DD144143A1 - ELECTRONIC CALL SWITCH - Google Patents

Abstract

The invention relates to an electronic call switch for telecommunications systems, which responds to the modes DC or AC call, without first being set to a specific mode. It is the object of the invention to provide an electronic call switch for DC and AC reception with a high sensitivity and a floating symmetric input which responds without prior switching to the signal type and which prevents the effectiveness of interfering signals or potentials. This has been achieved by converting an active quadrupole, which requires no additional power supply, into a change quantity. A downstream small transformer causes the galvanic separation and ensures the symmetry.

Description

Electronic call switch

Field of application of the invention

The invention relates to an electronic call switch for telecommunication systems, which responds to the modes of AC or DC without first being set to a certain mode of operation *

There are known solutions in which the telecommunications equipment operated on a telecommunication line to meet the requirements for line symmetry are terminated with a line transformer which is connected to the primary line to the telephone line and to the secondary side of which Call evaluation follows. ,

This is known, for example, in the inventions made by DT-PS 1,134,717..and DT-AS 1,132,978 in which the transmitter is used as a bandpass of the speech frequency band , However, this circuit concept is only possible. Evaluate AC Calls "The previously known further call organs, the Equal Wechselstfomanruf evaluate, have the disadvantage that no galvanic isolation between. Telecommunication line and evaluation circuit »»

In these solutions ground potential reaches the telecommunication line. E When several systems are interconnected

and when ground potential differences occur on the communication lines potential differences that can be recognized by the call organ as a call · This can lead to incorrect response of the call organs *. ^ relay call organs have this disadvantage. Not, but they are for many purposes, because with them no large Input resistance can be achieved and a relatively high response energy is required. The reliability of such circuits meet today's claims nothing The circuits described in DL-PS 82 757 and in the magazine "Military Technology '?, H» 9, 1967 "So 415» have the disadvantage. ,, That they require a large design, as the security for evaluating the ringing frequency compared to the speech signal makes a corresponding dimensioning of Hiederfrequenzleitungsübertragers required ·· the in DT-OS 2 30? 015 inventive concept described indeed eliminated the lack of size, but does not receive the required for the communication lines cable symmetry and galvanic isolation ·

Object of the invention. .

The invention provides an electronic call switch for DC and AC reception to be created _? which has a high sensitivity and is provided with a potential-free balanced input «,

Explanation of the essence of the invention:

The invention li, the task egt invention to provide an electronic call button _s is able to without a previous or switch to AC to address * DC signals '':

The call organ consists of an active quadrupole '.dem.' no additional operating voltage is supplied. · This quadrupole is parallel to the primary winding of the line transformer or, in the case of unbalanced lines, parallel

,. - - 3 - * 3-4 & Ό '

to the input circuit of the device · The high-impedance input of the quadrupole allows a permanent Anschaltung.an the trunk, without causing FehlanpassuRgen »The quadrupole is powered by the call energy ¹ The task of ^ invention is solved _s that im. Quadrupole the call information, (DC or AC voltage) can cause a generator to vibrate β The Wechselgröße- outgoing from the generator carries the call information and is inductively coupled to an evaluation device ·

The frequency range to be received theoretically goes from zero to infinity, thus also includes DC signals, the upper limit frequency z. B *, which can be used to determine the input circuit »* The sensitivity depends on the operating voltage of the generator used.» While the maximum upper limit of the input voltage is determined by the input circuit, the minimum input voltage that can trigger a switching process is essentially: the operating voltage of the generator "

embodiment

The invention will be explained in more detail with reference to an exemplary embodiment.

Figure 1 shows the ..Anschaltung .des Vierpols · ah. one. , : symmetric retransmission. It is always parallel the line transformer on the line to DC or We, ^ehsel: stromruf to recognize "·. _: . / '^"·:;^> Ν _ Figure 2 shows the block diagram of the entire" Anruforgansβ.

Via the series resistors 1, the call signal reaches the rectifier 2 ", the zener diode 3 limits the call voltage to the maximum value of the operating voltage of the generator 4 ₀ i This represents the input circuit, from the dimensioning of the frequency

and the maximum permissible input voltage U ^ dependent

The call signal causes the oscillation of the generator 4, the generated AC voltage but the micro-transformer 5 acts on another rectifier 6 ·· In the downstream DC amplifier 7, a switching operation is effective, which takes over the further evaluation of the ringing signal «. In practice, the generator is a bistable multivibrator constructed with bipolar transistors. Its oscillation takes place at call performances of 50 yUW.

Thus, with this call organ input resistances of about 50 kOhm can be realized «

The maximum input voltage U · ™ depends on the diodes used in the input circuit and is about 500 V.

The advantages of the circuit according to the invention are low call power of about 50 yuW and a symmetrisc'h high-impedance input. Due to the high impedance of the input 'misadjustments avoided' Furthermore, it is guaranteed that no potentials from the call organ on the FM line get «.

The call organ has good RF strength, i. h ", in strong RF fields and RF disturbance voltages on the FM line, there is no faulty response ₀ Without prior switching of the input circuit, this circuit is capable of detecting signal voltages of approx. _o 1 V up to more than 500 Y ·. ,

Integrating the circuit ζ, .B _β in the hybrid technology is possible. This results in weight and space savings, which are important for mobile Wechselprebhtechnik and the reliability of the call organ is further increased « ¹ - .. '. - . :;

Claims (1)

Claim of invention. :. , , , , Electronic call switch for DC or AC signals, which can be switched without prior switching to the respective one. Signal type with least energy consumption responsive, suitable for connection to any. Ge Fernmeldeleitungen because there is potential at the input potential, symmetry and galvanic isolation, characterized in that a high-impedance network is symmetrical, constructed on the telecommunications line (1), followed by a symmetrical rectification (2) with limit (3), with their energy output a generator (4) is operated -wird, so that the resulting change in size by a transformer symmetrically separated from the described circuit, is present for further evaluation «' , JOeiteri ZelcfiittiMen