR is “H” indicating a power-on state (PoWeR-on). The values of R6, R7, and R8 are determined so that the operation can be performed in this way. Resistors R20 and R21 for limiting the current are arranged at the output terminals of AMP2 and AMP3 when the output is “L” (in reality, the voltage is VEE). The detection notification unit 32 includes an LED 1 that is lit when the output of the AMP2 is “H” and an LED 2 that is lit when the output of the AMP3 is “H”.

  The operation of the detection unit 31 and the detection notification unit 32 will be specifically described. A subsequent apparatus having the same configuration as that of the present apparatus is connected to the subsequent stage of the detection apparatus 1 via the extension cable 5. In this apparatus, the voltage (+0.5 Vdc) superimposed on the transmission signal is almost halved by the input impedance matching resistors R11 and R12 (resistors having substantially the same values as R3 and R4) included in the receiving unit 20 of the subsequent apparatus. Value. Therefore, the voltage (voltage applied to the AMP2 minus terminal) taken out through the resistor R5 of this apparatus is approximately +0.25 Vdc. Therefore, if the values of resistors R6 and R7 are set so that + 0.375Vdc, which is intermediate between + 0.5Vdc and + 0.25Vdc, is applied to the positive terminal of AMP2, detection device 1 is connected to the subsequent stage. The output CN of the AMP2 becomes “H”, and the LED1 is lit.

  In the above state, when the power supply of the latter apparatus is turned on, the amount of bias (+0.5 Vdc) in this apparatus is canceled by the reverse voltage superimposing unit 23 of the latter apparatus. The voltage taken out via this becomes approximately 0V. Therefore, if the values of the resistors R6, R7, and R8 are set so that + 0.125Vdc, which is intermediate between + 0.25Vdc and 0V, is applied to the positive terminal of the AMP3, the power of the subsequent device is turned on. Furthermore, since the output CN of AMP2 and the output PWR of AMP3 are both "H", LED1 and LED2 are lit. As described above, the detection device 1 can detect and notify the connection state and the operation state of the extension cable 5 in the subsequent device by the detection unit 31 and the notification unit 32.

  Next, in FIG. 6, circuit examples of the detection unit 36 and the detection notification unit 37 constituting the situation detection block 30 are shown, and the operation of each unit will be described. In FIG. 6, the detection unit 36 takes out a signal (a signal biased to +0.5 Vdc) from the plus side of the extension cable 5 via the resistor R15, and digitally outputs it by an integrating circuit composed of the resistor R15 and the capacitor C5. The DC voltage of the signal from which the component has been removed is configured to be applied to the positive terminal of the AMP 12. The AMP 12 is a comparison circuit in which the output is switched depending on the magnitude relationship between the voltage applied to the negative terminal and the voltage applied to the positive terminal. If the voltage applied to the positive terminal of the AMP 12 (DC voltage superimposed on the above signal) is a predetermined value, it is output (output is “H”), otherwise it is not output (the output is “L”). "). The resistors R16 and R17 apply a voltage that becomes a threshold voltage to the minus terminal by dividing the power supply voltage so that the AMP 12 can determine the voltage applied to the plus terminal as described above. For example, the values of R16 and R17 may be determined so that the AMP 12 outputs when the power of the preceding apparatus is turned on. The detection notification unit 37 is configured by an LED 11 that is turned on when the output of the AMP 12 is “H”.

  When the preceding device is connected via the extension cable 5 and the power is turned on, the reverse voltage superimposing unit 23 of the detecting device 1 cancels the DC voltage superimposed in the preceding device, so that the resistor R15 The voltage applied to the plus terminal of the AMP 12 via the voltage becomes approximately 0 Vdc. If the values of resistors R16 and R17 are set so that -0.125Vdc, which is between -0.5Vdc and 0Vdc, is applied to the negative terminal of AMP12, the power of the previous device is turned on. The AMP 12 can output and inform the LED 11 by lighting it.

  The output terminal of the AMP 12 is connected to the process amplifier unit 22 (see FIG. 4) via a resistor R23 for limiting the current when VEE is output. The process amplifier unit 22 is connected to the output of the AMP 12. Works according to. When the power of the detection device 1 is turned on, when the previous device is not connected or is not turned on, −0.5 Vdc is applied to the positive terminal of the AMP 12 by the action of the reverse voltage superimposing unit 23. The Since −0.125 Vdc is applied to the negative terminal of the AMP 12, the AMP 12 does not output (the output is “L”). At this time, since no signal is transmitted and there is no need to operate the process amplifier unit 22, the process amplifier unit 22 is stopped.

  Therefore, by operating as “a state in which the LED 11 is lit is a state in which a signal is received from the detection device 1 in the previous stage”, an unnecessary amplification operation is performed in the process amplifier unit 22 in a state in which no signal is transmitted. This makes it possible to operate a more appropriate device without causing any trouble.

  Further, the process amplifier unit 22 is not limited to starting and stopping the operation based on the output of the detection unit 36, but may be operated as a predetermined signal amplification or attenuation, or an equalizer.

  Next, an example and operation of the circuit configuration of the determination unit 33, the oscillation unit 34, and the reverse voltage control unit 35 of the detection block 30, which are the main features of the detection apparatus according to the present invention, will be described with reference to FIGS. To do. The determination unit 33 includes an exclusive OR (XOR) circuit IC1 that receives the output CN and the output PWR of the detection unit 31 as inputs. As shown in FIG. 8A, the output XOR of IC1 is “L” when CN and PWR are both “L” or both are “H”. When one of CN and PWR is “H” and the other is “L”, the output is “H”.

  Therefore, when the output XOR of the IC 1 becomes “L”, the subsequent device is not connected via the extension cable 5 or the subsequent device is normally connected and the power is not turned on. In either case, the operation of the detection apparatus 1 is in a normal state. Therefore, when XOR is “L”, if the reverse voltage superimposing unit 23 continues to superimpose the reverse voltage, the normal state of the subsequent apparatus can be confirmed.

  As shown in FIG. 8A, when the output XOR becomes “H”, either CN or PWR is “L” and the other output is “H”. Here, when CN is “L”, the subsequent device is not connected via the extension cable 5. Therefore, PWR cannot be “H” in this state. This is because it is detected that the power supply of the subsequent apparatus is turned on even though the subsequent apparatus is not connected. Therefore, in the present embodiment, if it is possible to detect when CN is “H” and PWR is “L” and this state can be transmitted to the preceding apparatus, an abnormal operation of the succeeding apparatus is detected. It becomes possible to recognize with the device.

  Returning to FIG. 7, the oscillating unit 34 is a Schmitt inverter circuit that oscillates a signal for intermittently operating the reverse voltage superimposing unit 23 according to the output of the determining unit 33. In FIG. 7, the output terminal of the determination unit 33 is connected to the input terminal of the IC 2 via the diode D1. IC2 oscillates with a time constant linked to the time constant determined by resistor R19 and capacitor C4. As shown in FIG. 8B, when XOR is “L” (in a normal state), the input of IC2 becomes “L” by the action of the diode D1, so no oscillation occurs, and the output OSC of IC2 Remains constant at “H”. When XOR is “H”, the input of IC2 is not “L” and oscillates, and its output OSC repeats “L” and “H” at a constant cycle.

  The reverse voltage control unit 35 connects the VEE to the reverse voltage superposition unit 23 when the output SW of the negative logic product (NAND) circuit IC3 that inputs the XOR and the OSC and the IC3 is “H”. When it is “L”, it is constituted by the IC 4 that is a switch circuit that opens the connection between the VEE and the reverse voltage superimposing unit 23. As shown in FIG. 8C, when the XOR is “L”, the OSC is “H” and constant, so the output SW is “H” and the switch of the IC 4 is closed and the reverse voltage superimposing unit is closed. Since the VEE continues to be connected to 23, the reverse voltage continues to be superimposed. As described above, when XOR is “H”, IC2 oscillates and OSC repeats “L” and “H” at a constant cycle. Therefore, the output SW also matches “H” and “L” according to the cycle of output OSC. "repeat. Since the IC 4 intermittently connects the VEE to the reverse voltage superimposing unit 23 according to the SW cycle, the reverse voltage is intermittently superimposed according to the OSC cycle.

  Then, in the detection device 1, when the power of the subsequent device is not turned on (the reverse voltage cannot be detected), the LED 2 of the present device is turned off by the above operation, and the LED 2 of the previous device is intermittently superimposed. Blinks due to reverse voltage. Thus, even in the former apparatus, it is possible to notify and recognize that the operation of the latter apparatus is abnormal by blinking the LED.

Next, the above operation in a daisy chain configuration in which the detection devices 1 as shown in FIG. 9 are connected in multiple stages will be described with reference to FIGS. 10 and 11. The detection apparatus 1 is assumed to be a position C in FIG. Detection device 1 (A) connected to the left side in FIG. 9 rather than detection device 1 (C)
) And the detection apparatus 1 (B) are represented as “previous apparatus”. Further, the detection device 1 (D) connected to the right side in FIG. 9 with respect to the detection device 1 (C) is represented as a “subsequent device”. As already described, in the detection device 1 (C), when the reverse voltage superimposed by the detection device 1 (D), which is a subsequent device, cannot be detected, the LED 2 of the detection device 1 (C) is turned off, and the above description The reverse bias is intermittently superimposed when the transmitter 34 of the detection device 1 (C) starts to operate, and the LED 2 of the detection device 1 (B), which is the preceding device, blinks.

  FIG. 10 is a timing chart showing the relationship between input and output in the determination unit 33, the oscillation unit 34, and the reverse voltage control unit 35 of the detection apparatus 1 (C). A time T indicates when the reverse bias in the detection apparatus 1 (D) cannot be detected (when an abnormality occurs). As shown in FIG. 10, before time T, since both CN and PWR input to IC1 are “H”, the output XOR is “L”. After time T, CN input to IC1 remains “H”, and PWR changes from “H” to “L”. In response to this change in input, the output XOR of IC1 changes from “L” to “H”. Then, the IC 2 changes its input from “L” to “H” and starts an oscillation operation. However, it takes longer than the inversion period of oscillation linked to the time constant determined by R19 and C4 until the input of IC2 reaches the threshold voltage Vp determined to be “H”. For example, when the inversion period is 2 seconds, approximately 4 seconds, which is approximately twice the inversion period at the time of oscillation, passes after the output XOR changes from “L” to “H” until the output OSC oscillates. It will be.

  In this way, the IC 2 oscillates after one beat after the situation of the detection device 1 (D) changes and the reverse bias cannot be detected. As described above, the output SW of the IC 3 is a signal having the same cycle as the output OSC and the output is inverted. Therefore, the IC 4 repeats the switching operation in accordance with the cycle of the output SW, and the reverse bias by the reverse voltage superimposing unit 23 is the same. It will be superimposed intermittently with a period.

  Next, the operation of the output SW of IC3 and the operation of IC4 using the outputs XOR and OSC as inputs will be described with reference to the timing chart of FIG. The output SW of IC3, including the time from the time T until the OSC oscillates, repeatedly changes between “H” and “L”. IC4 is ON when SW is “H”, and VEE is connected to the reverse voltage superimposing unit 23, and is OFF when SW is “L”, and the connection between the reverse voltage superimposing unit 23 and VEE is disconnected. Is done. Accordingly, the reverse bias is intermittently superimposed corresponding to the SW inversion cycle, and this is transmitted to the detection device 1 (B), which is the preceding device.

  Next, the relationship between the output of the determination unit 33 and the input and output of the oscillation unit 34 in the detection apparatus 1 (B) will be described with reference to the timing chart of FIG. As described above, when the reverse bias is intermittently superimposed in the detection device 1 (C), this changes the output PWR in the detection unit 31 of the detection device 1 (B). Then, the output XOR of IC1 becomes an output that is inverted from the input PWR. As described above, when XOR changes from “L” to “H”, the IC 2 starts an oscillation operation, and the output OSC remains “H” until it oscillates, but the input is determined to be “H”. When the threshold voltage Vp is reached, it is inverted to “L”. However, as shown in FIG. 12, immediately after the time until the threshold voltage Vp is reached, or almost at the same time, XOR reaches the inversion period and becomes “L”. Then, the input of IC2 becomes “L” by the action of the diode D1, the oscillation operation is stopped, and the output OSC becomes “H”.

  Thereafter, since XOR repeats “L” and “H” in a 2-second inversion period, XOR becomes “L” before the input of IC2 reaches the threshold voltage Vp. That is, IC2 starts oscillating every time XOR becomes “H”, but since XOR is inverted to “L” before reaching threshold voltage Vp, output OSC does not oscillate, and “H” It remains constant. Thus, even if the reverse bias of the detection device 1 (C) is intermittently performed due to the fact that the reverse bias of the detection device 1 (D), which is the latter device, can no longer be detected, The oscillating unit 34 of the detection device 1 (B) that is the device does not oscillate.

  Then, the XOR input to the IC 3 is inverted at the same period as the reverse bias intermittent period in the detection device 1 (C), and the OSC may instantaneously become “L” after the time T. Since it is constant at “H”, the output SW is an output in which “L” and “H” are inverted in the same cycle as XOR. By this SW, the IC 4 of the detection apparatus 1 (B) operates, and the reverse bias is intermittently superimposed. That is, the reverse bias is superimposed with the same intermittent period as the reverse bias intermittent period of the detection apparatus 1 (C) which is the preceding apparatus.

  The reverse bias superimposed intermittently in the detection device 1 (B) is detected by the detection device 1 (A), and the LED 2 blinks by the same circuit operation as described above. Therefore, when the detection device 1 is connected as shown in FIG. 9 and the detection device 1 (D) is not turned on, the detection device 1 (C) turns off its own LED 2 and intermittently reverse bias. By superimposing, the status of the subsequent device is transmitted to the detection device 1 (B) in the previous stage, and the detection device 1 (B) blinks the LED 2 by the intermittent reverse bias of the detection device 1 (C), and the intermittent reverse operation described above. A reverse bias is intermittently superimposed at the same period as the bias and transmitted to the preceding detection device 1 (A). Thereby, the detection device 1 (A) blinks the LED 2 due to the intermittent reverse bias of the detection device 1 (B).

  As described above, by using the detection device according to the present invention, it is possible to visually recognize whether or not all the detection devices installed remotely are operating normally, and reverse for some reason. If there is a detection device in an abnormal state where the bias is not operating (for example, the power is not turned on), an abnormal device can be easily found by turning off or blinking the LED. Thereby, the efficiency of installation work and the efficiency of maintenance can be improved.

  In the detection device according to the present invention described above, the voltage value to be superimposed and the voltage value to be used for determination are fixed in advance by design, but the present invention is not limited to this, and is superimposed according to the line length of the extension cable. The voltage value and the voltage value used for determination may be variable.

  Furthermore, the notification means in the detection apparatus according to the present invention is not limited to LEDs, and may be notified by sound using a speaker.

  In the case of using a long-distance extension cable, the present invention incorporates the detection device according to the present invention into a cable extension device that amplifies a transmission signal and corrects distortion of the signal. An extension device can also be obtained.

It is a block diagram which shows the example of a function structure of the detection apparatus which concerns on this invention. It is a block diagram which shows the example of a more detailed functional structure of the said detection apparatus. It is a circuit diagram which shows the circuit example of the one part structure contained in the said detection apparatus. It is a circuit diagram which shows the circuit example of the one part structure contained in the said detection apparatus. It is a circuit diagram which shows the circuit example of the one part structure contained in the said detection apparatus. It is a circuit diagram which shows the circuit example of the one part structure contained in the said detection apparatus. It is a circuit diagram which shows the circuit example of the one part structure contained in the said detection apparatus. It is a figure which shows the relationship between the detection result of the said detection apparatus, and the output of each part. It is a block diagram which shows the structural example of the multistage connection using the said detection apparatus. It is a timing chart which shows the relationship between the status detection result of the back | latter stage apparatus in the said detection apparatus, and the signal notified to the front | former stage apparatus. It is a timing chart which shows the relationship between the status detection result of the back | latter stage apparatus in the said detection apparatus, and the signal notified to the front | former stage apparatus. It is a timing chart which shows the relationship between the status detection result of the back | latter stage apparatus in the said detection apparatus, and the signal notified to the front | former stage apparatus. It is a timing chart which shows the relationship between the status detection result of the back | latter stage apparatus in the said detection apparatus, and the signal notified to the front | former stage apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 DC voltage superposition part 12 Signal output part 13 Detection part 14 Detection notification part 23 DC reverse voltage superposition part 33 Determination part 34 Oscillation part 35 Reverse voltage control part

Claims (5)

An apparatus that transmits an electrical signal transmitted from a preceding apparatus to a subsequent apparatus, detects a situation of the subsequent apparatus, and transmits the situation to the preceding apparatus,
Connect the preceding device and the following device via a wired line,
A voltage superimposing unit that superimposes a DC voltage on the electric signal transmitted to the subsequent device;
A reverse voltage superimposing unit that superimposes a voltage having a polarity opposite to that of the direct current voltage on the electrical signal transmitted from the preceding device;
A control unit for controlling the operation of the reverse voltage superimposing unit according to the result of detecting the wire connection terminal voltage on the device side of the latter stage;
A detection apparatus comprising: The control unit
A detection unit for detecting a wire connection terminal voltage on the device side of the latter stage;
A determination unit that determines the status of the latter apparatus according to the detection result of the detection unit;
An oscillating unit that oscillates according to the determination result of the determining unit;
A reverse voltage control unit that intermittently operates the reverse voltage superimposition unit according to the determination result of the determination unit and the output of the oscillation unit;
The detection apparatus according to claim 1, comprising:   3. The detection device according to claim 2, wherein the reverse voltage control unit intermittently operates the reverse voltage superposition unit in synchronization with an operation cycle of the reverse voltage superposition unit of the subsequent device. The detection unit detects the wired line connection status and power-on status in the subsequent device,
The determination unit outputs an exclusive OR using the detection result of the detection unit,
The oscillation unit oscillates only when the output of the exclusive OR is “H”,
The reverse voltage control unit outputs a negative logical product using the output of the determination unit and the output of the oscillation unit, and operates the reverse voltage superposition unit by a switch that operates according to the output of the negative logical product. The detection device according to claim 2, wherein: A method executed by a detecting device that transmits an electrical signal transmitted from a preceding device to a succeeding device, detects the status of the succeeding device, and transmits it to the preceding device,
The detection device is connected to each of the preceding device and the subsequent device via a wired line,
The detection device superimposing a DC voltage on the electrical signal transmitted to the subsequent device;
The detection device superimposes a reverse voltage having a polarity opposite to that of the DC voltage on the electrical signal transmitted from the preceding device;
The detection device detects a wire connection end voltage on the device side of the subsequent stage, and controls the superposition of the reverse voltage according to the detection result;
A detection method comprising:

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