JPH06262985A - Voice switching device of audio apparatus - Google Patents

Abstract

PURPOSE:To reduce types of an AV apparatus connectible and restrictions on the number and prevent generation of noise sounds at the time of voice switching or at changing-over of the power supply. CONSTITUTION:A power on/off sensing signal S2 from a CD player 50 is fed in, and a mute signal whose rise timing is synchronized approx. with the sensing signal S2, is produced internally by an external mute circuit 60 which applies a mute to the audio signal at the time of voice switching by shutting electrically audio signal output lines L1, R1 for a certain time after changing-over from the specific timing before an external voice switching circuit 40 makes switching motion, and when the power-on sensing signal S2 is fed in, the audio signal output lines L3, R3 of the CD player 50 are connected with a voice switching circuit 12 after passage of a certain time, and then the power-off sensing signal S2 is fed in. After elapse of a certain period of time, the audio signal output lines L2, R2 of an on-board display device 3 are connected to the voice switching circuit 12 by the external voice switching circuit 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice switching device for performing voice switching when voices of a plurality of audio devices such as a vehicle-mounted cassette deck, a CD player, a television are output through a common speaker.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and weight reduction of various electronic devices, various types of audiovisual devices (hereinafter collectively referred to as AV devices) have been developed for in-vehicle use. It was Particularly in recent years, a cassette deck with a tuner, a CD player, a television, and the like are typical examples of in-vehicle AV devices.

When a plurality of these on-vehicle AV devices are mounted in a vehicle, it is required that the sound of each AV device can be output from a common speaker. In this case, for example, in the case of a combination of in-vehicle genuine AV devices manufactured by the same manufacturer, an audio switching circuit is provided in a device having a built-in amplifier, and this audio switching circuit allows, for example, the AV device on the side where the power is newly turned on. The audio signal output line is connected to an amplifier so that it can be output from a speaker.

However, when a newly purchased AV device is connected to an existing device connection configuration or when AV devices of different manufacturers are connected, the following obstacles are involved. For example, consider the case where the cassette deck and the television are integrally connected under the present circumstances.
The audio switching circuit is provided in the cassette deck, and the audio signal output line drawn from the television and the audio signal output line in the cassette deck can be switched with the amplifier in the cassette deck through the audio switching circuit. Connected in a state.

When an audio device such as a CD player is to be added to such a device connection configuration, the connection conditions between the devices are not always the same. For example, an input terminal of an audio switching circuit in a cassette deck or an external device. Power O from equipment
The connection may not always be achieved due to lack of N / OFF detection signal input terminals.

[0006] When a device of a manufacturer different from the existing device is to be connected, the mute circuit in the cassette deck can be used even if the above-mentioned input terminals have a surplus and an apparent connection can be achieved. There is no guarantee that the timing of muting the audio signal at the time of switching will be optimal with respect to the output timing of the audio signal from the additional AV device, and there is a problem that the mute does not work effectively. For example, pop noise occurs when an audio signal is input from an external device after a mute period in the cassette deck. In reality, in many cases, the mute circuit cannot be operated from the additional AV device, and the generation of pop noise cannot be prevented.

[0007]

As described above, conventionally, when the audio signals of a plurality of audio devices are output through the common audio output unit, there are restrictions on the type and number of the audio devices connectable to the common audio output unit. However, there is a problem that noise sound is generated at the time of voice switching even if the physical connection is possible.

The present invention is intended to solve such a problem, and in a configuration in which a plurality of audio devices are switchably connected to a common audio output section, the types of connectable audio devices. It is an object of the present invention to provide a voice switching device for an audio device, which can reduce the restrictions on the number of voices and the number of voices, and can prevent the generation of noise noise during voice switching or power source switching.

[0009]

In order to achieve the above-mentioned object, the audio switching apparatus for audio equipment of the present invention is an audio switching apparatus for switching the connection of each audio signal output line of a plurality of audio equipment to a common audio output section. In the device, each of the above-mentioned audio equipment is provided with its own power-on / off.
Detection signal output means for detecting F and outputting the detection signal to the outside, and switching connection means for switching connection between each of the audio signal output lines of each of the audio equipment and the audio output section,
And a detection signal input means for inputting a detection signal output from the detection signal output means of each of the audio equipment, and when a power-on detection signal from the audio equipment, which is the detection signal input means, is input, a predetermined value is obtained. After a lapse of time, connect the audio signal output line of the audio device whose power is turned on to the audio output section, and turn off the power from a certain audio device.
When a detection signal is input, the power is turned off after a predetermined time
And a voice switching circuit for operating the switching connecting means so as to disconnect the voice signal output line of the audio device from the voice output unit, and the voice signal output line between the voice switching circuit and the voice output unit. And also has detection signal input means for inputting the detection signal output from the detection signal output means of each of the audio equipment, and the detection signal input means turns on or turns on the power from any of the audio equipment. When an OFF detection signal is input, the audio signal output line between the audio switching circuit and the audio output section is electrically disconnected from a predetermined timing before the switching connection means operates, and this state is switched to the above-mentioned switching state. And a mute circuit for maintaining a predetermined time after the connection means operates.

[0010]

That is, in the present invention, when the audio switching circuit inputs the power-on detection signal from a certain audio device, after a predetermined time elapses, the audio signal output line of the audio device whose power is turned on is connected to the audio output section. Power from a certain audio device
When the FF detection signal is input, the power turns off after a predetermined time.
The switching connection means is operated so as to disconnect the audio signal output line of the audio device that has become FF from the audio output unit.

On the other hand, when the mute circuit inputs a power-on or power-off detection signal from the audio equipment, the mute circuit is provided between the audio switching circuit and the audio output section from a predetermined timing before the switching connecting means operates. The audio signal output line is electrically cut and muted, and this state is maintained for a predetermined time after the switching connection means operates.

That is, the audio switching circuit and the mute circuit can optimize the timing of switching the audio and the timing of muting for each AV device. Therefore, it is possible to reduce restrictions on the type and number of connectable audio devices, and it is possible to prevent generation of noise noise during voice switching or power source switching.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram for explaining the configuration of an audio switching device for an on-vehicle audiovisual device (hereinafter referred to as an AV device) according to an embodiment of the present invention.

In the figure, reference numeral 10 indicates a vehicle-mounted cassette deck with a tuner. The audio signal output line extracted from the amplifier 11 in the vehicle-mounted cassette deck 10 is connected to external left and right speakers 21, 21. An audio switching circuit 12 is provided in the vehicle-mounted cassette stereo 10. The audio switching circuit 12 connects the amplifier 11 to an external AV device, that is, a vehicle-mounted display device 30 and a vehicle-mounted CD player which will be described later. Fifty
And the audio signal output lines L1 and R1 from the audio signal output line from its own audio circuit 13 are switched. The switching of the audio switching circuit 12 is performed based on the power ON / OFF detection signal input from the external AV device. That is, when the power ON detection signal is input from the external AV device, the audio switching circuit 12 receives the external AV signal.
By connecting the audio signal output lines L1 and R1 of the device to the amplifier 11 unconditionally (even when the in-vehicle cassette deck 10 is playing) and inputting the power-off detection signal, the audio of the audio circuit 13 of itself is input. The switching operation is performed so that the signal output line is connected to the amplifier 11. Further, a mute circuit 14 is provided inside the vehicle-mounted cassette deck 10. When the power of the on-vehicle cassette deck 10 is turned on / off, the mute circuit 14 electrically disconnects the audio signal output line between the audio switching circuit 12 and the amplifier 11 for a certain period of time to mute the power. It operates so as not to supply an audio signal containing noise at the time of ON / OFF to the amplifier 11. In this case, the mute signal for operating the mute circuit 14 is output from the microcomputer in the vehicle-mounted cassette deck 10, and the mute operation is performed by the mute circuit 14 while the mute signal is output.

Reference numeral 30 denotes an on-vehicle display device (for example, manufactured by the same manufacturer) whose connection conditions match those of the on-vehicle cassette deck 10. Audio signal output lines L2 and L2 drawn from the audio circuit 31 in the in-vehicle display device 30.
Can be connected to an input terminal for an external AV device in the audio switching circuit 12 in the vehicle-mounted cassette deck 10 through an external audio switching circuit 40 described later. When the microcomputer 32 in the in-vehicle display device 30 detects ON / OFF of power-on of the in-vehicle display device 30 itself, the mute circuit 1 in the in-vehicle cassette deck 10 is detected.
4 has a function of outputting a mute signal M1 and outputting the detection signal S1 to the audio switching circuit 12 in the vehicle-mounted cassette deck 10.

Further, 50 is a navigation C whose connection conditions do not match those of the on-vehicle cassette deck 10 and the on-vehicle display device 30 (for example, different manufacturers).
It is a D player. The image information of the CD player 50 can be displayed on the in-vehicle display device 30. The audio signal output lines L3 and R3 drawn from an audio circuit (not shown) in the CD player 50 are the same as the audio signal output lines L2 and R2 from the in-vehicle display device 30 through the external audio switching circuit 40. It is connectable to the input terminal of the audio switching circuit 12 in the external AV equipment. Further, the microprocessor in the CD player 50 detects the ON / OFF state of power to itself and outputs the detection signal S2 to the vehicle-mounted cassette deck 10.
The audio is output to the internal audio switching circuit 12, the external audio switching circuit 40, and an external mute circuit 60 described later all at once.

The external audio switching circuit 40 connects the audio switching circuit 12 in the on-vehicle cassette deck 10 to the input terminals for the external AV equipment by connecting the audio signal output lines L2 and R2 from the on-vehicle display device 30 to the CD. This is for switching between the audio signal output lines L3 and R3 from the player 50, and the switching is performed by the power ON / OFF detection signal S2 from the CD player 50. That is, when the external audio switching circuit 40 receives the power-on detection signal S2 from the CD player 50, after a predetermined time elapses, the CD
When the audio signal output lines L3 and R3 of the player 50 are connected to the audio switching circuit 12 and the power OFF detection signal S2 is input, after a predetermined time elapses, the audio signal output lines L2 and R2 of the in-vehicle display device 30 are switched to the audio switching circuit. The switching operation is performed so as to connect with 12.

Reference numeral 60 denotes an external mute circuit interposed on the audio signal output lines L1 and R1 between the external audio switching circuit 40 and the audio switching circuit 12 in the on-vehicle cassette deck 10. The external mute circuit 60 can receive the power ON / OFF detection signal S2 from the CD player 50. When the power ON / OFF detection signal S2 is input, the rising timing is substantially synchronized with the detection signal S2. A mute signal is internally generated, and the audio signal output lines L1 and R1 are electrically disconnected from a predetermined timing before the external audio switching circuit 40 performs the switching operation for a predetermined time after the switching operation to switch the audio signal at the time of audio switching. It is designed to operate to mute. FIG. 2 shows a configuration example of the external mute circuit 60. As shown in the figure,
The external mute circuit 60 receives the power ON / OFF detection signal S2 from the CD player 50 and outputs the power ON.
A monostable multivibrator 61 that generates a mute signal M2 for a fixed time, for example, 2.5 seconds, whose rising timing is almost synchronized with the N / OFF detection signal S2, and a mute signal M output from the monostable multivibrator 61.
During the input period of 2, the audio signal output lines L1 and R1 between the external audio switching circuit 40 and the audio switching circuit 12 in the on-vehicle cassette deck 10 are grounded, and the signal transmission by the audio signal output lines L1 and R1 is performed. And a mute operation circuit section 62 for substantially disconnecting.

Next, the operation of this voice switching device will be described.

When the on-vehicle cassette deck 10 is used alone, the audio switching circuit 12 is provided on the on-vehicle cassette deck 10.
The audio signal output line from the audio circuit 13 in the amplifier 1
It is in the state of being connected to 1. At the same time when the power is turned on, the mute signal is output from the microcomputer to the mute circuit 14 for a certain period of time, so that the audio signal containing noise when the power is turned on is muted, and the mute circuit 14 is turned off after a certain period of time. In this state, the audio signal from the audio circuit 13 is transmitted through the amplifier 11 to the speaker 2
It is output from 1 and 21.

Thereafter, the power supply of the on-vehicle display device 30 is turned on.
Then, the microcomputer 32 in the in-vehicle display device 30 is connected to the mute circuit 1 in the in-vehicle cassette deck 10.
4 for a certain period of time, and the power is turned on to the audio switching circuit 12 in the vehicle-mounted cassette deck 10 after a predetermined time from the start of the mute signal output.
The detection signal S1 is output.

As a result, the mute circuit 14 in the vehicle-mounted cassette deck 10 is activated, and then the audio switching circuit 12 is switched to connect the audio signal output lines L2 and R2 of the vehicle-mounted display device 30 to the amplifier 11. It The external audio switching circuit 40 outputs audio signal output lines L2 and R2 of the in-vehicle display device 30 when the power source of the CD player 50 is off.
Is connected to the input terminal for the external AV equipment of the audio switching circuit 12 in the vehicle-mounted cassette deck 10.

Next, the case where the power of the CD player 50 is turned on will be described. In this case, the power ON detection signal S2 output from the CD player 50 is the audio switching circuit 12 in the in-vehicle cassette deck 10, the external audio switching circuit 40,
The signals are simultaneously output to the external mute circuit 60.

When the power ON detection signal S2 is input, the audio switching circuit 12 in the on-vehicle cassette deck 10 is connected to the audio signal output lines L1 and R1 for the external AV equipment regardless of the current connection state. Switch immediately.

On the other hand, when the power ON detection signal S2 from the CD player 50 is input, the external audio switching circuit 40 receives the power-on detection signal S2, and after a lapse of a predetermined time, for example, 30 msec, the in-vehicle cassette deck 1
The connection destination for the audio switching circuit 12 in 0 is switched to the audio signal output lines L3 and R3 from the CD player 50.

Further, when the external mute circuit 60 receives the power-on detection signal S2 from the CD player 50, it inputs this signal to the monostable multivibrator 61,
The monostable multivibrator 61 outputs the mute signal M2 whose rising timing is almost synchronized with the power-on detection signal S2 for a predetermined time, for example, 2.5 sec. The mute signal M2 turns on the transistor in the mute operation circuit unit 62, and the audio signal output lines L1 and R1 between the external audio switching circuit 40 and the audio switching circuit 12 in the in-vehicle cassette deck 10 are grounded. The mute by the external mute circuit 60 is activated.

FIG. 3 shows the power-on waveform of the CD player 50,
It is a figure which shows the noise waveform at the time of external audio switching circuit switching, and the rising waveform of a mute signal, respectively.

Thus, in this embodiment, the CD player 5
When the power-on detection signal S2 of 0 is turned on, the external mute circuit 60 is synchronized with the rising edge of the detection signal S2.
Mute signal M from the monostable multivibrator 61 in
2 is output and mute begins to work, and this state is maintained for 2.5 seconds. On the other hand, the external voice switching circuit 4
Since 0 starts the switching operation 30 msec after the power-on detection signal S2 is input, the external mute circuit 60 completely mutes an audio signal containing noise generated by this switching operation.

Even when the power source of the CD player 50 is turned off, the external audio switching circuit 40 and the external mute circuit 60 operate in the same manner. In this case, the external mute circuit 60 similarly generates a mute signal M2 whose rising timing is almost the same as the inverted signal of the power-on detection signal S2.

Thus, according to the voice switching device of the present embodiment, it is possible to improve the degree of freedom when connecting AV devices whose connection conditions do not match, for example, different manufacturers. In particular, it is possible to completely prevent generation of noise at the time of voice switching or power source switching, which is associated with the structure in which voices from a plurality of AV devices can be switchably output through a common speaker.

In the present embodiment, the case where a new AV device is added to the existing AV system configuration has been described as an example, and the case where there are two audio switching circuits in total has been described. Removing the switching circuit, all AV
It is also possible to switch the audio of the device by one external audio switching circuit and perform the mute by the external mute circuit. In this case, power ON / OFF detection signals from all AV devices are input to the external audio switching circuit, and a plurality of AV devices are simultaneously powered on in accordance with the audio output priority order defined in advance in the external audio switching circuit. In such a case, the AV device may be selected in the external audio switching circuit.

[0033]

As described above, according to the audio switching apparatus for audio equipment of the present invention, it is possible to connect a plurality of audio equipments to the common audio output section in a switchable manner. You can reduce the restrictions on the type and number of various audio equipment,
Moreover, it is possible to prevent generation of noise noise at the time of voice switching or power source switching.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining a configuration of an audio switching device for an on-vehicle AV device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration example of an external mute circuit in FIG.

FIG. 3 is a diagram showing a power-on waveform of a CD player, a noise waveform when switching an external audio switching circuit, and a rising waveform of a mute signal.

[Explanation of symbols]

10 ... In-vehicle cassette deck, 11 ... Amplifier, 12 ... Audio switching circuit, 13, 31 ... Audio circuit, 14 ... Mute circuit, 21 ... Left and right speakers, 30 ... In-vehicle display device, 32
… Microcomputer, 40… External voice switching circuit, 5
0 ... In-vehicle CD player, 60 ... External mute circuit, 6
1 ... Monostable multivibrator, 62 ... Mute operation circuit section.

Claims (2)

[Claims] 1. An audio switching device for switching connection of audio signal output lines of a plurality of audio devices to a common audio output unit, wherein each audio device is provided in each audio device and detects ON / OFF of power-on of itself. Detection signal output means for outputting a lever detection signal to the outside, switching connection means for switching the connection between each audio signal output line of each audio device and the audio output section, and the detection signal output of each audio device When a power-on detection signal from an audio device, which is a detection signal input means, is input, the power supply is turned on after a predetermined time has elapsed. When the audio signal output line of the audio device is connected to the audio output section and a power-off detection signal from a certain audio device is input, the power is turned off after a predetermined time has elapsed. The audio signal output line of the audio device which is turned off is operated via the audio switching circuit that operates the switching connection means so as to disconnect the audio signal output line from the audio output unit, and the audio signal output line between the audio switching circuit and the audio output unit. And a detection signal input means for inputting a detection signal output from the detection signal output means of each of the audio equipment, and the detection signal input means turns on the power from any of the audio equipment or When a power-off detection signal is input, the audio signal output line between the audio switching circuit and the audio output section is electrically cut off from a predetermined timing before the switching connection means operates, and this state is set as described above. A voice switching device for an audio device, comprising: a mute circuit which maintains a predetermined time after the switching connecting means operates. 2. A first audio device having an audio switching circuit for switching connection between an external audio signal output line from an external audio device to a common audio output section and its own audio signal output line, and the external audio signal output. A second audio device having a line, the external audio signal output line being connected as the external audio device to the audio switching circuit of the first audio device; Power on
Of the connection of the external audio signal output line between the detection signal output means for detecting ON / OFF and outputting the detection signal to the outside, and the audio switching circuit in the second audio device and the first audio device. ON / O
It has a connection switching means for switching the FF, and a detection signal input means for inputting the detection signal output from the detection signal output means of the second audio equipment, and the detection signal input means is used for the second audio equipment. When the power-on detection signal from the second audio device is input, the connection switching means is operated to connect the external audio signal output line after a predetermined time has elapsed, and the power-off detection signal from the second audio device is input. After a lapse of a predetermined time, an external audio switching circuit that operates the connection switching means to disconnect the external audio signal output line, and an external audio between the external audio switching circuit and the audio switching circuit in the first audio device. A detection signal input unit that is inserted into the signal output line and that receives a detection signal output from the detection signal output unit of the second acoustic device;
When the detection signal inputting means inputs the detection signal from the second audio device, the external audio signal output line is electrically disconnected from a predetermined timing before the switching connecting means operates, and this state is changed. A mute circuit for maintaining the switching connection means for a predetermined time after the operation, and a detection signal input which is provided in the first audio equipment and which inputs a detection signal output from the detection signal output means of the second audio equipment. Means for inputting a power-on detection signal from the second audio device with the detection signal input device, the external audio signal output line from the second audio device is connected to the audio output unit. When the voice switching circuit is operated and a power OFF signal is input, the voice switching circuit is connected so that the voice signal output line of the first audio device is connected to the voice output unit. A voice switching device for an audio device, comprising: a means for operating the voice switching device.