DK164979B - CONNECTION TO NOISE IMPACT OF IMPULS FROM A SINUS-AC AC POWER CIRCUIT, NECESSARY OF 16-KHZ FEED IMPULTS - Google Patents

Description

DK 164979 B

In telecommunications systems in which, during a connection, over the relevant subscriber connection line, without interfering effect on the utility signal transmission, signal pulses must be transmitted to a subscriber location participating in such a connection, such signal pulses are often transmitted in the form of a pulse from a sinusoidal alternating voltage without for the utility signal frequency range; Thus, one can transmit fee-counting pulses to be transmitted to a calling indicator available on a calling telephone subscriber site or to a coin telephone, in the form of a time zone-dependent consequence of pulses from a 16-kHz sine band voltage over the voice band.

For insertion on the switching station side of 15 16-kHz charge pulses into a subscriber connection line, it is known to connect a 16-kHz sine voltage source across clock controlled switch contacts to a transformer with a series winding parallel to the secondary winding circuit, as on the secondary side across a suction circuit (band). leads to the cores in the subscriber connection line where it is blocked in the direction of the switching location by means of a blocking circuit, cf. for example Krause: OrtsSmter mit WShlbetrieb, 5th edition, Goslar 1962, figure 155. Such a known circuit can be used both with blocking of the feed circuit by means of a choke capacitor coupler (see, e.g., Krause, at the above-mentioned location, Fig. 154 above) and by blocking the feed circuit by a transformer-condenser-coupler (see e.g. Krause, at the mentioned location, Figures 134 and 154 below) and finally also, if the subscriber connection line, as it is also known (e.g., from IEEE Transactions on Electron Devices, ED-25 (1978) 2, 175 ... 179, Figure 2, and from telcom report 7 (1984) 2, 86 .... 92, Figure 3), at the mediation site of -35 is terminated by two feed streams flowing through a capacitor connected to each other on the subscriber 2

DK 164979 B

the lower side of a wiring transformer with an optionally grounded winding away from the subscriber; However, due to the necessary call and shock resistance of the components and partly as a result of the pre-magnetization by means of the feed stream, this implies a relatively large space demand and relatively high costs, which in the future these two views will become significantly more important because telecommunications administrations switch to 10 circuit technically to prepare the possibility of a 16-kHz charge pulse input for all subscriber connections.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the input of pulses from a sinusoidal alternating voltage, in particular of 16-kHz charge pulses, into telecommunication lines, in particular subscriber connection lines, each terminated in galvanically separated and capacitively interconnected, by a feed current. flowing windings on (the wiring side of) a wiring transformer with an asymmetrically coupled winding of the side facing away from the telecommunication line. The object of the invention is to enable such a signal input from a central AC source in a large number of such telecommunication lines without any major circuit technical supply.

According to the invention, this is achieved by the fact that each such telecommunication line facing away from the line on the line transformer can be galvanically connected to the AC voltage source over a MOS-FET coupler if a control input coupled to an RC parallel link is connected to a pulse actuator controlled direct current coupling, which is fed from a voltage converter-rectifier coupler, which is fed from the AC power source.

The invention results in addition to the lapse of a separate AC voltage input circuit containing a transformer coupled to a resonant circuit, and in addition to 3

DK 164979B

the elimination of the need for call and shock-resistant components has the additional advantage of enabling a soft remote control of each coupler and thus a quiet switching on and off of the AC voltage within a wide range of voltage by means of operating respectively. control voltages extracted directly from the alternating voltage to be switched on without the need for an external DC supply, whereby the necessary equipment of the individual coupler is constantly provided 10 independently of the instantaneous value and amplitude of the alternating voltage, and no significant loss effect is required.

It should be noted here that German Patent No. 32 37 550 discloses a circuit for low noise 15 switching on and off of pulses from a sinusoidal AC voltage, in particular of 16 kHz charge pulses, in which the AC voltage source is connected to one of a constant resistor. and a controllable resistor formed voltage divider, wherein a pulse actuator is connected to a controllable operating amplifier serving a step-shaped pulse, to produce the controllable resistor input, and where after the output of the controllable resistor over which the ac pulses are decoupled, a further operational strengths which constitute an impedance converter stage. This known circuit not only necessitates separate power supplies to the operational amplifiers provided in the circuit, but possibly also a special, sufficiently efficient operational amplifier, the amplification of which also changes when changing the voltage divider ratio, which influences correspondingly the introduction of the alternating voltage. Further contact points with the invention, requiring neither a separate power supply nor an active pulse amplifier stage, are not available.

In one embodiment of the invention, the MOS-FET coupler leads to a midpoint outlet on the wiring converter.

DK 164979B

4, the winding facing away from the telecommunication line is cleaned, which enables an existing, conventional only for connecting very few telecommunication wires laid out alternating voltage source to also ensure sufficiently high signal levels for a large number of telecommunication lines as a result of the voltage transformation. Conveniently, a bandpass filter may also be inserted between the MOS-FET coupler and the outlet on the winding of the wiring transformer, which also includes the transformer partial spreading cell induction, which at least partially compensates for voltage loss associated with spreading cell windings.

Further features of the invention will be apparent from the following detailed explanation of an embodiment of a coupling according to the invention shown in the drawing.

In the drawing, a schematic and, to the extent necessary for the understanding of the invention, a section of a subscriber connection connection which terminates in a digital switching station an analogue subscriber connection line L and in which the subscriber connection line L is terminated with two of a feed DC current. galvanically spaced apart and capacitively interconnected on a conduit U, 25 if the one-side earth-connected and thus asymmetrically coupled winding away from the subscriber connection line L is connected to a winding indicated only in the drawing with some input and output coupling components. analog / digital interface coupling ADS. Such interface interfaces are known, for example, in the form of the so-called Customer Optimized Subscriber Line Audio-Processing Circuit Am 7905 - COSLAC from the company AMD or the so-called Signal-Processing Codec Filter PEB 2060 - SICOFI from the company Siemens (see also telcom report 35 7 (1974) 2, 86 ... 92) and therefore need not be considered further here.

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DK 164979B

For quiet input of pulses from a sinusoidal alternating voltage, for example 16-kHz charge pulses, into the subscriber connection line L, a midpoint outlet m of the conduit transformer U, away from the line L 5, is connected galvanically to the (16-kHz) alternating voltage source emitting voltage. over a MOS-FET coupler S. formed by two series-connected MOS-Feld transistors Ti and T2, for example two SIPMOS transistors BSS 100. Between the connection point 10 between the two field power transistors T1, T2 and their control electrodes, the parallel connection of a resistor Rp (on for example, 200 kOhm) and a capacitor Cp (of, for example, 220 nF). To the control input s coupled to this RC parallel link Rp, Cp on the MOS-FET coupler S 15, a direct current coupling J. controlled by an impulse impeller Z can be applied, as shown in the drawing, in principle (f. eg from Steimel: Elektronische Speisegeråte, Miinchen 1957, fig.

3.36) known as the DC voltage supply, 20 by feedback control, stabilized DC source with a series transistor T (e.g., type BC 307), a discriminator resistor R (e.g. 82.5 kOhm) and a zener diode V (e.g. type BZX 97 C3V9), which forms a comparative voltage encoder. The even-current switching circuit J is fed by a voltage converter G of the voltage converter U which is fed from the source voltage U, which, as also shown in the drawing, can be designed as one (in principle, for example, from Meinke / Gundlach: Taschenbuch der Hochfrequenz-30 technique, 1956). Fig. Y7.5.b known) cascade coupling with two (e.g., Meinke / Gundlach, at the indicated location, Fig. Y7.1 known) single-point rectifier ground couplings each with diode D1 and D1 respectively. D2 (for example BAY 43 type) and a series capacitor C1 (for example 100 nF) 35 respectively. a parallel capacitor C2 (for example 22 nF).

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DK 164979 B

Between the MOS-FET coupler S and the mid-point socket m of the wiring transformer ϋ away from the winding, a (16-kH2) bandpass filter BP is inserted which allows a selective input of the (16-kHz) 5 alternating voltage any from the alternator voltage generator U, in addition to the generating noise voltages. Conveniently, the band-pass filter BP's self-induction also comprises a scattering cell induction in the conduit transformer 0, so that by corresponding reactance compensation 10 a reduction in the voltage losses is obtained.

In addition, between the converter transformer ϋ and the analogue / digital interface coupling ADS, there is a (16-kHz) band-stop filter BSp in order to keep the alternating voltage pulses outside the conduit connection line L connected to the subscriber connection line L / digital interface connection ADS.

The bandpass filter BP and the bandstop filter BSp are not flowed through the feed direct current of the subscriber connection line L and are therefore not subject to pre-magnetization. Also, their components need not be call and shock voltage resistant so that in the two filters BP and BSp relatively small coil and capacitor forms can be used.

In the drawing, it is also suggested that between the pulse encoder Z and the power source switch J, a level adjustment switch R41, T40, R42 may be inserted if the output signals emitted by the impulse encoder Z are not suitable for constant control of the constant current source J, for example. .

The circuit outlined above with respect to its coupling technical structure ensures a quiet input of pulses from the alternating voltage supplied by the central 35 (16-kHz) AC voltage in a large number of subscriber connection lines L.

Claims (6)

1. Coupling for quiet input of pulses from a sinusoidal alternating voltage, in particular of 16-kHz transmit pulses, into at least one telecommunication line (L), in particular a subscriber connection line terminated by two feed-through galvanic galvanic DC 164979 B 8 separate but capacitively interconnected windings on the telecommunication side of a wiring transformer (U) with an asymmetrically coupled winding on the side facing away from the telecommunication line, with an AC supply source (U) and an impulse rate controlled coupler (U). , characterized in that each such telecommunication line (L) away from the winding of the line transformer (U) is galvanically connected to the AC voltage source (U) over a MOS-FET switch (S), if with an RC parallel circuit (Rp, Cp) coupled control input (s) is connected to a direct current coupling (J) controlled by a pulse actuator (Z) fed from a in the case of the alternating voltage source (U), voltage doubler-rectifier coupling (G) is born. 2. A coupling according to claim 1, characterized in that the direct current coupling (J) supplied with the unidirectional voltage comprises a feedback transistor stabilized (T) whose output electrode is connected to the control electrodes of two series connected field effect transistors (T1, T2). The MOS-FET coupler (S), and between whose connection point and their control electrodes the RC parallel (Rp, Cp) is connected. 3. A coupling according to claim 1 or 2, characterized in that the MOS-FET coupler (S) leads to a midpoint outlet (m) on the winding of the wiring transformer (U) away from the winding of the telecommunication line (L). A coupling according to claim 3, characterized in that a bandpass filter (BP) is included between the MOS-FET coupler (S) and the outlet (m) on the winding of the conduit transformer (U), which also comprises the partial spreading cell ventilation of the transformer. Coupling according to one or more of claims 1-4, characterized in that the rectifier coupling (G) is designed as a cascade coupling with two single-point rectifier basic couplings (C1, D1; D2, C2). 9 DK 164979B 5 A soft sensing of each coupler S is thereby obtained by a correspondingly slow charging and discharging of the capacitor Cp in the pulse former Rp, Cp. By changing the sizing of capacitor Cp and of resistors Rp and R, the rise and fall times of the pulse flanks can be varied. As already mentioned, coupler S can be realized with two SIPMOS transistors BSS 100, which allow a low ohmic throughput of the charge count pulse voltage. To equip the SIPMOS transistors, a port-15 voltage is required which is approx. 4 V above the maximum value of the voltage to be switched on, the Generator U of 16-kHz can optionally supply an alternating voltage with an amplitude Uy of a maximum of 9 V (and a minimum of 6.4 V). The minimum port voltage must then be approx. 16.7 V 20 (9 x 2 ^ + 4). The peak value rectifier coupling G in 1 / idle gives a DC voltage UG = 2x2 / 2xUu-2UD, where UD is the voltage drop across a rectifier diode (D1, D2). At UUmin = 6.4 V you get UGmin = 17.1 V. The cascade connection G does not load the 16-kHz generator U in the idle state. The current flowing under a count pulse is more than two orders of magnitude smaller than the charge count pulse current and can be neglected to that extent. 30 Coupling according to one or more of claims 1-5, characterized in that a level adjustment coupling (R41, T40, R42) is switched on after the pulse rate sensor (Z).