JP4213673B2 - CATV alarm device - Google Patents

Description

  The present invention relates to a device that monitors devices such as a signal processor, a modulator, a switch, and an amplifier used in a CATV broadcast system and issues an alarm when an abnormality occurs.

  In the currently operated CATV broadcasting system, not only independent broadcast programs and satellite broadcast programs are broadcast, but also terrestrial TV broadcasts such as VHF and UHF are retransmitted. This re-transmission of the terrestrial TV broadcast is generally performed by a head end facility 51 as shown in FIG.

  In the configuration example of FIG. 2, a VHF reception antenna 52 and a UHF reception antenna 53 are installed in the headend equipment 51, and terrestrial TV broadcast signals received by these antennas 52 and 53 are distributed to the distributors 54a and 54b. Each is input to. The distributors 54a and 54b to which the received signals are input distribute and output the received signals to the signal processors 55 installed in plural units, and the received signals are subjected to necessary processing in each signal processor 55. The signals are synthesized by the synthesizer 56 and sent to the trunk line 57.

  Among the above-described devices constituting the head end equipment 51, a device called a signal processor 55 is a terrestrial TV broadcast assigned to the signal processor 55 from a received RF signal such as a terrestrial TV broadcast radio wave or an FM broadcast radio wave. After extracting only the broadcast signal of the other channel (removing the broadcast signal of other channels) and converting it to an IF signal, and performing signal processing in the IF section, the IF signal is again converted into an RF signal (of the channel frequency of the CATV system). Signal) and output.

  In general, the signal processor 55 determines the number of received terrestrial TV broadcast channels (for example, in the case of VHF in the Kanto region, currently the first, third, fourth, sixth, eighth, tenth, and twelfth channels). Terrestrial TV broadcasting is performed, and the number of channels corresponding to seven) is set, and one channel is assigned to one signal processor 55. For example, in the configuration example of FIG. 2, the first channel of VHF is assigned to the signal processor 55a, and the third channel is assigned to the signal processor 55b, and only the broadcast signal of the first channel is sent from the signal processor 55b to the signal processor 55b. Only the third channel broadcast signal is output.

  As shown in FIG. 2, a number of devices are used in the head end equipment 51 of the CATV broadcasting system, and if an abnormality occurs in any of them, a broadcast failure may occur. The administrator of the headend equipment 51 needs to constantly monitor each component device and take immediate action if an abnormality occurs.

  As a method of monitoring the presence / absence of abnormality in each component device of the head end equipment 51, a method of monitoring an output signal of each component device is conceivable. However, in the case of a signal processor, it is not possible to determine whether there is an abnormality simply by monitoring the output signal. For example, since the broadcast signal is not input outside the broadcast time (such as midnight), the signal is not output.

  The present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide an alarm device that can accurately determine an abnormality of a device to be monitored.

The TV channel alarm device for CATV of the present invention has a switch, a frequency selector, an RF detector, an analog wave synchronous detector, a control unit, and an alarm output means. The signal input to the signal processor to be monitored and the signal output from the signal processor are input, and the signals are alternately output from the switch at regular intervals, and the frequency selection device The broadcast signal of the assigned channel is extracted from the input signal, and the IF signal is output. The output signal from the switch is input to the frequency selection device. The output IF signal is configured to be input to the RF detector and the analog wave synchronous detector, and the RF detector is a signal that is input alternately every predetermined time. The configured to deliver to the control unit is converted into a voltage, the control unit compares the level of the voltage delivered from the RF detector, based on the comparison result, whether there is an abnormality in the signal processor to be monitored And when it is determined that there is an abnormality, the alarm output means is activated to generate an alarm, and the control unit includes a reference value for analog waves and a reference value for digital waves. , Which are set individually in advance, and when determining the presence or absence of an abnormality, an appropriate reference value is automatically applied depending on whether the IF signal input to the RF detector is an analog wave or a digital wave. It is characterized by being configured.

  Furthermore, when the switch is configured to output only the signal on the output side of the device to be monitored by switching the mode, the device having only the signal output system is used as an alarm device for monitoring. It is also possible to do.

  Since the alarm device of the present invention is designed not to monitor only the signal on the output side of the device to be monitored but to compare the signal on the input side and the signal on the output side, Abnormalities can be accurately determined.

  In addition, when the frequency selection device is installed, it can be used as an alarm device for monitoring a signal processor used in the head-end equipment of the CATV broadcasting system, that is, as a TV channel alarm device for CATV, All channels of VHF, UHF, and CATV can be supported.

  Furthermore, since the detector is configured to convert the IF output from the frequency selection device into a voltage, and based on the converted voltage, the control unit compares the signal on the input side with the signal on the output side. The determination criteria can be set in detail according to the characteristics of the device. For example, the determination level can be set in 1 dB steps.

  Hereinafter, preferred embodiments of an “alarm device” according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram of a first embodiment “CATV TV channel alarm device 1” of the present invention. As is apparent from FIG. 1, the TV channel alarm device 1 includes an RF switch 2, 1 frequency selection device 3, second frequency selection device 4, detector (RF detector 5, synchronous detector 6), control unit 7, alarm output means (buzzer 8, display unit 9), and setting unit 10 Has been.

  The TV channel alarm device 1 is installed in the vicinity of the signal processor 55 to be monitored by the alarm device 1 among the signal processors 55 shown in FIG. 2, and the signal processor is supplied from the distributor 54a (or distributor 54b). The RF signal sent to 55 is branched and inputted, and the RF signal sent from the signal processor 55 to the synthesizer 56 is branched and inputted. That is, an RF signal (input-side signal) input to the signal processor 55 to be monitored and an RF signal (output-side signal) output from the signal processor 55 are respectively sent to the TV channel alarm device 1. Connected to input.

  As shown in FIG. 1, in the TV channel alarm device 1, the input side signal and the output side signal are input to the RF switch 2. The RF switch 2 selects and outputs one of the input signals, and the switching of the selection of the output signal is performed regularly (for example, 1). Every second). Accordingly, the RF switch 2 alternately outputs the input-side signal and the output-side signal at regular intervals.

  The signal output from the RF switch 2 is input to the first frequency selection device 3 and the second frequency selection device 4, respectively. These frequency selectors 3 and 4 extract only the broadcast signal of the channel (TV broadcast channel) assigned to the corresponding signal processor 55 and output the IF signal. The setting and changing of the assigned channel can be freely performed by the operator's operation of the setting unit 10, and when the setting unit 10 is operated, each frequency is selected in response to a command from the control unit 7. The assigned channels in the devices 3 and 4 are set or changed.

  The IF signal output from the first frequency selection device 3 is input to the RF detector 5. The RF detector 5 converts the input-side signal and the output-side signal that are alternately input at regular time intervals into a voltage, and sends the voltage to the control unit 7. The control unit 7 compares the conversion voltage level of the signal on the input side with the conversion voltage level of the signal on the output side. If the difference between the two is equal to or less than the reference value, the connected signal processor 55 is “normal”. If the difference between the two exceeds the reference value, it is determined that the signal processor 55 is “abnormal”.

  More specifically, when a broadcast of a channel assigned to the connected signal processor 55 is actually performed, a received signal including the broadcast signal is input to the signal processor 55. However, if the signal processor 55 is operating normally at this time, the RF signal of the channel broadcast is output from the signal processor 55. In this case, the voltage level difference compared in the control unit 7 should be within a certain range (below the reference value set in advance by the administrator). Therefore, in this case, it is determined as “normal”. On the other hand, when the RF signal of the channel broadcast is not output from the signal processor 55 even though the assigned channel is being broadcast, or when the level of the signal on the output side is abnormal The difference in voltage level compared in the control unit 7 exceeds the reference value, and in this case, it is determined as “abnormal”.

  Further, when the channel is not broadcast (such as midnight), the received signal including the broadcast signal is not input to the signal processor 55, and the signal processor 55 is operating normally at this time. In this case, since the RF signal is not output from the signal processor 55, the voltage level difference compared in the control unit 7 should be equal to or less than the reference value. Therefore, in this case, it is determined as “normal”. On the other hand, when the RF signal is output from the signal processor 55 even though the assigned channel is not broadcasted, the voltage level difference compared in the control unit 7 exceeds the reference value. In this case, it is determined as “abnormal”.

  When the control unit 7 determines that “abnormality exists”, the control unit 7 operates the buzzer 8 to emit an alarm sound, and further causes the display unit 9 to display a message indicating that an abnormality has occurred. It should be noted that the “voltage level difference reference value”, which is a determination criterion of “normal” or “abnormal”, can be freely set and changed by operating the setting unit 10.

  Further, the TV channel alarm device 1 is configured to be able to cope with not only analog waves but also digital waves. Specifically, as described above, the signal output from the RF switch 2 is configured to be input not only to the first frequency selection device 3 but also to the second frequency selection device 4 as described above. Similar to the first frequency selection device 3, the second frequency selection device 4 extracts only the broadcast signal of the channel assigned to the corresponding signal processor 55 and outputs the IF signal.

Then, the IF signal output from the second frequency selection device 4 is input to the analog wave synchronous detector 6 (analog detector). The analog wave synchronous detector 6 detects the presence or absence of an analog wave synchronization signal in the input IF signal and outputs the determination result to the control unit 7. Since the conventional analog TV broadcast waves it includes an analog wave of the synchronization signal, when a synchronization signal of an analog wave is detected by the synchronous detector 6 for analog waves, the control unit 7, the TV broadcast If the signal is determined to be an analog wave , on the contrary, if the analog wave synchronization signal is not detected, the control unit 7 determines that the TV broadcast signal is a digital wave.

  As described above, the TV channel alarm device 1 in FIG. 1 can determine whether the TV broadcast signal is an analog wave or a digital wave. Since the voltage level output from the RF detector 5 is different between the analog wave and the digital wave, the “reference value for the difference in voltage level” set as the analog wave determination criterion is used as it is. 1 can not be used (in this case, it cannot be determined accurately), but the TV channel alarm device 1 in FIG. 1 can determine the type of broadcast signal (analog / digital separately). The “reference value” for analog waves and the “reference value” for digital waves are individually set in advance in the control unit 7, and an appropriate “reference value” is set according to the type of broadcast signal to be input. Can be configured to be automatically applied, and in any case, it is possible to accurately determine “normal” or “abnormal”.

  Here, as an embodiment of the “alarm device” according to the present invention, the “TV channel alarm device for CATV” targeting a signal processor has been described, but the device targeted for monitoring is not necessarily a signal processor. However, the present invention is not limited to this, and it can also be used as an alarm device for monitoring a modulator (modulator), various switching devices, an amplifier and the like.

  In addition, by switching the mode of the RF switch 2 shown in FIG. 1, it is possible to transmit only the signal on the output side to the RF detector 5 or the like so that detection and determination can be performed. The present invention can be applied not only to a device having both an input system and an output system, but also to a device having only an output system.

1 is a configuration diagram of an alarm device 1 according to a first embodiment of the present invention. The block diagram of the general head end equipment 51. FIG.

Explanation of symbols

1: TV channel alarm device,
2: RF switch,
3: First frequency selection device,
4: Second frequency selection device,
5: RF detector,
6: Synchronous detector,
7: Control unit,
8: Buzzer
9: Display section
10: Setting section,
51: Headend equipment,
52: VHF receiving antenna,
53: UHF receiving antenna
54a: distributor
54b: Distributor,
55, 55a to 55h: signal processor,
56: Synthesizer,
57: Main line

Claims (1)

A switch, a frequency selection device, an RF detector, an analog wave synchronous detector, a control unit, and an alarm output means;
To the switch, a signal input to the signal processor to be monitored and a signal output from the signal processor are input, and from the switch, these signals are alternately output at regular intervals,
The frequency selection device is configured to extract only the broadcast signal of the assigned channel from the input signal and output the IF signal,
An output signal from the switch is input to the frequency selection device, and an IF signal output from the frequency selection device is input to the RF detector and the analog wave synchronous detector. ,
The RF detector is configured to convert a signal input alternately every predetermined time into a voltage and send it to the control unit,
The analog wave synchronous detector determines whether the input IF signal is an analog wave or a digital wave by detecting the presence of an analog wave synchronization signal in the input IF signal. ,
When the controller compares the level of the voltage sent from the RF detector and determines whether there is an abnormality in the signal processor to be monitored based on the comparison result, , Configured to emit an alarm by operating the alarm output means,
In the control unit, a reference value for analog wave and a reference value for digital wave are individually set in advance, and the IF signal input to the RF detector is analog wave when determining the presence or absence of abnormality. A TV TV alarm device for CATV, wherein an appropriate reference value is automatically applied depending on whether the signal is a digital wave or not .