JP2595421Y2 - Electronic volume device for audio equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electronic volume device for audio equipment.

"Prior art and its problems" The electronic volume used in audio equipment operates by receiving data (hereinafter DATA), clock (hereinafter CK) and strobe (hereinafter ST) signals from the CPU by up / down control such as key switches. However, this signal operation causes the signal components of DATA, CK, and ST to become noise in the audio output.

Conventionally, in order to reduce this noise, move the DATA, CK, ST pattern away from the audio signal, or DATA, CK, ST
The signal line was jumpered with a wire or the like to separate it from the audio amplifier signal line as much as possible so that the DATA, CK, and ST signals did not jump into the audio line.

However, the prior art could not sufficiently remove the noise component. Also, if the DATA, CK, ST signal line is close to the high impedance pattern of the audio amplifier, the DATA, CK, ST signal will jump directly into this pattern and generate noise, so pattern design for compact audio equipment There is also a disadvantage that the layout efficiency and the pattern layout design of the upper electronic component are restricted, and the design efficiency is deteriorated.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic volume device for audio equipment which can sufficiently remove noise generated at the time of up / down control by operating a key switch or the like and has a high pattern design efficiency in order to solve the above-mentioned problems of the prior art. It is to be.

"Means for solving the problem" In order to solve the above problem, the present invention adjusts the level of the audio input signal by the DATA, CK, ST signal output from the CPU at the time of up / down control by operating a key switch or the like. In the electronic volume to be performed, a high cut mute circuit or a trap mute circuit for removing a noise component appearing in an audio output signal of the electronic volume during the up / down control is operated by a mute signal output from the CPU only during the up / down control. Following the output of the mute signal, the CPU outputs DATA, CK, and ST signals to adjust the level of the audio input signal.When the power is turned on / off, the mode is switched, and the function is switched, the full-band mute circuit is switched from the CPU. Operate by the output mute signal An electronic volume apparatus of the audio equipment to symptoms.

[Operation] A mute signal is output from the CPU only during up / down control by operating a key switch or the like, and a high cut mute circuit or a trap mute circuit is operated to follow the output of the mute signal and adjust the level of the audio input signal. Therefore, noise components can be removed from the audio output signal. Then, at the time of power ON / OFF, mode switching, and function switching, the all-band mute circuit operates.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the drawing, 1 is an electronic volume, 2 is a CPU, 3 is a key switch, 4 is a high cut mute circuit, and 5 is a full band mute circuit.

The electronic volume 1 adjusts the level of an audio input signal (AUDIO INPUT) by the DATA, CK, and ST signals output from the CPU 2 when the key switch 3 is up / down controlled. At this time, since the DATA, CK, and ST signals of the CPU 2 appear as noise components in the audio output signal (AUDIO OUT), a high cut mute circuit 4 for removing the noise components is provided. This high cut mute circuit 4
A mute signal is output from the output port 6 provided in the CPU 2 during up / down control of the key switch 3 to operate. The DATA, CK, and ST signals are output from the CPU 2 following the output of the mute signal, and the electronic volume 1 is operated to adjust the level of the audio input signal (AUDIO INPUT). As a result, the audio output signal has a high-cut characteristic determined by R1 and C1 constituting the low-pass filter, and a noise component caused by the DATA, CK, and ST signals is removed by the high-cut mute circuit.

Also, the all-band mute circuit 5 operates by outputting a mute signal from the output port 7 provided in the CPU 2 separately from the high-cut mute circuit 4 only when the power of the audio equipment is turned on / off, when the mode is switched, and when the function is switched. This is to completely mute the entire band of the output signal. Therefore, when the key switch 3 is up / down controlled, the sound is cut off, and the CPU 2 does not operate the full band mute circuit 5.

In this embodiment, the high cut mute circuit 4 is used to remove a noise component appearing in the audio output signal at the time of up / down control of the key switch 3. However, the present invention is not limited to this. It doesn't matter.

"Effect" Since the present invention is configured as described above,
No noise component is output during down control, so that the listener does not feel uncomfortable. At the time of up / down control, the entire band is not muted, so that a normal sound signal is not interrupted. Further, there is no need to consider skipping the DATA, CK, ST signal lines with jumpers or the like in the pattern design, so that the efficiency in pattern design is greatly increased.

[Brief description of the drawings]

The drawing is a circuit diagram of an electronic volume device of an audio device according to an embodiment of the present invention. 1: Electronic volume, 2: CPU, 3: Key switch, 4: High cut mute circuit, 5: All band mute circuit

Claims (1)

(57) [Scope of request for utility model registration] The present invention relates to an up / down control of an audio output by operating a key switch or the like, and to adjust an output level of an electronic volume using data, a clock, and a strobe signal output from a CPU by the operation. In a volume device, a first mute circuit using a low-pass filter for removing the noise component in which the data, clock, and strobe signals jump into an audio line and appear as an audio component in an audio output signal of the electronic volume; Outputting a second mute circuit for removing the output signal over the entire band, and another mute signal for operating the first and second mute circuits, respectively;
Outputs a mute signal for operating the first mute circuit during the up / down control, and does not output a mute signal for operating the second mute circuit during the up / down control. And a CPU that outputs a mute signal for operating the second mute circuit at the time of function switching, and outputs the data, clock, and strobe signal following the output of the mute signal for operating the first mute circuit. An electronic volume device for audio equipment, characterized in that it has been made.