JP3236819B2 - Volume control device for audio equipment - 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 control apparatus for an audio device which prevents an unnatural change in volume caused by a power supply voltage fluctuation.

[0002]

2. Description of the Related Art FIGS. 3A and 3B are diagrams for explaining a conventional sound volume control device for audio equipment. FIG.
FIG. 4C is a relationship diagram between the input voltage and the sound volume, and FIG. Hereinafter, description will be made with reference to the drawings. An electronic volume is used for adjusting the volume of recent audio equipment, and an analog signal (voltage) adjusted by a user with a variable resistor is sent to a control unit such as a microcomputer and converted into a digital signal. Then, the control unit periodically instructs the electronic volume of the amount of attenuation for the audio signal.

[0003] Reference numeral 1 denotes an electronic volume used for volume control of audio equipment or the like, and an audio signal (radio, radio, etc.) input in response to a control signal (volume data) from a control unit 2.
This is for changing the attenuation rate of an output signal from a CD player or the like. Reference numeral 2 denotes a microcomputer (microcomputer) or the like which transmits (outputs) volume data obtained by digitally converting an analog signal corresponding to a volume adjustment operation by a user to the electronic volume 1 at predetermined transmission time intervals (for example, 30 to 50 ms intervals). It is the control part which was done. Reference numeral 3 denotes an amplifier that amplifies an audio signal whose volume has been adjusted by the electronic volume control 1. Reference numeral 4 denotes a speaker that converts an audio signal into sound. Reference numeral 5 denotes a volume control volume (variable resistor) for adjusting the volume by dividing the power supply voltage V (for example, 5 V) by a user's operation.
It is a rotary volume that can rotate to 0 degrees.

Next, a method of transmitting volume data will be described. The analog signal input from the volume adjustment volume 5 to the control unit 2 is sampled for a short time (for example, in units of μs) at predetermined time intervals (intervals of 30 to 50 ms), and
Resolution finer than one step (256 divisions, 19m
(V / 1 block, 58.6 mV / 1 step). For example, if the analog signal (voltage) is V1 in FIGS. 3B and 3C, steps 4, V4
Then, step 5 is performed. Then, the control unit 2 transmits (outputs) volume data corresponding to each step (for example, volume data of volume 4 in step 4) to the electronic volume 1. As a result, the input audio signal is adjusted by the electronic volume 1 based on the volume data and output to the amplifier 3.

[0005] When the power of the audio equipment is turned off,
The state immediately before disconnection (type of audio input source, reception frequency, disc changer number, volume, sound quality, etc.) is stored in the memory of the control unit 2, and when the power is turned on again, the same state as before the power was turned off is maintained. Will be reproduced. In this way, in response to a change in the volume adjustment volume due to the user's operation, volume data corresponding to the change amount is output to the electronic volume 1, and the volume is adjusted.

[0006]

Although a stabilized power supply is used for audio equipment, the power supply voltage fluctuates due to a temperature change or the like. For example, in FIG.
When the signal fluctuates from 1 to V2, the volume data does not change because it is in the same step. However, when the analog signal fluctuates from V3 to V4 (or V4 to V3), the step changes to a different step. 2 judges that the volume data has changed, changes the volume data, and transmits it to the electronic volume 1. That is, the control unit 2 instructs the electronic volume 1 to change (up or down) by one step in accordance with the changed value. for that reason,
The volume changes even though the user does not operate the volume adjustment volume 5 at all. In particular, when the volume position finally settled by the user is immediately before the boundary between the steps, the sound volume suddenly changes due to the above-described minute fluctuation.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a sound volume control device for audio equipment which does not cause a listener to feel an unnatural change in volume due to power supply fluctuation.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention converts an analog input signal for volume control into volume data composed of digital values, and converts the volume data based on the converted volume data. A volume control device for an audio device that controls the volume of an audio device to change to a volume corresponding to the volume data when the volume data exceeds a step provided at a predetermined interval. A timer means for measuring a required time interval, and when the time interval measured by the timer means is longer than a predetermined time interval, a change in the volume corresponding to the volume data when exceeding the one step is prohibited. It is characterized by having change prohibition means.

[0009] After the change of the volume is prohibited by the change prohibiting means, the power of the audio device is turned off,
After that, when the power-on detecting means for detecting that the power is turned on again and the power-on detecting means detects that the power is turned on again, the power of the audio equipment is turned off. When the period until the power is turned on again is longer than a predetermined period, the volume for which the change is prohibited by the change prohibiting means is corrected to a volume corresponding to the volume data when the one step is exceeded. It is characterized by having means.

[0010]

FIG. 1 is a block diagram for explaining a sound volume control device for an audio device according to an embodiment of the present invention. Hereinafter, description will be made with reference to the drawings. Reference numeral 1 denotes an electronic volume used for adjusting the volume of an audio device or the like. To change it. Reference numeral 2 denotes volume data obtained by digitally converting an analog signal corresponding to a volume adjustment operation by a user at a predetermined transmission time interval (for example, an interval of 30 to 50 ms).
Is a control unit composed of a microcomputer or the like that transmits (outputs) to the electronic volume 1. Reference numeral 3 denotes an amplifier that amplifies an audio signal whose volume has been adjusted by the electronic volume control 1. Reference numeral 4 denotes a speaker that converts an audio signal into sound. Reference numeral 5 denotes a volume adjustment volume (variable resistor) for dividing the power supply voltage V (for example, 5 V) by a user operation and adjusting the volume.

FIG. 2 is a flow chart for explaining the processing performed by the control unit of the volume control device of the audio equipment according to one embodiment of the present invention. Hereinafter, description will be made with reference to the drawings. In this example, the control unit 2 controls the power supply (5
V) The volume data is not changed in response to a voltage change due to a temperature change or the like.
In response to the voltage change caused by the above operation, the volume data is changed and output to the electronic volume 1 side.

In step S1, it is determined whether or not the A / D-converted digital signal has changed by one step. If the digital signal has changed by one step, the process proceeds to step S2. If not, the process ends. That is, it is determined whether or not the digital signal has changed when the analog signal input to the control unit 2 from the volume adjustment volume 5 is sampled at a predetermined time interval (30 to 50 ms interval) and converted into a digital signal. For example, in FIGS. 3B and 3C, the analog signal (voltage) is changed from the previous V1 to the current V2.
, The digital signal does not change within the same step (step 4). On the other hand, when the analog signal (voltage) has changed from the previous V3 to the current V4, it has changed to a different step (from step 4 to step 5), and the digital signal has changed by one step (volume data has changed). Judge.

In step S2, the change in one step is 1
It is determined whether or not it is within 0 seconds. If it is within 10 seconds, the process proceeds to step S3. If it is not within 10 seconds, step S4 is performed.
Move on to That is, the timer is set when the digital signal has changed last time, and it is determined whether or not the digital signal has changed this time within 10 seconds after that. More specifically, a timer is set from the time when the digital signal exceeds one step, and the time until the time when the digital signal exceeds the next step is counted. It is determined whether or not this time is within 10 seconds. Alternatively, a timer may be set from the time when the value (V3) immediately before the step boundary is reached, and the time until the value (V4) exceeding the step is reached may be counted.

In step S3, the volume data is changed, and the process ends. That is, the change in one step is 10
It occurs within seconds, and it is presumed that the volume adjustment volume was operated by the user's intention, not the fluctuation of the power supply voltage due to the temperature change (the fluctuation of the stabilized power supply of 5 V supplied to the volume adjustment volume). Is done. Therefore,
The control unit 2 changes the volume data to the electronic volume 1 (one step up or down) and outputs it.

In step S4, the process proceeds to step S5 without changing the volume data. In other words, it takes 10 seconds or more for the digital signal to change by one step, and the volume control volume 5 is not operated very slowly by the user's intention. (The fluctuation of the stabilized power supply of 5 V supplied to the volume adjustment volume 5), it is assumed that the analog signal input to the control unit 2 fluctuates. Therefore, although the digital signal corresponding to the analog input signal changes by one step, the control unit 2 outputs the conventional volume data to the electronic volume 1 without changing the volume data.

In step S5, it is determined whether or not the power of the audio device has been turned off. If the power has been turned off, the process proceeds to step S6. If the power has not been turned off, the process ends. That is, it is determined whether or not the power of the audio device has been turned off by the user. When the power of the audio equipment is turned off, the state immediately before the power is turned off (the type of the audio input source, the reception frequency, the disc changer number, the volume, the sound quality, etc.) is stored in the memory of the control unit 2.

In step S6, it is determined whether or not the power of the audio device is turned on. If the power is turned on, the process proceeds to step S7. If the power is not turned on, the process is terminated. That is, it is determined whether or not the power of the audio device is turned on again by the user. In step S7, it is determined whether or not the time from power-off to power-on is within 30 seconds. If it is within 30 seconds, the process proceeds to step S9, where the time from power-off to power-on is determined. Is longer than 30 seconds, step S8
Move on to In this embodiment, the control unit 2 does not change the volume data with respect to the electronic volume 1 even if the converted digital signal changes even if the analog signal changes slowly due to a temperature change or the like. Therefore, the control unit 2 is in a state where a difference is generated between the digital signal based on the input signal and the value (step) of the digital signal output to the electronic volume 1. Figure 3 actually
Since the step and the volume must be made to correspond according to the logic shown in (b), the volume data cannot be left as it is, and this difference needs to be corrected at some point. It is appropriate while the device is turned off. However, if the correction is made and the digital signal value is changed to a correct value (step) when the time between power-off and power-on is short, the user still remembers the previous volume and feels that the volume has changed rapidly. Therefore, the difference is corrected when the memory of the previous volume fades, and in this example, for example, 30 seconds is used as a rough guide.

In step S8, the volume data is corrected, and the process ends. In other words, after turning off the power, a long time elapses before the power is turned on again, and the volume of the volume before the power is turned off is faint, and the user does not feel the change in the volume. The volume data is changed to 1 and output (the number of steps to be corrected or correct volume data obtained by digitally converting a newly input analog signal is output).

In step S9, the process ends without correcting the volume data. In other words, since the time from turning off the power to turning it on again is relatively short, if a correction is made, the user has a memory of the volume before the power was turned off, and feels that the volume has changed. Is not performed,
The volume data transmitted to the electronic volume 1 immediately before turning off the power of the audio device stored in the memory of the control unit 2 is transmitted.

In this embodiment, the determination as to whether or not to correct the difference in volume fluctuation is made based on the time from when the audio equipment is turned off to when it is turned on again. However, the present invention is not limited to this. The determination may be based on the time when audio output such as mute and pause is interrupted. As described above, in this embodiment, to change only one step over 10 seconds or more, 58.6 mV / 10 sec, which is a very fine operation, is not possible with a normal operation of the user. In this example, attention is paid to this point, and if such a change occurs, it is not a user operation, but is regarded as occurring on the circuit and ignored. In the case of this example, when the change for two steps is performed over 10 seconds or more, it is determined that the operation is performed by the user, and the volume data is changed.

As described above, in this embodiment, even if the analog input signal for adjusting the volume changes due to a temperature change or the like, the volume data to the electronic volume is changed according to the change speed of the digitized signal. Since the determination is made, it is possible to prevent the listener from feeling an unnatural volume change due to a power supply fluctuation or the like. In addition, the volume data is corrected at an appropriate time. In this example, the predetermined time interval is set to 10 seconds. However, the present invention is not limited to this, and may be changed according to the circuit specifications and the user's operability.

[0022]

As described above, according to the present invention, it is possible to provide a sound volume control device for audio equipment which does not cause a listener to feel an unnatural change in volume due to power supply fluctuation.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining a volume control device for an audio device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a process performed by a control unit of the volume control device of the audio device according to the embodiment of the present invention;

FIG. 3 is a diagram for explaining a conventional sound volume control device for audio equipment.

[Explanation of symbols]

 1 ... Electronic volume, 2 ... Control unit, 3 ... Amplifier, 4 ... Speaker, 5 ... Volume adjustment volume.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04R 3/00 310 H03G 3/02

Claims (2)

(57) [Claims] An analog input signal for volume control is converted into volume data composed of digital values, and based on the converted volume data, when the volume data exceeds a step provided at a predetermined interval, the volume of the audio device is changed. A volume control device for an audio device that controls the volume data to change to a volume corresponding to the volume data, wherein the volume data is configured to measure a time interval required to exceed the one step, and When the measured time interval is longer than a predetermined time interval, the volume of the audio device is provided with a change prohibition unit that prohibits a change of a volume corresponding to the volume data when the one step is exceeded. Control device. 2. A power-on detecting means for detecting that the power of the audio equipment is turned off after the change of the sound volume is prohibited by the change prohibiting means, and thereafter the power is turned on again; When the detecting unit detects that the power is turned on again, if the period from when the power of the audio device is turned off to when the power is turned on is longer than a predetermined period, the change prohibition is performed. 2. The volume control device for an audio device according to claim 1, further comprising a correction unit configured to correct a volume whose change is prohibited by the unit to a volume corresponding to the volume data when the one step is exceeded.