JPS6336570B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a distributor used in wire communication equipment that allows television signals in the UHF and VHF bands, for example, and signals of a specific frequency, such as carrier intercom signals, to coexist.

It is conceivable to share common television reception equipment as a communication line such as a carrier-type intercom. For example, using the wiring diagram of wired communication equipment shown in FIG.
A transport type intercom 4 is connected to each of the terminals 3c. In such a wiring state, the receiving antenna 1
The television signal received is transmitted to the distributor 2 via the transmission line 6, divided into two parts to the distribution terminals 2a and 2b, and then sent to the television receiver 5 connected to the branch terminals 3b and 3d of the distributor 3, respectively. Supplied. on the other hand,
Communication signals between the carrier intercoms go back and forth between the branch terminals 3a and 3c of the branch 3. However, as is well known, in a distributor used for communal television reception, spurious signals leaking from the local oscillator of the television receiver flow backwards from the branch terminals of the divider, reach one distribution terminal, and pass through the other distribution terminal. The signal distribution characteristics are given directionality so as not to interfere with other television receivers. To explain this in detail, the distribution from input terminal 7 to distribution terminals 8 and 9 in FIG.
In the case of a 30dB distributor, it receives 3.8dB attenuation,
Also, the signal passing from the distribution terminal 8 to the input terminal 7 and the signal passing from the distribution terminal 9 to the input terminal 7 are similarly attenuated by 3.8 dB, but the signal passing from the distribution terminal 8 to the distribution terminal 9 is attenuated by 30 dB. .
In other words, in the wiring shown in Fig. 1, if the above-mentioned divider is used as the divider 2 and a divider with a coupling loss of 10 dB is used as the divider 3, the branch terminal 3 of the divider 2
The signals going back and forth between a and 3c are 10dB and 30dB.
This results in an additional 10 dB of attenuation, which means that the signal from the other party's carrier intercom is reduced by a factor of 316, significantly reducing the clarity of the communication. There is a problem.

The present invention is suitable for use when common television reception equipment is shared as a communication line of a specific frequency band such as a carrier intercom, and only signals of a specific frequency have bidirectionality, and television signals have directional properties. The object of the present invention is to provide a distributor having the following characteristics.

Hereinafter, drawings showing embodiments of the present application will be described. FIG. 3 shows a distributor of the present invention, with 10
is the input terminal, 11 is the first distribution terminal, 12 is the second
distribution terminal. Reference numeral 13 denotes a distribution element having directionality, and a well-known distribution circuit shown in FIGS. 5 and 6 is used. is the second distribution terminal 12
are connected to each. Reference numeral 14 denotes a bidirectionality generating element for giving the distributor bidirectional characteristics at a specific frequency, and the first distribution terminal 11 of the distributor
It has the function of passing only signals of a specific frequency with little attenuation among the signals going from the second distribution terminal 12 to the first distribution terminal 11 or from the second distribution terminal 12 to the first distribution terminal 11, and one end thereof, for example, the h side. is connected to the first distribution terminal 11, and the other end i side is connected to the second distribution terminal 12. It should be noted that the bidirectionality generating element may be of the circuit shown in FIG. 4, for example. FIG. 4 shows a series resonant circuit consisting of a coil 15 and a capacitor 16, the resonant frequency of which is set to the frequency of a specific frequency signal to be passed.

Next, the distribution circuit having the above configuration is shown in FIG. 7 in which, for example, the distribution element 13 of FIG. 3 is the one shown in FIG. 5, and the bidirectionality generating element 14 is the one shown in FIG. Regarding the distributor, the constants of each part will be explained assuming that the impedance of the input terminal 10, first distribution terminal 11, and second distribution terminal 12 is 75Ω, and the signal frequency of the carrier intercom is 20MHz.

In Fig. 7, 17 is an autotransformer for impedance matching, which uses a cylindrical ferrite core and has a primary winding L1 and a secondary winding L2 connected to it.
Constructed by winding with a ratio of 0.4:1. Reference numeral 18 denotes an autotransformer for signal distribution, which uses a cylindrical ferrite core and has a primary winding L3 and a secondary winding L4 wound thereon at a turns ratio of 1:1. 19 is a capacitor for impedance correction, and should be 2 to 4 PF. The coil 15 of the specific frequency bidirectional generation element 14 is 3μH, and the capacitor 16 is 20PF.

FIG. 8 shows a characteristic diagram of the distribution circuit configured with the above numerical values, where A is the distribution loss, which is the loss of the signal at the first distribution terminal 11 or 12 when the signal is input from the input terminal 10. Quantity B is an inter-terminal loss and indicates the amount of signal loss at the second distribution terminal 12 when the signal is input from the first distribution terminal 11. As shown in the figure, there is a distribution loss of 3.
5dB, terminal loss 30~35dB, 470~770MHz
In the UHF band, the distribution loss is 3.8dB, and the terminal loss is 25~
30dB, which is the frequency used by carrier intercoms.
At 20MHz, distribution loss and terminal loss were both 3.5dB. Note that when the configuration of the distributor 2 shown in FIG. 10dB and coupling loss 10dB and terminal loss
3.5dB, resulting in a total of 23.5dB. This means that
As mentioned above, the loss in the conventional example was 50 dB, so the loss is small compared to that, and the communication contents can be transmitted clearly.

In addition, FIG. 9 shows an example of a 3-divider, FIG. 10 shows an example of a 4-divider, FIG. 11 shows an example of a 6-divider, and FIG.
The figures each show an embodiment of eight distributors. In each figure, 20 indicates a distribution terminal.

As described above, the distributor of the present invention is designed to have directionality in television signals.
Since signals of specific frequencies are bidirectional, TV receivers connected to different distribution terminals will not have an adverse effect on the image quality of the other TV receiver. On the other hand, when a signal of a specific frequency is passed through the above-mentioned distributor, the loss is significantly reduced, making it possible to communicate with extremely high clarity, making it possible to accurately convey important communication contents. There is.

[Brief explanation of the drawing]

Figure 1 is a wiring diagram of wired communication equipment. FIG. 2 is a diagram showing the symbol mark of the distributor. FIG. 3 is a diagram showing the present invention. FIG. 4 is a diagram showing an example of a specific frequency bidirectionality generating element. 5 and 6 are diagrams showing known distribution elements. FIG. 7 is a diagram showing an example of the present invention. 8th
The figure is a characteristic diagram of the distributor shown in FIG. 7. FIG. 9 shows an embodiment in which the present invention is applied to a three-way divider, FIG. 10 to a four-way divider, FIG. 11 to a six-way divider, and FIG. 12 to an eight-way divider. 10...Input terminal, 11...First distribution terminal, 12
...Second distribution terminal, 13...Distribution element, 14...Bidirectionality generating element.

Claims (1)

[Claims] 1. A distribution element having a certain directional characteristic is configured to distribute a television signal inputted from an input terminal to a plurality of distribution terminals, and there is a bidirectional signal between the plurality of distribution terminals for a signal of a specific frequency. 1. A distributor characterized in that two-way generating elements having a characteristic of sex are connected.