JPH1168484A - Electronic volume and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress sudden increase of sound volume when the sound volume is successively increased in a high sound volume adjustment area of an amplifier, and to enable sudden decrease of the sound volume when the sound volume is successively reduced in the high sound volume adjustment area. SOLUTION: An electronic volume 100 is provided with an instruction means 11, a gain setting means 12 to set a gain value based on information U to instruct increase of the sound volume or information D to instruct decrease of the sound volume from the instruction means 11, and an amplifier 13 to increase or decrease the sound volume based on the gain value. In this case, when the entire gain adjustment ranges of the amplifier 13 is divided at least into two and the divided ranges are defined as a high sound volume adjustment area and a low sound volume adjustment area, varying speed of the gain value in the high sound volume adjustment area is defined as A and the varying speed of the gain value in the low sound volume adjustment area is defined as B, wherein the varying speed is set as A<B when the gain value of the amplifier 13 is successively increased in the high sound volume adjustment area, and set as A>B when the gain value of the amplifier 13 is successively decreased in the high sound volume adjustment area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic volume suitable for application to a volume control circuit for televisions, audios and the like, and a control method therefor. For more details,
When the volume is continuously increased in the large volume adjustment range in the small volume adjustment range, a sudden increase in the volume can be suppressed by making the gain value variable speed in the small volume adjustment range slower than the variable speed. Therefore, when the volume is continuously reduced in the large volume adjustment range, the volume can be sharply narrowed down by making the gain value faster than the variable speed of the gain value in the small volume adjustment range. .

[0002]

2. Description of the Related Art In recent years, audio systems such as mini components and micro components, televisions and CDs
In a radio cassette, an electronic volume having a lower noise characteristic than a so-called variable resistance type volume is often used.

FIG. 13 is a conceptual diagram showing the structure of an electronic volume 10 of this type. An operational amplifier 1 is connected to an input terminal 1A shown in FIG.
, An output OUT having a predetermined volume is obtained. A ladder resistance circuit 2 in which resistors made of semiconductor elements are integrated is connected to the operational amplifier 1.

On the other hand, for example, a push button type input switch circuit 3 for instructing the operational amplifier 1 to increase or decrease the volume is provided. When the user pushes the up button of the input switch circuit 3 by one, volume increase instruction information U is output, and when the user pushes the down button by one, volume decrease instruction information D is output. When the up button or the down button is continuously pressed, the information U or D is continuously output.

A microcomputer 4 is connected to the output stage of the input switch circuit 3 and receives volume increase instruction information U or volume decrease instruction information D, based on which the resistance value of the ladder resistance circuit 2 is adjusted. The gain value of the operational amplifier 1 is set.

Next, the operation of the electronic volume 10 will be described. FIG. 14 shows the continuous up output characteristic of the electronic volume 10. In FIG. 14, the vertical axis represents the gain value of the operational amplifier 1, the minimum gain value is −∞ dB, and the maximum gain value is 0 dB. The horizontal axis is the input switch circuit 3.
Is a continuous input time from the time t0 when the minimum gain value is set to the time t100 when the maximum gain value is set in the operational amplifier 1.

In such output characteristics, when the user continues to push the input switch circuit 3,
The volume increase instruction information U is continuously transmitted to the microcomputer 4
Is input to In this case, the gain value is increased one step at a time at the same variable speed every time a fixed time elapses from the pushed time over the entire volume adjustment range, that is, over the entire volume adjustment range. As a result, the resistance value of the ladder resistance circuit 2 is gradually reduced, and the gain value of the operational amplifier 1 approaches 0 dB.

Although the continuous down output characteristic of the electronic volume 10 is not shown (the time axis of the up characteristic is reversed), when the volume decrease instruction information D is continuously input, the whole volume adjustment is performed. Over the range, the gain value is reduced step by step at the same variable speed. As a result, the resistance value of the ladder resistance circuit 2 is gradually increased, and the gain value of the operational amplifier 1 approaches -∞dB.

When the user interrupts the push operation of the input switch circuit 3, the volume increase instruction information U is intermittently input to the microcomputer 4. In this case, over the entire volume adjustment range,
The gain value increases one step at a time. Similarly, when the volume reduction instruction information D is intermittently input, the gain value decreases by one step at every push time over the entire volume adjustment range.

By operating the input switch circuit 3 in this manner, the gain value of the operational amplifier (hereinafter also referred to as an amplifier) 1 can be controlled, so that the volume of an audio system or the like having the electronic volume 10 can be increased or decreased.

[0011]

By the way, a gain adjustment range of, for example, 50% or less of the entire gain adjustment range of the conventional electronic volume 10 is temporarily set as a small volume adjustment range, and 50% of the small volume adjustment range.
In the case where the gain adjustment range exceeding the maximum volume is set as the large volume adjustment range and the volume is to be continuously increased in the large volume adjustment range, the variable speed of the large volume adjustment range and the small volume adjustment range is the same in the conventional method. Since the gain value is set in the range, the user may feel that the volume increases rapidly in the large volume adjustment range.

[0012] Similarly, when the volume is reproduced at a high volume in the daytime and the same volume is forgotten and the reproduction is attempted at midnight, if the volume is not immediately lowered, the surroundings may be inconvenienced. Since the gain value is set at the same variable speed in the large volume adjustment region and the small volume adjustment region, it is not possible to sharply reduce the volume in the large volume adjustment region. As a result, there is a problem that an operation feeling suitable for actual use cannot be obtained, and the listener feels uncomfortable.

The present invention has been made to solve such a conventional problem. When the volume is continuously increased in the large volume adjustment range of the amplifier, it is possible to suppress a sudden increase in the volume. Another object of the present invention is to propose an electronic volume and a control method for the electronic volume which can sharply reduce the volume when the volume is continuously reduced in the large volume adjustment range.

[0014]

In order to solve the above-mentioned problems, an electronic volume and a method of controlling the same according to the present invention include an instructing means for instructing an increase or a decrease in volume, and information for instructing volume increase from the instructing means. An electronic volume comprising a gain setting means for setting a gain value based on volume decrease instruction information, and an amplifier for increasing or decreasing the volume based on the gain value from the gain setting means, wherein the minimum gain value of the amplifier is Between the maximum gain value and the maximum gain value, and when the entire gain adjustment range is divided into at least two sections to provide a large volume adjustment area and a small volume adjustment area, the variable speed of the gain value in the large volume adjustment area Is A, and the variable speed of the gain value in the low volume adjustment region is B. When the gain value of the amplifier is continuously increased in the high volume adjustment region, A <B
When the gain value of the amplifier is continuously reduced in the large volume adjustment range, A> B is set.

According to the electronic volume and the control method of the present invention, when the volume is continuously increased in the large volume adjustment range, the gain of the amplifier is slowly increased as compared with the case where the volume is increased in the small volume adjustment range. Since the value increases, it is possible to avoid a sudden increase in the volume in the large volume adjustment range.

In addition, when the volume is continuously reduced in the large volume adjustment range, the gain value of the amplifier decreases faster than when the volume is reduced in the small volume adjustment range.
The volume can be sharply reduced in the large volume adjustment range. As a result, an operation feeling suitable for actual use is obtained,
Less discomfort to listeners.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an electronic volume according to the present invention and a control method therefor will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an electronic volume 100 as an embodiment. In the present embodiment, when the variable speed of the gain value in the large / low volume adjustment range of the amplifier is A and B, if the volume is continuously increased in the large volume adjustment range, A <B is set. By doing so, it is possible to suppress an abrupt increase in the volume, and if the volume is to be continuously reduced in the large volume adjustment range, setting A> B allows the volume to be sharply reduced. It was made.

In FIG. 1, an electronic volume 100 has an instructing means 11 capable of continuously instructing an increase or decrease in volume.
Is provided, and the volume increase instruction information U or the volume decrease instruction information D is output intermittently or continuously by operating the instruction means 11 intermittently or continuously. A gain setting means 12 is connected to an output stage of the instruction means 11, and a gain value VR is set based on the volume increase instruction information U or the volume decrease instruction information D from the instruction means 11. An amplifier 13 for amplifying the input IN is connected to the output stage of the gain setting means 12, and the volume of the input IN is intermittently or continuously increased or decreased based on the gain value VR from the gain setting means 12.

In the electronic volume 100 of the present embodiment,
At the time of intermittent input, the gain is increased or decreased by one step as in the conventional case, and at the time of continuous input, the variable speed of the gain value is changed. It should be noted that the gain may be increased or decreased by one step in the small / medium volume adjustment region, the gain may be increased by one step when increasing in the large volume adjustment region, and the gain may be decreased by two steps when decreasing, so that the sound can be sharply narrowed down. Good.

FIG. 2 shows output characteristics when the electronic volume 100 is continuously raised. 2, the vertical axis represents the amplifier 13
For example, the minimum gain value is -∞dB, and the maximum gain value is 0 dB. The horizontal axis is indicating means 1
1 is the continuous input time by operating
3 is the time from time t0 when the minimum gain value is set to time t100 when the maximum gain value is set.

In this embodiment, when the entire gain adjustment range is between the minimum gain value and the maximum gain value of the amplifier 13, the intermediate gain value (approximately 50% of the maximum gain value) is used as a boundary. The range is divided into two. In this example, assuming that each of the two gain adjustment ranges is a large volume adjustment region and a small volume adjustment region, the output characteristics of the two are divided into a small volume adjustment region and a large volume adjustment region. It will be. Then, from the time t0 when the minimum gain value is set to the amplifier 13, the time is changed to the time t5 by the continuous operation of the indicating means 11.
When it reaches 0, an intermediate gain value is set in the amplifier 13.

When the variable speed of the gain value in the large volume adjustment region is A and the variable speed of the gain value in the small volume adjustment region is B, the gain value of the amplifier 13 is continuously changed in the large volume adjustment region. When increasing, that is, when the volume is continuously increased, the variable speeds A and B are set so that A <B. Specifically, since the variable speed A is set to 1 / α times (α ≧ 1) of the variable speed B, the time axis scale of the large volume adjustment area is obtained by multiplying the time axis scale of the small volume adjustment area by α. Becomes

FIG. 3 shows output characteristics when the electronic volume 100 is continuously down. In FIG. 3, the vertical axis represents the gain value of the amplifier 13 as in the case of continuous up. The horizontal axis is the continuous input time by the instruction means 11, and is the time from the time t0 when the maximum gain value is set to the amplifier 13 to the time t100 when the minimum gain value is set.

In the present embodiment, the amplifier 1
When the gain value of 3 is continuously reduced, that is, when the sound volume is continuously reduced, the variable speeds A and B are set so that A> B. Specifically, since the variable speed A is set to β times the variable speed B (β ≧ 1), the time axis scale of the large volume adjustment area is obtained by dividing the time axis scale of the small volume adjustment area by 1 / β. Become.

As described above, according to the electronic volume control 100 of the present embodiment, when the volume is continuously increased in the large volume adjustment range, the volume is increased in the small volume adjustment range as shown in FIG. Since the gain value of the amplifier 13 increases more slowly than in the case of, it is possible to avoid a sudden increase in volume.

Also, when the volume is continuously reduced in the large volume adjustment range, the gain value of the amplifier 13 is reduced faster than when the volume is reduced in the small volume adjustment range as shown in FIG. , The volume can be sharply reduced.

As a result, an operation feeling in accordance with a request to change the volume from a small volume to an optimum volume and a request to quickly lower the volume from a large volume can be obtained. Discomfort to the listener is reduced.

(Embodiment) In an electronic volume 200 as an embodiment, an operational amplifier (+ terminal) 21 as an amplifier 13 is connected to an input terminal 21A shown in FIG. 4 to amplify an input IN such as an audio signal. As a result, an output OUT having a predetermined volume is obtained. Of course, an input resistor for adjusting the bias current may be connected between the input terminal 21A and the + terminal of the operational amplifier 21.

The negative terminal of the operational amplifier 21 and the output terminal 2
1B is connected to a feedback resistor Rf, and a minus terminal thereof is further connected to a ladder resistor circuit 22 as a part of the gain setting means 12. The ladder resistance circuit 22 is formed by integrating resistors formed of semiconductor elements.

In this embodiment, the ladder resistance circuit 22 comprises, for example, five resistors R1 to R5 and five switching elements (hereinafter simply referred to as switches) S1 to S5. The resistor R1 is connected in series to the switch S1. Other resistors R2 to R5 are also connected in series to the respective switches S2 to S5. These five series circuits are connected in parallel and connected between the negative terminal of the operational amplifier 21 and the ground line GND. The above-mentioned switches S1 to S5 are composed of field effect transistors. Of course, the switches S1 to S5 may be constituted by bipolar transistors.

On the other hand, the electronic volume 200 is provided with an input switch circuit 23 as the instruction means 11. The input switch circuit 23 includes an up switch Su connected between points a and c (ground line GND), as shown in FIG.
A push-up / down switch 31 composed of a down switch Sd connected between points b and c, a resistor R11 connected between the power supply line VCC and the point a, and a power supply line VCC similarly. a resistor R12 connected to the point b
And inverters INV1 and INV2 for logical inversion connected to points a and b, respectively.

Then, the user sets the up switch Su to 1
When pushed, high-level volume increase instruction information U as shown in FIG. 6B is output from the inverter INV1. When the down switch Sd is pushed by one, the high-level volume decrease instruction information D as shown in FIG. 6C is output from the inverter INV2.

When the up switch Su or the down switch Sd is continuously pressed, the volume increase instruction information U or the volume decrease instruction information D is continuously output with respect to the system clock CLK as shown in FIG. 6A.

Returning to FIG. 4, the input switch circuit 23
A microcomputer 24 operating based on the system clock CLK is connected to the output stage, and receives the volume increase instruction information U or the volume decrease instruction information D, and adjusts the resistance value of the ladder resistance circuit 22 based on the input. .

That is, in this example, the microcomputer 2
4 to the ladder resistance circuit 22 output 5-bit switch selection data D1 to D5. For example, when high-level switch selection data D1 is output to the switch S1,
When the switch S1 is turned on and the low-level switch selection data D1 is output, the switch S1 is turned off.

When the switch S1 is turned on, the resistor R1 is connected between the negative terminal of the operational amplifier 21 and the ground line GND. When the switch S1 is turned off, the resistor R1 is connected between the negative terminal of the operational amplifier 21 and the ground line GND. Be separated. Similarly, the other switches S2 to S5 are turned on or off by the switch selection data D2 to D5. Thereby, the switch selection data D1
The resistance value of the ladder resistance circuit 22 can be changed based on D5, and the gain value of the operational amplifier 21 can be set.

FIG. 7 is a table summarizing the relationship between the 5-bit switch selection data D1 to D5 output from the microcomputer 24 to the ladder resistance circuit 22 and the gain value. In this example, the gain adjustment range with a gain value of -42 dB or less is the low volume adjustment range, and the gain adjustment range exceeding -42 dB is the high volume adjustment range.

The data for setting the maximum gain value 0 dB is "00000", the data for setting the intermediate gain value -42 dB is "10101", and the minimum gain value-値
Is "11111". Also, in this example, as shown in FIG.
Switch selection data D1 to D5 are prepared at intervals, and switch selection data D1 to D5 are prepared at intervals of -4 dB for a small volume adjustment range.

Next, a method of controlling the electronic volume 200 will be described. In this example, a case where the electronic volume 200 is controlled according to the following conditions will be described.

First, when the gain value (hereinafter referred to as VR value) of the operational amplifier 21 is continuously increased in the large volume adjustment range, that is, when the volume is continuously increased, the variable speeds A and B are set to A <B. Set to B. For example, if the variable speed B in the small volume adjustment range is set to the speed at which the VR value is stepped up once every 250 ms, the speed that is 1/2 times the speed is set as the variable speed A. That is, the variable speed A is 500 ms
The speed is such that the VR value is stepped up once every time. The variable speed B was set to 250 ms because
This is because a time related to one push of the down switch 31 is assumed.

When the VR value of the operational amplifier 21 is continuously reduced in the large volume adjustment range, that is, when the volume is continuously reduced, the variable speeds A and B are set so that A> B. For example, assuming that the variable speed B in the small volume adjustment range is a speed at which the VR value is stepped down once every 250 ms in the same manner as described above, the speed is twice as fast, that is,
The variable speed A is a speed at which the VR value is stepped down once every 125 ms.

Of course, if the variable speed B in the small volume adjustment range is 30
The speed at which the VR value is stepped down at a rate of once every 0 ms may be used. In this case, the speed is twice as fast, that is, the variable speed A is such that the VR value is stepped down at a rate of once every 150 ms. Speed. Note that the variable speeds A and B and the multiplication coefficients α and β are not limited to this example, and the ratio between A and B is appropriately selected.

FIG. 8 is an overall control flowchart (main routine) of the electronic volume 200 described above. FIG.
First, in step A1, the microcomputer 24 inputs a VR value. The VR value is set from a memory to a register in the micro computer 24 when the power of the audio equipment on which the electronic volume 200 is mounted is turned on. The VR value is executed by inputting an initial value set or inputting a final value set. If the previous VR value has been recorded in the memory, the final value is set in the register. If the VR value has not been recorded in the memory, the initial value is set in the register. Here, the VR value at the time of power-on can be set separately from the previous VR value.

Next, in step A2, the microcomputer 24 waits for a volume input instruction from the input switch circuit 23. Here, the user has to specify the desired volume,
The up switch Su or the down switch Sd is operated. If an instruction to input a volume is made by this operation, it is determined in step A3 whether the input instruction is to increase or decrease the volume.

Here, the volume increase instruction information U or the volume decrease instruction information D from the input switch circuit 23 is monitored by the microcomputer 24, and when the high level volume increase instruction information U is detected, the input instruction is issued to increase the volume. Is determined. When the high-level volume decrease instruction information D is detected, it is determined that the input instruction is a volume decrease.

When an instruction to increase the volume is received, the process proceeds to step A4, and the volume is increased. The up process shifts to the subroutine of FIG. 9 and is executed. When the input instruction for decreasing the volume is received, the process proceeds to step 5 and the volume is reduced. The down processing shifts to the subroutine of FIG. 10 and is executed.

In the case where the up processing is executed in accordance with the above input instruction, the processing shifts to the subroutine of FIG.
In step B1, the microcomputer 24 compares the VR value set in the register with the maximum gain value (VRmax). If the VR value of the register is equal to the maximum gain value of 0 dB, no up processing is necessary, and the process returns to the main routine.

If the VR value in the register is different from the maximum gain value in step B1, the process proceeds to step B2, and the microcomputer 24 determines whether the input instruction is continuous input or intermittent input. Here, the system clock C shown in FIG.
When high-level volume increase instruction information U is continuously detected for LK, it is determined that the volume increase instruction is a continuous input. Other than this is determined as a volume increase instruction by intermittent input.

Therefore, when the volume increase instruction is determined to be an intermittent input, the process proceeds to step B3, where the VR value is increased by one step (+1) as in the conventional method, and the data is stored in the ladder resistance circuit in step B4. 22. At this time, for example, -50 dB (101
Assuming that 11) has been set, -46 dB, which is one step higher, is set. Switch selection data D
“1110” is the ladder resistance circuit 22 as 1 to D5.
Is output to Then, -46 dB data is set (updated) in the register.

If the voice increase instruction is a continuous input, the process proceeds to step B5 to determine whether the current gain adjustment range is a large volume adjustment range or a small volume adjustment range. In this determination, first, the current gain setting value set in the register is compared with the intermediate gain value −42 dB which is the control boundary value. If the current gain setting value is equal to or less than -42 dB, it is determined that the current gain adjustment range is the small volume adjustment range. Conversely,
If the current gain setting is greater than -42 dB,
It is determined that the current gain adjustment range is a large volume adjustment range.

Therefore, if it is determined that the current gain adjustment range is in the small volume adjustment range, the process proceeds to step B6 to check whether the continuous input time has exceeded 250 ms. If the continuous input time does not exceed 250 ms, it is determined that a push error has occurred and the process returns to the main routine. If the continuous input time is 250 ms or more, the process proceeds to step B7, where the VR value is increased by one step (+1), and the data is stored in the ladder resistance circuit 2 in step B8.
Transfer to 2. Then, the process returns to the main routine.

If it is determined in step B5 that the current gain adjustment range is in the high volume adjustment range, the process proceeds to step B9 to check whether the continuous input time has exceeded 500 ms. If the continuous input time does not exceed 500 ms, the process returns to the main routine. If the continuous input time is 500 ms or more, the process proceeds to step B10, where the VR value is increased by one step at a rate of once every 500 ms, and the data is stored in the ladder resistance circuit 2 in step B11.
Transfer to 2. Then, the process returns to the main routine.

According to the electronic volume 200 provided with the input switch circuit 23 as described above, at the time of intermittent up, one VR per push in the entire gain adjustment range from -∞dB to 0 dB in step B3 of FIG. The value (level) is increased. On the other hand, at the time of continuous up, -∞
Step B in the small volume adjustment range from dB to -42 dB
As shown in FIGS. 7 and B8, one VR value (level) is increased once every 250 ms, and is changed from -40 dB to 0 d.
In the large sound volume adjustment range up to B, one VR value (level) is increased once every 500 ms as shown in steps B9 and B10.

Therefore, when the volume is continuously increased in the large volume adjustment range, it takes twice as long in step B9 as compared with the case where the volume is continuously increased in the small volume adjustment range in step B6. Since the VR value of the operational amplifier 21 gradually increases, a sudden increase in the volume can be avoided.

Next, when the down processing is executed in the main routine of FIG. 8, the processing shifts to the subroutine of FIG. 10, and first, at step C1, the VR value and the minimum gain value VRmin of the register in the microcomputer 24 are determined. Compare. If the VR value of the register is equal to the minimum gain value,
Since no down processing is required, the process returns to the main routine. If the VR value of the register is different from the minimum gain value in step C1, the process proceeds to step C2 to determine whether the volume reduction instruction is a continuous input or an intermittent input. The determination here is the same as the up processing, and thus the description thereof is omitted.

If the volume decrease instruction is an intermittent input, the process proceeds to step C3 to determine whether the current gain adjustment range is a large volume adjustment range or a small volume adjustment range. If the current gain adjustment range is the large volume adjustment range, the process proceeds to step C4, and the VR value is reduced by two steps (-2). For example, assuming that a VR value of -20 dB (01010) is set in the register, -24 dB of two steps down is set. As a result, “01100” is transferred to the ladder resistance circuit 22 as the switch selection data D1 to D5 in step C6. At this time, the register has -24 dB
Are set (updated).

If it is determined in step C3 that the current gain adjustment range is in the small volume adjustment range, the process proceeds to step C5, in which the VR value is reduced by one step (-1), and the data is laddered in step C6. Transfer to the resistance circuit 22.

If the volume decrease instruction is a continuous input in step C2, the process proceeds to step C7 to determine whether the current gain adjustment range is a large volume adjustment range or a small volume adjustment range.
If the current gain adjustment range is the small volume adjustment range, the process proceeds to step C8 to check whether the continuous input time has exceeded 250 ms. If the continuous input time does not exceed 250 ms, the process returns to the main routine.

If the continuous input time is equal to or longer than 250 ms, the flow shifts to step C9, where the VR value is decreased by one step (-1), and the data is transferred to the ladder resistance circuit 22 in step C10. Then, the process returns to the main routine.

If the current gain adjustment range is the large volume adjustment range in step C7, the process proceeds to step C11 to check whether the continuous input time has exceeded 125 ms. If the continuous input time does not exceed 125 ms, the process returns to the main routine. 125ms continuous input time
In the above case, the process proceeds to step C12, in which the VR value is decreased by two steps (-2), and the data is transferred to the ladder resistance circuit 22 in step C13. Then, the process returns to the main routine.

According to the electronic volume 200 having the input switch circuit 23, two levels are reduced by one push in the large volume adjustment range (from 0 dB to -40 dB) at the time of intermittent down, and the small volume Adjustment area (-4
In 2 dB to -∞ dB), one push downs one level.

On the other hand, as shown in step C11, two VR values are reduced once every 125 ms in the loud volume adjustment range during continuous down, and as shown in step C8 in the small volume adjustment range. Thus, one VR value is reduced once every 250 ms.

Therefore, when the sound volume is continuously reduced in the large sound volume adjustment range, compared with the case where the sound volume is continuously reduced in the small sound volume adjustment region in step C8, V C is determined in step C11.
Since the R value quickly decreases in a quarter of the time, the volume can be sharply reduced. This allows
An operation feeling that meets a listener's request to change the volume from a small volume to an optimum volume and a request to reduce the volume from a large volume quickly.

In the above-described electronic volume 200, an input switch circuit 23 'having a rotary encoder 41 as shown in FIG. In the rotary encoder 41 of the present example, as shown in FIG. 11, for example, a rotor 41A having 16 blades is connected to a point c (ground line GND). The rotor 41A is in contact with two contactors 41B and 41C which are arranged shifted by Δd.
These contacts 41B and 41C are connected to points a and b, respectively. And, like the input switch circuit 23,
A resistor R11 is connected between the power supply line VCC and the point a. A resistor R12 is similarly connected between the power supply line VCC and the point b.
NV1 and INV2 are connected.

Then, the user moves the rotor 41 from the current position.
When A is rotated in the up direction (clockwise direction), high-level volume increase instruction information U as shown in FIG. 12 is output from the inverter INV1 first, and the volume decrease instruction information D is delayed from the information U by the inverter INV2. Output from

When the rotor 41A is rotated in the down direction (counterclockwise), the high-level volume decrease instruction information D as shown in FIG. Volume increase instruction information U is output from inverter INV2. When the rotator 41A is continuously rotated in the up or down direction, two-phase volume increase / decrease instruction information U / D is continuously output. The two-phase volume increase / decrease instruction information U / D is transmitted to the microcomputer 24.
Monitored by

Therefore, also in the electronic volume 200 using the rotary encoder 41, the microcomputer 24 determines that the rotary encoder 41 is rotating, so that the volume is continuously increased in the large volume adjustment range. Occasionally, the VR value of the operational amplifier 21 increases more slowly than when the volume is increased in the small volume adjustment range, so that a sudden increase in the volume can be avoided.

When the volume is continuously reduced in the large volume adjustment range, the VR value of the operational amplifier 21 decreases faster than when the volume is reduced in the small volume adjustment range. You can narrow down.

In this example, the control boundary value between the small sound volume adjustment region and the large sound volume adjustment region is set to approximately 50% of the maximum gain value 0 dB (-42d).
B) has been described, but the present invention is not limited to this, and the control boundary value is almost 30% (−24d).
Even in the case of B), the same effect can be obtained.

In this example, the case where the entire gain adjustment range is divided into two has been described. However, the entire gain adjustment range is divided into three, and the small volume adjustment range, the medium volume adjustment range, and the large volume adjustment range are divided. , A variable speed of the gain value may be set. Further, an operation feeling suitable for actual use can be obtained.

[0072]

As described above, according to the electronic volume and its control method of the present invention, the variable speeds of the gain values in the large volume adjustment region and the small volume adjustment region of the amplifier are A and B.
When the gain value of the amplifier is continuously increased in the loudness adjustment range, A <B is set, and when the gain value of the amplifier is continuously decreased in the loudness adjustment range, , A> B.

With this configuration, when the volume is continuously increased in the large volume adjustment range, the gain value of the amplifier is increased more slowly than when the volume is continuously increased in the small volume adjustment range. Therefore, a sudden increase in the volume in the large volume adjustment range can be avoided.

Further, when the volume is continuously reduced in the large volume adjustment range, the gain value of the amplifier decreases faster than when the volume is continuously reduced in the small volume adjustment range. The volume can be rapidly reduced in the volume adjustment range. As a result, an operation feeling suitable for actual use is obtained, and discomfort to the listener is reduced.

Therefore, the electronic volume and the method of controlling the same according to the present invention are extremely suitable for application to a volume control circuit for a television, audio or the like.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an electronic volume 100 as an embodiment.

FIG. 2 is a diagram showing output characteristics when the electronic volume is continuously raised.

FIG. 3 is a diagram illustrating output characteristics when the electronic volume is continuously down.

FIG. 4 is a diagram showing a configuration of an electronic volume 200 as an embodiment.

FIG. 5 is a diagram illustrating a configuration of an input switch circuit 23;

FIG. 6 is a diagram showing an output waveform of the input switch circuit 23.

FIG. 7 is a table showing a relationship between a gain value of the operational amplifier 21 and switch selection data.

8 is an overall control flowchart of the electronic volume 200. FIG.

FIG. 9 is a flowchart (subroutine) of an electronic volume 200 up process.

FIG. 10 is a flowchart (subroutine) of a down process of the electronic volume 200;

FIG. 11 is a diagram illustrating a configuration of an input switch circuit 23 ′ including a rotary encoder 41.

FIG. 12 is a diagram showing an output waveform of an input switch circuit 23 ′.

FIG. 13 is a diagram showing a configuration of a conventional electronic volume 10;

FIG. 14 is a diagram showing output characteristics of a conventional electronic volume 10;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Instruction means 12 Gain setting means 13 Amplifier 1,21 O-amplifier 2,22 Ladder resistance circuit 3,23 Input switch circuit 4,24 Microcomputer 10,100,200 Electronic volume

Claims (3)

[Claims] 1. An instructing unit for instructing an increase or decrease in volume, a gain setting unit for setting a gain value based on volume increase instruction information or volume decrease instruction information from the instruction unit, and An electronic volume including an amplifier that increases or decreases a volume based on a gain value, wherein a total gain adjustment range is between a minimum gain value and a maximum gain value of the amplifier, and the total gain adjustment range is at least 2 When divided into a large volume adjustment region and a small volume adjustment region, A is a variable speed of the gain value in the large volume adjustment region, and B is a variable speed of the gain value in the small volume adjustment region. When the gain value of the amplifier is continuously increased in the loudness adjustment range, A <B is set. When the gain value of the amplifier is continuously decreased in the loudness adjustment range. An electronic volume, characterized in that it is set to A> B. 2. When the gain value of the amplifier is continuously increased in the loudness adjustment region, the variable speed of the gain value in the loudness adjustment region is changed by changing the gain value in the low volume adjustment region. When the gain value of the amplifier is continuously reduced in the loud volume adjustment region, the variable speed of the gain value in the loud volume adjustment region is set to 1 / α times the speed. 2. The electronic volume according to claim 1, wherein the variable speed is set to [beta] times the variable speed of the gain value. 3. A control method of an electronic volume for adjusting a gain value of an amplifier based on instruction information on an increase or decrease of a volume, wherein a total gain adjustment range is set between a minimum gain value and a maximum gain value of the amplifier. When the entire gain adjustment range is divided into at least two parts to be a large volume adjustment region and a small volume adjustment region, the variable speed of the gain value in the large volume adjustment region is A, and the gain in the small volume adjustment region is When the variable speed of the value is B, when the gain value of the amplifier is continuously increased in the loudness adjustment range, A <B is set. In the loudness adjustment range, the gain of the amplifier is set. A method for controlling an electronic volume, wherein A> B is set when the value continuously decreases.