DE1021026B - Circuit arrangement for generating double current symbols - Google Patents

Description

The invention relates to a circuit arrangement for converting single-stream symbols in double stream symbols. The most varied of types are under current symbols in the circuit arrangement according to the invention Understand direct current characters in the form of pulse combinations, telex characters, etc. Such characters can generally only be shown with simple means in the form of single-stream characters produce. For example, it is common for teletyping machines to use the machines themselves only to be equipped with a normally closed or normally open contact, which is then only able to provide single current symbols to create.

In the electrical generation of such characters, too, arise in many cases due to the peculiarity of the electrical or electronic switching devices, which, as is well known, can only give yes-no signs, Single stream symbol.

However, when transmitting such characters, it is known to be particularly advantageous to use double-stream characters to be used, since the transmission security is essential when transmitting such characters is increased without the message flow becoming smaller or a substantial circuit complexity would have to be driven.

It is known to use relay converters to generate double-stream characters from single-stream characters. the known relay converters, however, have the disadvantage that additional distortions occur during implementation, which can only be compensated with increased effort. In the circuit arrangement according to the invention should now, depending on the position of a working or break contact, the for example by the transmitter of a teletype machine is operated, so generally a single current switch, a consumer double current sign are fed.

Particular difficulties arise when it comes to a consumer that has a reactance, z. B. has an inductive resistor, as is the case, for example, with a polarized relay or Receiving magnets to receive the double stream characters is the case.

Double current symbols can be sent to a consumer depending on the position of a contact, i.e. in Dependence on single current characters according to the circuit arrangement according to the invention thereby supplied be that the double stream character evaluating consumer, z. B. a polarized relay in which Diagonal of a bridge circuit is arranged that said contact this bridge circuit in one controls the external branches and that by using at least one current-direction-dependent resistor the bridge is balanced in such a way that the

Circuit arrangement
for generating double stream cells

Applicant:
Siemens & Halske Aktiengesellschaft,

Berlin and Munich,
Munich 2, Wittelsbacherplatz 2

Benno Hausmann, Munich,

and Dipl.-Ing. Fritz Hennig, Munich-Solln,

have been named as inventors

Currents of the same magnitude in opposite directions flow through users in the two positions of the contact and that those appearing in place of the user Short-circuit currents and no-load voltages in the two possible positions of the contact are each oppositely equal.

It is known per se, with the aid of a bridge circuit, which is formed by at least one discharge vessel is controlled to convert single-stream characters into double-stream characters. But are with the well-known Circuit does not meet the conditions of the same short-circuit current and the same open-circuit voltage, so that the time constant in the consumer circuit for the different polarities of the current to be delivered characters is different, which has the consequence that distorted double-stream characters are generated.

The invention will be explained with reference to the Ausführungsbeispieis shown in Fig. 1 of the drawing. Depending on the position of contact k , a polarized relay V representing the consumer should receive double current signals. The voltage source E feeds the bridge via the terminals P 1 and P 2. By appropriately dimensioning the resistors Wl to W 4, the bridge could be adjusted without using a resistor-rectifier combination in the bridge diagonal so that the relay V acting as a consumer is traversed by positive or negative currents of the same size, depending on the position in which the contact k was brought. In the case of a bridge in which all bridge branches are equipped with linear resistors, the one between the terminals would be available to the consumer when the consumer is switched off

709 810/106

Claims (3)

occurring short-circuit current and the no-load voltage for the two current directions are different. The invention is based on the knowledge that the generation of distortion-free double-current characters has the same current strengths and the same edge steepness, i.e. H. Assumes the same time constants of the circuit for separating and character current steps. The same time constants are only achieved if, as mentioned, the short-circuit current and open-circuit voltage are the same in both operating modes. However, according to the invention, both conditions and the condition of the operating current can easily be met by a direction-dependent resistor in the form of the resistor-rectifier combination IV5 and Gl connected upstream of the relay V. In this case, of course, the resistors Wi to Wk must be dimensioned differently than if this resistor-rectifier element were not present. As the illustrated embodiment shows, it is thus possible, with a bridge arrangement according to the invention, to produce double-current symbols as a function of a single contact in a completely symmetrical manner and thus free of distortion. In Fig. 2, a further embodiment of the circuit arrangement according to the invention is shown, which is particularly simple in its structure. In this exemplary embodiment, the individual bridge branches are formed by the two halves of a voltage source E, the contact k and the resistor W6. The diagonal branch of the bridge is constructed in the same way as the diagonal branch of the bridge according to the exemplary embodiment according to FIG. 1. In the exemplary embodiment explained last, the adjustable resistor W6 is used to set the current flowing through the relay V when the contact k is open. In this case, the rectifier Gl is controlled in its forward direction, so that the resistor Wl is bridged. The current in the bridge diagonal is set via the resistor Wl, provided that the contact k is closed. In this case, the rectifier Gl acts as a high-ohm resistor, so that the resistor W7 is practically the only decisive factor for the current in the diagonal. In a circuit of this type, resistances W6 and W1 of at least approximately the same size result after adjustment. In addition, it should be noted that the current flowing through the contact k is greater than the current flowing through the relay V. In the embodiment according to FIG. 2, the contact current, assuming that the resistance of the relay V is of the order of magnitude of the resistors W6 and W1, would assume three times the value of the relay current. For this reason it can sometimes prove necessary to attach a spark quenching capacitor to this contact k. It should be mentioned, however, that such a capacitor causes an asymmetry in the curve of the double current, which would then have to be compensated for by an asymmetry of the circuit (asymmetry of the short-circuit currents). For measuring purposes and similar tasks in which a relatively small current is used and in which a distortion-free implementation is particularly important, it is therefore particularly advantageous to work with an unconnected contact or a very small spark quenching capacitor. As the illustrated embodiments show, double currents already occur in the bridge diagonal, and any consumer of double current symbols, be it in the form of a measuring device, a modulator, etc., can be arranged in this diagonal. The circuit according to the invention can also be implemented in a way other than that described. For example, instead of a contact, any other switch, e.g. B. an electronic switch can be used to control the bridge. PATKN TA N S P R Γι: H K 1. Circuit arrangement for generating double current characters in a consumer with any Impedance by a simple current switch, characterized in that the Consumers of the double stream symbols, e.g. B. a polarized relay, in the diagonal of a Brückensclialtung and the single current switch is arranged in one of the outer branches of this bridge circuit is and that with the help of at least one current direction-dependent resistor in the Bridge diagonal the bridge is balanced so that the consumer, z. B. a polarized relay two positions of the single current switch flowed through by oppositely equal currents and that the occurring at the terminals of the consumer when the consumer is switched off Short-circuit currents and no-load voltages for both positions of the switch, respectively are oppositely equal, 2. Circuit arrangement according to claim 1, characterized in that the current direction-dependent Resistance consists of a resistor-rectifier combination, in which resistance and rectifiers are connected in parallel to each other. 3. Circuit arrangement according to claim 1 and 2, characterized in that the current is direction-dependent Resistance in the bridge diagonal in series with the consumer, e.g. B. a polarized Relay, is arranged. 1 sheet of drawings © 7C9 810/106 12.57