Surveillance Equipment and CATV Systems

Abstract

The amplifier and power supply are monitored using a simple configuration. [Solution] In a monitoring device 10, a transmission signal from an amplifier is input to an RF input terminal, and power from a power supply is supplied to a PS input terminal. A monitoring unit 14 acquires a transmission signal level value of the amplifier and a power supply voltage value of the power supplied from the power supply, and transmits them from a wireless transmission unit 15. In this case, the transmission signal level value and the power supply voltage value are periodically transmitted from the wireless transmission unit 15, and when the transmission signal level value or the power supply voltage value reaches a threshold value, the transmission signal level value or the power supply voltage value that exceeds the threshold value is temporarily transmitted from the wireless transmission unit 15.

Description

[Technical field]

[0001] The present invention relates to a monitoring device that monitors amplifiers installed in a transmission path for cable television (CATV), and a CATV system to which the monitoring device is applied. [Background technology]

[0002] Patent Document 1 discloses a monitoring device that monitors the operating state of a power supply in a cable television, and a CATV system equipped with this monitoring device. Fig. 13 shows a block diagram of a conventional CATV system 200, and Fig. 14 shows a functional block diagram of a conventional monitoring device 201. In a conventional CATV system 200 shown in FIG. 13, a broadcast signal transmitted from a CATV station 203 through an optical fiber cable 211 is converted from an optical signal to an electric signal by an O / E converter 204 and transmitted to a coaxial cable 212. The broadcast signal transmitted through the coaxial cable 212 is amplified by amplifiers 205, 205, ... provided at appropriate locations, distributed by a tap-off 206, and then sent to each subscriber's home 207. The amplifiers 205, 205, ... are driven by power supplied from a power supply 202. The power supply 202 is installed overhead on the coaxial cable 212, and steps down AC power from a commercial power source to a predetermined voltage (for example, 30V or 60V) and outputs it to one or more amplifiers 205. The power supply 202 also outputs AC power to a monitoring device 201 that monitors its own operating state.

[0003] 14 includes a control unit 311 having a CPU, a converter 312, a voltage detection sensor 313, a step-down unit 314, a wireless communication unit 315, and a battery 316. The converter 312 converts AC power supplied from the power supply 202 into DC power and outputs it to the voltage detection sensor 313 and the step-down unit 314. The step-down unit 314 steps down the DC power supplied from the converter 312 to a predetermined voltage (e.g., 5V) and outputs it to the control unit 311 and the wireless communication unit 315. The voltage detection sensor 313 detects the output voltage from the converter 312 and outputs the detection result to the control unit 311. The wireless communication unit 315 is a communication module capable of transmitting various information to the outside by an LPWA (Low Power Wide Area) wireless communication method. The wireless communication unit 315 is driven by power supplied from the power supply device 202 via the converter 312 while the power supply from the power supply device 202 is stopped, and is driven by power from the battery 316 while the power supply from the power supply device 202 is stopped. The presence or absence of power supply from the power supply device 202 is determined by the value of the output voltage from the converter 312 detected by the voltage detection sensor 313. While the power supply from power supply device 202 is stopped, wireless communication unit 315 is driven by power from battery 316. Similarly, control unit 311 and voltage detection sensor 313 are also driven by power from battery 316 while the power supply from power supply device 202 is stopped. Note that control unit 311 is connected to voltage detection sensor 313 that detects the output voltage of battery 316, and receives an input of the detection result from voltage detection sensor 313.

[0004] Thus, in conventional CATV system 200, power supply device 202 is installed aerial on coaxial cable 212, and is configured to supply power to amplifier 205 as well as to monitoring device 201. Conventional monitoring device 201 includes battery 316 and wireless communication unit 315 that transmits predetermined information to the outside by wireless communication, and wireless communication unit 315 runs on the power supplied from power supply device 202 to monitoring device 201 while power is being supplied from power supply device 202 to monitoring device 201, and runs on power from battery 316 while power is not being supplied from power supply device 202 to monitoring device 201, and transmits information to the outside indicating which power it is running on. [Prior art documents] [Non-patent literature]

[0005] [Patent Document 1] Patent No. 7280572 Summary of the Invention [Problem to be solved by the invention]

[0006] In the conventional CATV system described above, the operation of the power supply is monitored, but instead, it is sometimes required to monitor the level of the transmitted transmission signal. Here, it is also known that a monitoring device for the transmission signal level of the amplifier is installed at the end of the transmission line, and the transmission signal level value is sent back to the CATV transmission source to monitor the fluctuation of the transmission signal level value. However, in the conventional broadcast reception and communication equipment via coaxial cable, the transmission line may be a complex transmission line or a transmission line in which measuring instruments from different manufacturers are mixed. In this case, there is a problem that the measuring instrument system becomes bloated, such as preparing many measuring instruments or measuring instruments from each manufacturer to obtain the transmission signal level value.

[0007] Therefore, the present invention aims to provide a monitoring device that can monitor the operating status of amplifiers installed in the transmission path of a CATV system and the operating status of a power supply that supplies power with a simple configuration, and to provide a CATV system to which the monitoring device is applied. [Means for solving the problem]

[0008] The monitoring device of the present invention, which can achieve the above-mentioned object of the present invention, is a monitoring device that monitors at least one of an amplifier installed on a cable television transmission path and a power supply that supplies power to the amplifier, and comprises a monitoring unit that receives power from the power supply and acquires a transmission signal level value of the amplifier and a power supply voltage value of the power supplied from the power supply, and a wireless transmission unit that wirelessly transmits the transmission signal level value and power supply voltage value acquired by the monitoring unit to the outside, and has the most main feature that the wireless transmission unit periodically transmits at least one of the transmission signal level value and the power supply voltage value acquired by the monitoring unit, and when the transmission signal level value or the power supply voltage value reaches a threshold value, temporarily transmits at least the transmission signal level value or the power supply voltage value that exceeds the threshold value.

[0009] The monitoring device of the present invention described above further comprises an RF input terminal to which at least the transmission signal output from the amplifier is input, a PS input terminal to which power supplied from the power supply is input, and a power supply changeover switch that is switched to send to the monitoring unit either the power supplied from the power supply input to the RF input terminal of the amplifier or the power input to the PS input terminal, and the monitoring unit acquires the power supply voltage value of the power sent from the power supply changeover switch. In addition, in the monitoring device of the present invention described above, a battery is connected to the circuit to which power is supplied, and when the monitoring unit detects that the power supply voltage value acquired by the monitoring unit has dropped from a constant value, power from the battery is replenished to the circuit.

[0010] Furthermore, the CATV system of the present invention, which can achieve the above-mentioned object of the present invention, has at least a cable television transmission path, an amplifier installed on the cable television transmission path, a power supply device that supplies power to the amplifier, a monitoring unit and a wireless transmission unit, and is capable of monitoring at least one of the amplifier and the power supply device, and is equipped with a monitoring device to which power is supplied from the power supply device, the monitoring unit of the monitoring device acquires a transmission signal level value of the amplifier and a power supply voltage value of the power supplied from the power supply device, and the wireless transmission unit periodically transmits at least one of the transmission signal level value and the power supply voltage value acquired by the monitoring unit by wireless to the outside, and when the transmission signal level value or the power supply voltage value reaches a threshold value, at least the transmission signal level value or the power supply voltage value that exceeds the threshold value is temporarily transmitted by wireless to the outside.

[0011] In the CATV system of the present invention described above, the monitoring device has an RF input terminal and a PS input terminal, the RF input terminal is connected to an output terminal from which the amplified transmission signal of the amplifier is output, and the PS input terminal is connected to a terminal from which power supplied from the power supply of the amplifier is output, thereby monitoring the transmission signal level value of the amplifier and the power supply voltage value of the power transmitted over the cable television transmission path. In addition, in the CATV system of the present invention, the monitoring device has an RF input terminal and a PS input terminal, the RF input terminal is connected to an output terminal from which the amplified transmission signal of the amplifier is output, and the PS input terminal is connected to a power output terminal of the power supply, thereby monitoring the transmission signal level value of the amplifier and the power supply voltage value of the power supplied from the power supply. Furthermore, in the CATV system of the present invention, the monitoring device has an RF input terminal and a PS input terminal, the RF input terminal is connected to a level signal distributor provided in the cable television transmission path, and the PS input terminal is connected to a power distributor provided in the cable television transmission path, so as to monitor the transmission signal level value transmitted to the cable television transmission path and the power supply voltage value transmitted on the cable television transmission path. Furthermore, in the CATV system of the present invention, the monitoring device has an RF input terminal and a PS input terminal, the RF input terminal is connected to a level signal distributor provided in the cable television transmission path, and the PS input terminal is connected to a power output terminal of the power supply device, so as to monitor the transmission signal level value transmitted to the cable television transmission path and the power supply voltage value of the power supplied from the power supply device. Furthermore, in the CATV system of the present invention, the monitoring device has an RF input terminal and a PS input terminal, the RF input terminal is connected to an output terminal from which the amplified transmission signal of the amplifier is output, and the PS input terminal is connected to a power distributor provided in the cable television transmission path, and monitors the transmission signal level value of the amplifier and the power supply voltage value of the power transmitted over the cable television transmission path. Furthermore, in the CATV system of the present invention, the monitoring device has an RF input terminal, a PS input terminal, and a power supply changeover switch, wherein at least the transmission signal output from the amplifier is input to the RF input terminal, and power supplied from the power supply is input to the PS input terminal, and the power supply changeover switch switches to send to the monitoring unit either the power supplied from the power supply input to the RF input terminal of the amplifier or the power input from the PS input terminal, and the monitoring unit acquires the power supply voltage value of the power sent from the power supply changeover switch. Furthermore, in the CATV system of the present invention, the monitoring device is provided with a battery connected to a circuit to which power is supplied, and when the monitoring unit detects that the power supply voltage value acquired by the monitoring unit has dropped from a constant value, power from the battery is replenished to the circuit. Effect of the Invention

[0012] The monitoring device and CATV system of the present invention acquire the transmission signal level value output from the amplifier and the power supply voltage value supplied from the power supply, and periodically transmit at least one of the acquired transmission signal level value and power supply voltage value, and when the transmission signal level value or power supply voltage value reaches a threshold value, a special transmission of at least the transmission signal level value or power supply voltage value that exceeds the threshold value is performed. This makes it possible for the monitoring device and CATV system of the present invention to monitor the operating states of the amplifier and the power supply with a simple configuration. Since the transmission signal level value output from the amplifier corresponds to the transmission signal level value transmitted over the cable television transmission path, and the power supply voltage value of the power supplied from the power supplier corresponds to the power supply voltage value of the power transmitted over the cable television transmission path, the monitoring device and CATV system of the present invention are capable of monitoring the transmission signal level value transmitted over the cable television transmission path or the power supply voltage value of the power transmitted over the cable television transmission path with a simple configuration. [Brief description of the drawings]

[0013] [Figure 1] 1 is a functional block diagram showing a configuration of a monitoring device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a functional block diagram showing a specific configuration of a monitoring device according to an embodiment of the present invention. [Diagram 3] 4 is a time chart showing power supply voltage values ​​over time that are periodically transmitted in the monitoring device according to the embodiment of the present invention. [Figure 4]4 is a time chart showing transmission signal level values ​​with respect to time periodically transmitted in a monitoring device according to an embodiment of the present invention. [Diagram 5] 4 is a time chart showing a power supply voltage value with respect to the elapsed time during which regular transmission and special transmission are performed in the monitoring device according to the embodiment of the present invention. [Figure 6] 4 is a time chart showing transmission signal level values ​​with respect to the elapsed time of regular transmission and special transmission in the monitoring device according to the embodiment of the present invention. [Figure 7] 1 is a functional block diagram showing the configuration of a CATV system according to a first embodiment of the present invention to which a monitoring device of the present invention is applied. [Figure 8] FIG. 11 is a functional block diagram showing the configuration of a CATV system according to a second embodiment of the present invention to which a monitoring device of the present invention is applied. [Figure 9] FIG. 11 is a functional block diagram showing the configuration of a CATV system according to a third embodiment of the present invention to which a monitoring device of the present invention is applied. [Figure 10] FIG. 11 is a functional block diagram showing the configuration of a CATV system according to a fourth embodiment of the present invention to which a monitoring device of the present invention is applied. [Figure 11] FIG. 13 is a functional block diagram showing the configuration of a CATV system according to a fifth embodiment of the present invention to which a monitoring device of the present invention is applied. [Figure 12] FIG. 13 is a functional block diagram showing the configuration of a CATV system according to a sixth embodiment of the present invention to which a monitoring device of the present invention is applied. [Figure 13] FIG. 1 is a functional block diagram showing a configuration of a conventional CATV system. [Figure 14] FIG. 1 is a functional block diagram showing a configuration of a monitoring device in a conventional CATV system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] <Monitoring device according to an embodiment of the present invention> The configuration of a monitoring device 10 according to an embodiment of the present invention is shown in Figures 1 and 2. Figure 1 is a functional block diagram showing the configuration of the monitoring device 10, and Figure 2 is a functional block diagram showing the specific configuration of the monitoring device 10. The monitoring device 10 according to the embodiment of the present invention shown in these figures can monitor the transmission signal level value of a transmission signal output from an amplifier installed in a cable television transmission path of a CATV system, and can monitor the power supply voltage value of power from a power supply device that serves as the operating power source for the amplifier. The monitoring device 10 according to the embodiment of the present invention has an RF input terminal, a PS input terminal, and an output terminal OUT, and the RF input terminal can be connected to an output monitor terminal of the amplifier, and can be connected to a level signal distributor that distributes the transmission signal installed in the cable television transmission path. The PS input terminal is a power input terminal to which power is supplied, and can be connected to a power output terminal of the amplifier and a power output terminal of the power supply device, and can be connected to a power distributor that distributes power installed in the cable television transmission path. In the cable television transmission path of a CATV system, it is generally considered that the transmission signal is transmitted and the power supplied to the amplifier is transmitted at the same time. The transmission signal is one or more RF signals such as a CATV upstream signal of 10 to 55 MHz, a terrestrial digital television broadcast signal of 70 to 770 MHz, and a BS / CS broadcast signal of 1032 to 3224 MHz. A transmission signal is input to the input terminal of the amplifier, which amplifies the transmission signal and outputs it from the output terminal, and a monitor signal of the amplified transmission signal is output from the output monitor terminal. Power from a power supply that serves as an operating power source can be input to the input terminal of the amplifier together with the transmission signal, and the amplifier operates using the power supplied to it and can output the power from the power output terminal. The power supplied together with the amplified transmission signal can be output from the output terminal of the amplifier.

[0015] As described above, in the monitoring device 10, a transmission signal is input to the RF input terminal connected to the output monitor terminal of the amplifier, and power serving as an operating power source can also be input. The transmission signal input to the RF input terminal is input to the detector 12 and detected, and the detected transmission signal level value is input to the monitoring unit 14. Specifically, as shown in FIG. 2, the transmission signal input to the RF input terminal is level-adjusted to an appropriate level by an attenuator (ATT) 22 and input to the detector 12. The ATT 22 is configured to obtain an attenuation amount of, for example, a maximum of 60 dB. The monitoring unit 14 is configured with a microcomputer 25, and the adjustment amount of the ATT 22 is digitally controlled by the microcomputer 25. Moreover, power supplied from a power supply is directly or indirectly input to the PS input terminal. Surge protective devices (SPDs) 21 and 23 are connected to the RF input terminal and the PS input terminal, respectively, as protection against lightning damage.

[0016] The power input to the RF input terminal as the operating power is sent to one terminal of the power switch (power switch SW) 11, and the power supplied from the power supply to the PS input terminal is sent to the other terminal of the power switch SW11. The power switch SW11 appropriately selects and outputs one of the powers according to the state of power supply to the monitoring device 10. That is, when power is input only to the RF input terminal, switching is performed to one terminal so that the power input to the RF input terminal is output, when power is input only to the PS input terminal, switching is performed to the other terminal so that the power input to the PS input terminal is output, and when power is input to both the RF input terminal and the PS input terminal, switching is performed to a desired terminal so that any desired power is output. The power output from the power switch SW11 is supplied to a first rectifier 13 and a second rectifier 16. The first rectifier 13 rectifies the power and detects the power supply voltage value of the power. The power supply voltage value detected by the first rectifier 13 is input to the monitoring unit 14. The second rectifier 16 rectifies the power to produce a DC power supply, which is supplied as an operating power supply to each circuit of the monitoring device 10. Furthermore, a battery 17 is connected to the output side of the second rectifier 16, and when the power supply voltage output from the second rectifier 16 drops, power is supplemented from the battery 17 and supplied to each circuit of the monitoring device 10 as an operating power supply.

[0017] Specifically, as shown in FIG. 2, the DC power rectified by the second rectifier 16 is controlled so as not to exceed a certain value. For example, if the voltage exceeds 68 [V], the voltage is reduced to 68 [V]. The DC power from the second rectifier 16, which is controlled so as not to exceed a certain value, is supplied to the first DC-DC converter 29 and stepped down to, for example, 13 [V]. Furthermore, the DC power stepped down by the first DC-DC converter 29 is supplied to the second DC-DC converter 30 and stepped down to, for example, 3.3 [V] and supplied to each circuit of the monitoring device 10 as an operating power source. An electric double layer capacitor 31, which is the battery 17, is connected to the circuit connecting the first DC-DC converter 29 and the second DC-DC converter 30. When the voltage output from the first DC-DC converter 29 drops to, for example, 13 [V] or less, the voltage from the electric double layer capacitor 31 is automatically supplemented, and, for example, 13 [V] is supplied to the second DC-DC converter 30. The electric double layer capacitor 31, which is used as the battery 17, is a secondary battery and can be used by connecting multiple batteries. Although a primary battery can be used as the battery 17, the battery size and the installed circuit would be large, so that the electric double layer capacitor 31, which is used as a secondary battery, is considered to be suitable for a compact circuit design.

[0018] The monitoring unit 14 stores the initial level value as a normal level value, and stores the acquisition time when the transmission signal level value from the detector 12 is acquired and the acquisition time when the power supply voltage value from the first rectifier 13 is acquired. The monitoring unit 14 calculates the difference between the transmission signal level value input from the detector 12 and the stored normal level value, and stores the difference as a differential level value. The monitoring unit 14 also detects when the differential level value becomes too large or too small and reaches a predetermined threshold, and when the power supply voltage value of the power input from the first rectifier 13 drops and reaches a predetermined threshold. The monitoring unit 14 is connected to a wireless transmission unit 15, which periodically transmits the differential level value and the power supply voltage value calculated by the monitoring unit 14 together with the acquisition time at a predetermined time interval. When the differential level value reaches a predetermined threshold, the differential level value and the acquisition time are temporarily transmitted from the wireless transmission unit 15 under the control of the monitoring unit 14. Furthermore, when the power supply voltage value of the power input from first rectifier 13 reaches a predetermined threshold value, the power supply voltage value and the acquisition time are temporarily transmitted from wireless transmission unit 15 under the control of monitoring unit 14. An antenna is connected to output terminal OUT of monitoring device 10, and the transmission signal from wireless transmission unit 15 is transmitted from the antenna connected to output terminal OUT.

[0019] Specifically, as shown in FIG. 2, the monitoring unit 14 is composed of a microcomputer 25, and a set switch (SET SW) 24 is connected to the microcomputer 25. By pressing the SET SW 24 immediately after the monitoring device 10 is installed, the initial level value is stored in the microcomputer 25 as a normal level value. In addition, a real-time clock 28 is connected to the microcomputer 25, and the acquisition time when the transmission signal level value from the detector 12 is acquired and the acquisition time when the power supply voltage value of the power from the first rectifier 13 is acquired are stored in the microcomputer 25. Furthermore, a plurality of LEDs 27 are connected to the microcomputer 25, and the LEDs 27 are turned on or blinked depending on the acquisition status of the transmission signal level value and the power supply voltage value of the amplifier. The microcomputer 25 calculates the difference between the acquired transmission signal level value and the stored normal level value, and stores the difference as a difference level value. In addition, the microcomputer 25 detects when the difference level value reaches a predetermined threshold value and when the power supply voltage value of the power input from the first rectifier 13 reaches a predetermined threshold value. A LPWA (Low Power Wide Area-network) unit 26 is connected to the monitoring unit 14 as a wireless transmission unit 15, and the unit 26 periodically transmits the difference level value and power supply voltage value calculated by the monitoring unit 14 together with the acquisition time at a predetermined time interval. When the difference level value reaches a predetermined threshold, the unit 26 temporarily transmits the difference level value and the acquisition time under the control of the monitoring unit 14. When the power supply voltage value of the power input from the first rectifier 13 reaches a predetermined threshold, the unit 26 temporarily transmits the power supply voltage value and the acquisition time under the control of the monitoring unit 14. An antenna is connected to the output terminal OUT of the monitoring device 10, and the transmission signal from the unit 26 is transmitted from the antenna connected to the output terminal OUT.

[0020] In the monitoring device 10 according to the embodiment of the present invention, when the RF input terminal is connected to the output monitor terminal of the amplifier, the monitoring device 10 can monitor the operating state of the amplifier. When the PS input terminal is connected to the power output terminal of the amplifier, the monitoring device 10 can monitor whether or not power is being supplied from the power supply to the amplifier. When the PS input terminal is connected to the power output terminal of the power supply, the monitoring device 10 can monitor the operating state of the power supply. When the RF input terminal is connected to a level signal distributor that distributes a transmission signal provided on a cable television transmission path, the monitoring device 10 can monitor the transmission signal level value of the transmission signal transmitted on the cable television transmission path and whether or not the cable television transmission path has deteriorated or been disconnected. When the PS input terminal is connected to a power distributor that distributes power provided on the cable television transmission path, the monitoring device 10 can monitor the power supply voltage value of the power transmitted on the cable television transmission path and whether or not the cable television transmission path has deteriorated or been disconnected.

[0021] <Periodic transmission and special transmission of the monitoring device according to the embodiment of the present invention> Next, the regular transmission and special transmission performed by the monitoring device 10 of the embodiment of the present invention will be described. Fig. 3 is a time chart showing the power supply voltage value versus time for regular transmission in the monitoring device 10 of the embodiment of the present invention, Fig. 4 is a time chart showing the transmission signal level value versus time for regular transmission, Fig. 5 is a time chart showing the power supply voltage value versus time for special transmission, and Fig. 6 is a time chart showing the transmission signal level value versus time for special transmission. In the time chart shown in FIG. 3, the horizontal axis represents elapsed time and the vertical axis represents power supply voltage value. The power supply voltage value of the power input to the monitoring device 10 is periodically transmitted at a predetermined time interval from time A to J, for example, every 30 minutes, together with the time of acquisition. In the example shown in FIG. 3, a power supply voltage value of about 35 [V] is periodically transmitted at 30-minute intervals together with the time of acquisition, and it can be seen that the power supply voltage value is stable and in a normal state. In addition, in the time chart shown in FIG. 4, the horizontal axis represents elapsed time and the vertical axis represents the transmission signal level value, but the transmission signal level value is the difference level value calculated by the monitoring unit 14. The difference level value of the transmission signal input to the monitoring device 10 is periodically transmitted at a predetermined time interval from time A to J, for example, every 30 minutes, together with the time of acquisition. In this case, the power supply voltage value shown in FIG. 3 and the difference level value shown in FIG. 4 are periodically transmitted at the same timing from time A to J. In the example shown in FIG. 4, a difference level value of approximately 0 [dB] is periodically transmitted at 30-minute intervals along with the acquisition time at times A to J, which are the same as the power supply voltage value, and it can be seen that the difference level value is stable and in a normal state.

[0022] Next, a case where an abnormality occurs in the power supply voltage value of the power input to the monitoring device 10 will be described with reference to the time chart shown in Fig. 5. The power supply voltage value of the power input to the monitoring device 10 is the power supply voltage value acquired by the microcomputer 25 serving as the monitoring unit 14, and in Fig. 5, the horizontal axis represents the elapsed time and the vertical axis represents the power supply voltage value. Here, the normal value of the power supply voltage is, for example, 60 [V], and the first threshold value Vth1, which is the lowered abnormal value, is, for example, 35 [V]. The microcomputer 25, which is the monitoring unit 14, acquires the power supply voltage value of the power input to the monitoring device 10 at short intervals, and the power supply voltage value acquired at intervals of, for example, 30 minutes is periodically transmitted from the LPWA unit 26, which is the wireless transmission unit 15, together with the time at which it was acquired. Then, at time A, 30 minutes after the start of monitoring, the normal value of 60 [V] of the power supply voltage value was acquired, and so this is periodically transmitted together with the time A at which it was acquired. Furthermore, at time B, 60 minutes later, the power supply voltage value was acquired as 50 [V], but this is within the normal value range, and so this is periodically transmitted together with the time B at which the power supply voltage value was acquired as 50 [V]. Next, for example, when the power supply voltage value acquired at time C 75 minutes later falls to the threshold value of 35 [V], the microcomputer 25, which is the monitoring unit 14, commands the LPWA unit 26, which is the wireless transmission unit 15, to immediately transmit the power supply voltage value that has fallen to 35 [V] as a voltage abnormality together with the time C at which it was acquired. The LPWA unit 26, which is the wireless transmission unit 15, monitors the surrounding LPWA radio wave environment and transmits data consisting of the power supply voltage value that has fallen to 35 [V] and the time C at which it was acquired, at a timing when the communication does not collide with the communication of other wireless devices. After that, for example, at time D 90 minutes later, the acquired power supply voltage value further falls to 20 [V] and remains within the abnormal value range, so the power supply voltage value is not transmitted and is put on hold.

[0023] Further time passes, and for example, at time E after 120 minutes, the acquired power supply voltage value further drops to 10 [V]. In this case, if a power supply voltage value lower than the second threshold value Vth2 of, for example, 15 [V] is acquired, the voltage output from the rectifier 16 is cut to 0 [V] so that the internal circuit of the monitoring device 10 does not malfunction. Then, for example, 13 [V] is replenished from the electric double layer capacitor 31, which is the battery 17, and the internal circuit of the monitoring device 10 is driven. The transmission of the power supply voltage value remains on standby. Further time passes, and for example, the power supply voltage value acquired at time F after 150 minutes has recovered to 28 [V]. However, since the acquired power supply voltage value remains within the abnormal value range, the transmission of the power supply voltage value remains on standby, but since a power supply voltage value higher than the second threshold value Vth2 has been acquired, the internal circuit of the monitoring device 10 is driven by the power output from the rectifier 16. Further time passes, and for example, the power supply voltage value acquired at time G after 160 minutes has been acquired is higher than 35 [V]. Since a power supply voltage value higher than 35 [V] is higher than the first threshold value Vth1, the power supply voltage value is deemed to be within the normal range, and the microcomputer 25 serving as the monitoring unit 14 instructs the LPWA unit 26 serving as the wireless transmission unit 15 to immediately transmit data consisting of the power supply voltage value restored before it becomes higher than the first threshold value Vth1 and the acquired time G. The LPWA unit 26 serving as the wireless transmission unit 15 monitors the surrounding LPWA radio wave environment and transmits data consisting of the power supply voltage value restored before it becomes higher than the first threshold value Vth1 and the acquired time G at a timing when the communication does not collide with the communication of other wireless devices. Here, since the power supply voltage value has returned to the normal range, the elapsed time is reset to 0 minutes.

[0024] At time H, 30 minutes after the reset, the acquired power supply voltage value is restored to 60 [V], and data consisting of the power supply voltage value of 60 [V] and the acquired time H is periodically transmitted. Furthermore, at time I, 60 minutes after the reset, the acquired power supply voltage value is also 60 [V], and data consisting of the power supply voltage value of 60 [V] and the acquired time H is periodically transmitted. Here, for example, if the power supply voltage value acquired at time J, 80 minutes after the reset, becomes 35 [V], which is the first threshold value Vth1, the power supply voltage value of 35 [V] and the acquired time J are temporarily transmitted as a voltage abnormality of the power supply voltage value, as in the case of time C described above. At times K, L, and M, as time passes, the acquired power supply voltage value remains below the first threshold value Vth1, as in the case of times D and E, so transmission is suspended. As described above, the power supply voltage value acquired every 30 minutes is transmitted at a fixed time together with the time of acquisition, and when the acquired power supply voltage value becomes equal to or lower than the first threshold value Vth1, the power supply voltage value is transmitted as a voltage abnormality together with the time of acquisition. When the acquired power supply voltage value is maintained equal to or lower than the first threshold value Vth1, the transmission is suspended, so that the amount of transmitted data can be reduced and monitoring can be performed efficiently. Furthermore, when the acquired power supply voltage value becomes equal to or lower than the second threshold value Vth2 and becomes low enough to cause malfunction of the internal circuit of the monitoring device 10, the input power is cut off, and instead, power is replenished from the electric double layer capacitor 31, which is the battery 17, to drive the internal circuit. This prevents the operation of the monitoring device 10 from stopping. By operating the monitoring device 10 as described above, it becomes possible to perform monitoring sufficiently even when a secondary battery such as the electric double layer capacitor 31 is used, and the internal circuit of the monitoring device 10 can be designed compactly. The normal voltage range of the power supply voltage is a voltage range Vz1 higher than the first threshold Vth1 up to 60 [V], and the abnormal voltage range of the power supply voltage is a voltage range Vz2 and a voltage range Vz3. The voltage range Vz2 is a voltage range higher than the second threshold Vth2 and equal to or lower than the first threshold Vth1, and the voltage range Vz3 is a voltage range equal to or lower than the second threshold Vth2. When the power supply voltage is within the voltage range Vz1 and the voltage range Vz2, the internal circuit of the monitoring device 10 is operated by the supplied power. When the power supply voltage is within the voltage range Vz3, the internal circuit of the monitoring device 10 is operated by the power supplemented from the electric double layer capacitor 31, which is the battery 17, so that the operation of the monitoring device 10 does not stop.

[0025] Next, a case where an abnormality occurs in the differential level value of the transmission signal level values ​​of the transmission signals input to the monitoring device 10 will be described with reference to the time chart shown in Fig. 6. The differential level value is a differential level value calculated by the microcomputer 25 serving as the monitoring unit 14 as described above based on the transmission signal level value of the transmission signal input to the monitoring device 10, and in Fig. 6, the horizontal axis represents elapsed time and the vertical axis represents the differential level value. Here, the thresholds for the difference level values ​​are set as follows: for example, the third threshold Sth3 is 12.8 [dB], and the fourth threshold Sth4 is −10 [dB], and the range Sa where the difference level value is equal to or greater than the third threshold Sth3 and the range Sb where the difference level value is equal to or less than the fourth threshold Sth4 are set as abnormal value ranges for the difference level values, and the range Sn where the difference level value is greater than the fourth threshold Sth4 and less than the third threshold Sth3 is set as normal value range.

[0026] The microcomputer 25, which is the monitoring unit 14, acquires the differential level value of the transmission signal input to the monitoring device 10 at short intervals, and the differential level value acquired at intervals of, for example, 30 minutes is periodically transmitted from the LPWA unit 26, which is the wireless transmission unit 15, together with the time at which it was acquired. At time A, 30 minutes after the start of monitoring, a differential level value of 0 [dB] is acquired, which is within the normal range, and is periodically transmitted together with the acquisition time A. As time passes, for example, at time B, 50 minutes later, a differential level value that has fallen to −10 [dB] of the fourth threshold value Sth4 is acquired. In this case, the microcomputer 25, which is the monitoring unit 14, commands the LPWA unit 26, which is the wireless transmission unit 15, to temporarily transmit the immediately decreased differential level value together with the acquisition time B as a level abnormality of the differential level value. The LPWA unit 26, which is the wireless transmitting unit 15, monitors the surrounding LPWA radio wave environment and transmits data consisting of the differential level value lowered to -10 [dB] and the acquired time B at a timing when the communication does not collide with the communication of other wireless devices.

[0027] As time passes, for example, at time C after 60 minutes, a difference level value that has dropped to -15 [dB] is acquired, and at time D after 90 minutes, a difference level value that has dropped to -18 [dB] is acquired, and the acquired difference level value remains within the abnormal value range, but here, the difference level value is periodically transmitted as a value of -10 [dB] together with the acquired times C and D. The reason that the difference level value is set to a value of -10 [dB] is that values ​​below that are outside the normal measurement range of the microcomputer 25 which is the monitoring unit 14. Further, when a differential level value that has recovered to be greater than -10 dB is acquired at time E, for example, 110 minutes later, the differential level value is deemed to have been restored to the normal range, and the microcomputer 25 serving as the monitoring unit 14 commands the LPWA unit 26 serving as the wireless transmission unit 15 to immediately and temporarily transmit the restored differential level value together with the acquisition time E. The LPWA unit 26 serving as the wireless transmission unit 15 monitors the surrounding LPWA radio wave environment and transmits data consisting of the differential level value that has recovered to be greater than -10 dB and the acquisition time E at a timing when the communication does not collide with communications of other wireless devices. As time passes, the difference level values ​​acquired at time F, time G, and time H are within the normal range, so the acquired difference level values ​​are periodically transmitted from the LPWA unit 26, which is the wireless transmission unit 15, together with the times F, G, and H at which they were acquired. Furthermore, for example, when the difference level value acquired at time I, 185 minutes later, rises to +12.8 dB of the third threshold Sth3, the microcomputer 25, which is the monitoring unit 14, commands the LPWA unit 26, which is the wireless transmission unit 15, to immediately transmit the increased difference level value as an abnormality in the difference level value together with the time I at which it was acquired. The LPWA unit 26, which is the wireless transmission unit 15, monitors the surrounding LPWA radio wave environment and transmits data consisting of the difference level value that has risen to +12.8 [dB] and the acquired time I at a timing at which the communication does not collide with the communication of other wireless devices.

[0028] As time passes, for example, at time J after 210 minutes, the acquired differential level value is about 18 dB, and the acquired differential level value remains within the abnormal value range, but the acquired differential level value is periodically transmitted together with the acquisition time J. Furthermore, when a differential level value that has recovered to a value smaller than +12.8 dB is acquired at time K after 235 minutes, for example, the differential level value is deemed to have been restored to the normal value range, and the microcomputer 25 serving as the monitoring unit 14 commands the LPWA unit 26 serving as the wireless transmission unit 15 to immediately transmit the restored differential level value together with the acquisition time K. The LPWA unit 26 serving as the wireless transmission unit 15 monitors the surrounding LPWA radio wave environment and transmits data consisting of the acquired time K and the differential level value that has recovered to a value smaller than +12.8 dB at a timing when the communication does not collide with the communication of other wireless devices. Further, at times L, M, and N, differential level values ​​within the normal range are acquired, and the acquired differential level values, similar to times F, G, and H, are periodically transmitted from the LPWA unit 26, which is the wireless transmitting unit 15, together with the times L, M, and N at which they were acquired.

[0029] In addition, in the time charts shown in Fig. 5 and Fig. 6, individual operations are shown in separate time series in order to easily explain each operation. In reality, they operate in the same time series as the time charts shown in Fig. 3 and Fig. 4. For example, when 30 minutes has elapsed in the time chart shown in Fig. 5, the operation at 30 minutes has elapsed in the time chart shown in Fig. 6 is performed, and if the elapsed time in the time chart shown in Fig. 5 is reset to 0 minutes at 160 minutes, the elapsed time in the time chart shown in Fig. 6 is also reset to 0 minutes at 160 minutes. In addition, at the timing when regular transmission is performed in the time chart shown in Fig. 5, regular transmission is also performed in the time chart shown in Fig. 6, and at the timing when special transmission is performed or transmission is stopped in the time chart shown in Fig. 5, special transmission is also performed or transmission is stopped in the time chart shown in Fig. 6.

[0030] The difference level value and the power supply voltage value periodically transmitted from the wireless transmission unit 15 together with the acquisition time, and the difference level value or the power supply voltage value temporarily transmitted from the wireless transmission unit 15 together with the acquisition time are received by a monitoring unit of the CATV system, for example, a CATV station. In this case, the monitoring unit of the CATV station monitors the operating state of the amplifier and the operating state of the power supply, and also monitors the cable television transmission line for deterioration or disconnection. In addition, if a dedicated monitoring unit that receives the difference level value and power supply voltage value periodically transmitted from the wireless transmission unit 15 together with the acquisition time, and the difference level value and power supply voltage value temporarily transmitted from the wireless transmission unit 15 together with the acquisition time, is installed in the CATV system, the monitoring unit monitors the operating state of the amplifier and the operating state of the power supply, and also monitors the cable television transmission line for deterioration or disconnection.

[0031] <CATV system according to the first embodiment of the present invention> FIG. 7 is a block diagram showing the configuration of a CATV system 101 according to a first embodiment of the present invention. In the CATV system 101 of the first embodiment of the present invention shown in Fig. 7, a plurality of amplifiers 112, 114, 116, 118, 120, 121... are provided at predetermined positions of a cable television transmission path made of a coaxial cable, and the amplifiers 112-121... provided in the CATV system 101 of the first embodiment can receive power from a power supply 111 as an operating power source together with a transmission signal at their input terminals, and can operate with the power input to the input terminals. The amplifiers 112-121... amplify the transmission signal input to their input terminals to a predetermined transmission signal level and output it from their output terminals, and have output monitor terminals for monitoring the output transmission signal. The amplifiers 112-121... can output the input power superimposed on the transmission signal from their output terminals. In the CATV system 101 of the first embodiment, a monitoring device of an embodiment of the present invention is applied, and the operating status of amplifiers at predetermined locations among the amplifiers 112 to 121, etc. is monitored by the monitoring device of the present invention, and the operating status of the amplifiers is also monitored by the monitoring device of the present invention.

[0032] In a CATV system 101 according to a first embodiment of the present invention shown in Fig. 7, a transmission signal transmitted from a CATV station 110 through a cable television transmission line made of a coaxial cable is input to a power supply 111 provided on the cable television transmission line. The transmission signal is one or more RF signals selected from a CATV upstream signal of 10 to 55 MHz, a terrestrial digital television broadcast signal of 70 to 770 MHz, and a BS / CS broadcast signal of 1032 to 3224 MHz. The power supply 111 outputs the input transmission signal directly to the cable television transmission line, and supplies power to the cable television transmission line via a power supply inserter (not shown) provided on the cable television transmission line connected to a power output terminal of the power supply 111. The power supplied to the cable television transmission line is used as the operating power source for a plurality of amplifiers 112, 114, 116, 118, 120, 121, ... provided at predetermined locations. The transmission signal and power sent from power supply 111 to the cable television transmission path are input to an input terminal of first amplifier 112. Power supply 111 can be installed aerial on the cable television transmission path.

[0033] In the first amplifier 112, a transmission signal input to the input terminal is amplified to a predetermined transmission signal level and output from an output terminal. Also, the first amplifier 112 operates by power input to the input terminal, and the power input to the input terminal is superimposed on the transmission signal and output from the output terminal, and the power input to the input terminal is output from the power output terminal. The RF input terminal of the first monitoring device 113 is connected to the output monitor terminal of the first amplifier 112, and the PS input terminal of the first monitoring device 113 is connected to the power output terminal of the first amplifier 112. The first monitoring device 113 is configured by the monitoring device 10 according to the present invention, and the first monitoring device 113 operates as described above to monitor a difference level value based on a transmission signal level value output from the first amplifier 112 input to the RF input terminal, and a power supply voltage value of the power supplied to the PS input terminal. The output terminal of the first amplifier 112 is connected to the input terminal of the second amplifier 114 via a cable television transmission line, and a distributor 112a is connected midway through this cable television transmission line. The distributor 112a distributes the transmission signal transmitted over the cable television transmission line into multiple signals, and each of the distributed signals is supplied to multiple subscriber homes 112b. This allows each subscriber home 112b to receive the transmission signal and watch terrestrial digital television broadcasts and BS / CS broadcasts.

[0034] In the second amplifier 114, a transmission signal input to the input terminal is amplified to a predetermined transmission signal level and output from an output terminal. The second amplifier 114 operates by power input to the input terminal, and the power input to the input terminal is superimposed on the transmission signal and output from the output terminal, and the power input to the input terminal is output from the power output terminal. The RF input terminal of the second monitoring device 115 is connected to the output monitor terminal of the second amplifier 114, and the PS input terminal of the second monitoring device 115 is connected to the power output terminal of the second amplifier 114. The second monitoring device 115 is configured by the monitoring device 10 according to the present invention, and the second monitoring device 115 operates as described above to monitor the difference level value based on the transmission signal level value output from the second amplifier 114 and the power supply voltage value of the power supplied to the PS input terminal. The output terminal of the second amplifier 114 is connected to the input terminals of the third amplifier 116 and the fourth amplifier 118 by cable television transmission paths, respectively. In this case, the transmission signal output from the output terminal of the second amplifier 114 is split into two, and the split transmission signals are input to the input terminals of the third amplifier 116 and the fourth amplifier 118, respectively.

[0035] In the third amplifier 116, a transmission signal input to the input terminal is amplified to a predetermined transmission signal level and output from the output terminal. Also, the third amplifier 116 operates by power input to the input terminal, and the power input to the input terminal is superimposed on the transmission signal and output from the output terminal, and the power input to the input terminal is output from the power output terminal. The RF input terminal of the third monitoring device 117 is connected to the output monitor terminal of the third amplifier 116, and the PS input terminal of the third monitoring device 117 is connected to the power output terminal of the third amplifier 116. The third monitoring device 117 is configured by the monitoring device 10 according to the present invention, and the third monitoring device 117 operates as described above to monitor the difference level value based on the transmission signal level value output from the third amplifier 116 and the power supply voltage value of the power supplied to the PS input terminal. In addition, in the fourth amplifier 118, a transmission signal input to the input terminal is amplified to a predetermined transmission signal level and output from the output terminal. Also, the fourth amplifier 118 operates by power input to the input terminal, and the power input to the input terminal is superimposed on the transmission signal and output from the output terminal, and the power input to the input terminal is output from the power output terminal. The RF input terminal of the fourth monitoring device 119 is connected to the output monitor terminal of the fourth amplifier 118, and the PS input terminal of the fourth monitoring device 119 is connected to the power output terminal of the fourth amplifier 118. The fourth monitoring device 119 is configured by the monitoring device 10 according to the present invention, and the fourth monitoring device 119 operates as described above to monitor the difference level value based on the transmission signal level value output from the fourth amplifier 118 and the power supply voltage value of the power supplied to the PS input terminal.

[0036] The output terminal of the third amplifier 116 is connected to the input terminal of the fifth amplifier 120 via a cable television transmission line, and a distributor 116a is connected midway through this cable television transmission line. The distributor 116a distributes the transmission signal transmitted over the cable television transmission line into multiple signals, and each of the distributed signals is supplied to multiple subscriber homes 116b, respectively. This allows each subscriber home 116b to receive the transmission signal and watch terrestrial digital television broadcasts and BS / CS broadcasts. The output terminal of the fourth amplifier 118 is connected to the input terminal of the sixth amplifier 121 via a cable television transmission line, and a distributor 118a is connected midway along this cable television transmission line. The distributor 118a distributes the transmission signal transmitted over the cable television transmission line into a plurality of signals, and each of the distributed signals is supplied to a plurality of subscriber homes 118b. This allows each subscriber home 118b to receive the transmission signal and watch terrestrial digital television broadcasts and BS / CS broadcasts. Further amplifiers can be connected to the fifth amplifier 120 and the sixth amplifier 121. However, the explanation of the fifth amplifier 120, the sixth amplifier 121, and the further connected amplifiers is similar to the amplifiers described above, so the explanation is omitted.

[0037] As described above, in the CATV system 101 of the first embodiment of the present invention, the RF input terminals of the first monitoring device 113 to the fourth monitoring device 119 are connected to the output monitor terminals of the first amplifier 112 to the fourth amplifier 118, so that it is possible to monitor the operating states of the first amplifier 112 to the fourth amplifier 118. Also, the PS input terminals of the first monitoring device 113 to the fourth monitoring device 119 are connected to the power output terminals of the first amplifier 112 to the fourth amplifier 118, so that it is possible to monitor whether or not power is being supplied from the power supply 111 to the first amplifier 112 to the fourth amplifier 118.

[0038] <CATV system according to a second embodiment of the present invention> FIG. 8 is a block diagram showing the configuration of a CATV system 102 according to the second embodiment of the present invention. In the CATV system 102 of the second embodiment of the present invention shown in Figure 8, the configuration differs from that of the CATV system 101 of the first embodiment in that the power supply 111-2 has two power output terminals, a first power output terminal and a second power output terminal, and that the second power output terminal of the power supply 111-2 provided on the cable television transmission line is connected to the PS input terminal of the first monitoring device 113-2, but the other configurations are similar to those of the CATV system 101 of the first embodiment. Therefore, the following describes only the configuration of the CATV system 102 of the second embodiment, which differs from the configuration of the CATV system 101 of the first embodiment, and a description of the other configurations will be omitted.

[0039] In the CATV system 102 of the second embodiment shown in Fig. 8, the power supply 111-2 outputs the input transmission signal to the cable television transmission path as it is, and the first power output terminal of the power supply 111-2 is connected to a power supply inserter (not shown) provided on the cable television transmission path connected to the first amplifier 112-2, and supplies power to the cable television transmission path via the power supply inserter. The power supplied to the cable television transmission path is used as the operating power of the first amplifier 112-2 to the sixth amplifier 121 provided at predetermined positions. The transmission signal and power sent from the first power output terminal of the power supply 111-2 to the cable television transmission path are input to the input terminal of the first amplifier 112. In addition, the second power output terminal of the power supply 111-2 is connected to the PS input terminal of the first monitoring device 113-2, and power is directly supplied to the PS input terminal from the second power output terminal of the power supply 111-2. Furthermore, the output monitor terminal of the first amplifier 112 is connected to an RF input terminal of a first monitoring device 113-2. The power supply 111-2 can be installed aerial on the cable television transmission path.

[0040] As described above, in the CATV system 102 of the second embodiment of the present invention, the RF input terminals of the first monitoring device 113-2 to the fourth monitoring device 119 are connected to the output monitor terminals of the first amplifier 112 to the fourth amplifier 118, so that it is possible to monitor the operating states of the first amplifier 112 to the fourth amplifier 118. Also, since the PS input terminal of the first monitoring device 113-2 is connected to the second power output terminal of the power supply 111-2, it is possible to monitor the operating state of the power supply 111-2 and to monitor whether or not power is being supplied from the power supply 111-2 to the first amplifier 112. Furthermore, since the PS input terminals of the second monitoring device 115 to the fourth monitoring device 119 are connected to the power output terminals of the second amplifier 114 to the fourth amplifier 118, it is possible to monitor whether or not power is being supplied from the power supply 111-2 to the second amplifier 114 to the fourth amplifier 118. In the CATV system 102 of the second embodiment of the present invention described above, the power supply 111-2 is configured to have two power output terminals, a first power output terminal and a second power output terminal, but instead, the power supply 111-2 may have one power output terminal and be connected to the power supply inserter. The power supply inserter may then be configured to have two power output terminals, a first power output terminal and a second power output terminal, with the first power output terminal of the power supply inserter connected to the cable television transmission line and the second power output terminal connected to the PS input terminal of the first monitoring device 113-2.

[0041] <CATV system according to the third embodiment of the present invention> FIG. 9 is a block diagram showing the configuration of a CATV system 103 according to the third embodiment of the present invention. The CATV system 103 of the third embodiment of the present invention shown in Figure 9 differs from the configuration of the CATV system 101 of the first embodiment in that the power output terminal of the first power supply device 111-3 is connected to the PS input terminal of the first monitoring device 113-3, and in that power is supplied to the cable television transmission path from a second power supply device (not shown) installed somewhere, but the other configurations are similar to the configuration of the CATV system 101 of the first embodiment. Therefore, the following describes only the configuration of the CATV system 103 of the third embodiment, which differs from the configuration of the CATV system 101 of the first embodiment, and a description of the other configurations will be omitted.

[0042] In the CATV system 103 of the third embodiment shown in FIG. 9, the first power supply device 111-3 is not configured to supply power to the cable television transmission path, so the cable television transmission path is not provided with a power supply inserter to which the first power supply device 111-3 can be connected. The power output terminal of the first power supply device 111-3 is connected to the PS input terminal of the first monitoring device 113-3, and power is directly supplied to the PS input terminal from the first power supply device 111-3. In addition, the output monitor terminal of the first amplifier 112 is connected to the RF input terminal of the first monitoring device 113-3. Furthermore, power is supplied to the cable television transmission path from a second power supply device (not shown) installed somewhere. In this case, the power output terminal of the second power supply device is connected to a power supply inserter (not shown) installed in the cable television transmission path, and power is supplied to the cable television transmission path via this power supply inserter. The power supplied to the cable television transmission path is used as the operating power for the first amplifier 112 to the sixth amplifier 121 provided at predetermined locations. The first power supply device 111-3 and the second power supply device can be installed aerial on the cable television transmission path.

[0043] As described above, in the CATV system 103 of the third embodiment of the present invention, the RF input terminals of the first monitoring device 113-3 to the fourth monitoring device 119 are connected to the output monitor terminals of the first amplifier 112 to the fourth amplifier 118, so that it is possible to monitor the operation states of the first amplifier 112 to the fourth amplifier 118. Also, the PS input terminal of the first monitoring device 113-3 is connected to the power output terminal of the first power supply 111-3, so that it is possible to monitor the operation state of the first power supply 111-3. Furthermore, the PS input terminals of the second monitoring device 115 to the fourth monitoring device 119 are connected to the power output terminals of the second amplifier 114 to the fourth amplifier 118, so that it is possible to monitor whether or not power is being supplied from the second power supply to the second amplifier 114 to the fourth amplifier 118.

[0044] <CATV system according to the fourth embodiment of the present invention> FIG. 10 is a block diagram showing the configuration of a CATV system 104 according to the fourth embodiment of the present invention. The CATV system 104 of the fourth embodiment of the present invention shown in FIG. 10 differs from the configuration of the CATV system 101 of the first embodiment in that a power distributor 141 for distributing the power transmitted through the cable television transmission line and a level signal distributor 142 for distributing the transmission signal transmitted through the cable television transmission line are provided midway through the cable television transmission line where the output terminal of the first amplifier 112-4 is connected to the input terminal of the second amplifier 114, and in that a first monitoring device 113-4 is connected to the power distributor 141 and the level signal distributor 142, but the other configurations are similar to the configuration of the CATV system 101 of the first embodiment. Therefore, the following describes only the configuration of the CATV system 104 of the fourth embodiment, which differs from the configuration of the CATV system 101 of the first embodiment, and a description of the other configurations will be omitted.

[0045] In the CATV system 104 of the fourth embodiment shown in FIG. 10, an output terminal of a first amplifier 112-4 is connected to one end of a cable television transmission line, and an input terminal of a second amplifier 114 is connected to the other end of the cable television transmission line. In the cable television transmission line, a transmission signal is transmitted, and power supplied from a power supply 111 is also transmitted. The power transmitted through the cable television transmission line is used as operating power for the first amplifier 112-4 to the sixth amplifier 121 provided at a predetermined position. A power distributor 141 for distributing the power transmitted through the cable television transmission line and a level signal distributor 142 for distributing the transmission signal transmitted through the cable television transmission line are provided midway through the cable television transmission line. A power output terminal for outputting the power distributed by the power distributor 141 is connected to a PS input terminal of a first monitoring device 113-4, and the power transmitted through the cable television transmission line is supplied to the PS input terminal. In addition, the output terminal that outputs the transmission signal distributed by the level signal distributor 142 is connected to an RF input terminal of the first monitoring device 113-4, and the transmission signal transmitted through the cable television transmission path is received at the RF input terminal.

[0046] As described above, in the CATV system 104 of the fourth embodiment of the present invention, the RF input terminal of the first monitoring device 113-4 is connected to the level signal distributor 142 provided in the cable television transmission line connecting the output terminal of the first amplifier 112-4 and the input terminal of the second amplifier 114, so that the transmission signal level value of the transmission signal on the cable television transmission line can be monitored as a differential level value. This makes it possible to monitor the operating state of the first amplifier 112-4 and to monitor deterioration and disconnection of the cable television transmission line. In addition, the RF input terminals of the second monitoring device 115 to the fourth monitoring device 119 are connected to the output monitor terminals of the second amplifier 114 to the fourth amplifier 118, so that the operating states of the second amplifier 114 to the fourth amplifier 118 can be monitored. Furthermore, since the PS input terminal of first monitoring device 113-4 is connected to power distributor 141 provided on the cable television transmission line connecting the output terminal of first amplifier 112-4 and the input terminal of second amplifier 114, it is possible to monitor the power supply voltage value of the power on the cable television transmission line. This makes it possible to monitor the operating state of power supplier 111 as well as to monitor deterioration and disconnection of the cable television transmission line. In the CATV system 104 of the fourth embodiment of the present invention described above, the power distributor 141 is provided in the cable television transmission path between the first amplifier 112-4 and the second amplifier 114, but the power distributor 141 may also be provided in the cable television transmission path between the power supply 111 and the first amplifier 112-4.

[0047] <CATV system according to the fifth embodiment of the present invention> FIG. 11 is a block diagram showing the configuration of a CATV system 105 according to the fifth embodiment of the present invention. The CATV system 105 of the fifth embodiment of the present invention shown in FIG. 11 differs from the configuration of the CATV system 101 of the first embodiment in that the power supply 111-5 has two power output terminals, a first power output terminal and a second power output terminal, the second power output terminal of the power supply 111-5 provided on the cable television transmission path is connected to the PS input terminal of the first monitoring device 113-5, a level signal distributor 142 for distributing a transmission signal transmitted on the cable television transmission path and a power distributor 141 for distributing power transmitted on the cable television transmission path are provided midway along the cable television transmission path connecting the output terminal of the first amplifier 112-5 to the input terminal of the second amplifier 114-5, and the first monitoring device 113-5 is connected to the level signal distributor 142 and the second monitoring device 113-5 is connected to the power distributor 141, but the other configurations are similar to the configuration of the CATV system 101 of the first embodiment. Therefore, the following describes only the configuration of the CATV system 105 of the fifth embodiment, which differs from the configuration of the CATV system 101 of the first embodiment, and a description of the other configurations will be omitted.

[0048] In the CATV system 105 of the fifth embodiment shown in Fig. 11, the power supply 111-5 outputs the input transmission signal to the cable television transmission line as it is, and the first power output terminal of the power supply 111-5 is connected to a power supply inserter (not shown) provided on the cable television transmission line connected to the first amplifier 112-5, and supplies power to the cable television transmission line via the power supply inserter. The power supplied to the cable television transmission line is used as the operating power of the first amplifier 112-5 to the sixth amplifier 121 provided at a predetermined position. The transmission signal and power sent from the first power output terminal of the power supply 111-5 to the cable television transmission line are input to the input terminal of the first amplifier 112-5. The second power output terminal of the power supply 111-2 is connected to the PS input terminal of the first monitoring device 113-5, and power is directly supplied to the PS input terminal from the second power output terminal of the power supply 111-5. Furthermore, an output terminal of the first amplifier 112-5 is connected to one end of a cable television transmission line, and an input terminal of the second amplifier 114-5 is connected to the other end of the cable television transmission line. A power distributor 141 for distributing the power transmitted through the cable television transmission line and a level signal distributor 142 for distributing the transmission signal transmitted through the cable television transmission line are provided in the middle of the cable television transmission line. An output terminal for outputting the transmission signal distributed by the level signal distributor 142 is connected to an RF input terminal of a first monitoring device 113-5, and the RF input terminal receives the transmission signal transmitted through the cable television transmission line. A power output terminal for outputting the power distributed by the power distributor 141 is connected to a PS input terminal of a second monitoring device 115-5, and the power transmitted through the cable television transmission line is supplied to the PS input terminal of the second monitoring device 115-5. The power supply 111-5 can be installed aerial on the cable television transmission line.

[0049] As described above, in the CATV system 105 of the fifth embodiment of the present invention, the RF input terminal of the first monitoring device 113-5 is connected to the level signal distributor 142 provided in the cable television transmission line connecting the output terminal of the first amplifier 112-5 and the input terminal of the second amplifier 114-5, so that the transmission signal level value of the transmission signal on the cable television transmission line can be monitored as a differential level value. This makes it possible to monitor the operating state of the first amplifier 112-5 and to monitor deterioration and disconnection of the cable television transmission line. In addition, the RF input terminals of the second monitoring device 115-5 to the fourth monitoring device 119 are connected to the output monitor terminals of the second amplifier 114-5 to the fourth amplifier 118, so that the operating states of the second amplifier 114-5 to the fourth amplifier 118 can be monitored. Furthermore, since the PS input terminal of the second monitoring device 115-5 is connected to the power distributor 141 provided on the cable television transmission line connecting the output terminal of the first amplifier 112-5 and the input terminal of the second amplifier 114-5, it is possible to monitor the power supply voltage value of the power on the cable television transmission line. This makes it possible to monitor the operating state of the power supplier 111-5 and to monitor deterioration and disconnection of the cable television transmission line. Furthermore, since the PS input terminals of the third monitoring device 117 and the fourth monitoring device 119 are connected to the power output terminals of the third amplifier 116 and the fourth amplifier 118, it is possible to monitor whether or not power is being supplied from the power supplier 111-5 to the third amplifier 116 and the fourth amplifier 118. In the CATV system 105 of the fifth embodiment of the present invention described above, the power supply 111-5 is configured to have two power output terminals, a first power output terminal and a second power output terminal, but instead, the power supply 111-5 may have one power output terminal, which is connected to the power supply inserter. The power supply inserter may then be configured to have two power output terminals, a first power output terminal and a second power output terminal, with the first power output terminal of the power supply inserter connected to the cable television transmission line and the second power output terminal connected to the PS input terminal of the first monitoring device 113-5.

[0050] <CATV system according to the sixth embodiment of the present invention> FIG. 12 is a block diagram showing the configuration of a CATV system 106 according to the sixth embodiment of the present invention. The CATV system 106 of the sixth embodiment of the present invention shown in FIG. 12 differs from the configuration of the CATV system 101 of the first embodiment in that the power output terminal of the first power supply device 111-6 is connected to the PS input terminal of the first monitoring device 113-6, power is supplied to the cable television transmission path from a second power supply device (not shown) installed somewhere, a level signal distributor 142 is provided in the cable television transmission path connecting the output terminal of the first amplifier 112-6 to the input terminal of the second amplifier 114, and the first monitoring device 113-6 and the level signal distributor 142 are connected, but the other configurations are similar to the configuration of the CATV system 101 of the first embodiment. Therefore, the following describes only the configuration of the CATV system 106 of the sixth embodiment, which differs from the configuration of the CATV system 101 of the first embodiment, and a description of the other configurations will be omitted.

[0051] In the CATV system 106 of the sixth embodiment shown in FIG. 12, since the first power supply device 111-6 is not configured to supply power to the cable television transmission path, a power supply inserter to which the first power supply device 111-6 can be connected is not provided on the cable television transmission path. The power output terminal of the first power supply device 111-6 is connected to the PS input terminal of the first monitoring device 113-6, and power is directly supplied from the first power supply device 111-6 to the PS input terminal. In addition, power is supplied to the cable television transmission path from a second power supply device (not shown) installed at a certain location. In this case, the power output terminal of the second power supply device is connected to a power supply inserter (not shown) installed on the cable television transmission path, and power is supplied to the cable television transmission path through this power supply inserter. The power supplied to the cable television transmission path is used as the operating power source for the first amplifier 112-6 to the sixth amplifier 121 installed at a predetermined location. Furthermore, an output terminal of first amplifier 112-6 is connected to one end of a cable television transmission line, and an input terminal of second amplifier 114 is connected to the other end of the cable television transmission line. A level signal distributor 142 is provided in the middle of the cable television transmission line to distribute a transmission signal transmitted through the cable television transmission line. An output terminal that outputs the transmission signal distributed by level signal distributor 142 is connected to an RF input terminal of first monitoring device 113-6, and the RF input terminal receives the transmission signal transmitted through the cable television transmission line. Note that first power supply 111-6 and second power supply can be installed aerial on the cable television transmission line.

[0052] As described above, in the CATV system 106 of the sixth embodiment of the present invention, the RF input terminal of the first monitoring device 113-6 is connected to the level signal distributor 142 provided in the cable television transmission line connecting the output terminal of the first amplifier 112-6 and the input terminal of the second amplifier 114, so that the transmission signal level value of the transmission signal on the cable television transmission line can be monitored as a differential level value. This makes it possible to monitor the operating state of the first amplifier 112-6 and to monitor deterioration and disconnection of the cable television transmission line. Furthermore, the RF input terminals of the second monitoring device 115 to the fourth monitoring device 119 are connected to the output monitor terminals of the second amplifier 114 to the fourth amplifier 118, so that the operating states of the second amplifier 114 to the fourth amplifier 118 can be monitored. Furthermore, the PS input terminal of the first monitoring device 113-6 is connected to the power output terminal of the first power supply 111-6, so that the operating state of the first power supply 111-6 can be monitored. Furthermore, since the PS input terminals of the second monitoring device 115 to the fourth monitoring device 119 are connected to the power output terminals of the second amplifier 114 to the fourth amplifier 118, it is possible to monitor whether or not power is being supplied from the second power supply to the second amplifier 114 to the fourth amplifier 118. [Industrial Applicability]

[0053] The CATV system according to the embodiment of the present invention includes an amplifier installed on a cable television transmission path, and a power supply that supplies power to the amplifier or a monitoring device, and the monitoring device acquires a transmission signal level value of the amplifier and a power supply voltage value from the amplifier or the power supply device, and wirelessly transmits the acquired transmission signal level value and power supply voltage value to the outside, and the wireless transmission transmits the transmission signal level value or the power supply voltage value periodically, but when the transmission signal level value or the power supply voltage value reaches a threshold value, an emergency transmission is performed. This makes it possible for the CATV system according to the embodiment of the present invention to monitor the operating state of the amplifier and the operating state of the power supply device with a simple configuration. In the CATV system 101 of the first embodiment to the CATV system 106 of the sixth embodiment of the present invention described above, all amplifiers in the CATV system can be set to output power supplied to the amplifier from the output terminal and transmit it over the cable television transmission line, and can also be set to receive power transmitted over the cable television transmission line from the output terminal and transmit the received power from the input terminal. As a result, in the CATV system 103 of the third embodiment and the CATV system 106 of the sixth embodiment, no matter where the second power supply is installed, it is possible to transmit power used as an operating power source to amplifiers upstream and downstream of the second power supply. The connection mode of a specific monitoring device in the CATV system 101 of the first embodiment to the CATV system 106 of the sixth embodiment of the present invention described above may be the connection mode of another monitoring device, or may be the connection mode of any monitoring device in another CATV system. Furthermore, the monitoring device may be connected to each amplifier, or may be connected only to amplifiers located near the start point or branch point of the cable television transmission path, or may be connected to the transmission path. In addition, a distributor that distributes the power taken in from the cable television transmission path and the amplified transmission signal may be built into each amplifier in the CATV system 101 of the first embodiment to the CATV system 106 of the sixth embodiment of the present invention described above, so that power is output from a power output terminal provided in the amplifier and the transmission signal is output from an output monitor terminal.

[0054] In the monitoring device according to the embodiment of the present invention described above, the transmission signal level value and the power supply voltage value acquired by the monitoring unit are periodically transmitted, but either the transmission signal level value or the power supply voltage value may be periodically transmitted. That is, in the monitoring device according to the embodiment of the present invention, at least one of the transmission signal level value and the power supply voltage value acquired by the monitoring unit is periodically transmitted. In addition, in the monitoring device according to the embodiment of the present invention, when the transmission signal level value or the power supply voltage value reaches a threshold, an emergency transmission is performed. In this case, only the transmission signal level value or the power supply voltage value exceeding the threshold may be temporarily transmitted, or both the transmission signal level value and the power supply voltage value may be temporarily transmitted. In the description of the monitoring device according to the embodiment of the present invention, the transmission signal level value is monitored as a differential level value, but since the differential level value is a level value based on the transmission signal level value, monitoring the differential level value is synonymous with monitoring the transmission signal level value. In the CATV system according to the embodiment of the present invention, the amplifier and the power supply are monitored by the monitoring device according to the embodiment of the present invention, but it is also possible to monitor either the amplifier or the power supply. In other words, in the CATV system according to the embodiment of the present invention, at least one of the amplifier and the power supply is monitored by the monitoring device. In the monitoring device of the embodiment of the present invention described above, the RF input terminal is connected to the output monitor terminal of the amplifier. However, the output monitor terminal is a terminal from which a monitor signal that monitors the transmission signal output from the amplifier is output, and since the monitor signal is equivalent to the transmission signal output from the output terminal, the output monitor terminal can also be called an output terminal. [Explanation of symbols]

[0055] 10 monitoring device, 12 detector, 13 rectifier, 14 monitoring section, 15 radio transmission section, 16 rectifier, 17 battery, 25 microcomputer, 26 unit, 27 LED, 28 real-time clock, 29 DC-DC converter, 30 DC-DC converter, 31 electric double layer capacitor, 101, 102, 103, 104, 105, 106 CATV system, 110 CATV station, 111 power supply, 112, 114, 116, 118, 120, 121 amplifier, 112a, 116a, 118a distributor, 112b, 116b, 118b subscriber's premises, 113, 115, 117, 119 monitoring device, 141 power distributor, 142 level signal distributor, 200 CATV system, 201 monitoring device, 202 Power supply, 203 CATV station, 204 O / E converter, 205 amplifier, 206 tap-off, 207 subscriber's premises, 211 optical fiber cable, 212 coaxial cable, 311 control section, 312 converter, 313 voltage detection sensor, 314 step-down section, 315 wireless communication section, 316 battery

Claims

1. A monitoring device for monitoring at least one of an amplifier installed in a cable television transmission path and a power supply that supplies power to the amplifier, comprising: a monitoring unit that is supplied with power as an operating power source from the power supply and that acquires a transmission signal level value of the amplifier and a power supply voltage value of the power supplied from the power supply; a wireless transmission unit capable of wirelessly transmitting to an external device the transmission signal level value acquired by the monitoring unit and wirelessly transmitting to an external device the power supply voltage value acquired by the monitoring unit, a power supply voltage value output from the power supply unit and a power supply voltage value output from the power supply unit when the power supply voltage value is within a normal range and the power supply voltage value is within a normal range; when the power supply voltage value falls to a first threshold and enters an abnormal value range, and when the power supply voltage value changes from the abnormal value range to a normal value range, the power supply voltage value is temporarily transmitted, and the periodic transmission of the power supply voltage value is put on hold while the power supply voltage value remains within the abnormal value range; and the monitoring unit operates using power supplied from the power supply until the power supply voltage value falls to a second threshold which is lower than the first threshold.

2. The monitoring device according to claim 1, characterized in that when the transmission signal level value acquired by the monitoring unit becomes equal to or greater than a third threshold and falls within the abnormal value range, when the transmission signal level value becomes equal to or less than a fourth threshold and falls within the abnormal value range, and when the transmission signal level value moves from the abnormal value range to a normal value range between the third threshold and the fourth threshold, the transmission signal level value is transmitted temporarily, and even if the transmission signal level value remains within the abnormal value range, the transmission signal level value is transmitted periodically.

3. an RF input terminal to which at least the transmission signal output from the amplifier is input; a PS input terminal to which power supplied from the power supply is input; a power supply changeover switch configured to change over so as to send to the monitoring unit either the power supplied from the power supply and input to the RF input terminal of the amplifier or the power input to the PS input terminal; 2. The monitoring device according to claim 1, wherein the monitoring unit acquires a power supply voltage value of the power sent from the power supply changeover switch.

4. a battery connected to a circuit through which power is supplied to the monitoring unit; A monitoring device as described in any one of claims 1 to 3, characterized in that when the monitoring unit detects that the power supply voltage value acquired by the monitoring unit has dropped to the second threshold, power from the battery is replenished to the circuit, and the monitoring unit operates using power from the battery.

5. A cable television transmission path; an amplifier installed on the cable television transmission path; a power supply for supplying power to the amplifier; a monitoring device including at least a monitoring unit and a wireless transmission unit, capable of monitoring at least one of the amplifier and the power supply, and receiving power from the power supply as an operating power source; Equipped with a power supply voltage value acquired by the power supply unit from the power supply device, the power supply voltage value acquired by the power supply unit being transmitted to the power supply device via a power line; a power supply voltage value acquired by the power supply unit being transmitted to the power supply device via a power line; a power supply voltage value acquired by the power supply unit being transmitted to the power supply device via a power line; a power supply voltage value acquired by the power supply unit being transmitted to the power supply device via a power line;

6. The CATV system described in claim 5, characterized in that when the transmission signal level value acquired by the monitoring unit becomes equal to or above a third threshold and falls within the abnormal value range, when the transmission signal level value becomes equal to or below a fourth threshold and falls within the abnormal value range, and when the transmission signal level value moves from the abnormal value range to a normal value range between the third threshold and the fourth threshold, the wireless transmitting unit transmits the transmission signal level value temporarily, and even if the transmission signal level value remains within the abnormal value range, the transmission signal level value is transmitted regularly.

7. the monitoring device has an RF input terminal and a PS input terminal; 6. The CATV system according to claim 5, wherein the RF input terminal is connected to an output terminal from which the amplified transmission signal of the amplifier is output, and the PS input terminal is connected to a terminal from which power supplied from the power supply of the amplifier is output, and the transmission signal level value of the amplifier and the power supply voltage value of the power transmitted over the cable television transmission path are monitored.

8. the monitoring device has an RF input terminal and a PS input terminal; 6. The CATV system according to claim 5, wherein the RF input terminal is connected to an output terminal from which the amplified transmission signal of the amplifier is output, and the PS input terminal is connected to a power output terminal of the power supply, so that the transmission signal level value of the amplifier and the power supply voltage value of the power supplied from the power supply are monitored.

9. the monitoring device has an RF input terminal and a PS input terminal; The CATV system according to claim 5, characterized in that the RF input terminal is connected to a level signal distributor provided in the cable television transmission path, and the PS input terminal is connected to a power distributor provided in the cable television transmission path, and the transmission signal level value transmitted to the cable television transmission path and the power supply voltage value transmitted on the cable television transmission path are monitored.

10. the monitoring device has an RF input terminal and a PS input terminal; 6. The CATV system according to claim 5, wherein the RF input terminal is connected to a level signal distributor provided in the cable television transmission path, and the PS input terminal is connected to a power output terminal of the power supply, and the transmission signal level value transmitted to the cable television transmission path and the power supply voltage value supplied from the power supply are monitored.

11. the monitoring device has an RF input terminal and a PS input terminal; The CATV system according to claim 5, characterized in that the RF input terminal is connected to an output terminal from which the amplified transmission signal of the amplifier is output, and the PS input terminal is connected to a power distributor provided in the cable television transmission path, and the transmission signal level value of the amplifier and the power supply voltage value of the power transmitted over the cable television transmission path are monitored.

12. The monitoring device has an RF input terminal, a PS input terminal, and a power supply changeover switch, The CATV system of claim 5, characterized in that at least the transmission signal output from the amplifier is input to the RF input terminal, power supplied from the power supply is input to the PS input terminal, the power supply changeover switch switches to send to the monitoring unit either the power supplied from the power supply input to the RF input terminal of the amplifier or the power input from the PS input terminal, and the monitoring unit acquires the power supply voltage value of the power sent from the power supply changeover switch.

13. A CATV system as described in any one of claims 5 to 12, characterized in that the monitoring device is equipped with a battery, and when the monitoring unit detects that the power supply voltage value acquired by the monitoring unit has dropped to the second threshold value, the monitoring unit operates using power from the battery.

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