FI65521B - ANORDNING FOER BORT KOPPLING AV STOERPULSER - Google Patents

Description

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Federal Republic of Germany-Förbundsrepubliken Tyskland (DE) P 261852U.O

(71) Neumann Elektronik GmbH, Bulowstrasse IOU-IIO, D-U330 Miilheim-Ruhr,

Federal Republic of Germany-Förbundsrepubliken Tyskland (DE) (72) Dirk Neumann, Mulheim, Walter Herrmann, Mulheim, Federal Republic of Germany-Förbundsrepubliken Tyskland (DE) (7U) Oy Kolster Ab (5U) Switching device for switching off interference pulses - Anord av störpulser

The invention relates to a switching device for switching off interference pulses, which interference pulses are generated by a relay contact connected to a signal line in a switching event in a signal line connected simultaneously to direct current upon the occurrence of said interference pulses, a claw pulse of adjustable width is applied, which is applied to a gate circuit arranged between the amplifier and the loudspeaker, which then at least almost cuts off the current flow between the amplifier and the loudspeaker.

If the low-frequency or high-frequency amplifier is supplied with operating voltage in addition to the low-frequency or high-frequency signal via a dual cable, then when this cable is connected and disconnected, interference pulses are generated which can be heard as a ratchet in the speaker or telephone. These interference pulses are caused by switching and disconnection asymmetry, line inductance and capacitance, and operating voltage height relative to the shifted low-frequency or high-frequency level. Thus, for example, a supply voltage of 60 volts when connecting and disconnecting a cable can generate a few 100 mV interference pulses which, due to amplification, can be detected in the connected loudspeaker or telephone handset as an unpleasant ratchet.

Unfortunately, in the absence of a low frequency signal, the limitation provided by the diodes cannot destroy the ratchet.

The object of the invention is to provide a device for eliminating an interference pulse generated due to a switching event in a line supplied simultaneously with direct current and low frequency or high frequency alternating current, which leads to an amplifier to which a loudspeaker or telephone headset is connected so that the interference pulse can be completely eliminated.

According to the invention, this object is achieved in that a delay element is connected to the relay control line between said switch and the relay winding and said pulse sensor is connected to the switch output, the pulse sensor having two branches output from the switch output connected to a monostable multivibrator. each has a differentiation element, whereby a supply circuit is connected to the second branch before the differentiation element, which gives a voltage signal when the switch opens. In this case, the charging circuit may include a charging capacitor when the switch is closed, which, when the switch is closed, is connected in parallel to a discharge circuit connected to the differential member, which is broken when the switch is opened.

In the following, the switching device according to the invention will be explained in more detail in connection with the accompanying figures.

Figure 1 schematically shows a switch device according to the invention.

Figure 2 shows an embodiment of a control circuit and a pulse sensor for the circuit according to the invention shown in Figure 1.

Figure 3 shows graphically the signal flow 3 65521 at different points in the circuit of Figure 2.

Figures 4-6 show other embodiments of the gate circuit of Figure 1 arranged between the amplifier and the speaker.

The connection shown in Fig. 1 comprises a signal dual line leading to an amplifier V to which, for example, a speaker L is connected. a delay element consisting of a capacitor C1. Further, a pulse sensor is connected to the switch S, the output of which is connected to the relay winding of the relay A, the contacts a of which are arranged in the line between the amplifier V and the speaker L.

When switch S closes, the signal line is switched in slow motion via relay B. At the same time, a rectangular signal is applied to the relay A via the pulse sensor, as explained in more detail below. The switching deceleration of the relay B and the pulse sensor are such that during the switching event the contacts a of the relay A open briefly in the signal line during the switching event and thus the speaker is amplified during the interference pulse.

Of course, instead of relay A, other gate circuits can also be used to disconnect the connection between amplifier V and speaker L. A few of these are outlined below.

Figure 2 shows in connection with an embodiment of the circuit only the control circuit of the relay B and the pulse sensor. Figure 3 is a graphical representation of the signal flow at a few points @ - (J) in the circuit.

The pulse sensor in the circuit according to Fig. 2 has a monostable multivibrator, the output of which is connected to a relay A or another, e.g. a gate circuit described below. The multivibrator is controlled manually from the switch S via two branches, one of which operates when the switch S closes and the other when the switch S opens.

As can be easily seen from the circuit according to Fig. 2, when the switch S closes, the following happens: a) A capacitor C1 is charged via a diode D1, a resistor R1 and a relay B is connected. Thus, the signal line is connected in slow motion through the contacts b shown in Fig. 1. The deceleration is then determined according to the time constants 4 65521 of the delay element R1, C1. It is illustrated in Figure 3 in connection with the potential flow (5).

b) Through a resistor R2, a differential element R3, C2 and a diode D2, the voltage signal applied to (1) in a differentiated form (3) enters the input of a monostable multivibrator which produces a rectangular pulse (see (4)) through which relay A is switched simultaneously and as a result, the connection between the amplifier V and the loudspeaker L is briefly disconnected via the contacts a (Fig. 1).

s) Charging capacitor C3 is charged via diode D4 and resistor R6.

d) Transistor T1 is connected via resistor R7 and conducts away the plus potential between resistor R5 and capacitor C4.

When the switch S opens, the following happens: e) The transistor T1 enters the closed state.

f) The positive potential stored in capacitor C3 flows through resistor R5 and capacitor C4 and diode D3 and reaches differential element C4, R4 in differentiated form as a short control pulse to a monostable multivibrator, which in turn provides a rectangular signal by which relay A ) temporarily disconnects the connection between amplifier V and speaker L.

g) The positive potential stored in the capacitor C1 slows down the output of the relay B and thus the disconnection of the signal line leading to the amplifier V via the contacts b.

The operation of the circuit so that the deceleration when the signal line is connected and disconnected is such that the interference pulse that occurs is at the exact time at the output of the amplifier V, when the connection between the amplifier V and the speaker L is disconnected. Since the connection and disconnection of the signal line are fixedly connected to the generation of the output signal, no rattan interference can occur in the speaker L in this case.

When the switch S closes in the operating branch, the resistor R8 connected in parallel with the capacitor C2 acts to discharge the potential in the capacitor C2, so when the switching event repeats rapidly, the capacitor C2 is reliably discharged and there is no interference in generating the output signal.

Of course, instead of the relay A shown in Fig. 1, other gate circuits can also be used to separate the connection between the amplifier V and the speaker L.

Thus, e.g., as shown in Fig. 4, a relay A1 with a rest contact ai can be used, by means of which the connection between the amplifier V and the speaker L in one branch is cut off briefly when the signal line is connected or disconnected, the contact ai being bypassed by an adjustable resistor R9 removal of depth.

The diode circuit shown in Fig. 5 has the following mode of operation: The signal current passes from amplifier V through transformer Tri, diodes D5 and D6 and transformer Tr2 to speaker L. The output signal from the pulse sensor passes through transistor T2 and provides a bias voltage of U. D5 and D6.

2

By converting the resistors RIO, the discharge depth can be adjusted, if necessary.

In the diode circuit shown in Fig. 6, the signal current flows from amplifier V through transformer Tri, diodes D7, D8, D9, D10 and transformer Tr2 to loudspeaker L. The output signal passes from pulse sensor via transistor T3 to diodes D7, D8, D9, D10 and provides the necessary short-circuit. This diode arrangement itself enters the closed state in the de-energized state. The removal depth can be adjusted, if necessary, with a resistor R11.

Claims (2)

65521 A switching device for switching off interference pulses, which interference pulses are generated by a relay contact (b) connected to a signal line in a switching event simultaneously connected to a loudspeaker (L), a tripping switch (S) with its pulse sensors, which, in the event of said interference pulses, gives a dredged pulse of adjustable width to a gate circuit arranged between the amplifier and the loudspeaker, which then at least almost interrupts the current flow between the amplifier and the loudspeaker, characterized by , Cl) is connected to the control line of the relay (B, b) between said switch (S) and the relay coil (B) and that said pulse sensor is connected to the output of the switch (S), the pulse sensor having two monostable outputs from the output of the switch (S). connected to the multivibrator a branch connected in parallel, each having a differential element (C2, R3, D2 or C4, R4, D3), the other branch being connected to the supply circuit (D4, R6, C3) before the differentiation element, which gives a voltage signal when the switch (S) opens. Switching device according to claim 1, characterized in that said supply circuit comprises a capacitor (C3) which charges when the switch (S) is closed, which is connected in parallel with the discharge circuit (T1) connected in parallel with the differentiation element (C4, R4, D3), which breaks when the switch (S) opens.