FI63139C - COPYING INSTRUCTIONS FOR IN-HOUR OPERATION WITH BRACKETS AND RADIOL LINKS - Google Patents

Description

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Saksein Li i tt otta a valta-Förbunds republiken OVskland (DE) P 2533711-5 (71) Siemens Aktiengesellschaft, Berlin / Munchen, DE; Wittelsbacherplatz 2, D-8000 Munchen 2, Federal Republic of Germany-Förbundsrepubliken Tyskland (DE) (72) Klaus Boshold, Eichenau, Federal Republic of Germany-Förbundsrepubliken lyskland (DE) (7 ^) Berggren Oy Ab (5I +) -sissa - Kopplingsanordning för in- och urkoppling av tilläggssignaler vid radiolinkanläggningar

The invention relates to switching for switching additional signals in and out in transmission devices, in particular in intermediate stations of radio link facilities, which are otherwise used for transmitting wide modulation bands, e.g. in frequency modulated form, and in which additional signals are fed to receiving mixers in both directions by modulating their local oscillators.

In addition to the area actually occupied by conventional type, e.g. frequency modulated telecommunication signals, it is customary for radio link connections to transmit additional signals such as service calls and control signals. Thus, for example, in an 1880 voice channel radio link system, a portion of the baseband band of 0.3 to about 51 * kHz is reserved for thirteen additional service channels having a bandwidth of 3.1 kHz and is used to transmit additional signals.

At intermediate stations where no detection is performed, the receiver oscillator is made modulated for input of maintenance signals. The additional signals are then separated by a second intermediate frequency output of the receiver to which a detector is connected. Service signals must be sent in both directions of transmission and must also be received in both directions. This is shown in the block diagram of Figure 1, in which such an additional signal ZS comes from the second direction to the receiver E1, which after mixing it converts to the intermediate frequency ZF, which is passed on via a transmitter including an output mixer to the antenna for transmitting radiation. The same applies to the return direction, respectively, in which the transmitter and receiver are denoted by reference numerals S2 and E2. It follows from the input method that the input signals also become separated at the station itself. Self-listening interferes and, in addition, acoustic crosstalk from the service call output to the input may occur, i.e., feedback may form, causing distortion and, in extreme cases, oscillation, i.e., rendering the system unusable for transmitting additional signals.

The object of the invention is to avoid these disadvantages.

This task is solved in switching to switch additional signals in and out in transmission devices, in particular in radio link intermediate stations, which are otherwise used to transmit wide modulation bands, e.g. in frequency modulated form, and is introduced into an electronic fork coupling, in which the opposite-phase cancellation of the parallel-frequency and in-phase parts of the second direction takes place and from which an additional signal of the opposite direction is obtained in pure form.

In addition, a circuit is preferred in which the one-way signal is applied to a common base transistor and the other direction signal to a co-emitter transistor, and the collectors of both transistors are connected to the same load resistor, most preferably followed by an additional amplifier. .

A preferred development of the circuit is obtained in such a way that feedback paths are formed on the collector side of the common amplifier stage of the common amplifier stage connected downstream of both transistors, by means of which the gain of both branches can be set A * '* 3.

In this way, it is advantageously provided that the signals coming from both channels simultaneously add up in opposite phase in the fork coupling and cancel each other out. In addition, the fork coupling, which is most preferably implemented in an electronic form of the type described above, has the advantage that the two inputs of the maintenance signals become separated from each other.

The invention is explained in more detail below in connection with Figures 1 and 2.

Both signal outputs 1 and 2 of the additional signals are led to the fork connection G in Fig. 1, and at 3 the two signals are separated from each other and the signals are obtained released from their respective parts.

Since the realization of a coil-based fork becomes technically difficult and unfeasible in practice, especially in large frequency ranges, in many cases it is better to use the coupling shown in more detail in Figure 2.

Figure 2 shows a transistor circuit in which the first signal 1 is applied to a transistor stage Ts1 in a common base circuit. The second signal 2 is applied to a second transistor stage Ts2 in common emitter coupling. The collectors of both connections are directly connected to each other and each connection thus has a common output resistor R19 together with the input resistor of the additional transistor stage Ts3 for additional gain and other functions. Transistor Ts3 is connected to a common emitter circuit, and the output of both signals is then formed by switching point 3 via C11 and R23. In order to match the inputs of both connections, which are completely different due to their different characteristics, there is a resistor R5 at the input of the common base stage Ts1 to increase the input resistance. In contrast, alongside the input of transistor Ts2, there is a parallel resistor R14 to reduce this relatively high input resistance so much that both input resistors become at the same value Z.

By using, on the one hand, a common base connection and, on the other hand, a common base connection and the same amplification on both paths,

Claims (2)

4 63139 that the in-phase and level-equal portions of both inputs 1 and 2 disappear at the output. In order to improve the linearity and stability of the system, feedback from the common output stage Ts3 to both input stages has been performed. In this case, part of the output energy of the transistor Ts3 is fed back via the adjustable resistor R9 from the collector to the emitter of the transistor Ts1. On the other hand, in order to apply a feedback field voltage to the emitter of the transistor Ts2, a voltage divider R20, Cl4, R18 is formed alongside its resistor R17. The resistor R18 is likewise made adjustable so that the feedback of both branches can be matched to each other and the gain of both paths can be set equal. Phase correction, which in practice becomes necessary at high frequencies, can be performed with adjustable reactive elements in the respective branches. In this way, a very good separation of the desired type of input can be obtained. 1. Switching for switching additional signals on and off in transmission devices, in particular at intermediate stations of radio link facilities, which are otherwise used to transmit wide modulation bands, e.g. in frequency modulated form, and in which additional signals are ) the additional signals (1, 2) obtained by detecting the relevant subbands of the intermediate frequencies (ZF) are applied to an electronic fork coupling (G), in which the opposite frequency of the same frequency and in-phase parts are reversed in phase and the additional signal of the opposite direction is obtained in pure form. A circuit according to claim 1, characterized in that the second direction signal is applied to a common base transistor (Ts1) and the second direction signal to a common emitter circuit (Ts2) and the collectors of both transistors are connected to the same load resistor (R19), most preferably followed by an additional amplifier (Ts3) and that, in addition, the input resistors of both connections are made equal by the additional connections of the parallel (R14) and series resistors (R5). r '1' '