JPS6332283B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a muting actuation device for making the noise generated when switching a non-shooting switch inaudible.

Conventionally, for example, in audio equipment, no effective measures have been taken to deal with the noise that occurs when switching non-shooting switches such as push button switches, rotary switches, slide switches, etc. It was jarring.

In order to prevent this noise from being heard, it is sufficient to detect that the noise will occur and activate the muting circuit. Although it is possible to realize a device that operates in this manner without considering economic efficiency, it is necessary to make the configuration as simple as possible, to reduce the cost, and to operate reliably.

The present invention provides a device for electrically simply and reliably detecting the movement of a non-shooting switch and activating a muting circuit to suppress noise. Explain in detail.

FIG. 1 is an explanatory diagram showing the operation of a slide switch, which is a typical non-shooting switch.

In the figure, 1, 2, 3 are switch terminals, 4
indicates a contact.

In the switch state (a), terminals 1 and 2 are short-circuited by contactor 4. In state (b), contactor 4 slides and contacts only terminal 2, and terminals 1 and 3
have not had contact with any of them. In the state shown in (c), the contactor 4 short-circuits the terminals 2 and 3.

In the present invention, the fact that the contactor 4 is in the state shown in FIG. 1(b) is used to detect that noise will be generated and to take measures to suppress it.

FIG. 2 is a circuit diagram of a main part for explaining one embodiment of the present invention, and the same parts as those explained with reference to FIG. 1 are indicated by the same symbols.

In the figure, D ₁ , D ₂ , D ₃ , D ₄ are diodes,
Q is a transistor, C is a capacitor, R ₁ and R ₂ are resistors, M is a mutating circuit, L ₁ and L ₂ are signal lines, and Z _D is a Zener diode. In addition, the Zener diode Z _D is the transistor Q
This is to apply a voltage to the emitter of the circuit, and is unnecessary if a circuit configuration using a separate power supply is adopted. Also, it can be considered that _the diodes D ₁ and D ₂ are connected to different circuits, for example, an AM circuit is connected to the diode D ₁ and an FM circuit is connected to the diode _{D 2 .} This prevents the influence from the circuit. The switch then switches and connects the +B power supply to those circuits.

In the illustrated state, +B voltage is supplied to the AM circuit via terminal 2, contactor 4, and terminal 1.
Also, there is a diode at the base of transistor Q.
Since the +B voltage is applied through _D3 , transistor Q is cut off.

If the contactor 4 is moved to a state similar to that shown in FIG. 1b, the voltage supply to the AM circuit is cut off, and the voltage supply to the base of the transistor Q is also cut off. Therefore, transistor Q turns on,
A voltage appears at the collector, and this voltage turns on the transistor in the muting circuit M, so that the signal lines L ₁ and L ₂ are grounded and the audio is cut off. At the same time, the transistor Q
Said voltage appearing at the collector of also charges the capacitor C.

If the contactor 4 is further moved to a state similar to that shown in FIG. 1c, voltage is supplied to the FM circuit and voltage is again applied to the base of the transistor Q. Therefore, although the transistor Q is cut off, the discharging voltage of the capacitor C is applied to the muting circuit M, so that the muting operation is still continued. Muting is canceled when the voltage on capacitor C reaches a level insufficient to activate the transistors in muting circuit M. Needless to say, this time is determined by the time constant depending on the capacitor C and the resistors R ₁ and R ₂ .

In the embodiment described above, if the switch is used as a so-called on-off switch by using only terminals 1 and 2, for example, the capacitor C is not necessary.

FIG. 3 is a main circuit diagram illustrating a case where a rotary switch is used as the switch.

In the figure, 11a, 11b, 11c, 11d
Terminal ₁ 14 is a contact, and D ₁₁ , D ₁₂ , D ₁₃ , and D ₁₄ are diodes.

In this configuration, the contact 14 is connected to the +B power supply,
Each terminal 11a... is connected to a circuit, and the output side of the diode _D11 ... is connected to the base of the transistor Q in Fig. 2, and its operation is exactly the same as that explained in connection with Fig. 2. It is.

As can be seen from the above explanation, according to the present invention, the noise generated during the operation of a non-shooting switch is suppressed by operating a muting circuit using the output of an active element that becomes conductive when the switch operates. Therefore, it is possible to reliably detect and suppress the occurrence of noise with an extremely simple configuration.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the operation of the switch, FIG. 2 is a circuit diagram of a main part for explaining one embodiment of the present invention, and FIG. 3 is a circuit diagram of a main part for explaining another embodiment. In the figure, 1 to 3 are terminals, 4 is a contact, and D ₁
~ _D4 is a diode, Q is a transistor, C is a capacitor, _R1 and _R2 are resistors, M is a muting circuit, and _L1 and _L2 are signal lines.

Claims (1)

[Scope of Claims] 1. A non-shooting switch having a common terminal connected to a power source, a plurality of terminals connected to each circuit, and a contact for shorting the common terminal and the terminals; a diode whose anode is connected to each circuit side contact; and an input terminal to which all of the cathodes of the diode are connected, and when the voltage at the input terminal is low, a muting operation output is generated, and the voltage at the input terminal is low. A mutating actuating device comprising: a semiconductor circuit that releases the muting actuating output after a predetermined period of time after the value becomes high; and a muting circuit that is actuated by the output of the semiconductor circuit.