JPH0822338B2 - Sound source chip including internal mixer with external audio signal input terminal - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound source chip constituting a computer game device.

[0002]

2. Description of the Related Art Conventionally, a sound source chip incorporated in a computer game device has a sound source output section, an internal volume circuit for controlling the volume of a sound signal from the sound source output section, and a sound signal output from the sound source output section on multiple channels. In this case, an internal mixer circuit for mixing the audio signals from the respective channels, an A / D converter, etc. are integrated into one chip.

Recently, in order to improve the sound output performance of a computer game device, a sound source output unit such as a programmable sound generator (PSG) or an adaptive differential pulse code modulation decoder (ADPCM), or a sound input from an external audio device is used. The functions that can be supported are expanding.

When a plurality of sound sources are incorporated, the sound source chips are independent for each sound source, and the sound output from each sound source chip is further output after mixing through an external mixer circuit.

[0005]

As described above, when a plurality of kinds of sound sources are incorporated in one device, the outputs from the respective sound sources must be controlled. Therefore, in addition to the mixer circuit inside the chip, an external mixer. Circuit is needed.

In the case of supporting a sound input from an external audio device, for example, if a sound source such as a compact disc player that does not have a volume control is included, the output from another sound source is balanced, so that a different sound volume is obtained. A volume circuit for control is also required. As described above, in order to use a plurality of types of sound sources, the number of circuits required increases and the number of parts incorporated in the device increases.

[0007] Computer game devices have become composed of a plurality of sound sources in order to achieve multipurpose or to realize high sound quality. To support the sound source configuration,
Various necessary circuits have also been incorporated. However, since the computer game device is usually treated as a toy, it is necessary to reduce the cost more than to pursue high performance.

Therefore, in terms of cost reduction and downsizing of the device, it is preferable that the number of parts constituting the device is small. It is an object of the present invention to obtain a sound source chip capable of supporting voice input from various external sound sources and reduce the number of parts incorporated in one device.

[0009]

In order to solve the above problems, according to the present invention, an internal audio signal input terminal is provided in an internal mixer circuit of a sound source chip to mix an audio signal from the outside of the sound source chip. Is possible.

Some audio inputs from external audio equipment such as compact discs are not volume-controlled, so an external audio input terminal is provided in the internal volume circuit and output from the internal volume circuit to the internal mixer circuit. I do.

The structure of the sound source chip of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram of an example of a sound source chip of the present invention. The drawing shows an example in which an external audio input terminal is provided in the internal volume circuit to perform volume control and mixing.

The various sound sources in the figure are multi-channel one sound sources,
Multiple sound sources are possible. Although one volume circuit and one mixer circuit are shown in the figure, two mixer circuits can be built in to support stereo, or multiple volume circuits can be provided to support multiple audio inputs from the outside. It is possible. If the volume circuit is not required, connect the external audio input terminal directly to the mixer circuit.
Or it is also possible to provide more than one.

[0013]

Embodiments of the present invention will be described with reference to the drawings. Figure 2
FIG. 3 is a block diagram showing an example of a computer game device incorporating the tone generator chip of the present invention.

FIG. 3 shows an adaptive differential pulse code modulation decoder (ADPC) as a sound source output unit in the embodiment of the present invention.
FIG. 3 is an overall block diagram of a sound source chip having two channels M) and a programmable sound generator (PSG).

The volume circuit incorporates one voltage-controlled amplifier (VCA) for each of the left and right sides of VCAR and VCAL for controlling the volume of a PCM signal using a compact disc as a sound source. To the VCA input terminals (indicated by VCAR-IN and VCAL-IN in the figure),
There are two corresponding output terminals, VCAR-OU in the figure
VCA output terminal, VCAR and VCA when T and VCAL-OUT are used as an internal volume circuit
L is a VCA output terminal for externally attaching the volume circuit.

The case of using the built-in volume circuit will be described as an example. FIG. 4 is an overall block diagram when the built-in volume circuit is used in the embodiment of FIG.
As shown in the figure, the PCM signal from the CD is supplied with two V from the terminals of VCALIN and VCARIN via the capacitor.
Entering into CA. The volume of the PCM signal is controlled by the VCA and then input to the mixer. Built-in V
The CA rewrites the volume registers R15 and R16 to amplify or attenuate the output of the PCM sound source.

As shown in the figure, two mixers are built in, and they are stereo compatible. In this embodiment, a total of four left and right audio signals are sent to the mixer from a PCM signal from a CD, a 2-channel ADPCM and a 6-channel PSG as external audio equipment.

In the embodiment shown in FIG. 4, since the built-in volume circuit is used, VCAR-OUT, LINER and V
CAL-OUT and LINE are connected, but when using the external volume circuit, VCAR and VCAL
Is connected to the input terminal of the external volume circuit.

[0019]

As described above, the sound source chip of the present invention is
Since the internal mixer circuit is provided with the external audio signal input terminal, the external audio output can be mixed with the audio output from the internal sound source. By adding an internal volume circuit to the internal mixer circuit and processing the external audio signal via the volume, it is possible to handle audio input from an external audio device whose volume is not controlled.

Further, since the mixer circuit and the volume circuit inside the sound source chip are made to correspond to the external audio output, it is possible to reduce the number of parts constituting the well-known sound source chip. Since the number of parts is reduced, there are effects such as simplification of the device and cost reduction.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an example of a sound source chip of the present invention.

FIG. 2 is a block diagram of an embodiment of a computer game device incorporating the tone generator chip of the present invention.

FIG. 3 is an overall block diagram of a sound source chip according to an embodiment of the present invention.

FIG. 4 is an overall block diagram of a sound source chip according to an embodiment of the present invention.

Claims (2)

[Claims] 1. A tone generator chip for a computer game apparatus, comprising an internal mixer circuit with an input terminal for an audio signal from the outside of the chip. 2. A sound source chip for a computer game device, comprising a sound signal input terminal from the outside of the chip, and an internal volume circuit for outputting to an internal mixer circuit.