JPH0591599A - Mode changeover circuit - Google Patents

Abstract

PURPOSE:To improve the space factor and to reduce the cost of the surrounding mode changeover circuit of the audio device. CONSTITUTION:The circuit is provided with a level volume 1 connected to the first rear channel input (a) and a sound volume 2, an input changeover switch 16 connected to the second rear channel input (b) and a center channel input (c), a level volume 14 connected to the common output of the input changeover switch 16 and a sound volume 15, an output changeover switch 17 connected to the output of this sound volume 15, the output (e) of the second rear channel and the center channel output, and an output changeover switch 18 connected to the first rear channel output (d) and the second rear channel output (e). Thus the circuit improving the space factor and reducing the cost can be provided in the surrounding mode/prologic mode changeover.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mode switching circuit for a surround circuit of an audio device.

[0002]

2. Description of the Related Art In recent years, surround circuits and pro-logic circuits (Dolby Pro-logic circuits developed by Dolby) for the purpose of reproducing a sound field have spread in audio equipment, and mode switching circuits for switching these modes are Widely used.

An example of the above-mentioned conventional mode switching circuit will be described below with reference to the drawings.

FIG. 2 shows the volume of a conventional mode switching circuit.
2 shows a level control circuit block.
In FIG. 2, a is the first rear channel input, b is the second rear channel input, c is the center channel input, d is the first rear channel output, and e is the second rear channel output. , F is the center channel output, 1, 3 and 5 are the level control volume of each channel, 2, 4 and 6 are the volume control volume of each channel, 7, 8 and 9 are the low level of each channel. Frequency amplifier (hereinafter abbreviated as amplifier), 10,
Reference numerals 11 and 12 are speakers for each channel, and 13 is a surround circuit and a professional logic circuit. Further, FIG. 3A shows a normal surround mode state,
(B) shows a professional logic mode state.

First, in the normal surround mode, as shown in FIG. 2A, the rear L channel signal (hereinafter, RL signal Abbreviated) is entered and the second rear
The rear and R channel signals (hereinafter,
(Abbreviated as RR signal), the center channel input C has no input signal, and the R signal of the first rear channel is input.
The L signal and the RR signal of the second rear channel are the level controls 1 and 3 of each channel and the front
The level / volume is controlled by the volume / volumes 2 and 4 linked with the channels, amplified by the amplifiers 7 and 8 of the respective channels, and output from the speakers 10 and 11.

Further, in the case of the professional logic mode, as shown in FIG.
The rear channel input (a) and the second rear channel input (b) are rear channel signals (hereinafter abbreviated as R signals)
, And the center channel signal (hereinafter abbreviated as C signal) is input to the center channel input C,
R on the first rear channel and the second rear channel
The signal is the level volume 1, 3 of each channel.
And the level and volume are controlled by the volume and volume 2 and 4 which are linked to the front channel, and amplified by the amplifiers 7 and 8 of the respective channels, and the speaker 10 and
The C signal of the center channel output from 11 is
The level / volume is controlled by the level volume 5 and the volume / volume 6 interlocked with the front channel, amplified by the amplifier 9, and output from the speaker 12.

[0007]

However, the conventional mode switching circuit as described above requires an independent level / volume control circuit for each channel, resulting in a large circuit scale and deterioration of the space factor. It had a problem of cost increase.

In view of the above conventional problems, the present invention provides a mode switching circuit for the purpose of improving the space factor and reducing the cost.

[0009]

In order to solve the above-mentioned problems, a mode switching circuit of the present invention comprises a first volume connected to a first rear channel input, an output of the first volume and a first volume. A second volume connected between the first rear channel outputs, a first switch connected to the second rear channel input and the center channel input, and a common output of the first switch. A third volume, a fourth volume connected in series with the third volume, and a second volume connected to the output of the fourth volume, the second rear channel output, and the center channel output. Switch, and a third switch connected to the first rear channel output and the second rear channel output.

[0010]

The present invention has the above structure,
With the level and volume control circuit of only the minimum required number of channels in each mode of Pro mode and Pro Logic mode, it was configured on hardware so that the input / output required in each mode can be selected by the switch circuit and used. Therefore, it is possible to provide a mode switching circuit for the purpose of improving the space factor and reducing the cost.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the mode switching circuit of the present invention will be described in detail below with reference to FIG.

FIG. 1 shows a circuit block of a mode switching circuit of a surround circuit in an embodiment of the present invention.

In FIG. 1, those having the same functions as those in FIG. In FIG. 1, 1
4 is the level control volume of the second channel, 15 is the volume control volume of the second channel
Volume, 16 is input selector switch, 17, 18
Is an output changeover switch. Further, FIG. 7A shows a normal surround mode state, and FIG.
Indicates logic mode state.

The operation of the mode switching circuit configured as described above will be described below.

First, in the normal surround mode, as shown in FIG. 1A, the RL signal is input from the surround circuit 13 to the first rear channel input a,
The level / volume is controlled by the level / volume 1 and the volume / volume 2 linked to the front channel, and the output selector switch 18 is turned off, so that the signal is amplified by the amplifier 7 and output from the speaker 10.

The RR signal is input from the surround circuit 13 to the second rear channel input B, and the input of the second channel level control volume 14 is selected by the input selector switch 16. RR
The signal is input and the level volume 14 and front
Level / volume is controlled by volume / volume 15 linked with the channel, and output selector switch 1
The amplifier 8 of the second rear channel is selected by 7, amplified by the amplifier 8 and output from the speaker 11. There is no input signal on the center channel input C.

In the case of the professional logic mode, as shown in FIG. 3B, the surround signal causes the R signal to be input to the first rear channel input a and the second rear channel input b. Since the input selector switch 16 selects the center channel, the output selector switch 18 is on, and the switch 17 selects the center channel amplifier, the R signal is the level of the first rear channel. The level and volume are controlled by the volume 1 and the volume 2 linked with the front channel, amplified by the first and second rear amplifiers 7 and 8 and output from the speakers 10 and 11.

The C signal is input to the center channel input C and the C signal of the center channel is
The level and volume are controlled by the volume 14 and the volume 15 linked with the front channel, which is amplified by the amplifier 9 and output from the speaker 12.

As described above, according to the present embodiment, the level / volume control circuit which has conventionally been configured by using six volumes in the mode switching between the normal surround mode and the professional logic mode is used. Since it can be configured with four volumes and three switches, it is possible to realize a mode switching circuit which has a better space factor and a lower cost than conventional ones.

[0020]

As described above, according to the present invention, the first volume connected to the first rear channel input and the second volume connected to the first volume output and the first rear channel output. Volume, a first switch connected to the second rear channel input and the center channel input, a third volume connected to the common output of the first switch, and a series connection with the third volume. A fourth switch connected to the second volume switch, a second switch connected to the output of the fourth volume, the second rear channel output and the center channel output, the first rear channel output and the second switch. It consists of a third switch connected to the second rear channel output and is the minimum required in each of the Surround and Pro Logic modes. With a level / volume control circuit with only a certain number of channels, the input / output required in each mode can be selected and used with a switch circuit, so a mode switching circuit with a better space factor and lower cost than before can be realized. Is possible.

[Brief description of drawings]

FIG. 1A shows a surround mode of a circuit block diagram of a mode switching circuit of a surround circuit in an embodiment of the present invention. FIG. 7B shows a professional logic mode of the circuit block diagram of the mode switching circuit of the surround circuit in the embodiment of the present invention.

FIG. 2A shows a surround mode of a circuit block diagram of a mode switching circuit of a conventional surround circuit. (B) shows the pro-logic mode of the circuit block diagram of the mode switching circuit of the conventional surround circuit.

[Explanation of symbols]

 1,3,5,14 Level control volume 2,4,6,15 Volume control volume 7,8,9 Low frequency amplifier 10,11,12 Speaker 13 Surround circuit and professional logic circuit 16 Input selector switch 17, 18 Output selector switch 1st rear channel input 2nd rear channel input 2 center channel input 2nd 1st rear channel output 2nd rear channel output・ Channel output

Claims (1)

[Claims] 1. A first volume connected to a first rear channel input, a second volume connected between an output of the first volume and a first rear channel output, and a second volume. A first switch connected to the rear channel input and the center channel input of the
A third volume connected to the common output of the switch, a fourth volume connected in series with the third volume, an output of the fourth volume, a second rear channel output and a center volume. A second switch connected to the channel output and a third switch connected to the first rear channel output and the second rear channel output
And a switch for switching the mode.