FR2486344A1 - Switching matrix for telephonic or tv communications system - has controller for row and column switches operating via transfer and filter circuits to block control signals when passing data - Google Patents

Abstract

The switching grid controller uses a matrix of rows and columns such as are used in nodal centres of telecommunication systems, and enables a single control signal to be used to link a selected column (10a) and line (10w). A control circuit (5) connected to a given switch (A2) linking a line and column is coupled by the line and column to the associated output and input selectors (3,2) and comprises a standard address decoding circuit. The connection between the control circuit and the column and row is made through a transfer and filter circuit (70,71,72) to the column and through the switch (A2) to the line. The transfer filter circuit passes selector control signals, to the selectors while blocking switched information signals and filter circuits in the input and output selector circuits block the control signals while passing information signals to the column and from the line.

Description

 The present invention relates to a device for controlling a switching grid of the type of column and row switching grids which allow, in particular, the switching operations of telephony or television signals in the nodal centers of telecommunications systems. .

 These switching gates are made up of several identical elementary gates, each giving the possibility of switching certain input columns with certain output lines of the switching grid.

It is known to effect the switching of a given line with a given column of the switching grid by means of three separate commands.
- the commands of an input selector and an output selector which allow one to choose one of the elementary grids,
- the command of a link switch which allows, inside the selected grid, to establish contact between the desired row and column.

 The present invention aims to simplify the control device of the switching gate By allowing the use of a single command to establish a circuit with a given column and line.

 This is achieved, in particular, by producing, from the control signal of a given switch, one or two ancillary signals which are routed through the column and line relating to the given switch to the relative input and output selectors to this given switch, in order to control them.

The invention will be better understood and other characteristics will appear with the aid of the description ciapre's and of the figures relating thereto which represent:
- Figure 1 a simplified and partial diagram of a switching grid,
FIGS. 2 and 3 partial diagrams of elementary grids with the relative switching control device,
- Figures 4, 5 and 6 of embodiments of elements of Figure 2.

 In the various figures, the corresponding elements are identified by the same symbols.

 Figure 1 shows, schematically, a switching grid, 1, formed of nine identical elementary grids, such as the elementary grid 10; these grids are arranged three by three horizontally and vertically.

The elementary grids, such as the grid 10 are composed of four columns 10a t 10b v 10C t 10d and four rows 10V, 10W r 10X ion crossing y without contact in 4 x 4 = 16 positions; link switches, such as switch A2 shown diagrammatically by a black point, make it possible to make contact points between these columns and these lines (in the case of switch A2 between column 10a and line IO
Figure 1 shows part of the grid control device t. This control device comprises link switches such as A2 and input selectors of which only one, 2, has been shown and output selectors of which also only one, 3, has been shown.

 There are thirty-six input selectors in grid 1; they each bring together the columns of the same row (for example the first for selector 2) of the same horizontal row of grids.

elementary (for example the upper row for selector 2), to switch one of these columns at their entry, and using contactors indicated by a black point, 2, in the closed position.

vs
Similarly, the output selectors are thirty-six in number; they each bring together the lines of the same rank (for example the second for selector 3) of the same vertical row of elementary grids (for example the right row for selector 3), to switch one of these lines to their outlet, S, using contactors indicated by a black dot, 3a 'in the closed position.

 it is recalled that in a switching grid like that of FIG. 1, there cannot be simultaneous contact between a line and two columns or between a column and two lines and that an input or output selector does not never has two contactors closed simultaneously.

 The description which has just been made with the aid of FIG. 1 relates to both the known art and the present invention. On the other hand, what follows relates specifically to the invention and will make it possible to show how it is possible to establish a connection such as the connection E - 2 - A2 - 3a - S using a single command acting at a time on three switching devices: the link switch, A2 r and the input, 2, and output selectors, 3. The rest of the description will also show that the control device is not connected to the three devices by three separate links but is connected to one of them by its own link and to the other two through the switching gate t thus the additional connections necessary for the routing of the switching control signals will be minimized.

 FIG. 2 shows an elementary grid, 10 of which only one column, 10a, and four rows 10v, 10w, 10x and 10y have been represented. Only the connections and circuits necessary for the connection through column 10a and line t w have been shown in full; the other connections and other circuits have only been sketched out or have been replaced by broken lines.

The link using column 105 and line 10w comprises, between its input E and its output S, an input selector, 2, a link switch A2 and an output selector 3. A signal switched by this link meets successively between E and S
- an amplifier, 20, with low impedance output followed by a high pass filter 21; these two circuits forming the input circuits of the input selector 2
- the contact of a relay 2c, contact which is then in the closed position; this relay constitutes the contact of the input selector, 2, relating to column 10
at
- column 10a
- the contact of a relay A2, contact which is then in the closed position to determine a point of contact between column 10a and line 10
- the 10W line,
- the contact of a relay 3a 'contact which is then in the closed position, this relay constitutes the contactor of the output selector 3, relating to line 10
a high-pass filter 30 followed by an amplifier 31 with low impedance output; these two circuits forming the output circuits of the output selector 3.

The control of the three relays A2 r 2, 3 per
a setting the establishment of the link indicated above is done, as shown in Figure 2, by means of a set of circuits consisting of an address decoder 5, the coils of relays A2 '2c and 3a and coupling circuits between the decoder 5 and the coils.

 The address decoder 5 is a conventional address decoder, used in known devices for switching a switching grid to determine, as a function of the information it receives, whether the column-row contact point to which it is affected, must be established. In the case where this contact point must be established, the address decoder, the output of which had the level "0", goes to the level "1"; a control circuit, 6, transforms this level "1" into a supply voltage of the excitation coil of the relay A2 'thus causing the contact of this relay to close.

A signal transformer 71 receives, through an OR gate, 70, this level "1" of output from the address decoder 5; it transforms the level "1" received into a supply voltage which, after passing through a low-pass filter 72 is applied on the one hand, via column 10a r to an amplifier 2 'for controlling the
c coil of relay 2c and on the other hand, via column 10a, the closed contact of relay A2 and line tw, to an amplifier 3 'for controlling the coil-of relay 3
aa
Thus, thanks to a single command provided by the address decoder 5, the three switching members
A2 r 2c '3a have been triggered.

The filter 72 of FIG. 2 has the function of preventing the passage of the signal to be switched through column 10 and line 10w (signal received at input E); as for filters 21 and 30 their role is to prevent the passage of the signal supplied by the signal transformer 71 and which only serves to trigger the relays 2c and 3
at
The OR gate, 70, is a gate with four inputs which receives, in addition to the output signal from the address decoder 5, the output signals from the three address decoders, not shown, relating to the links in column 10 with the lines 10V w 10 and 10; a
avxy such an embodiment makes it possible to use the signal transformer 71 and the filter 72 whatever that of the four lines 10V, 10w, 10x and 10y which is to be connected to the column 10a
The diagram according to FIG. 2 requires that the contact of the relay A2 allows the signal supplied by the signal transformer 71 to pass. The elementary grid 10 then only requires four sets of circuits such as 70-71-72: one per column. On the other hand, each of the link switches placed between a row and a column, such as A2, requires, for its control, its own address decoder, such as 5, and its own control circuit such as 6.

There are link switches that do not pass signals from signal transformers, such as 71, to trip contactors, such as 3; this is for example the case
a when the relay A2 is replaced by an electronic relay which does not allow bare DC voltages to pass and the signal supplied by the signal transformer 71 is a DC voltage; in this case the diagram according to figure 2 can be modified to give the diagram according to figure 3.

In the diagram of FIG. 3, only one column, 10a, and a line 10 of an elementary grid 10 have been shown. Column 10a is connected to the contactor 2 of an input selector 2 and the 10W line is connected
c to the contactor 3a of an output selector 3; a link switch A2 makes it possible to establish a point of contact between the column 10a and the line 10W. Contactors 2 and 3 r like switch A2 t on the contrary
ca corresponding elements of Figure 2, do not allow the passage-by their contact of the continuous signal which is sent to their trigger control amplifiers, 2 'and 3'; nevertheless, for the sake of
cc for simplification the switch A2 and the contactors 2c '3a are shown diagrammatically in the form of mechanical relays.

As in the example according to FIG. 2, the connection switch A2 of FIG. 3, serves to establish the junction between the column 10a and the line 10w; it is triggered by means of an address decoder 5 and a control circuit 6 which are specific to the column-line link, 10a - 10w X to be established. On the other hand, contactors 2c and 3 receive on the input of their
a control amplifiers 2'c '- 3' of the signals supplied by a set of circuits 71-72-73 specific to the line-column junction 10 - 10; in the example of the
aw figure 2 circuits 70-71-72 were common to the four possible connections between column 10a and lines 10v 10w 10 10. Thus, for a grid elé
xy mentaire with four columns and four rows which required in total, in the case of figure 2, four sets of circuits such as 70-71-72, it is necessary to, in the case of figure 3 to have sixteen sets - circuits such as 71-72-73: one for each possible junction between columns and rows. An assembly such as 71-72-73 (FIG. 3) is composed of a signal transformer 71 connected to the output of the address decoder 5, and of two low-pass filters 72, 73 these these filters couple the output of the signal transformer 71 respectively in column 10a and in line 10w.

 It is the obligation to transmit the signal necessary for tripping the contactor 3a without passing through the contact of the link switch A2 which prevents the use, as in FIG. 2, of a mime set of circuits for tripping the contactor 2c of the column 10a and all the contactors such as 3a relating to the lines of the elementary grid 10. In fact, wires.

very identical to the filter 73 should couple the output of the signal transformer 71 to each of the other lines, not shown, of the elementary grid; thus the contactor 3a t as well as the other contactors not shown, relating to these lines, would be engaged whatever the connection to be established. However such an operation is incompatible with a correct use of a switching grid where a connection cannot be done that by ordering the only switching devices relating to the link under penalty of losing switching possibilities, in fact, as it was indicated previously, a selector never has two contactors closed simultaneously so well qbe, needlessly close one of its contactors makes it unusable for making a connection which does not include this unnecessarily closed contactor.

The diagram according to FIG. 2 has been drawn by taking as a concrete example a switching gate designed to switch information signals situated in the band 300 kHz-12 MHz; in this grid the control signals of the link switches, such as
A2, and contactors, such as 2 and 3a, are
ca continuous voltages. it is also possible to design switchgear control devices t using control signals other than direct voltages, by choosing a frequency band for the control signals different from the frequency band of the information signals.

 The following figures show how certain circuits of FIG. 2 are produced in the case of the concrete example mentioned above.

FIG. 4 is a detailed diagram of the assembly constituted by the control circuit 6 and the link switch A2 of FIG. 2. An npn transistor, T, mounted as a common emitter receives on its base, through a circuit of level adaptation R1, R2, the output signal from address decoder 5 (figure) t the level adaptation circuit consists of a resistor R connected between the output of address decoder 5 and the base of the transistor T1 and a resistor R2 connected between the base of the transistor T1 and the ground; the level adaptation circuit is intended to allow coupling between the address decoder 5 which in the example described, is produced in CMOS circuits (abbreviation of the English words "complementary metal-oxide-semiconductor") operating with a voltage supply voltage of 12 volts, and the control voltage of the base of transistor T1 which is chosen to be 0.6 volts. The collector of transistor T1 is connected to a + 5V potential point by the assembly formed by the coil of relay A2 in Figure 2 and a diode D1 mounted in reverse. A power decoupling capacitor, C1 r connects the potential point + 5V to ground. A capacitor, C2 connects the emitter of transistor T1 to ground, it constitutes, with diode D1 D a transistor protection circuit T1 during relay A2 switching
The contact of relay A2 performs, when it is closed, the junction between column 10 and the line of in FIG. 2.

 The values of the elements of the circuit according to FIG. 4 as well as of the elements of the circuits according to FIGS. 5 and 6 will be given after the description of FIGS. 5 and 6.

 FIG. 5 is the detailed diagram of the signal transformer, 71, of FIG. 2. This diagram shows an npn transistor, T2, mounted as a common emitter with a resistor R3 connecting its base to the output of the OR gate, 70, of Figure 2. The collector of transistor T2 is connected directly to the input of the filter, 72, of Figure 2 and, through a resistor R4 at a point of potential + 5V. A capacitor, C3 B for power decoupling, connects the + 5V potential point to ground.

FIG. 6 is the detailed diagram of the assembly constituted by the amplifier 2'c and the contactor 2c in FIG. 2, it should be noted that the detailed diagram of the amplifier 31a associated with the contactor 3
aa of figure 2 corresponds, with the references close, to the diagram of figure 6.

Figure 6 shows two npn transistors, T3
T4, associated in a Darlington assembly: the input of the assembly is done on the base cu transistor T3 through a -resistor R5, the emitter of the transistor T3-is connected to the base of the transistor T4 e the emitter of the transistor T4 is connected to ground and the collectors of transistors T3 and T4 are interconnected and coupled through a load constituted by the coil of relay 2
c at a point at a potential of + 5V. A diode D2 and a capacitor C4 provide a protection circuit for transistor T4 during the switching of relay 2; at
c for this purpose the diode D2 is connected in reverse between the collector of the transistor T4 and the point at the potential of + 5V, and the capacitor C4 is connected between the collector of the transistor T4 and the ground.

The values or the references of the various elements of FIGS. 4 5 and 6 are the following
- transistors T1, T2 t T3 and T4: type 2N2222A
manufactured by THOMSON-CSF
- resistance R1: 3.3 kohms
- resistors R2, R3, R4: 10 kohms
- resistance R5: 22 kohms
- diodes D1, D2: reference 1N4148, manufactured by
THOMSON-CSF
- switch A2 and contactors 2 and 3: relay
it
mercury wet contact electromagnetic,
in sealed ampoule, manufactured by the Company
OREGA under reference 136 R04 808.

 it should be noted that various other devices for controlling a switching gate can be produced without departing from the scope of the invention. In particular when, unlike the examples described above, the signals to be switched have a spectrum which goes up to continuous, the frequency or the frequency band of the signal supplied by the signal transformer 71 (FIGS. 2 and 3) must be located outside this spectrum; the filter 72 in FIG. 2 must then be a bandpass filter centered on the frequency or the average frequency of the signal supplied by the signal transformer 71, and the filters 21 and 30 in FIG. 2 must be band-cut filters centered on this same frequency.

 Another variant of the gate control device consists in connecting the output of the filter 72 (FIG. 2) no longer on column 10a but on line 10w; similarly the three assemblies not shown, identical to the assembly 70-71-72 (FIG. 2), will no longer be connected to the columns of the elementary grid 10 but to the lines 10v 10 and 10y of this elementary grid.

Claims (5)

 1. Device for controlling a switching grid, comprising input (2) and output (3) selectors intended for selecting the columns and the rows of the grid respectively and link switches (A2) intended for establishing contact points between the rows (10W) and the columns (10a) of the grid, characterized in that, for the input selector (2), the switch (A2) and the output selector (3) given, relating to a switching to be established by a column (lova) and a given line (10w), it comprises a single control member (5) connected to the given switch (A2) and coupled, respectively by the column (10a) and the line (1 w) data, to the input (2) and output (3) selectors given, and in that the single control member (5) comprises a circuit (5) for decoding the address of the given switch .  2. Control device for a switching gate according to claim 1, in which the given switch (A2) allows the passage of the selector control signals (2, 3), characterized in that the two couplings between the member single control (5) and on the one hand the given column (10a), on the other hand the given line (10w), are carried out through a transfer and filtering circuit (70-71-72) connected to the output of the single control member and in that one of the two couplings is effected through the given switch (A2).  3. Device for controlling a switching gate according to claim 2, characterized in that the transfer and filtering circuit - (70-71-72) lets the selector control signals pass and arrives the information signals to be switched by means of the gate, and in that the input selectors (2) comprise an input filtering circuit (21), the output selectors an output filtering circuit (30), and in that that the filter circuits stop the selector control signals and allow the information signals to be switched to pass by means of the gate.  4. A control gate control device according to claim 1, in which the given switch (A2) arrives the selector control signals, characterized in that the two couplings between the single control member (5) and on the one hand the given column (10a), on the other hand the given line (10) r are carried out through a transfer circuit (71) connected to the output of the single control member and respectively, two circuits filter t72- 73), one of the filter circuits (72) coupling the output of the transfer circuit to the given column and the other (73) coupling the output of the transfer circuit to the given line.  5. Switching grid (1) characterized in that it comprises a switching device according to any one of the preceding claims.