JP2002300421A - Series unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adequately demodulate television signals in the VHF and UHF bands, even if television signals are contained in the BS and CS bands. SOLUTION: The series unit 1, having a distributor circuit 7 for distributing television signals from an input terminal 6 to output a plurality of output terminals 4, 5. A distribution line for the specified output terminal 4 includes a lowpass filter 8, which attenuates or cuts television signals in the BS and CS bands but passes television signals in the VHF and UHF bands.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial unit which is installed on a wall surface of a room and supplies a television signal to a television receiver.

[0002]

2. Description of the Related Art Conventionally, a serial unit for supplying television signals of VHF, UHF, CATV, BS and CS to a television receiver has a plurality of output terminals, for example, two output terminals. A television signal is input from a coaxial cable connected to the terminal, divided into two by a distribution circuit, and supplied to each output terminal.

[0003]

However, in such a conventional series unit, VHF and UHF
When a television signal including a wide band channel (for example, 24 channels) including high frequencies of BS and CS is input to a television receiver that demodulates only a television signal of a (CATV) band, the total of the television signal is input to a tuner input unit. There is a problem that the power is increased to cause signal saturation (saturation), noise is generated, and the S / N ratio is deteriorated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a serial unit which can appropriately perform demodulation operation without deterioration of VHF and UHF band television signals even when BS and CS band television signals are included. And

[0005]

In order to achieve this object, the present invention is configured as follows. The present invention provides a series unit that distributes a television signal from an input terminal to output to a plurality of output terminals, and attenuates or cuts an unnecessary television signal band in the television signal to a distribution line for a specific output terminal. An output filter is provided.

Here, the filter of the series unit is a low-pass filter that attenuates or cuts the television signal band of BS and CS and passes the television signal band of VHF and UHF. Therefore, by connecting a television receiver that demodulates only the television signals in the VHF and UHF bands to the output terminal provided with the low-pass filter, the total power at the tuner input section is reduced to an appropriate level, resulting in signal saturation. To prevent noise generation.

Further, a switch for selectively inserting and connecting a low-pass filter to the distribution line is provided.
TV signals in the F, UHF, BS, and CS bands and TV signals in only the VHF and UHF television signal bands can be selected.

In the series unit of the present invention,
VHF and UHF are connected to one distribution line of the two output terminals.
A high-pass filter is provided to attenuate or cut the TV signal band of and pass the TV signal band of BS and CS,
The other distribution line may be provided with a low-pass filter that attenuates or cuts the BS and CS television signal bands and passes the VHF and UHF television signal bands. Thus, the output terminal can be used as a dedicated output terminal for television signals in the VHF, UHF, BS and CS bands and a dedicated output terminal for television signals in VHF and UHF.

Also in this case, two switches for selectively inserting and connecting each of the high-pass filter and the low-pass filter to the distribution line are provided, and it is possible to selectively use the dedicated output terminal or not.

Further, in the serial unit of the present invention, the television signal from the input terminal is distributed to three output terminals, and the VHF and UHF television signal bands are attenuated or cut by the distribution line to the first output terminal. And a high-pass filter for passing the BS and CS television signal bands.
Is provided with a low-pass filter that attenuates or cuts the television signal band of BS and CS and passes the television signal band of VHF and UHF, and the distribution line to the third output terminal is directly connected. To do.

In this case, the second output terminal is used as an output terminal for the CATV signal, and is also used as an input terminal for the upstream CATV signal. The directly connected third output terminal is used as an input terminal for a CATV upstream signal and an output terminal for CATV, BS, and CS.

[0012]

1 is an explanatory view of a series unit according to the present invention. FIG. 1 (A) is a front view, FIG. 1 (B) is a side view, and FIG. 1 (C) is a circuit diagram. ing.

FIG. 1A shows a series unit 1 according to the present invention.
As shown in (B), it is composed of a series unit main body 2 and a terminal block 3. The series unit main body 2 is a metal member formed by, for example, aluminum die casting, and the terminal block 3 is formed of a synthetic resin.

Behind the serial unit main body 2 is an input terminal 6
Are connected to connect a coaxial cable.

In this embodiment, the terminal block 3 is provided with two first output terminals 4 and two second output terminals 5 above and below. The first output terminal 4 and the second output terminal 5 function as branch terminals for the input of a television signal from a rear input terminal, and are connected to a television terminal of a television receiver.

In the circuit of the series unit of the present invention shown in FIG. 1C, a distribution circuit 7 is provided following the input terminal 6, and the distribution circuit 7 is composed of inductances L1 and L2 and a capacitor C. The television signal from the terminal 6 is divided into two with a loss of, for example, about 4 dB, and the distribution line from the inductance L2 is connected to the first output terminal 4 and the second output terminal 5.

According to the present invention in such a series unit, a low-pass filter 8 is provided in a distribution line from the distribution circuit 7 to the second output terminal 5. The low-pass filter 8 has a filter characteristic of attenuating or cutting the television signals in the BS and CS bands among the television signals in the VHF, UHF, BS and CS frequency bands from the input terminal 6.

Since the low-pass filter 8 is provided in the distribution line for the second output terminal 5 in this manner, the television signals in the BS and CS bands included in the television signal from the second output terminal 5 are sufficiently attenuated. The total power at the tuner input section of the receiver is maintained at an appropriate level. Therefore, the second output terminal is used as a terminal dedicated to a television receiver that reproduces only television signals in the VHF and UHF bands.

On the other hand, the first output terminal 4 is directly connected to the distribution line from the distribution circuit 7, and is connected to VHF, UHF, BS
And the television signal of the CS frequency band can be taken out as it is. Therefore, the first output terminal 4 is connected to a tuner or a television receiver that receives a BS or CS signal.

FIG. 2A shows V, V with respect to the demodulator input level when a television receiver is connected to the second output terminal 5 when the low-pass filter 8 of FIG. 1C is not provided.
U, BS, and CS represent flat input S / N ratios.
Here, 90d for U and V as demodulator input levels
B, 80dB, 70dB, 60dB, BS, CS
90dB, 80dB, 70dB, 60d for
B, and UHF channels 14, 16, 1
Flat input S for 8,20,22,24,26
The N ratio is shown.

When the low-pass filter 8 is not provided, for example, when the channel CH14 is viewed,
The flat input S / N ratio is -29 dB with respect to the demodulator input level of 90 dB.
The / N ratio is at least 42 dB, and the standard S / N ratio is at least 36 dB, which is 6 dB lower than the C / N ratio.

On the other hand, the flat input S / N ratio for the channel CH14 is -29 dB, the demodulator input level is 90 dB-29 dB = 61 dB, and the S / N ratio corresponding to the total power is 36 dB in the standard. This is significantly higher than the above, which causes saturation in which signal saturation occurs at the tuner input section, and noise occurs.

On the other hand, when the low-pass filter 8 is provided on the distribution line of the second output terminal 5 as in the series unit of the present invention shown in FIG. 1C, V, V as shown in FIG.
Flat input SN ratios of U, BS, and CS can be obtained.

For example, looking at the channel CH14 when the demodulator input level is 90 dB, the flat input S / N ratio is-
46 dB, and 90 dB-46 dB = 44 dB, so that the total power is not so high in view of the S / N ratio of 36 dB in the standard of the television receiver, so that saturation due to signal saturation at the tuner input section can be reliably avoided.

FIG. 3 shows another embodiment of the series unit of the present invention. FIG. 3 (A) is a front view, and FIG. 3 (B) is a circuit diagram thereof. In this embodiment, FIG.
The low-pass filter 8 provided in the distribution line for the second output terminal 5 from the distribution circuit 7 provided in the third embodiment can be selectively connected to the distribution line by the switch 9.

Although two terminals are shown on the back of FIG. 3A, one is an input terminal for a television signal, and the other is an output terminal for outputting the television signal to the next serial unit as it is. The output terminal is omitted in FIG.

For this reason, a switch 9 is provided on the right side of the second output terminal 5 provided on the terminal block 3 of the series unit 1 in FIG. 3 (A). Reference numeral 5 is used as a television output terminal for outputting all input signals in the VHF, UHF, BS and CS bands, and when the switch 9 is switched to the lower side, VHF, UHF
It can be used as a television output terminal in the HF band.

Specifically, as shown in FIG. 3B, the changeover switch is a slide switch for switching between the changeover terminal a side and the changeover terminal b side. Directly connected to VHF, UHF, BS and C
It can be used as an output terminal for an S-band television signal, and when switched to the b side, a low-pass filter 8 is inserted and connected. Therefore, the second output terminal 5 can be used as an output terminal for a VHF and UHF band television signal. Therefore, a switch can be appropriately switched by a tuner device connected to the output terminal, and deterioration of a television signal can be suppressed.

FIG. 4 shows another embodiment of the series unit according to the present invention. In this embodiment, the TV signal in the VHF and UHF bands is attenuated or cut at the first output terminal side, and the signals in the BS and CS bands are attenuated. It is characterized in that only television signals can be extracted.

FIG. 4A is a front view of the series unit, and has a first output terminal 4 and a second output terminal 5 as in the embodiment of FIG. As shown in FIG. 4 (B), a circuit diagram is provided following the input terminal 6 and the distribution circuit 7 is provided.
A high-pass filter 10 is newly provided on the distribution line for the second output terminal 5 from the second output terminal 5. High pass filter 10
Attenuates or cuts television signals in the VHF and UFH bands and passes television signals in the BS and CS bands.

For this reason, the first output terminal 4 can be used as a dedicated terminal for television signals in the BS and CS bands, whereas the second output terminal 5 is provided with a low-pass filter 8 in the distribution line so that the VHF and UHF bands can be used. It can be used as a dedicated terminal for TV signals.

FIG. 5 shows another embodiment of the series unit of the present invention, in which a changeover switch is provided for each of the high-pass filter 10 and the low-pass filter 8 provided in the embodiment of FIG. It is characterized by being connectable.

FIG. 5A is a front view of the series unit 1, and a high-pass filter 10 is selectively connected to the distribution line for the first output terminal 4 in FIG. Switch 11 is provided. A switch 9 for selectively connecting the low-pass filter 8 to the distribution line for the second output terminal 5 is also provided on the right side of the second output terminal 5 below.

The switches 9 and 11 connect the respective distribution lines to the first output terminal 4 and the second output terminal 5 in a state where the switches 9 and 11 are switched to the illustrated side a in FIG. 5, and the televisions in the VHF, UHF, BS and CS bands, respectively. Can be used as a signal terminal. On the other hand, when the switches 9 and 11 are switched to the b side, a low-pass filter 8 and a high-pass filter 10 are inserted and connected to each distribution line, and the first output terminal 4 can be used as a dedicated output terminal for the BS and CS bands. The second output terminal 5 is VH
It can be used as a dedicated output terminal for F and UHF. Therefore, switching can be appropriately performed according to the device connected to each of the output terminals 4 and 5, and deterioration of the television signal can be suppressed.

FIG. 6 shows another embodiment of the series unit according to the present invention. This series unit is characterized in that three output terminals are provided. FIG. 6A is a front view of the serial unit 1, and the terminal block 3 has a first output terminal 4 and a second output terminal 4.
The third output terminal 12 is provided following the output terminal 5.

The circuit of this series unit is as shown in FIG. The distribution circuit 13 provided following the input terminal 6
Inductances L3, L4, L5 and L6 from the input side
The input television signal is divided into three by L7.
The three distribution lines from the distribution circuit 13 are connected to the first output terminal 4, the second output terminal 5, and the third output terminal 12, respectively.

A distribution line for the first output terminal 4 is provided with a high-pass filter 10 for passing output signals in the BS and CS bands, and a distribution line for the second output terminal 5 is provided with a low-pass filter 8. The low-pass filter 8 is intended to connect a coaxial cable of a CATV system to the input terminal 6, and functions as an output terminal for extracting a downstream CATV signal in the CATV system. Also, an upstream CATV signal can be input.

That is, the CATV signal is an up signal of 10 to 50 MHz and a down signal of 70 to 770 MHz.
It is composed of an F signal and a UHF signal, and these signals pass through the low-pass filter 8, and the TV signals in the BS and CS bands are attenuated or cut.

Further, the third output terminal 12 is directly connected to a distribution line from the distribution circuit 13. As a result, the third output terminal 12 is an output terminal for a downstream CATV signal, an input terminal for an upstream CATV signal in a CATV system, and BS and C
It can be used as an output terminal for an S band television signal.

In the above embodiment, a low-pass filter or a high-pass filter is provided which attenuates or removes unnecessary TV signal band signal components on the distribution lines of the corresponding output lines by performing two distribution and three distribution. As an example, the number of distributions can be appropriately determined as needed, and the characteristics of the high-pass filter and the low-pass filter to be used can be appropriately selected according to the band of the television signal to be attenuated.

In the series unit as shown in FIG. 6, a changeover switch may be provided as appropriate. In the above embodiment, VHF and UHF television signals can be replaced by CATV signals. In addition, one output terminal is controlled by a switch, so that all TV signals, B
It may be possible to select three stages of passing through S and CS or passing through VHF and UHF. Further, the CATV signal is not limited to a bidirectional signal, and may be a unidirectional signal including only a downstream CATV signal. In FIG. 6, the third output terminal 12 for outputting all signals may not be provided.
A configuration in which two output terminals of BS, CS and CATV are provided may be used. Thus, an appropriate combination can be adopted, and a filter can be provided in accordance with the television signal band to be output.

[0042]

As described above, according to the present invention, the TV signal band of BS and CS is attenuated or cut on the line for a specific output terminal in the series unit, so that the TV signal band of VHF and UHF and CATV can be obtained. By providing at least a low-pass filter that passes the band, V
When a television receiver that demodulates only HF and UHF band or CATV television signals is connected, the total power due to the BS and CS television signals at the tuner input section is suppressed to an appropriate level to suppress the signal saturation ( Thus, it is possible to reliably prevent a decrease in image quality due to noise caused by saturation.

By providing a switch for selectively connecting a filter used for removing a necessary television signal to the output terminal, the output terminal can be connected to, for example, VHF, UHF, or BS.
And an output terminal dedicated to VHF and UHF television signals, and can be used freely according to the situation of the television receiver used by the user. .

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a configuration and a circuit showing an embodiment of a series unit according to the present invention.

FIG. 2 is an explanatory diagram of a measurement result of a flat input S / N ratio with respect to an input level by the present invention and a conventional series unit.

FIG. 3 is an explanatory diagram of a configuration and a circuit showing another embodiment of the present invention including a switch for switching connection of a low-pass filter.

FIG. 4 is an explanatory diagram of a configuration and a circuit showing another embodiment of the present invention including a low-pass filter and a high-pass filter.

FIG. 5 is an explanatory diagram of a configuration and a circuit showing another embodiment of the present invention including a switch that switches between a low-pass filter and a high-pass filter.

FIG. 6 is an explanatory diagram of a configuration and a circuit showing another embodiment of the present invention provided with a low-pass filter, a high-pass filter, and three directly connected output terminals.

[Explanation of symbols]

 1: series unit 2: series unit main body 3: terminal block 4: first output terminal 5: second output terminal 6: input terminal 6a, 6b: input / output terminal 7, 13: distribution circuit 8: low-pass filter (LPF) 9 , 11: switch 10: high-pass filter (HPF) 12: third output terminal

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 5C056 FA02 HA14 HA15 JA01 5C064 BA02 BC14

Claims (7)

[Claims] 1. A series unit for distributing a television signal from an input terminal and outputting it to a plurality of output terminals, wherein a distribution line for a specific output terminal attenuates or cuts an unnecessary television signal band in the television signal. A series unit, characterized in that a filter for outputting the output is provided. 2. The series unit according to claim 1, wherein said filter is a low-pass filter that attenuates or cuts a television signal band of BS and CS and passes a television signal band of VHF, UHF and CATV. And a series unit. 3. The series unit according to claim 2, further comprising a switch for selectively inserting and connecting said low-pass filter to a distribution line. 4. The series unit according to claim 1, wherein
VHF and UHF are connected to one distribution line of the two output terminals.
And cut or attenuate CATV TV signal band
And a high-pass filter that passes the television signal band of CS, and attenuates or cuts the television signal band of BS and CS to provide VHF, UHF, and CA on the other distribution line.
A series unit comprising a low-pass filter for passing a TV signal band of a TV. 5. The series unit according to claim 4, further comprising one or more switches for selectively inserting and connecting said high-pass filter and / or low-pass filter to a distribution line. 6. The series unit according to claim 1, wherein the television signal from the input terminal is distributed to three output terminals, and a distribution line to the first output terminal is provided with a television signal band lower than BS and CS. A high-pass filter that attenuates or cuts and passes the television signal band of BS and CS, and supplies BS and CS to the distribution line to the second output terminal.
A series unit, comprising: a low-pass filter that attenuates or cuts the television signal band of (1) and passes a television signal band lower than BS and CS, and furthermore, a distribution line to a third output terminal is directly connected. 7. The series unit according to claim 1, wherein
A high-pass filter that attenuates or cuts the CATV signal band and passes the BS and CS television signal bands is provided in one of the two output terminal distribution lines, and the other distribution line attenuates or cuts the BS and CS television signal bands. And a low-pass filter for passing a CATV signal band.