DE1288164B - Circuit arrangement for generating an identification or selective call sign - Google Patents

Description

The invention relates to a circuit arrangement for generating a consisting of different successive audio-frequency character steps Identification or selective call sign by means of a self-oscillating oscillator, whose resonant circuit consists of a single capacitor with a fixed capacity and an in consists of several sections of different inductance subdivided single coil and in which the individual connections of the coil sections each have at least one of several that can be actuated automatically one after the other in the required sequence Switches can be interconnected with the capacitor, in particular in telecommunications systems in radio telephone systems with selective calling.

Each subscriber station can use the identifier for they send out a characteristic call signal to be received at a central station. This possibility is e.g. B. important when a subscriber station in case of danger Must send out an emergency call and has no opportunity to respond otherwise, z. B. by speaking, to be recognized.

The selective call generator located at the central station serves to to send out a specific sequence of tone-frequency ringing signals in order to select from a number of Subscriber stations to reach a specific subscriber from this central point, without disturbing the other participants.

It is known, for these cases, a sequence of tone-frequency ringing signals to send out different frequencies with those of the transmitter of the identification or selective call generator is modulated. A possible circuit device to select the desired one Subscriber station is described in German patent specification 902 742, in which particularly the setup of the receiving end of this message traffic is explained while the use of this known circuit arrangement on the transmitter side only briefly is treated. Both devices use to check the received call signals or for the transmission of the call signals in the prescribed sequence switching devices, which are formed from stepping mechanisms and / or relays.

When using stepper mechanisms and / or relays it is very inconvenient that they take up a large space, a large power consumption have, are prone to failure, are subject to wear and tear and are expensive to manufacture are.

In addition, there are frequency-determining resonant circuits with a fixed capacitor and a coil with taps for oscillators and filters with mechanical and electronic switches including automatic switch actuation known. Timing circuits with astable and monostable multivibrators are also included to the state of the art.

The purpose of the invention is now to provide a device for transmitting the Call signals in the prescribed order for an identification or selective call transmitter propose, in particular, through the possibility of using integrated Building blocks is smaller, cheaper and more reliable than known facilities.

The invention is that one of monostable multivibrators Existing derailleur system, where each time a multivibrator tips over into his unstable position only this multivibrator has a corresponding return delay gives a long output signal each time a multivibrator is tilted back into its stable position each subsequent multivibrator tilts into its unstable position, with the tilting back of the last multivibrator into its stable position the arrangement returns to its rest position and the individual multivibrators each have one of the The duration of the output signals to be generated have a corresponding return delay, on the input side with a send button and gradually on the output side with the control inputs the individual switch is connected so that with a single actuation of the Send button first the first multivibrator and then the other multivibrators tilt one after the other into their unstable positions and in each case for the duration of their output signals the switches assigned to the tone frequencies of the individual character steps step by step press one after the other.

In a further embodiment of the invention, an electronic switching device be arranged, which automatically when you press the send button a microphone of the Transmitter switches off as well as the signal path from the oscillator to the transmitter releases and at Tilt back the last monostable multivibrator of the chain circuit, the microphone switches on and interrupts the signal path. In this way the ringing signals not bothered by any discussion of the microphones, and the participant needs do not make the mentioned switchings by hand. The electronic Switching device be a bistable multivibrator, which when the send button is pressed tilted from its first stable position into a second stable position and when tilting back the last monostable multivibrator of the chain circuit into its first stable Position is tilted back.

It may be desirable that between the individual tone-frequency ringing signals a break should be observed. This can according to further features of the invention by interposing a delay element between two successive ones monostable multivibrators of the derailleur can be achieved.

The invention also enables selectable selective call generators Interconnection of changeover switches between the switching transistors and taps the self-induction of the oscillating circuit. The switching transistors can thus be selected Self-induction taps are switched.

Further details of the invention, as well as its mode of operation, are explained on the basis of the drawings, in which exemplary embodiments of an identifier and selective call transmitter are shown. In Fig. 1 shows an arrangement with the one consisting of four steps of given lengths and given frequencies Characters can be generated; F i g. 2 shows an arrangement with which a consisting of three steps of predetermined lengths, but selectable frequencies Characters can be generated; F i g. 3 and 4 are shown arrangements with which the characters generated in each case with disconnection of the microphone circuit to the input a transmitter can be created; F i g. 5 and 6 are the timing charts two characters shown; F i g. 7 shows an arrangement with which a from four steps of given lengths and given frequencies and between the steps of pauses of predetermined lengths existing characters can be generated can.

The arrangement according to FIG. 1 is primarily for electronic Identifier determined with fixed call frequencies. The arrangement contains a feedback transistor oscillator and a frequency change causing it Control device. The frequency-determining part of the oscillator consists of the Coil 2 wound on core 1 with taps 3 and 4 and the capacitor 5, the transistors 6 to 9 each with a part of the coil 2 to form a Resonant circuit is interconnectable. The control device consists of the send button 10 and a chain circuit consisting of the monostable multivibrators 11 to 14, whose tilting stages are indicated by an arrowhead when the arrangement is at rest designated rest positions. The working position outputs of the individual tilt levels the chain circuit are connected to the control inputs via lines 15 to 18, i. H. connected to the bases of transistors 6 to 9. To oppress another Type of information, in the given example speech information, during generation of the individual drawing steps, the bistable flip-flop 19 is provided, which in the Retirement is ineffective.

When the transmit button 10 , which initiates signal generation, is pressed, the monostable flip-flop 11 and, via the line 20, also the bistable flip-flop 19 flip into their working positions. The monostable multivibrator 11 controls the transistor 6 through the line 15, and the oscillator thus oscillates at the predetermined first symbol frequency. The transistor 22 serves as an oscillator transistor, while the transistor 23 acts as an amplifier transistor. the coils 24 and 25, which are also wound on the core 1, effect a galvanic separation of the resonant circuit from the power supply of the transistors, which is fixed in terms of potential, especially during vehicle operation. The filter element 26 to 28, which consists of two capacitors and a coil, serves to suppress undesired high-frequency vibrations. The bistable flip-flop 19 controls the switch 30 in its working position via the line 29 so that the transistor 23 can amplify the symbol frequency. At the same time it separates the speech path leading from the microphone 31 via the amplifier 32 and the switch 33, so that no disturbing speech information can reach the transmitter 35 via the amplifier 34 and the antenna 36 to the remote receiver during the character frequency generation. After the return delay time inherent to the monostable multivibrator 11 has elapsed, the latter tilts back into its rest position and thus ends the generation of the first symbol frequency. At the same time, however, it controls the monostable multivibrator 12 into its working position via the line 37, which controls the transistor 7 through the line 16, and the oscillator thus oscillates at the predetermined second symbol frequency until the multivibrator 12 has elapsed its own return delay time returns to its rest position. The same applies to the monostable flip-flops 13 and 14, which are used to generate the third and fourth symbol frequency and, after their own return delay times have elapsed, each tilt back into their rest positions. The monostable flip-flop 14 also controls the bistable flip-flop 19 to its rest position with its tilting back via the line 21 , whereby the switch 30 is opened to prevent further character amplification and the switch 33 is closed to bring the microphone circuit back to the transmission path to turn on. The coupling between the transistors 22 and 23 takes place via the capacitor 38, while the adjustable output energy is fed to the amplifier 34 via the line 39.

The arrangement according to FIG. 2 is primarily intended for an electronic selective call transmitter with optionally emitting calling frequencies; however, it can also be used as an identifier that can be easily changed. With regard to the parts provided with the same reference numerals, this arrangement corresponds to the arrangement according to FIG. 1 match. The three monostable flip-flops 51 to 53 successively control the three switches 54 to 56 of the frequency-determining parts 2 to 5 to generate a character consisting of three steps. With the help of the switch groups 57 to 59, within each of which only a single switch can be switched on, it is possible, with the same arrangement, to successively generate several characters consisting of three steps that have mutually different frequencies or frequency sequences. In addition, in the arrangement according to FIG. 2 the switches 30 and 33 can be controlled directly by the transmit button 10 and by the monostable multivibrator 53, which saves a bistable multivibrator for controlling them. It is necessary, however, that the switches 30 and 33 themselves are bistable and can be switched on and off via separate lines, unless they can be directly controlled by the rest position output potential of the monostable multivibrator 53.

The arrangements according to FIG. 3 and 4 are used for recording and amplification of speech currents or their suppression, including the microphone 31 with the transistor 40 is connected. To suppress the flow of speech during character generation by one of the arrangements according to FIG. 1 or 2, it is sufficient for the arrangement F i g. 3 to disconnect the line 41 from the positive potential, while it is in the Arrangement according to FIG. 4 is sufficient to connect the line 43 to the positive potential.

The in F i g. The characters U (t) shown in FIGS. 5 and 6 consist of steps 44 to 47, of which step 44 has a length that differs from steps 45 to 47. The step lengths are determined by the return delay times of the monostable multivibrators. When using monostable multivibrators with the same return delay times, only the same step lengths or integer multiples thereof can be achieved. The characters according to Fig. 5 and 6 differ from one another in that the symbol according to FIG. 5 no pauses and the sign after F i g. 6 has pauses inserted between the individual drawing steps.

The arrangement according to FIG. 7 contains in addition to those already in the arrangement described in accordance with F i g.1 Divide the three other monostable Flip-flops 48 to 50, which have a return delay time at the end of each character step generate a correspondingly long pause step.

In the arrangements described, 6 to 9 and 54 to 56 switching transistors are required as transistors. The switches 30 also contain switching transistors. With a suitable construction of the bistable multivibrator 19, a special switching transistor can be omitted in the switch 30; its bistable multivibrator 19 must then supply the emitter voltage required for transistor 23 from one of its transistors. With a suitable construction of the monostable multivibrators 11 to 14 or 51 to 53, each containing two transistors, they can also take over the functions of the switching transistors 6 to 9 and 54 to 26. In this way, the switching transistors can also be saved here. The bistable multivibrator 19 can even be saved if the last monostable multivibrator of the respective ladder circuit on the one hand and the switches 30 and 33 on the other hand are dimensioned in a suitable manner.

Claims (4)

Claims: 1. Circuit arrangement for generating an identification or selective call sign consisting of different successive tone-frequency character steps by means of a self-oscillating oscillator whose resonant circuit consists of a single capacitor of fixed capacitance and a single coil divided into several sections of different inductance and in which the individual connections of the coil sections can be interconnected with the capacitor via at least one of several switches that can be automatically operated one after the other in the required sequence, in telecommunications systems, in particular in radio telephone systems with selective calling, characterized in that one of monostable multivibrators (11 to 14 in (Fig. 1 ; 51 to 53 in FIG. 2) an existing chain circuit in which with each time a multivibrator tips over into its unstable position, only this multivibrator generates an output signal a b gives, each time a multivibrator is tilted back into its stable position, the subsequent multivibrator tilts into its unstable position, with the tilting back of the last multivibrator (14 in FIG. 1; 53 in FIG. 2) the arrangement returns to its stable position and the individual multivibrators each have a return delay corresponding to the duration of the output signals to be generated, on the input side with a transmit button (10) and gradually on the output side with the control inputs (bases) of the individual switches (6 to 6) 9 in FIG. 1; 54 to 56 in FIG. 2) is connected in such a way that when the transmit button (10) is actuated once, the first multivibrator (11 in FIG. 1; 51 in FIG . 2) and then the further multivibrators (12, 13, 14 in FIG. 1; 52, 53 in FIG. 2) one after the other tilt into their unstable positions and each time the audio frequencies of the individual character steps for the duration of their output signals Activate the assigned switches (6, 7, 8, 9 in FIG. 1; 54, 55, 56 in FIG. 2) one after the other. 2. Circuit arrangement according to claim 1, characterized by an electronic switching device which automatically switches off a microphone (31) of the transmitter (35) when the transmit button (10) is actuated and releases the signal path (39) from the oscillator to the transmitter and when the last monostable is tilted back Multivibrators (14 or 53) of the chain circuit switches the microphone on and interrupts the signal path. 3. Circuit arrangement according to one of claims or 2, characterized in that a delay element between two successive monostable multivibrators (z. B. 11 and 12) of the chain circuit is provided. 4. Circuit arrangement according to a of claims 1 to 3, characterized in that between the switching transistors (54, 55, 56) and the taps (e.g. 3, 4) of the self-induction (2) of the resonant circuit Changeover switches (57, 58, 59) are used to connect the switching transistors to selectable taps the self-induction are plausible.