SU772509A3 - Telephone line state control device - Google Patents

Abstract

In a telephone subscribers line equipment the state of the loop is sensed by a Hall effect cell which is inserted into the magnetic circuits of detector windings. This arrangement enables the detector circuit to be decoupled from the line circuit. Two detector coils are each connected to the connecting wires between the subscribers equipment and telephone line terminals. A Hall effect cell is mounted in a gap in the magnetic circuit coupling two detector coils. A threshold level circuit output gives the loop state. This threshold circuit gives a high ratio between switch on a switch off states of the magnetic field.

Description

(54) STATE CONTROL DEVICE

one

The invention relates to telecommunications.

It is known a telephone line condition monitoring device containing a switching unit, the first and second inputs of which are connected respectively via the first and second separation capacitors to the wires of the telephone line, a threshold node whose output is connected to the third input of the switching unit, the fourth input of which is connected through the third separation capacitor with a call current generator and a voltage limiter connected to a common bus, the call current generator being connected through the first DC source a common bus, the fifth input of the switching unit is connected to the output of the measuring unit, as well as the second and third sources of direct current, the corresponding poles of which are connected to the common bus 13.

However, the known device has low reliability.

The purpose of the invention is to increase the reliability of the device.

For this, the telephone line monitoring device with the TELEPHONE LINE

A switching unit, the first and second inputs of which are connected respectively via the first and second coupling capacitors to the telephone line wires, the threshold node, the output of which is connected to the third input of the switching unit, whose fourth input is connected to the call current generator and the limiter via the third coupling capacitor voltage connected to the common bus, the call current generator through the first DC source connected to the common

15 by bus, the fifth input of the switching unit is connected to the output of the measuring unit, as well as the second and third sources of direct current, the corresponding poles of which are connected to the common

20 bus, introduced a magnetic inductive element with a Hall sensor. Moreover, the first winding of the magnetic inductive element is connected between the first wire of the telephone line and the pole

25 of the second DC source, the second winding of the magnetic inductance element. Connected between the second wire of the telephone line and the common bus connected through the third winding of the magnetic inductance element.

a voltage limiter, the first second terminals of the Hall sensor are connected respectively to the pole of the DC source and the common bus, the third output of the Hall Sensor is connected to the input of the threshold node, the fourth winding of the magneto-inductive element is connected to the input of the measuring unit.

The magnetic inductive element is designed as a magnetic core, on which all windings are made and in which air gap a Hall sensor is located.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - dependence of the resulting magnetic field B f (i), - where B is magnetic induction (magnetic field), i is the instantaneous value of current; in fig. 3 shows a magnetic inductive element.

The telephone line condition monitoring device contains a switching unit 1, first and second coupling capacitors 2 and 3, telephone line wires 4, 5, threshold node 6, coupling capacitor 7, call current generator 8, voltage limiter 9, first constant source 10 current, measurement unit 11, second and third sources 12 and 13 of direct current, magnetically inductive element 14, containing a Hall sensor 15, the first, second, third and fourth windings 16, 17, 18, 19 of core 20 (see FIG. 3).

The device works as follows.

The source 10 of direct current is polarized so that the current E coming from the generator 8 of the call current that flows along the winding 18 of the sound signal causes a magnetic field in the magnetic circuit whose direction is opposite to the field generated by the current 3 in the telephone line. The current So is constant and permanent. When the current in the telephone line is Zo, the magnetic field in the air gap 21, in which the Hall sensor 15 is placed, is zero, since the bw-DO currents cancel each other out. The resulting magnetic field B f (I) therefore intersects the abscissa axis at the point DQ (see Fig. 2). From here follows a graphical method for selecting the strength of the input current, denoted by Zo. This method is particularly easy to follow in Figure 2, which shows the resultant field B as a function of current strength i. The proportionality ratio between the magnetic field B and the current causing it i B / i p is graphically represented with a straight slope p passing through the origin O which cannot pass

through the magnitudes of the magnetic field Q and BS, since the ratio is much larger than the predetermined ratio of the corresponding current strengths close to two. This allows such a shift to occur so that for i O the resultant field becomes equal to the negative magnetic field B.Q. Then you can draw a straight L g that passes through the points with coordinates (V., 3), (, 23). This straight line, which intersects the axis of the magnetic fields at the BoL point, is the ultimate solution for satisfying the predetermined conditions. It has the following formula:

5 F (1) PL i - BOL.

in which designations are entered, on the one hand, for inclination

R..

 3 0 and, on the other hand, for absolute

Magnetic field BQ

BOL BC - 2B.

Its expression in given values is

b- (vVT

From the graph in FIG. 2, it follows that the family of straight lines, which intersects the axis of current strength at the point enclosed between point ij and point

23, and the axis of the magnetic fields below the point BO, in the direction of large negative magnitudes, satisfies the imposed requirements.

These direct satisfies the inequalities

bib ..

p7 /

CB,) 7, V2b ,.

The graph shows the direct S belonging to this direct family. Its intersection point with the abscissa axis gives a value of 3, for which the resulting magnetic field is zero.

It can be seen that the choice of the value of a constant permanent current 3 having the opposite direction is between. igv. and 23, that is, between the minimum value

slightly less than 3, and a value of 23.

The greater the ratio B (h / H, the closer the value of iov. To the value of 3. In practice, it suffices to enter into the winding of 18 tones the current Zo of which is between the stored values 3 and 23, in order to create the conditions necessary for detecting the state of the circuit It should be noted, however, that the more the value of Zo is chosen, the more emphasized should be the inclination of the straight line B –f f (i) / since p must exceed the value

Bc

23-Zoey.

To increase the slope, you must either increase the number of turns of the windings, or reduce the thickness of the airspace 21 in which the Hall sensor 15 is placed. In practice, it is better to choose the DO value close enough to D, so as not to get too much slope, as this underlines the graphical solution.

In order not to interfere with the introduction of a sound signal, a montage-current injector with a large impedance is used to perform a high-impedance current generator 8. The capacitor 7 filters the content, the prescription in order to subtract from it the action of the generator of the audio signal in the drawing is not shown.

Claims (2)

1. A telephone line condition monitoring device containing a switching unit, the first and second inputs are connected via the first and second separators respectively to the telephone line wires, the threshold node, the output of which is connected to the third input of the switching unit, the fourth input of which is through the third separation capacitor connected to a call generator and a voltage limiter connected to a common bus with a call current generator The first DC source is connected to the common bus, the fifth switching input is connected to the output of the measuring unit, and the second and third DC sources, the corresponding poles of which are connected to the common bus, are that, in order to increase the reliability of the device, a magnetically inductive element with a Hall sensor was inserted into it, with the first coil of the magnetoinductive element connected between the first wire of the telephone line and the pole of the second DC source, the second winding of the magnetoinductive the element is connected between the second wire of the telephone line and the common bus connected through the third winding of the magnetoinductive element with a voltage suppressor, the first and second terminals of the Hall sensor are connected 0, respectively, with the pole of the third source of direct current and the common bus, and the third output of the Hall sensor is connected to the input of the threshold node, the fourth winding of the magnetic inductive element is connected to the input unit of measurement. 2. A device according to claim 1, characterized in that the magnetically inductive element is designed as 0 of the magnetic core, on which all the windings are made and in which the Hall sensor is located in the air gap. Information sources, 5 taken into account in the examination 1. The patent of France No. 2301982, cl. H 04 M 3/22, 1976.