JPH05122795A - Surround processor - Google Patents

Abstract

PURPOSE:To realize the free variable of the polarity frequency of a phase shifter by controlling a variable resistance circuit using the control data of the circuit. CONSTITUTION:A differential amplifier 1 generates an input signal L1 and a difference signal R1 (indirect sound signal L-R) to output a signal phi (L-R) after the phase shift processing of a phase shifter 8. An adder 5 adds the signal L1 and the signal phi (L-R) to be outputted as a signal L0. An adder 7 adds the signal R1 and a signal phi (L-R) whose phase is reversed by an inverter 6 to be outputted as the signal R0. A microcomputer 11 reads the control data corresponding to the specified surround effect from a RAM 10, and a switch control circuit obtains a phase shift indirect sound signal with the prescribed polarity frequency according to the data. Thus, the surround effect can be enjoyed according to the type of programs of music or the like and the need of a user by freely varying the polarity frequency of the circuit 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surround processor, and more particularly to a matrix type surround processor.

[0002]

2. Description of the Related Art A conventional surround processor, as shown in FIG.
3, a differential amplifier 3, a phase shift circuit 4, and adders 5, 7
And an inverter 6. Phase shift circuit 4
Was composed of an operational amplifier 41, resistors R41 to R43, and a capacitor C41.

Next, the operation of the conventional surround processor will be described.

An audio L channel input signal LI,
The R channel input signal RI is input through the buffers 2 and 3, respectively, and the differential amplifier 1 generates and outputs a difference signal between the two signals, that is, an indirect sound signal LR. next,
The indirect sound signal L-R is input to the phase shift circuit 4, is subjected to a predetermined phase shift, and the phase shift indirect sound signal φ (L-R).
Is output. Next, the L-channel input signal LI and the phase-shifted indirect sound signal φ (LR) are added by the adder 5 and output as a new L-channel output signal LO to which indirect sound is added. On the other hand, the adder 5 adds the R channel input signal RI and the phase-shifted indirect sound signal φ (LR) whose phase is inverted by the inverter 6, and outputs it as a new R channel output signal RO to which indirect sound is added. Was to be done.

[0005]

In the conventional surround processor described above, since the phase shift circuit is composed of the operational amplifier and the fixed three resistors and capacitors, the pole frequency of the phase shift circuit is fixed. However, the frequency characteristics of the output signal related to the surround effect are fixed, and the surround effect cannot be changed according to the type of program such as music and the preference of the user.

[0006]

A surround processor according to the present invention provides an original signal for both left and right channels and an indirect sound signal generated by a phase shift circuit for changing the phase of an amplitude difference signal of the original signal. In addition, in a surround processor that generates left and right channel surround signals, a variable resistor circuit that sets the pole frequency of the phase shift circuit, and the variable resistor circuit that sets the pole frequency corresponding to a predetermined surround effect. And a resistance control circuit for controlling the variable resistance circuit by reading the control data from the storage circuit according to a control signal.

[0007]

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

FIG. 1 is a block diagram showing an embodiment of a surround processor of the present invention.

The surround processor of this embodiment is shown in FIG.
As shown in, the buffers 2 and 3 for the respective LR channels, the differential amplifier 3, the phase shift circuit 8, the adder 5,
7, the inverter 6, and the resistance ladder circuit 8 of the phase shift circuit 8
The switch control circuit 9 for controlling the switch of No. 1, the RAM 10 storing the resistance value data of the resistance ladder circuit 81 corresponding to the surround effect, the control of the phase shift circuit 8 and R
A microcomputer 10 for writing data to the AM 10 and the like, and a user
And a remote controller 12 for giving a control instruction to the. The phase shift circuit 8 includes an operational amplifier 41 similar to the conventional example.
In addition to the resistors R41 and R43 and the capacitor C41, n stages of resistors R81 to R8n connected in series and switches S81 to short-circuit or open the respective connection points.
S8n and the resistance ladder circuit 81.

Next, the operation of this embodiment will be described.

First, as in the conventional case, an audio L channel input signal LI and an R channel input signal RI are input via buffers 2 and 3, respectively, and a differential amplifier 1 outputs a difference signal between the two signals, that is, an indirect sound signal L. -R is generated and output. Next, the indirect sound signal L-R is input to the phase shift circuit 8, a predetermined phase shift is performed, and the phase shift indirect sound signal φ (LR) is output. Next, the L-channel input signal LI and the phase-shifted indirect sound signal φ (LR) are added by the adder 5 and output as a new L-channel output signal LO to which indirect sound is added. On the other hand, the phase shift indirect sound signal φ (L-
R) is added and output as a new R channel output signal RO to which an indirect sound is added.

Here, the phase shift circuit 8 has a structure in which the resistor R42 which determines the pole frequency of the phase shift circuit 4 in the conventional example is replaced with a resistor ladder circuit 81 which is a variable resistor circuit.
The resistances R1 to Rn of the resistance ladder circuit 81 are weighted from r to 2 ^n-1 r.

The user uses the remote controller 12 to issue a command to the microcomputer 11 to select a desired surround sound effect. The microcomputer 11 reads from the RAM 10 the control data of the switches S81 to S8n that set the resistance value that generates the pole frequency corresponding to the specified surround effect, and inputs the control data to the switch control circuit 9. The switch control circuit 9 switches the switch S8 of the resistance ladder circuit 81 according to the control data read from the RAM 10.
By controlling 1 to S8n, a phase-shifted indirect sound signal having a predetermined pole frequency can be obtained.

Table 1 shows an example of the relationship between the switch control data read from the RAM 10 and the resistance value of the resistance ladder circuit 81 and the corresponding pole frequency.

[0015]

[Table 1]

As described above, by varying the phase of the indirect sound signal L-R added to both the L and R channels of the original audio signal, the frequency characteristic of the output signal changes, and various surround effects can be enjoyed. .

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made. For example, it is needless to say that an EEPROM in which control data is stored in advance may be used instead of the RAM without departing from the gist of the present invention.

[0018]

As described above, the surround processor of the present invention comprises a variable resistance circuit for setting the pole frequency of the phase shift circuit, a storage circuit storing control data of the variable resistance circuit corresponding to the surround effect, By providing a resistance control circuit that reads control data from the memory circuit and controls the variable resistance circuit, the pole frequency of the phase shift circuit can be freely changed, so that surround sound can be used according to the type of program such as music and the taste of the user. There is an effect that you can enjoy the effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a surround processor of the present invention.

FIG. 2 is a block diagram showing an example of a conventional surround processor.

[Explanation of symbols]

 1, 2 buffer 3 differential amplifier 4,8 phase shift circuit 5,7 adder 6 inverter 9 switch control circuit 10 RAM 11 microcomputer 12 remote control 41 operational amplifier 81 resistance ladder circuit C41 capacitors R41 to R43, R81 to R8n resistance S81 ~ S8n switch

Claims (2)

[Claims] 1. A surround signal for both left and right channels is generated by adding an original signal for both left and right channels and an indirect sound signal generated by including a phase shift circuit for changing the phase of an amplitude difference signal of the original signal. In a surround processor, a variable resistance circuit that sets a pole frequency of the phase shift circuit, a storage circuit that stores control data of the variable resistance circuit that sets the pole frequency corresponding to a predetermined surround effect, and a control circuit. A surround processor, comprising: a resistance control circuit that reads the control data from the storage circuit by a signal and controls the variable resistance circuit. 2. The variable resistance circuit has a resistance ladder circuit having a plurality of resistors connected in series and a plurality of switches for connecting and disconnecting the connection points, and the storage circuit has a resistance value corresponding to the pole frequency. And a resistance control circuit having a switch control circuit for controlling connection / disconnection of the plurality of switches based on the control data of the switch read from the RAM. The surround processor according to claim 1, wherein: