JPH0425760B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a broadband channel system, and more particularly to a broadband channel system capable of reducing crosstalk.

Conventional technology and problems Conventionally, when configuring a single-stage concentrator communication line with a large number of input/output terminals, a large number of small-scale switch matrices (hereinafter abbreviated as primary switches) were used. , connect multiple outgoing lines,
That is, a configuration in which the output terminal side of the primary switch is directly connected is common. However, even when the crossing points of these primary switches are open, there is a small capacitance between the switches and signal leakage occurs.
There is a possibility of crosstalk when there are multiple connected input and output terminals that are active on the same primary switch. Therefore, when multiple output terminals are connected, crosstalk from other primary switches may be added. For this reason, in the conventional configuration method, crosstalk is surrounded by multiple connections of outgoing lines and multiple crosstalk becomes large. Therefore, in order to apply it to a wideband communication path, for example, a communication path for video signals, the crosstalk characteristics for the primary switch must be made strict. There was a need for this, and there were problems with its feasibility and economy. In order to improve this, a wideband channel configuration as shown in FIG. 1 has been proposed (for example, IEICE Technical Report CS75-100.1975).

In Figure 1, LC is a concentrator channel device, A ₁₁ ,
~A _1n , ~, A _l1 ~A _ln is its input terminal, B ₁ , ~B _o
are the same output terminals, Q ₁₁ ~, Q _l1 are switch matrices with m inputs and n outputs (hereinafter abbreviated as m x n) and constitute primary switches, and S ₁ and S _o are l x 1
(hereinafter referred to as secondary switches), M is the number of input terminals of the line concentrator LC, and N is the number of output terminals, and in the example of FIG. 1, N=n.
In addition, each of the primary switches Q ₁₁ to _{Q l1} is arranged so that m conductors connected to m input terminals and n conductors connected to n output terminals intersect, and the intersection point is It consists of a switch matrix with switches. In addition, each of the secondary switches S ₁ to _{S o} is arranged so that n conductors connected to n input terminals and one conductor connected to one output terminal intersect, and a conductor is connected to the intersection point. This is a switch row provided with switches (S ₁₁ , ~S _1l , etc.). Each of the above-mentioned switches may be a switch that performs on/off operation, and may be a mechanical switch or an electronic switch. However, even when these switches are in the off state, there is a small amount of capacitance between them, making it difficult to completely eliminate signal leakage. 111, ~11n, ~1m in Figure 1
1, .about.1mn, etc. exemplify the cross point switches of the primary switch _Q11 , and _S11 to _S1l exemplify the cross point switches of the secondary switch _S1 .

Here, m is the number of input terminals of each of the primary switches Q ₁₁ to _{Q l1} , n is the number of output terminals, and l is the number of primary switches Q ₁₁ to Q _l1 . The number of input terminals M of the line concentrator LC is m×l, and the secondary switches S _{1 to S o} are the f-th (1≦f≦
The number of input terminals is equal to n.

The reason why crosstalk can be reduced with the configuration shown in Figure 1 is that the output sides of the primary switches Q ₁₁ to Q _l1 are
This is because they are connected to the next switches S ₁ to _{S o} .
That is, the required input terminal A ₁₁ of the line concentrator LC
When connecting ~A _ln and output terminals B ₁ ~ _{B o} , the intersection point switch of the primary switch and secondary switch that connects both terminals is closed, but other intersection points within the secondary switch are closed. Since all switches are kept open, the crosstalk signal will pass through the open primary switch and secondary switch in two stages, and the minute capacitance that exists between the switches in the off state will be in series. , the level of crosstalk from other switch matrices is reduced and multiple crosstalk is reduced.

However, when realizing the configuration shown in Fig. 1, the primary switches Q ₁₁ to Q _l1 and the secondary switches S ₁ to _{S o} are each made into LSIs and mounted on a printed board, or the primary switches Q ₁₁ to _{Q l1 are} A conceivable method is to mount the secondary switches S ₁ to _{S o} on a printed circuit board and connect them using a back wiring board or the like. In either case, l×n lead-in wires are required from the primary switch to the secondary switch, and when the number M of input terminals and the number N of output terminals of the line concentrator LC become large, crosstalk between the parallel wiring can be ignored. Because it will disappear,
It is necessary to reduce crosstalk by widening the wiring space. Therefore, it is necessary to lower the packaging density or use a multilayer pattern in the wiring portion, which poses problems in packaging.

In addition, even at a stage when there are few subscribers such as in the initial stage of introduction, 2
The next switch must be installed in a fixed manner to some extent, which poses a problem in terms of expandability.

Purpose of the Invention In order to solve these drawbacks, the present invention provides a plurality of lattice-type switches each having a crosstalk reduction switch added to each terminal on the output side of the switch matrix constituting the primary switch. The purpose of this is to significantly reduce the number of wires without deteriorating the crosstalk characteristics of the communication path, and to create a communication path with good expandability. The aim is to realize this.

Embodiments of the Invention Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a connection diagram of the first embodiment of the present invention. This embodiment is configured as a concentrator channel.

In Figure 2, LC is a concentrator channel device, A ₁₁ ,
~A _ln , ~, A _l1 ~A _ln is its input terminal, B ₁ , ~B _o
are the same output terminals, Q ₁₁ to _{Q l1} constitute a primary switch with an m×n switch matrix, and P ₁₁ to P _l1
is a lattice type switch, and each has a built-in switch matrix that constitutes the primary switches Q ₁₁ to Q _l1 , and their input terminals are the same, but each output of the switch matrix Q ₁₁ to _{Q l1} Switches that can be turned on and off on the terminal side (Figure ₂
X _1o ) are added to form the output terminals of the lattice type switches P ₁₁ to P _l1 . In order to distinguish P ₁₁ to P _l1 from other switch matrices such as Q ₁₁ to _{Q l1} , they will be referred to as lattice type switches. M is the number of input terminals of the line concentrator LC, and N is the number of output terminals. In the example of FIG. 2, N=n as in FIG. 1. In addition, each of the primary switches Q ₁₁ to _{Q l1} is arranged by intersecting m conductors connected to m input terminals and n conductors connected to n output terminals, and a switch is placed at the intersection point. This is a switch matrix with Grid type switches P ₁₁ to P _l1 are each primary switch.
Q ₁₁ to Q _l1 are built in, and as illustrated in P ₁₁ , its n output terminals are connected to switches X ₁₁ to X _1o , respectively.
are connected to the output terminals B ₁ to _{B o} of the line concentrator LC via the line concentrator LC. The above-mentioned switch may be a switch that performs an on/off operation, and may be a mechanical switch or an electronic switch. However, even when these switches are in the off state, there is a small amount of capacitance between them, making it difficult to completely eliminate signal leakage. In Fig. 2, 111, ~ 11n,
~1m1, ~1mn, etc. illustrate the intersection point switches of the primary switch _Q11 .

Here, m is the number of input terminals of the primary switches Q ₁₁ to _{Q l1} or grid type switches P ₁₁ to _{P l1} , n is the number of output terminals, and l is the number of primary switches Q ₁₁ to _{Q l1} or grid type switches P. ₁₁ ~ P _l1 is the number. The number M of input terminals of the line concentrator LC is m×l. In addition _, the number N of output terminals of the line concentrator LC is such that each output terminal B _{1 to B o} is connected to the f- _th (1≦ _f
≦n) is configured by connecting multiple output terminals, so it is equal to n as in FIG.

Of the secondary switches S ₁ of the concentrator LC in FIG. 1, the switch that connects the output of the primary switch Q ₁₁ is the switch X ₁₁ of the lattice switch P ₁₁ of the concentrator LC in FIG. 2. Therefore, the crosstalk reduction effect of the switch can be considered to be equivalent to that of the concentrator communication path device shown in Figures 1 and 2.
Although the same is true for LC, the number of outgoing multi-wires is n in the embodiment shown in Fig. 2, compared to l x n in Fig. 1, so the number of outgoing multi-wires is as shown in Fig. 1. The number of input terminals M and the number of output terminals N of the concentrator LC in the conventional example shown in Fig. 1 are increased, and the parallel fabric between the primary switch and secondary switch is It is also effective against crosstalk between lines, and is extremely effective in improving the mounting efficiency of the wiring section. In addition, in this example, there is a large economical effect due to the reduction in the number of printed layers in the wiring section.
Furthermore, since the wiring section and grid switch section require simple multi-connections, it is easy to add switches, and changing the concentration ratio can be easily handled by simply increasing l (the number of primary switches or grid switches). can.

In this embodiment, by appropriately selecting the number m of input terminals m the number n of output terminals and the number l of the primary switches Q ₁₁ to Q _l1 , it is possible to configure not only a concentrating line but also a non-concentrating line communication path device. You can also do it.

In the embodiment shown in FIG. 2 above, the number of output terminals N is 1.
Although the number of output terminals of the next switch is equal to n (N=n), FIG. 3 is a connection diagram of a second embodiment of the present invention in which N>n can be satisfied. Third
In the figure, LC' is a channel device, L ₁ to _{L r} are r partial channel devices having the same configuration as the concentrator channel device LC shown in FIG. 2, and A ₁₁ to A _1n , to A _l1 , respectively. ~
A _ln is the input terminal of the communication path device LC′, B ₁₁ ~B _1o ~ _{B r1}
~B _ro is also an output terminal. Input terminal A ₁₁ ~
The inputs from A _1n are branched and input to corresponding input terminals of partial channel devices L ₁ to L _r , respectively, via buffer amplifiers BA. Partial channel device L ₁
~L _r 's respective output terminals B ₁₁ ~B _1o , ~, B _r1 ~
B _ro constitutes the output terminal of the present communication channel device LC'.
Therefore, the number N of output terminals of the communication line device LC' is n×r
Next n (lattice switch P ₁₁ , ~P _l1 , ~, P _1r ~P _lr
(number of output terminals, etc.) can be increased.

In the communication path device LC′ of FIG. 3, the buffer amplifier BA has grid type switches P ₁₁ to P _l1 ,
〜、P _1r 〜P _lr In addition to suppressing the impedance drop when branching to the input terminal, the buffer amplifier
In BA, taking advantage of the fact that the signal has directionality,
It is possible to block crosstalk signals from other grid switches and limit crosstalk to its own grid switch. Note that the buffer amplifier BA may be a branch amplifier with one input and multiple outputs. This makes crosstalk independent of the number M, N of the input and output terminals of the channel device LC', and the crosstalk standard required per crosspoint switch remains unchanged. The lattice type switches P ₁₁ ~ _{P l1} , ~P _1r ~P _lr in Figure 3 can be implemented in the package as shown in Figure 3 by converting them into LSI, and in this case, the output multi-wire is the wiring inside the package cage. Furthermore, when a lattice type switch _P11 or the like is mounted on a package, output multi-wires can be realized using a back wiring board, etc.

Effects of the Invention As explained above, according to the present invention, when the scale of the wideband channel device is equal to the number of output lines of the lattice type switch that is its component, the output power is reduced as in the first embodiment. This can be achieved by simple multi-connection of terminals, and if the number of output lines is greater than the number of output lines of the grid type switch, a buffer amplifier is installed on the input side as in the second embodiment, and the output lines of the grid type switch can be connected multiple times via the buffer amplifier. By connecting, expansion is easy, crosstalk is small, and a wideband communication path of any switch size can be realized economically.

Further, the present invention has the advantage that a wideband communication path with little crosstalk can be easily realized even when a multi-stage link is configured using a known technology using the communication path device realized.

It should be noted that since the present invention utilizes various advantages while improving the crosstalk characteristics by devising the configuration, there are no restrictions on the structure of the switch or the type of switch.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a conventional broadband channel device, FIG. 2 is a configuration diagram of a first embodiment of the present invention, and FIG. 3 is a configuration diagram of a second embodiment of the present invention. M...Number of input terminals, N...Number of output terminals, P ₁₁ ~
P _l1 ~P _1r ~ _{P lr} ...Grid type switch, m...Number of grid type switch input terminals, n...Number of grid type switch output terminals, _A11 ~A _1n , ~, A _l1 ~A _ln ...Input terminal,
B ₁ ~ _{B o} , B ₁₁ ~ B _{1 o} , ~, B _r1 ~ B _ro ... Output terminal,
l, r...Number of switches, 111~11n, ~,
1m1~1mn;X ₁₁ ~X _1o ...Switch, BA...
…Buffer amplifier, Q ₁₁ , Q _l1 …m×n switch matrix (primary switch), S ₁ ~ _{S o} …l
×1 switch row (secondary switch).

Claims (1)

[Claims] 1. A communication path configured by adding a switch that can be turned on and off as an output terminal to each output terminal side of a switch matrix with m inputs and n outputs (m and n are integers of 2 or more). 1. A wideband communication channel system characterized in that a plurality of lattice-type switches are provided to form a plurality of lattice-type switches, and a necessary number of output terminals of the switches capable of being turned on and off at the same position of each of the lattice-type switches are connected in multiple ways. 2. A lattice-type switch that forms a communication path by adding a switch that can be turned on and off as an output terminal to each output terminal side of a switch matrix with m inputs and n outputs (m and n are integers of 2 or more). A plurality of communication path devices are provided, and the output terminals of the above-mentioned on/off switches located at the same position of each of the above-mentioned lattice type switches are connected in multiple ways as many times as necessary, and a plurality of communication path devices are used, and a plurality of communication path devices are used. is a wideband communication line system characterized by configuring one communication line device by inserting a buffer amplifier or a branch amplifier corresponding to each input terminal.