JPS6211086Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a muting device for a signal reproduction system constituted by a plurality of signal devices.

In audio equipment and the like, there is a so-called component type system in which a plurality of individual signal devices are used for signal reproduction and these are connected to each other to form a single signal reproduction system. In such a signal reproducing system, a signal line for transmitting a reproduced signal and, if necessary, a power supply line for supplying a power supply voltage are usually provided between the individual signal devices. In the case of such a signal reproducing system, there is no special control means for controlling the operation of each individual signal device, and for example, when noise occurs in an individual signal device, this noise can be removed outside the signal device. It is impossible to do so.

For this reason, in conventional signal playback systems, it is necessary to prevent as much noise as possible from occurring in the signal line when power is turned on or when a switch is changed in each signal device such as a tuner or preamplifier, and to prevent noise from occurring within each signal device. A method used was to remove noise from the signal line by providing an independent muting circuit. However, in such a case, costs will increase because a muting circuit is provided in each signal device, and muting may be applied at a stage where the signal level is weak, so there is a possibility that sufficient noise removal performance may not be obtained. There were some drawbacks such as:

SUMMARY OF THE INVENTION An object of the present invention is to provide a muting device that eliminates noise generated in each signal device by providing a single switch circuit in a signal reproduction system having a plurality of signal devices.

Next, the muting device according to the present invention will be described in detail with reference to the drawings. The drawing is a block diagram of an embodiment of a muting device according to the present invention. In this figure, the parts surrounded by broken lines indicate individual signal devices, and the signal reproduction system shown in this figure is composed of a tuner 1, a tape deck 2, a control amplifier 3, a power amplifier, or a power amplifier 4, etc. There is. When reproducing signals using this system, tuner 1
Alternatively, the signal from the tape deck 2 is adjusted in signal level, frequency characteristics, etc. in the control amplifier 3, and then power amplified in the power amplifier 4 to drive the speaker 6 and the like. At this time, in each signal device, pop noise is often generated when the power supply voltage is turned on, and switching noise is often generated when input signals are switched. Such pulsed noise is amplified during the signal transmission process and is ultimately input to the speaker 6. This pulsed noise is not only difficult to hear when listening to audio from this device, but also causes overcurrent to flow in the power amplification element and the speaker 6, causing damage. In addition to the above-mentioned pulse noise, for example, when the tuner 1 is used, continuous white noise may occur when the tuner is detuned.

The muting device according to the present invention is configured to temporarily stop the transmission of the output signal of the power amplification device to prevent the generation of noise when the above-mentioned various types of noise occur. For this purpose, a muting control means 7 for detecting the timing of the muting operation is provided in each signal device, and a switch circuit 9 is provided on the output line 8 of the power amplifier 4. The muting control means 7 and the switch circuit 9 are connected by a muting line 10, and when a muting control signal is input from either one of the muting control means 7, the switch circuit 9 is activated and the switch circuit 9 is activated. Transmission of the signal from the output line of the amplifier 4 is turned off.

The muting control means 7 generates a predetermined muting control signal when noise occurs on the signal line in each signal device, and can be constructed using various circuits known in the prior art. For example, the mutating control means 7
The switching transistor is composed of a predetermined time constant circuit and a switching transistor connected to the power supply line of each signal device, and the switching transistor is turned on for a predetermined period of time after the power supply voltage is turned on to generate a muting control signal. Can be done. Further, even when changing the band of the tuner, detuning, etc., a muting control signal can be obtained by generating a predetermined drive voltage for the switching transistor.

Next, the switch circuit 9 uses, for example, a relay inserted and connected to the output signal line of the power amplifier 4 to bring the contacts into a non-conducting state when the mutating control signal is input, so that the output signal line of the power amplifier 4 is connected to the output signal line of the power amplifier 4. It can be configured to turn off the transmission of signals to the speaker 6. Further, the switch circuit 9 may be provided with a transistor for driving the relay, and in this case, the muting control signal only requires a small amount of electric power. Furthermore, the switching element is not limited to the relay, but other switching elements such as semiconductor elements may also be used.

Further, in this embodiment, the switch circuit 9 is provided inside the power amplifier 4, but the method is not limited to this method. It may be configured to turn the signal on and off.

As described above, the muting device according to the present invention is configured to turn on and off the transmission of noise-generating signals all at once using a switch circuit connected to the output line of the power amplifier. It is possible to reduce manufacturing costs compared to the method of providing a circuit, and since multiple muting control signals are input to a single switch circuit, the configuration is simplified and a complete noise cancellation effect can be achieved. It has become a characteristic to demonstrate.

[Brief explanation of the drawing]

The drawing is a block diagram showing an embodiment of a muting device according to the present invention. Explanation of symbols of main parts, 4...Power amplifier,
5...Signal line, 6...Speaker, 7...Mumuting control means, 8...Output line, 9...
...Switch circuit.

Claims (1)

[Scope of utility model registration request] Provided in each of a plurality of signal devices including a power amplification device and capable of forming a signal reproduction system through predetermined connections, the signal device generates a muting control signal when noise occurs in the signal line of the signal device, and generates a muting control signal of the signal device. A plurality of muting control means that differ depending on the type of noise generated in the signal line,
the output line being connected to the output line of the power amplifying device and connected to the plurality of mutating control means via a mutating line to receive the mutating control signal; A muting device characterized by comprising a single switch circuit that cuts off transmission of all signals from.