KR20030010481A - Public device for Hybrid Fiber Coaxial - Google Patents

Abstract

According to an aspect of the present invention, in an optical fiber coaxial cable (HFC: hybrid fiber coaxial) including a noise filter for removing noise included in a frequency, the noise filter has an RF (Radio Frequency), which is an uplink frequency, and an intermediate frequency (IF). 1) output to the first mixer, SAW (Surface Acoustic Wave) filter to remove noise by filtering the IF (Intermediate Frequency) output from the first mixer, IF (Surface Acoustic Wave) filter IF A second mixer for outputting an intermediate frequency (RF) as a radio frequency (RF), a frequency synthesizer for converting a frequency, and the frequency synthesizer are controlled to output a radio frequency (RF), which is an uplink frequency from the first mixer, as an intermediate frequency (IF). IF (Local Oscillator Frequency) is added to RF (Radio Frequency), which is the uplink frequency, or IF (Intermediate) from which noise is removed through Surface Acoustic Wave (SAW) filter in the second mixer. And a controller for controlling the frequency synthesizer to remove a local oscillator frequency (LOF) from the intermediate frequency (IF) such that a frequency is originally a radio frequency (RF).

Therefore, according to the present invention, a plurality of bidirectional services can be implemented in one network by effectively removing the uplink noise components, and the effect of quickly adapting to various field situations can be obtained.

Description

Public device for optical coaxial hybrid cable network {Public device for Hybrid Fiber Coaxial}

The present invention relates to a hybrid fiber coaxial cable network (HFC), and more particularly to an optical fiber coaxial mixed cable network (HFC) capable of effectively eliminating uplink noise components to implement a plurality of bidirectional services in one network. Hybrid fiber coaxial noise filter.

In the related art, as shown in FIG. 1A, an ISP (Internet Service Provider) service (B) for providing an optical cable Internet service is installed in a hybrid fiber coaxial (HFC) in which a cable TV service (A) is installed. The network was constructed.

In the cable TV service (A) and ISP (Internet Service Provider) service (B) which provide the above-mentioned two-way service, the downlink signal can be appropriately serviced, but the upstream service is an unwanted noise component (power noise) coming from each home. It is not possible to separate the correct upstream signal and it is impossible to monitor the cable network.

In particular, the ISP (B) service, which provides the optical cable Internet service, cannot receive the correct signal of the upstream cable modem and thus exhibits a significant degradation in communication settings and speeds with the cable modem. have.

As described above, the ISP (B) service (B) and the cable TV service (A), which are intended to provide two-way services, cannot receive the respective uplink signals accurately and thus cannot be serviced. Likewise, each service provider installs its own new self-network to minimize upstream consonants and provide services.

However, when providing a service by minimizing upstream noise components by installing a unique new self-network as described above, performance for cost is very inefficient.

1 (C) shows an Internet Service Provider (BIS) service (B) for providing an optical cable Internet service in a hybrid fiber coaxial (HFC) in which a cable TV service (A) is installed, The noise filter 10 is provided to the cable of the ISP (Internet Service Provider) service (B) side.

Although the noise filter 10 of FIG. 1C is installed to remove noise mixed with an upstream signal received by the ISP (Internet Service Provider) service B, the noise filter 10 is a specific frequency channel. In other words, it can be used only for a specific bidirectional service by using a filtering technique that passes only a specific uplink channel.

The uplink frequency channel of the bidirectional service using the hybrid fiber coaxial (HFC) consists of 72 channels.

When using a noise filter for filtering by passing only a specific uplink frequency channel as described above, each noise filter product for the 72 uplink frequency channels should be considered, which causes a problem of very slow field response.

Accordingly, an object of the present invention is to solve the conventional problems, and the purpose of the present invention is to effectively remove the upstream noise component present in the premises network to enable various bidirectional services in the hybrid fiber coaxial (HFC). have.

1 is a view showing the configuration of a hybrid fiber coaxial (HFC) in accordance with the prior art.

2 is a block diagram of a noise filter according to the present invention;

Figure 3 is a view showing the configuration of a hybrid fiber coaxial (HFC: Optical Fiber Coaxial Cable network) installed with a noise filter according to the present invention.

*** Explanation of symbols for the main parts of the drawing ***

100: noise filter according to the present invention

101: duplexer 102: the first mixer

103: SAW (Surface Acoustic Wave) filter 104: second mixer

105: Local 106: Controller

107: Amplifier 200: Dividers

The present invention for achieving the above object, the bidirectional premises amplifier designed for indoor facilities, bidirectional trunk amplifier for compensating for the level reduction of the signal in the coaxial cable, divider for classifying the communication service according to the user's request, the In an optical fiber coaxial cable (HFC) composed of a noise filter disposed on a coaxial cable separated from a divider and removing noise included in a frequency, the noise filter has an upper frequency RF (Radio Frequency). A first mixer outputted at an Intermediate Frequency (SA), a Surface Acoustic Wave (SAW) filter for removing noise by filtering an IF (Intermediate Frequency) output from the first mixer, and a noise removed from the SAW (Surface Acoustic Wave) filter A second mixer for outputting IF (Intermediate Frequency) as RF (Radio Frequency), a frequency synthesizer for converting frequency, and the frequency sum Add a Local Oscillator Frequency (LOF) to the RF (Radio Frequency) which is the uplink frequency so that the RF (Radio Frequency) which is an uplink frequency in the first mixer is output as an IF (Intermediate Frequency), or the second mixer In order to remove the Local Oscillator Frequency (LOF) from the IF (Intermediate Frequency) so that the IF (Intermediate Frequency) from which the noise is removed through the Surface Acoustic Wave (SAW) filter becomes the RF (Radio Frequency) which is the original uplink frequency. A controller for controlling the frequency synthesizer is included.

Hereinafter, with reference to the accompanying drawings, the present invention to achieve the above object will be described in detail.

2 shows a block diagram of a noise filter according to the present invention.

As shown in FIG. 2, in the noise filter according to the present invention, a duplexer 101 for separating up and down frequencies, and an RF (Radio Frequency) which is an uplink frequency separated from the duplexer 101 are combined with a LOF (Local Oscillator Frequency). A first mixer 102 outputted at an Intermediate Frequency, a surface acoustic wave (SAW) filter 103 for removing noise by filtering the IF (Intermediate Frequency) output from the first mixer 102, and the SAW The IF (Local Oscillator Frequency) added by the first mixer is removed from the IF (Intermediate Frequency) from which noise is removed through the Surface Acoustic Wave (103) filter 103, and is output as an RF (Radio Frequency) which is originally an uplink frequency. Noise is removed through the SAW (Surface Acoustic Wave) filter 103 by adding a LOF (Local Oscillator Frequency) to the 2nd mixer 104 and the RF (Radio Frequency) which is an uplink frequency in the first mixer 102. The first at an IF (Intermediate Frequency) To remove the LOF (Local Oscillator Frequency) was added in the book consists of a controller 106 for controlling a frequency synthesizer 105 for generating a specific frequency.

When the noise filter configured as described above is installed in an optical fiber coaxial cable (HFC), noise mixed in an uplink frequency can be effectively removed, so that an accurate uplink frequency can be received by the operator.

Therefore, two-way services such as cable TV service and ISP (Internet Service Provider) service can reduce the cost when constructing a network in the hybrid fiber coaxial (HFC).

In addition, the noise filter according to the present invention has a built-in controller for converting the uplink frequency channel, has a structure that can change the channel while filtering a specific uplink frequency channel of the uplink channel having 72 channels Therefore, it can be applied to various field situations.

An optical coaxial mixed cable network (HFC: hybrid fiber) provided with a noise filter according to the present invention is shown in FIG. 3.

In FIG. 3, the downlink frequency sent by the provider side is configured and transmitted by a simple transfer path, and the uplink frequency RF (Radio Frequency) transmitted by the subscriber side is separated by the subscriber 200 through the divider 200.

RF (Radio Frequency), which is an uplink frequency separated from the divider 200, passes through the noise filter 100 installed in the corresponding cable of each operator.

In FIG. 2, RF (Radio Frequency), which is the uplink frequency passing through the noise filter, passes through a duplexer 101 that separates up and down frequencies.

Radio frequency (RF), which is an uplink frequency passed through the duplexer 101, is combined with a local oscillator frequency (LOF) sent by the frequency synthesizer 105 under the control of the controller 106 in the first mixer 102, and thus, an IF of 70 MHz ( Output Intermediate Frequency).

The noise filter according to the present invention removes noise using a surface acoustic wave (SAW) filter 103 that performs IF (Intermediate Frequency) filtering, which allows only a specific uplink frequency to pass and effectively removes noise components.

Therefore, RF (Radio Frequency), which is the uplink frequency to remove noise, should be IF (Intermediate Frequency) using 70MHz.

In addition, according to a specific uplink channel of the 72 uplink channels, the controller 106 has an RF (Radio Frequency) of 70 MHz, which is an uplink frequency using 5 to 42 MHz input to the first mixer 102. The frequency synthesizer 105 is controlled to be

Under the control of the controller 106, the frequency synthesizer 105 adds a local oscillator frequency (LOF) using 75 to 112 MHz to a radio frequency (RF), which is an up frequency using the 5 to 42 MHz. RF (Radio Frequency) is set to IF (Intermediate Frequency) using 70MHz.

The intermediate frequency (IF) using the 70 MHz is filtered by the surface acoustic wave (SAW) filter 103 to remove noise.

IF (Intermediate Frequency) using the 70MHz noise is removed is the second mixer 104, RF (Radio Frequency) that is an uplink frequency using the original 5 ~ 42MHz, so that the controller 106 is a frequency synthesizer ( 105).

Under the control of the controller 106, the frequency synthesizer 105 removes a local oscillator frequency (LOF) added by the first mixer 102 from an IF (intermediate frequency) from which noise is removed, thereby reducing the original up frequency. RF (Radio Frequency) is outputted and sent to the operator.

Therefore, the provider side can secure only its own uplink frequency, and noise components included in the uplink frequency can be eliminated to reduce the bidirectional communication setting and speed reduction as much as possible.

The amplifiers 107 shown in FIG. 2 are configured according to an up / down conversion in which a LOF (Local Oscillator Frequency) is added to and removed from an uplink frequency in the first mixer 102 and the second mixer 104. Compensate for damage.

The noise filter according to the present invention can be modified to provide more services through wideband channel filtering to accommodate VOD service or Internet service requiring high-speed data. By applying only the uplink filtering structure, it can be transformed into a single service.

Therefore, according to the present invention, a noise filter is installed in a hybrid fiber coaxial (HFC) to smoothly receive an uplink signal transmitted by lower cable modems at a service side of a cable TV and an ISP (Internet Service Provider). By doing so, the interactive service provider can have an efficient market response capability by minimizing the cost and time of installing the new dedicated network, and can respond quickly to various field situations.

In addition, it may have the effect of providing a service by installing a plurality of bidirectional services in a conventional hybrid fiber coaxial cable (HFC: installed).

Claims (1)

Bidirectional internal amplifier designed for indoor facilities, Bidirectional trunk amplifier for compensating signal level drop in coaxial cable, Divider classifying communication service according to user's request, Coaxial cable separate from the divider and included in frequency In optical fiber coaxial cable (HFC) composed of a noise filter to remove noise, The noise filter includes a first mixer in which an uplink frequency of RF (Radio Frequency) is output as IF (Intermediate Frequency), and an SAW (Surface Acoustic Wave) for filtering out IF (Intermediate Frequency) output from the first mixer to remove noise A second mixer for outputting IF (Intermediate Frequency) from which noise is removed from the SAW filter, a second synthesizer for outputting a radio frequency (RF), a frequency synthesizer for converting a frequency, and the first synthesizer by controlling the frequency synthesizer. Add a Local Oscillator Frequency (LOF) to the RF (Radio Frequency) so that the uplink frequency is output as an IF (Intermediate Frequency), or SAW (Surface Acoustic Wave) in the second mixer It is also possible to remove LOF (Local Oscillator Frequency) from the IF (Intermediate Frequency) so that the IF (Intermediate Frequency) from which the noise is removed through the filter becomes the original RF (Radio Frequency). Guangdong axis mixture characterized in that includes a controller that controls the frequency synthesizer cable network (HFC: Hybrid Fiber Coaxial).