JPH0638343U - Equipment for satellite broadcasting reception - Google Patents

Abstract

(57) [Abstract] [Purpose] In a television receiving system in which a mixed signal of BS, UHF and VHF signals is supplied to a BS tuner through a coaxial cable, a booster having a BS-IF band amplifier in the middle of the coaxial cable. A circuit can be inserted. [Structure] A coaxial cable 14 in which a booster circuit 15 is coupled to a BS tuner 6 via a BS / U, VHF mixer.
Has been inserted in the middle of. The booster circuit 15 includes a mixing circuit unit S1, a demultiplexing circuit unit M1, a BS-IF amplifying unit B1 and the like, and a direct current voltage is supplied to the B1 from the BS tuner 6 via the coaxial cable 14. A monitor output branch section D1 may be provided between the branching circuit section M1 and the output terminal OUT.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a satellite broadcast receiving device, and more particularly, to a simple device that enables preferable satellite broadcast wave reception by inserting it into an existing VHF / IHF broadcast wave receiving system.

[0002]

[Prior art]

 A television system that receives 950 to 1750 MHZ (1035 to 1335 MHZ in the case of Japan), which is the first IF band of satellite television broadcasting, has, for example, the configuration shown in FIG. In the figure, 1 is a BS antenna, 2 is a UHF antenna, 3 is a VHF antenna, 4 is a BS converter, 5 is a UHF / VHF mixer, 6 is a BS tuner, 7 is a UHF / VHF demultiplexer, and 8 is television reception. Machines 9 and 10 are coaxial cables.

As is well known, the received signal in the BS-IF band naturally has a large loss in the coaxial cable as compared with that in the conventional VHF and UHF bands. Normally, the distance over which a BS-IF band reception signal can be transmitted without using a booster is, for example, 58 m using TV EFCY of JIS cable. However, this is a case where one TV receiver is used, and in recent years, there is a tendency for common reception by a plurality of TV receivers to become common even in general households. In such a case, a distributor is required, In addition, because it is necessary to transmit with a single coaxial cable, it is necessary to mix or demultiplex the existing VHF and UHF band received signals, so the cable length inevitably becomes shorter due to the loss of each device, The use of boosters is inevitably required.

In this case, if the booster is planned to be used from the beginning of designing the receiving equipment and a construction is carried out, a commercially available BS-IF band amplifier can be used. It requires a power source and is expensive and requires the above power source, which is very inconvenient when adding an additional unit.

In order to improve this point, a television joint reception system having a configuration as shown in FIG. 7 has also been proposed. In the figure, 11 is a 4-distributor, 12 is a BS / U, VHF mixer, 13 is a BS-IF line booster, and a DC voltage is supplied to the booster 13 and the BS converter 4 from the BS tuner 6 through the coaxial cable 14. 15V is supplied.

[0006]

[Problems to be solved by the device]

 However, in the system configuration of FIG. 7, since a mixed signal of VHF, UHF and BS-IF is transmitted via the coaxial cable 14, it is not possible to insert an amplifier in the cable, and the installation location is It is limited and cannot be used for line expansion. In addition, in order to judge whether the output level of the booster 13 is proper, the output side coaxial cable of the booster 13 must be removed, so that the DC voltage cannot be supplied to the BS converter 4 and the booster 13 and the operation becomes impossible. Therefore, it is necessary to use an external DC power supply and a power inserter in order to enable the above determination, which makes maintenance and inspection difficult and causes problems such as interruption of transmission signals.

Therefore, the object of the present invention is to install a booster circuit in the middle of a coaxial cable through which a mixed signal of VHF, UHF and BS-IF bands is transmitted even if the system has the same configuration as the above-mentioned conventional system. Is possible. Another object of the present invention is to easily monitor the output of the booster circuit.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention has a BS antenna connected to one input of a BS / U, VHF mixer via a BS converter, and a UHF antenna and a VHF antenna via a UHF / VHF mixer. BS / U, VHF mixing in a satellite broadcasting receiving device connected to the other input of the BS / U, VHF mixing and the output of the BS / U, VHF mixing is connected to the BS tuner by a coaxial cable. Circuit is connected in the middle of the coaxial cable between the receiver and the BS tuner. This booster circuit is connected to the output terminal and the VHF / UHF band low-pass filter and BS band high-pass filter connected to the input terminal. It has a mixing circuit section and a BS-IF band amplification section, the low-pass filter is connected to one input of the mixing circuit section, and the high-pass filter is the BS. It is connected to the other output of the mixer circuit section via the IF band amplification section, and the DC voltage from the BS tuner is sent from the output terminal to the BS-IF band amplification section via the coaxial cable and to the BS converter via the input terminal. The point is that it is configured to be supplied.

Further, in the satellite broadcast receiving device, the booster circuit has a monitor terminal, a monitor output branch circuit section is provided between the mixing circuit section and the output terminal, and the monitor output branch circuit section is monitored. You may connect to the terminal.

[0010]

[Action]

 In the present invention, the booster circuit having the BS-IF band amplifier unit is connected to the BS tuner by the coaxial cable via the BS / U, VHF mixer to which the BS, UHF and VHF television receiving antennas are connected. It can be installed in the middle of the above coaxial cable of the television receiving system. In this booster circuit, the BS-IF band amplifying unit is operated by being supplied with a DC voltage from the BS tuner via a coaxial cable, allowing the VHF and UHF signals to pass and increasing only the BS-IF band signal. Compensates for loss in coaxial cables, distributors, etc. Further, in this case, the output level of the booster circuit can be easily monitored by providing the monitor output branch circuit section and the monitor terminal in the booster circuit.

[0011]

【Example】

 The present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 shows a television co-reception system in which the BS-IF line booster circuit 15 of the present invention is used. A similar circuit is shown, and FIG. 2 shows an embodiment of the booster circuit 15.

In FIG. 2, IN is an input terminal on the antenna side, OUT is an output terminal on the receiver side, M is a monitor terminal, B1 is a high frequency amplifier for the BS-IF band, P1 is a pass circuit for UHF and VHF signals, and S1 is BS. -Low-pass filter LP in IF / U, VHF branch circuit ₁ And high pass filter HP₁Consists of. M1 is a BS-IF / U, VHF mixing circuit unit, which is a low-pass filter LP.₂And high pass filter HP₂Consists of. DC is a DC voltage supply circuit, C1 and C2 are DC blocking high frequency passing capacitors, L1 and L2 are high frequency blocking DC passing choke coils, D1 is a monitor output branch circuit, and LED is an indicator lamp.

The booster circuit 15 is inserted in the middle of the coaxial cable 14, and the mixed signal of BS-IF, UHF, and VHF supplied to the input terminal IN is BS-IF and UHF, VHF signals by the demultiplexer S1. The VHF and UHF signals are passed through the pass circuit P1, the BS-IF signal is amplified by the amplifier B1, the UHF and VHF signals are mixed again in the mixer M1, and the output branch circuit D1 for monitoring is used. Is transmitted from the output terminal OUT to the receiver side by the coaxial cable 14.

Since the booster circuit constitutes a closed loop circuit by the demultiplexer S1, the mixer M1 and the amplifier B1, the frequency characteristic of the insertion loss of the demultiplexer S1 and the mixer M1 is a problem. Becomes That is, the commercially available BS-IF / U, VHF demultiplexer and mixer are not designed for the system as described above, and the terminal loss between BS and UV is not satisfactory. If these are used, the closed loop circuit may be oscillated due to the feedback of the amplified signal by the booster in the BS-IF band.

For example, the characteristics of the equipment used for receiving Japanese TV broadcasting are that the insertion loss in the U and VHF passbands 76 to 770 MHZ is 1.3 dB or more, and the stopband attenuation in the stopbands 1035 to 1335 MHZ. Is 20 dB or less, conversely, the insertion loss in the BS-IF pass band 1035 to 1335 MHZ is 1.5 dB or less, and the stop band attenuation amount in the stop band 76 to 770 MHZ is 20 dB or more. However, since there is no stipulation for the attenuation amount in the intermediate band 770 to 1035 MHZ, the characteristic curve H1 of the high-pass filter and the characteristic curve L1 of the low-pass filter that form the above-mentioned demultiplexer and mixer are as shown in FIG. Therefore, at the cross point of about 900 MHz of both characteristic curves, there is only about 5 to 10 dB of attenuation, and therefore the loss between terminals ab and cd shown in FIG. 8 is about 10 to 20 dB and between a and d. The total loss between terminals varies from 20 to 40 dB. In addition, even in the existing booster, the stop band is defined by 76 to 770 MHZ, and no consideration is given to the range from 770 to 1035 MHZ, and 900 MHZ close to the amplification band has almost the same gain as the amplification band. . Therefore, when the total terminal loss between a and d is small, feedback may occur and oscillate. If such oscillation occurs, it not only hinders the own system, but also causes the radio waves emitted by other televisions to oscillate. It interferes with the receiver.

Therefore, in the present invention, it is preferable to use, for example, the high-pass filter and the low-pass filter having the characteristics shown in FIG. 4, which form the branching circuit section S1 and the mixing circuit M1. That is, as shown in FIG. 4, the demultiplexing circuit unit S1 and the mixing circuit unit M1 are low-pass filters LP ₁ and LP ₂ having an insertion loss of 1.2 dB in the pass band 76 to 770 MHZ and a stop band attenuation amount of 35 dB in the stop band 870 MHZ or more. , High-pass filters HP ₁ and HP ₂ having an insertion loss of 1.2 dB in the pass bands 1035 to 1335 MHZ and a stop band attenuation amount of 35 dB in the stop band of 825 MHZ or less are used. According to the combination of such filters, the attenuation amount of 25 dB is obtained at the cross point of the characteristic curves of both filters of about 860 MHZ, so that the terminal loss between ab and cd is 35 dB or more between 0 to 1500 MHZ. Since the total inter-terminal loss is 70 dB, stable demultiplexing mixing is possible without oscillation even if the amplifier B1 has a gain of 40 dB.

The demultiplexing circuit unit and the mixing circuit unit are a combination of a low pass filter and a high pass filter, but may be a combination of a low pass filter and a band pass filter. Although the output level of the booster circuit can be arbitrarily monitored by the monitor output branch circuit D1, it is preferable to use, for example, the unidirectional coupler shown in FIG. 5 as the monitor output branch circuit. The directional coupler is selected so that the insertion loss between the input and the output is about 1 dB and the coupling loss between the monitor output and the input is -20 dB or -10 dB lower than the output level of the BS-IF line booster circuit.

[0018]

[Effect of device]

 As is apparent from the above description, according to the device having the BS-IF band amplifying unit of the present invention, since the VHF and UHF television band pass circuits are provided, the VHF and UHF signals are transmitted to the coaxial cable. However, the BS-IF signal can be easily transmitted using the same coaxial cable, and it becomes possible to supply the VHF, UHF and BS-IF signals to a plurality of television receivers, and the above-mentioned equipment. The installation location is not limited, and the system can be expanded easily, so the system has a high degree of freedom. Further, since the pass-through circuit is built-in, an external demultiplexer and mixer are not required, so that stable and easy transmission to VHF and UHF signals is possible. Furthermore, if a monitor output branch circuit is provided, the output level of the booster can be easily confirmed without interrupting signal transmission through the coaxial cable. Moreover, since the amplifier B1 is supplied with the DC voltage from the BS tuner via the coaxial cable together with the BS converter, an external DC power source and a power source inserter are not required.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an embodiment of the present invention.

FIG. 3 is a characteristic diagram of commercially available demultiplexing and mixing circuit low-pass and high-pass filters.

FIG. 4 is a characteristic diagram of low-pass and high-pass filters used in the demultiplexing and mixing circuit of the present invention.

FIG. 5 is a diagram showing an example of a monitor output branch circuit.

FIG. 6 is a schematic diagram illustrating a conventional BS-IF, UHF and VHF television receiving system.

FIG. 7 is a schematic diagram illustrating a conventional BS-IF, UHF and VHF television receiving system.

FIG. 8 is a schematic diagram showing an embodiment of the present invention.

[Explanation of symbols]

S1 BS-IF / U, VHF demultiplexing circuit unit M1 BS-IF / U, VHF mixing circuit unit LP ₁ , LP ₂ low pass filter HP ₁ , HP ₂ high pass filter B1 BS-IF band high frequency amplifier D1 monitor output branch Circuit 14 Coaxial cable 15 BS-IF line booster circuit

Claims (2)

[Scope of utility model registration request] 1. A BS antenna is connected via a BS converter to one input of a BS / U, VHF mixer, and UH
The F antenna and the VHF antenna are connected to the other input of the BS / U, VHF mixer via the UHF / VHF mixer, and the output of the BS / U, VHF mixer is connected to the BS tuner by a coaxial cable. In the satellite broadcasting receiving device, a booster circuit is connected in the middle of the coaxial cable between the BS / U, VHF mixer and the BS tuner,
This booster circuit has VHF / UH connected to the input terminal.
An F-band low-pass filter and a BS-band high-pass filter, a mixing circuit unit connected to an output terminal, and a BS-IF band amplifying unit are provided, and the low-pass filter is connected to one input of the mixing circuit unit, The high-pass filter is connected to the other output of the mixing circuit section through the BS-IF band amplification section, and the DC voltage from the BS tuner is transmitted from the output terminal to the BS-IF band amplification section and the input terminal by the coaxial cable. A satellite broadcast receiving device, characterized in that it is configured to be supplied to a BS converter. 2. The booster circuit has a monitor terminal,
The satellite broadcast receiving apparatus according to claim 1, wherein a monitor output branch circuit section is provided between the mixing circuit section and the output terminal, and the monitor output branch circuit section is connected to the monitor terminal.