JPH01265796A - Catv repeater - Google Patents

Abstract

PURPOSE:To facilitate the maintenance and management of a CATV network by allowing a central monitor station to monitor an outgoing pilot signal level and an incoming pilot signal level in each repeater. CONSTITUTION:The central monitor station 31 monitors repeaters 33, 34 connecting to a transmission line 32. The repeaters 33, 34 has a function of monitoring the incoming pilot signal level and sending the resulting monitor signal to the incoming transmission line 32 and the central monitor station 31 monitors the level state of the outgoing pilot signal and the incoming pilot signal of the repeaters 33, 34. Thus, the maintenance and management of the CATV network are facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a CA TV repeater constituting a CATV network.

Conventional technology Conventionally, a CA TV repeater has a function of transmitting a sine wave signal having a frequency unique to the repeater to the master 8 in the upstream direction as a monitoring signal, and also has the function of transmitting a sine wave signal having a frequency unique to the repeater as a monitoring signal in the upstream direction. At times, an amplitude modulated signal is generated using this sine wave signal as a carrier wave, and has the function of sending it to the upstream transmission path as a signal indicating the monitoring status, and by detecting the amplitude modulated signal at the central monitoring station, the corresponding repeater was conducting surveillance.

Problems to be Solved by the Invention The conventional CA TV repeater described above monitors the level of the pylon 1 signal in the downward direction, but has the disadvantage that it does not monitor the level of the pilot signal in the upstream direction. .

The present invention has been made in view of the above-mentioned conventional situation,
Therefore, an object of the present invention is to have each repeater monitor the upstream pilot signal level and send a monitoring signal based on the result to the upstream transmission path, and a central monitoring station to monitor the downstream pilot signal level of each repeater. A new CAT that can monitor the level status of the direction pylon l-signal and the upstream pylon l-signal.
The goal is to form a V network.

Means for Solving the Problems In order to achieve the above object, the CATV repeater according to the present invention, during normal operation, sends a sine wave signal having a frequency unique to the repeater as a monitoring signal to the transmission line in the direction of the cable. When the downlink pilot signal level exceeds the threshold value, it generates an amplitude modulation signal using a sine wave signal as a carrier wave, and sends the signal excluding the lower side band to the 11th direction transmission line. In addition, when the pilot signal level in the direction of the arrow exceeds the reference value, it generates an amplitude modulation signal using a sine wave signal as a carrier wave, and sends the signal excluding the lower sideband of that signal to the upstream transmission path. Prepared and configured.

Embodiment Next, a preferred embodiment of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a CATV repeater according to the present invention.

Referring to FIG. 1, the central monitoring station 3I monitors a repeater 33 and a repeater 34 connected to the transmission line 32. This carrier signal is sent to the monitoring signal switching section 4.
At the same time as the signal is input to the modulator 7, the signal is about to be input to the modulator 46.

In the modulation section 46, the signal amplitude-modulated by the modulation signal generated from the modulation signal generation section 45 is manually transmitted to a filtering section 42 having a characteristic of removing lower sideband waves and a filtering section 43 having a characteristic of removing sideband waves. be done.

When the level of the downstream pylon I signal exceeds the reference value, the downstream amplifier 37 detects this state and outputs the selection signal 40 to the monitoring signal switching section 47.

At this time, the supervisory signal switching unit 47 selects only the supervisory signal from which the lower sideband has been removed from among the three human signals, and outputs it to the coupler 36 . This monitoring signal passes through the directional coupler 35 and is output to the transmission path 32 in the upstream direction, and the central monitoring station 3 detects the frequency component of the monitoring signal to detect the monitoring signal of the frequency of the repeater 33. Detects the absence of lower sideband waves,
At 33, the repeater learns that the level of the downlink pilot signal has exceeded the reference value.

When the level of the uplink pylon 1 exceeds the reference value, the -] direction amplifier 39 detects this state and outputs the selection signal 41 to the monitoring signal switching section 47.

At this time, the supervisory signal switching unit 47 selects the supervisory signal from which the upper sideband has been removed from among the three inputs, and selects the supervisory signal from which the upper sideband has been removed, and switches the supervisory signal to the upstream transmission path 32 as in the case of the downstream pilot signal described above.
Send to. By detecting the frequency component of the monitoring signal, the central monitoring station 31 detects that there is no upper side (IF wave) of the monitoring signal of the frequency specific to the repeater 3; Know that the level has exceeded the standard value.

When the levels of the -1 direction pilot signal and the down direction pilot signal are both at the reference value and are operating normally, the selection signal 40 and the selection signal 4 are sent to the monitoring signal switching section 47.
1 is not input, and at this time, the sine wave carrier signal generator 4
The carrier signal generated from 4 is selected and sent to the upstream transmission path 3z. The central monitoring station 31 analyzes the frequency components of the monitoring signal sent from the repeater 33, detects that the signal is a sine wave, and transmits the signal to the repeater 33.
know that it is working properly.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the central monitoring station can monitor the status of the tridirectional pilot signal level and the upstream pilot signal level in each repeater.
This has the effect of making maintenance and management of the CA TV network easier.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the functions within a C A TV network and repeater according to the present invention. 31, Central monitoring station, 32. ,,transmission line,33. ,,
Relay, 34, Relay, 35. ,,directional coupler,
36. , ,Coupler 37 , ,Amplifier 3g , ,Directional coupler 341 . ,,amplifier 40, ,selection signal,
41. ,,selection signal,42. ,,filtering section 43, ,filtering section 44. , , carrier signal generation section, 4, , modulation signal generation section, 46. ,,modulation section, 47. ,, Monitoring signal switching unit patent applicant 1” Hondenki Co., Ltd. Agent Patent attorney Yutabe Kumagai 61

Claims (1)

[Claims] In a CATV network where the operating status of CATV repeaters is monitored by a central monitoring station, when the pilot signal level in the downstream direction of the transmission path exceeds a reference value, an amplitude modulated signal excluding the lower sideband is used as a monitoring signal in the upstream direction. C, characterized in that it has a function of transmitting to the transmission path and a function of transmitting an amplitude modulated signal excluding the upper sideband to the upstream transmission path as a monitoring signal when the upstream pilot signal level exceeds a reference value.
ATV repeater.