JPS6329335Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the connection of the feeder line in television communal reception equipment, such as a distributor, branching filter, or amplifier. The present invention relates to a feeder line connection section in a communal receiving device that can also selectively connect the feeder lines of the present invention.

Conventional communal receiving equipment is equipped with a matching box at the feed line connection section, and when connecting an unbalanced feed line, the matching box is disconnected and used. When used, there was a problem that the high frequency characteristics could be deteriorated due to forgetting to disconnect it. In addition, in the case of the above-mentioned configuration, the matching device is relatively expensive, so there is a problem that the price offered to consumers becomes high.

Therefore, the present invention has been developed to eliminate the above-mentioned problems, and allows for selective connection of either unbalanced or balanced feeder lines, without the need for disconnecting, and at low cost. The present invention aims to provide a power supply line connection section in a communal receiving device that enables the provision of the following information.

The drawings showing the embodiments of the present application will be described below. FIG. 1 shows a duplexer as an example of communal reception equipment. In this figure, 1 is the input terminal, which is the UHF input terminal from the antenna or common reception line.
This is the terminal where the VHF TV signal is input.
a pair of unbalanced terminals 2 for connecting an unbalanced feeder line;
It is comprised of a pair of balanced terminals 3 for connecting a balanced type feeder line. The unbalanced terminal 2 is composed of a signal terminal 4 connected to a signal circuit, which will be described later, and a ground terminal 5 connected to a ground circuit. In addition, the balanced terminal 3 is
It is composed of a pair of signal terminals 4 and 6. Note that although the signal terminal 4 is shared by the unbalanced terminal 2, these may be provided separately. Reference numeral 7 indicates an output terminal, which is composed of a UHF output terminal 8 for outputting a UHF television signal and a VHF output terminal 9 for outputting a VHF television signal. The output terminal 8 is constructed in a well-known manner so that a balanced power supply line can be connected thereto, and the output terminal 9 is constructed so that an unbalanced power supply line can be connected thereto.

Next, the joint reception circuit will be explained. Reference numeral 10 indicates a well-known branching circuit, which is composed of a high-pass filter 11 and a low-pass filter 12. The high-pass filter 11 filters out the TV broadcast signal.
Passes UHF (470~770MHz) signals and
As is well known, it is composed of capacitors C ₁ and C ₁ and a coil L ₁ so as to block signals of up to 220 MHz.
Furthermore, the low-pass filter 12 includes coils L ₃ , L ₃ ' and a capacitor so as to pass the VHF signal among the television broadcast signals and block the UHF signal.
It is constructed using _C3 . 13 is an impedance converter that balances the unbalanced (75Ω, for example) output of the high-pass filter 11 (200 or 300Ω).
It consists of a coil _L2 and a capacitor _C2 . As is clear from the figure, the above-mentioned communal reception circuit is of an unbalanced type, and numeral 21 represents an unbalanced signal circuit, and 22 represents a grounding circuit. Next, 14 is a conversion element having one end connected to the signal terminal 6 and the other end connected to the ground circuit 22, which is constituted by a resistor R and a capacitor _C4 . For example, a 47Ω, 1/6W carbon film resistor is used as the resistance R. Further, as the capacitor _C4 , for example, a capacitor of 7 pF is used. Of these elements, the resistor R mainly acts as an impedance conversion element for TV signals in the VHF band, and the capacitor
_C4 primarily acts as an impedance conversion element for television signals in the UHF band.

In the case of the above configuration, when the television signal from the antenna is sent using an unbalanced feed line (coaxial cable), the feed line is connected to the connection terminal 2 as is well known, that is, the core wire The signal terminal 4
The external conductors are connected to the ground terminal 5, respectively. Then, the feeder line is connected to the branching circuit 10 with good matching, and the TV signal sent from the feeder line is
As is well known, the UHF television signal is output from the output terminal 8 through a wide-pass filter 11 and an impedance converter 13. Further, the VHF television signal is outputted from the output terminal 9 via the low-pass filter 12.

On the other hand, the TV signal from the antenna is connected to a balanced feeder (e.g. ribbon feeder, spectacle feeder).
If the power is being sent using a power supply line, connect the power supply line to the connection terminal 3 in a well-known manner. Then, the feeder line is connected to the demultiplexing circuit 10 through the conversion element 14 with good matching, and the TV signal coming from the feeder line is demultiplexed in the same way as in the above case, and is converted to UHF.
A television signal is output from an output terminal 8, and a VHF television signal is output from an output terminal 9, respectively.

Next, FIG. 2 shows the results of measuring the characteristics of the structure described above. In this figure, (a) and (b) show the results of measuring the levels of the signals appearing at the output terminals 9 and 8 by inputting a signal from the unbalanced terminal 2, respectively. Again (ha)
and (D) show the results of measuring the levels of the signals appearing at the output terminals 9 and 8, respectively, by inputting signals from the balanced terminal 3. In the measurement system diagram in FIG. 2, reference numerals 21 and 22 indicate television signal generators with unbalanced output and balanced output, respectively, and indicators 23 and 24 indicate balanced input and unbalanced input, respectively.

As described above, this invention includes the unbalanced terminal 2 directly connected to the community reception circuit and the balanced terminal connected to the circuit via the conversion element 14, so that when connecting the feeder line, Regardless of whether the terminal is a balanced type or an unbalanced type, the above-mentioned terminals can be selectively used to make connections with good matching.

Moreover, even if the conversion element 14 is selectively used as described above, since the conversion element 14 is originally separated from the unbalanced terminal 2, the unbalanced feed line is connected to transmit the television signal. In some cases, it is possible to make a well-matched connection as described above just by making the connection in the usual way, and it is useful because even if an amateur makes the connection, it is possible to transmit a television signal with good characteristics.

Furthermore, even though the present invention is equipped with the conversion element 14 as described above, its configuration consists of a resistor R and a capacitor.
Since the structure uses a generally inexpensive element called _C4 , there is an economical effect that it can be provided at a low price.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is a circuit diagram of a duplexer, and FIG. 2 is a graph showing characteristics. 2... Unbalanced feed line connection section, 3... Balanced feed line connection section, 10... Branching circuit.

Claims (1)

[Scope of utility model registration request] A communal reception circuit including an unbalanced signal circuit and a ground circuit is provided with a pair of unbalanced terminals for connecting an unbalanced feeder line and a pair of balanced terminals for connecting a balanced feeder line. In the feed line connection section of the communal receiving equipment, one of the unbalanced terminals is connected to the signal circuit, the other terminal is connected to the ground circuit, and one of the pair of balanced terminals is connected to the signal circuit. circuit, and the other terminal is connected to the ground circuit via a conversion element, and the conversion element is connected to a TV signal.
Community reception characterized by being configured by connecting in parallel a resistor configured to perform a conversion action on VHF band signals and a capacitor configured to perform a conversion action on UHF band signals of television signals. Feed line connection in equipment.