DE876253C - Circuit for the automatic replacement of one oscillator or amplifier with another - Google Patents

Description

The invention relates to a circuit through which an oscillator or amplifier by means of 'discharge tubes generated or amplified electrical vibrations are fed to a consumer.

If such a circuit is to be operated continuously, it is essential that a backup oscillator or amplifier is available which is activated in the event of a fault in the oscillator or amplifier that is normally in operation. It is common, for example, in carrier wave telephony systems with a number of speech channels, to take the carrier waves required for the various channels from a common carrier wave generator, for example by frequency multiplication. In order to prevent all channels from becoming unusable in the event of a disturbance in this carrier wave generator, through which it stops oscillating or only generates vibrations with a reduced amplitude, a reserve carrier wave generator must be provided, which is automatically put into operation in the event of a disturbance and on this Way gives the opportunity to continue operations uninterrupted.

As an example of a circuit with an amplifier that must be in continuous operation, a telephone transmission system with on-line repeaters can be cited will. In the event of a fault, e.g. B. as a result of an occurring on one of the amplifier tubes Damage, the defective amplifier must be replaced automatically by a spare amplifier.

According to the invention; in a circuit that has two oscillators or amplifiers with discharge tubes and contains a load and in which the oscillator or amplify the load normally feeding at a If the interference is replaced by the other, the two oscillators or amplifiers are set up in such a way that that an at least brief change in one of the operating voltages) or one of the electrical ίο constants of one of the oscillators or amplifiers a sudden permanent change in its operating condition.

The invention is explained in more detail in the drawing.

In Fig. Ι the circuit of an oscillator with a feedback discharge tube 1 is shown. The lattice circle of this tube contains an oscillating circuit 2 which is in an inductive relationship to the anode circuit by means of a feedback coil 3. The cathode line also contains resistors 4 and 5, which are bridged by a capacitor 6, which practically means a short circuit for the vibrations to be generated. These resistors are connected in series with a resistor 7 to the anode voltage source 8 and are dimensioned so that the voltage drop causes such a negative grid bias that the tube 1 is blocked and the circuit does not oscillate. In parallel with the resistor 5 are a. Switch ¹ 9 and a resistor 10 bridged by a capacitor 11 are provided. By closing this switch 9, the negative grid bias is reduced to such an extent that the circuit begins to oscillate. Correct setting of the circuit can ensure that the oscillations persist even after the switch 9 has been opened again. However, if the steepness of the tube 1 decreases either through age or as a result of a reduction in one of the supply voltages / so> the circuit stops oscillating and the oscillations no longer start automatically, not even after the tube has been replaced or the supply voltages return to normal Got value back. .- ._

To explain the mode of operation described above, FIG. 2 shows the relationship between the grid bias voltage v _{s of} the tube 1 and the. The amplitude of the generated vibrations is shown. In the case of small values of the grid prestress, no vibrations are generated at all. If, however, the bias voltage is _{increased to a value z / g} ', the circuit suddenly begins to oscillate, with the. Amplitude ... of the generated vibrations i '_ . A further increase of the bias, the amplitude of the vibrations generated increases according to the curve to be off. If the grid bias is then reduced again, the amplitude decreases according to curve bc and jumps at v _g "_ from the value i" . suddenly .to the value zero.

- With the circuit according to Fig. 1 is now opened when. ..Switch 9 .the _ grid bias is set to a value w _g0 lying between v _s " and v _g ' , at which vibrations do not start automatically. By briefly closing switch 9, the grid bias is briefly to the value v / or higher After the switch 9 has been opened again and the grid bias has thus again _{assumed its original value ^ 0} , the oscillations remain with an amplitude i _a Because when the tube oscillates, no undistorted anode alternating current is formed due to the large negative grid bias voltage, since the negative half-waves are wholly or at least partially suppressed, while the positive ones develop undistorted present, which is greater than the anode direct current, which flows in a vibrationless state.

However, if the voltage of the source 8 falls below a certain value as a result of a disturbance, the vibrations stop and cannot start again, even after the tension the source 8 has returned to the usual value. At the same time, the middle one takes Anode direct current down to the value zero. The same happens if a different operating voltage or one of the electrical constants of the circuit, e.g. B. the steepness of the tube i, smaller will.

It follows from the above that the oscillator circuit is thus set up and adjusted is that 'an at least brief change in one of the operating voltages is a sudden one A permanent change in the operating state requires a non-working oscillator is put into operation after a brief increase in the grid prestress, while after a change one of the operating voltages or one of the electrical constants that cause a decrease in the The amplitude of the generated vibrations causes the oscillator to be put out of operation.

In Fig. 3, two such oscillators are shown, where like reference numerals designate the same parts as in FIG. The parts of the right in the figure shown oscillator 12 are through Comms from those of the left oscillator 13 differentiated. .

The anode circuit of the oscillator 13 contains a relay 15 bridged by a capacitor 14, that actuates a switch i6-. If this relay is excited by the anode current of the tube i ', then stands the switch 16 to the right, so that via a coil 17 'coupled to the coil 3' the to the terminals and 19 connected consumers receive energy from the oscillator 13.

It is assumed that oscillator 12 Vibrations generated, but this can now not deliver any energy to the consumer. However, falls the oscillator 13 due to a disturbance on the above, in connection with FIG. 1 described

Out, as a result of the decrease in the mean Anode direct current de-energizes the relay 15, the switch 16 assumes the position shown, and the oscillator 12 now supplies energy to the consumer via the anode coil 3 and the coupling coil 17.

It follows that these oscillators are switched in such a way that they are switched off of the oscillator feeding the consumer due to the change in the mean anode current of the oscillator brings about the switching of the consumer to the reserve oscillator.

In Fig. 4, a further embodiment of the subject invention is shown. The circuit essentially corresponds to that of FIG. 3, with the proviso that in the oscillator 12, the relay 20, the contacts 23, 25 and 26, the relay 21, the contacts 9, 9 'and 27, and the relay 22 that the contacts 16 operate have been added; in the case of the oscillator 13, relay 15 actuates contacts 24 and 28. All contacts are shown in the rest position, ie in the position in which the associated relay is not energized. Furthermore, the circuit is provided with two alarm circuits A and B , whereby the alarm circuit A should give an alarm if the oscillator normally in operation (the main oscillator) fails and the backup oscillator is switched over, while the alarm circuit B should give an urgent alarm, if both oscillators fail.

The oscillator 12 is the main oscillator and 13 is the reserve oscillator; both are continuously in operation.

Since both oscillators are working, the relays 20 are under the influence of the mean anode currents and 15 excited; Contacts 23 and 24 are closed, contacts 25, 26 and 28 are open.

Since the contacts 26 and 28 are open, the alarm circuit A is not in operation. Relay 21 is energized because contacts 23 and 24 are closed; the contacts 9, 9 'and 27 are thus open; since contact 27 is open, the urgent alarm circuit is also open.

Since relay 22 is not energized as a result of the opening of contact 25, contact 16 takes the one shown Position on, and the consumer is therefore coupled to the oscillator 12.

If now, as a result of one of the above-mentioned causes, a fault occurs in the oscillator 12, as a result of which If this fails, the relay 20 is de-excited as a result of the reduction in the mean anode current, whereby contacts 25 and 26 are closed and 23 are opened.

The following now happens: As a result of the closing of 26, an alarm is given; as a result of the Closing 25 relay 22 is energized, the contact 16 switches over and the consumer with the Oscillator 13 couples. Opening 23 has no further effect.

Should oscillator 13 also fail, whereby the relay 15 is de-energized, the contact 24 opens, whereby 21 de-energizes, contact 27 is closed and an urgent alarm in circuit B is made.

The same happens, of course, if both oscillators are used simultaneously, e.g. B. as a result of a fault in the common supply voltage.

As a result of the de-energization of the relay 21, the contacts 9 and 9 'are also closed, whereby the negative grid bias is reduced so that when the supply voltage returns both oscillators come into effect again. This will make relays 20 and 15 re-energized and contacts 9 and 9 'reopened. By means of the circuit mach Fig. 4 is thus achieved that when both oscillators due to the lack of at least one of the supply voltages are put out of action under the influence of the mean anode currents of a discharge tube a switch takes place, whereby both oscillators are placed in such a position that at least one feeds energy to the consumer when the missing supply voltage returns;

Properties similar to those shown in the circuit according to FIG. 1 are associated with the circuit according to FIG. 5 achievable, in the same reference numerals again represent the same parts as in the previous figures. In this circuit, a coil 29 is coupled to the anode coil 3, which part of the output energy a rectifier 30 supplies. The rectified voltage thus obtained, the arises across the resistor 10, is used to that occurring across the resistors ^ and 5 reduce negative grid bias.

The mode of operation of this circuit is as follows: The one occurring via resistors 4 and 5 large negative bias prevents the tube 1 from generating vibrations. If switch 9 closed briefly, the operating point of the tube 1 is shifted in such a way that vibrations are generated and in the coil 29 an alternating voltage is induced. This tension is from the Rectifier 30- rectified, as a result of which an equalizing voltage occurs across the resistor 10, which shifts the operating point of the tube 1 in such a way that vibrations are continuously generated. However, if as a result of a fault, for example, the supply voltage falls below a certain value decreases, the amplitude of the generated vibrations, the compensating grid voltage, decreases across the resistor 10 decreases and the negative grid voltage of the tube 1 is increased. Through this in turn, the amplitude of the generated vibrations is reduced, etc., so that eventually the tube is taken out of service.

In this circuit, care must be taken that an increase in the grid bias does not increase the amplitude of the generated vibrations, because otherwise the circuit will intermittently begins to oscillate, which must be avoided. If this condition is not met, a limiting Element to be inserted into the circuit, e.g. B. a voltage limiter, such as a Glow lamp, parallel to the resistor io <.

The principle applied in the oscillator circuit of Fig. 5 is also applied to amplifiers applicable. Two cases are to be distinguished

divorce. In one case they contain those to be reinforced Vibrations, 'a component of constant size and frequency, such as those found in e.g. B. occurs in amplifiers for carrier wave telephony ~. Here the output side of the amplifier an alternating voltage of constant magnitude is taken and fed to a rectifier corresponding to that shown in FIG. 5 reproduced .basic ideas. In the second case, where there is no constant component, is, like "for example, in amplifiers for speech and Music is created by means of an auxiliary oscillation lying outside the frequency range, which is transmitted to the grid is fed to one of the tubes, the same effect can be achieved, which ... will be discussed with reference to FIG

should be . . .-

Here in . .is. . A resistor-coupled two-stage amplifier is shown in which the tube 1 receives such a large negative bias that it is blocked in the manner already mentioned several times by means of parts 4, 5, 6, 7, 10 and 11. _ The vibrations to be amplified, e.g. B. over a. Telephone line is received ,, the grid of the tube are the low-frequency transformer 32. 1. _fed: and also a .Hilfsschwingung; with a frequency outside the range to be amplified and a constant amplitude via the transformer .33 pressed onto this grid. The tube 50 is by means of the usual capacitor 34 and. Resistor 35 coupled to the anode circuit of the tube ι. The tube 50 is negatively biased by one of one. Capacitor. 37 .., bridged cathode resistance 36. ._ ._., ...: ·. In the output circuit of the tube 50 is z. B. a telephone line 38 connected via an output transformer 3.9. The primary coil of the output transformer is bridged by a capacitor 40. The output circle also contains the circle 41 which is tuned to the auxiliary oscillation; any vibrations occurring in this circuit induce an alternating voltage in coil 42, which is rectified by rectifier 30 so that. a DC voltage occurs across the resistor.

When starting up the switch 9 is closed briefly, · the setting of the tube is then normal and both those from transformer 32 as well as the vibrations supplied by the transformer 33 are amplified by the device. As a result, over the circle 41, the Coil 42 and the rectifier 30 apply a DC voltage to the resistor 10, whereby the normal The setting of the tube 1 remains, even if the switchg is opened again. Even this circuit can again be expanded according to FIG.

However, it sinks, e.g. B. as a result of a disturbance, such as a change in the electrical Constants of the device, the amplitude of the. If vibrations are amplified or generated, the one occurring at the resistance 10 is also reduced Compensation voltage; the tube 1 is on a.

more unfavorable operating point set, reducing the amplitude of the in the output circuit Apparatus occurring stresses are reduced even more, etc. and ultimately what the Device puts itself out of service.

The circuits according to FIGS. 5 and 6 also have the inherent property that after a brief elimination of the blocking, vibrations are continuously generated or amplified and a compensation voltage is taken from these generated or amplified vibrations, which at least partially eliminates the blocking voltage and which after a at least a short-term change in one of the operating voltages or one of the electrical constants, which causes a decrease in the amplitude of the generated or amplified vibrations, decreases so quickly that the oscillator ⁸ Q or amplifier is put out of operation.

Claims (8)

Patent claims: 1. Circuit for the automatic replacement of a Oscillator. or amplifier by another, characterized in that both oscillators or amplifiers are set up in such a way that even a brief change one of the operating voltages or one of the electrical constants of one of the oscillators or amplifier causes a sudden, permanent change in its operating status. 2. The circuit of claim 1, the two oscillators contains, characterized in that both oscillators have such a negative grid bias have that after at least a brief increase in this grid bias continuous vibrations are generated, and as a result of at least one short-term change in one of the operating voltages or one of the electrical constants, which causes a decrease in the amplitude of the generated vibrations, the oscillator is taken out of service. 3. A circuit according to claim I, characterized in that both oscillators or amplifiers are blocked by a voltage applied to one of the electrodes of a discharge tube and are set up in such a way that after at least a brief removal of this blocking, vibrations are continuously generated or amplified, the generated or amplified vibrations, a compensation ^{voltage is taken which at least partially eliminates the reverse voltage U} 5 and which decreases so quickly after an at least brief change in one of the operating voltages or one of the electrical constants that causes a decrease in the amplitude of the generated or amplified vibrations, that the oscillator or amplifier . instinct is set, 4. Circuit according to claim 2 or 3, characterized. marked that the with the decommissioning ¹² S. set the consumer feeding Oscillator or amplifier-related change in the mean anode current of an oscillator or amplifier tube switching the consumer to the other oscillator or Amplifier causes. 5. Circuit according to claim 4, characterized in that that as a result of the change in the mean anode current also the one not with the Consumer connected oscillator or amplifier is put into action. 6. A circuit according to claim 4, characterized in that when both oscillators or Amplifier put out of action due to the absence of at least one of the supply voltages are, under the influence of the mean anode currents of a discharge tube of both Oscillators or amplifiers switching takes place, causing both oscillators or Amplifiers are placed in such a position that at least one upon return of the ao the lack of supply voltage supplies energy to the consumer. 7. A circuit according to claim 2, 3, 4, 5 or 6, characterized in that the daiß with the decommissioning of the oscillator or amplifier feeding the consumer of the mean anode current of an oscillator or amplifier tube creates an alarm circuit sets in motion. 8. Circuit according to claim 2, 3, 4, 5, 6 or 7, characterized in that when both oscillators or amplifiers are taken out of service become an alarm circuit under the influence of the change in the mean anode currents of a The discharge tube of both oscillators or amplifiers is started. 1 sheet of drawings © 5094 4.53