JP2003318673A - Electrical volume circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an electrical volume circuit for reducing shock sounds, which occur when a volume setting value of an electrical volume is switched. <P>SOLUTION: A determining part 60 for amount of change in volume determines whether the amount of change in present volume-setting data, and newly input volume setting data are the predetermined minimum amount of change; if a determination result is larger than the minimum amount of change, a volume-setting control part 50 sequentially switches the volume setting value in turn by predetermined minimum step widths up to the newly input volume setting data. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic volume circuit which is controlled by an MCU and which controls volume, and more particularly to an electronic volume circuit which is applied to electronic equipment such as audio equipment.

[0002]

2. Description of the Related Art An electronic volume circuit is used for volume control of audio equipment. The electronic volume is for proportionally dividing and outputting a constant reference voltage based on a digital input of several bits.
There is an A (Voltage Controlled Amplifier) method. The ladder resistance method attenuates the signal according to the resistance ratio,
In the method, a signal is increased or decreased by voltage control using a voltage control amplifier. Both methods are based on MCU (Micro Contro
ller Unit) is often controlled.

FIG. 11 shows the configuration of a conventional electronic volume circuit. The conventional electronic volume circuit in FIG. 11 includes an electronic volume 10, a decoding unit 20, and an M
It has a CUI / F 30 and an MCU 40.

The MCU 40 is composed of a microcontroller and outputs volume setting data to the MCU I / F 30. The MCU I / F 30 is an interface that reads the volume setting data set by the MCU 40 and outputs it to the decoding unit 20. The decoding unit 20 controls the electronic volume 10 so that the output signal has a value corresponding to the volume setting data input from the MCU I / F 30.
Output the volume setting value to. Electronic volume 10
Outputs the output signal by adjusting the volume of the input signal based on the volume setting value set by the decoding unit 20.

[0005]

As described above, in the conventional electronic volume circuit, the volume value of the electronic volume 10 is set almost at the same time as the timing when the MCU I / F 30 takes in the volume setting data output from the MCU 40. Therefore, when the set value of the volume for the electronic volume 10 output from the decoding unit 20 changes abruptly, for example, when it is changed from 0 dB to −10 dB, the output signal level changes abruptly as shown in FIG. To do. At this time, if the analog signal level is large (the difference from the analog reference level is large), the change amount of the output signal becomes large, and the shock sound is generated at the timing when the volume setting value set in the electronic volume 10 from the decoding unit 20 changes. There was a problem that (pop noise) occurred.

The present invention has been made in view of the above,
An object of the present invention is to obtain an electronic volume circuit that reduces a shock noise generated when switching the volume setting value of the electronic volume.

[0007]

In order to achieve the above object, an electronic volume circuit according to the present invention is newly input in an electronic volume circuit for adjusting the volume of an input signal based on input volume setting data. Volume change amount determining unit that determines whether or not the change amount of the volume setting data is greater than a predetermined minimum change amount, and the change amount of the volume setting data newly input in the volume change amount determining unit is the minimum. A volume setting control unit that sequentially changes the volume setting value for the input signal from the current volume setting value to the value of the newly input volume setting data by a predetermined minimum step width when it is determined that the change amount is larger than the change amount. It is characterized by including.

According to the present invention, the volume change amount determination unit determines whether or not the change amount between the current volume setting data and the newly input volume setting data is a predetermined minimum change amount, When the determination result is larger than the minimum change amount, the volume setting control unit sequentially switches the volume setting value up to the value of the newly input volume setting data by a predetermined minimum step width.

In the electronic volume circuit according to the next invention, in the above invention, the volume setting control unit determines that a change amount of the volume setting data newly input in the volume change amount determining unit is larger than a minimum change amount. If it is determined, the amount of change between the current volume setting value and the setting value of the newly input volume setting data is equally divided so that the volume switching ends within a predetermined volume switching time. A volume step width determining unit that determines the width is provided, and the volume setting value for the input signal is changed by the determined step width.

According to the present invention, when the volume change amount determining unit determines that the change amount of the newly input volume setting data is larger than the minimum change amount, the volume step width determining unit determines the predetermined volume. So that the volume switching is completed within the switching time,
The amount of change between the current volume setting data and the newly input volume setting data is equally divided to determine the step width, and the volume setting control unit sets the volume setting value up to the value of the newly input volume setting data. The step widths determined by the volume step width determination unit are sequentially switched.

In the electronic volume circuit according to the next invention, in the above invention, when the volume setting control unit determines that the change amount of the volume setting data is larger than the minimum change amount, A volume step time determining unit that determines a step time for changing the volume setting value so that the volume switching is completed using the minimum step width and within a predetermined volume switching time is provided. The volume setting value for the input signal is changed by the minimum step width at intervals.

According to the present invention, when the volume change amount determining unit determines that the change amount of the newly input volume setting data is larger than the minimum change amount, the volume step time determining unit determines the current volume setting data. When switching the change amount of the newly input volume setting data with the minimum step width, the step time for changing the volume setting value is determined so that the volume switching is completed within the predetermined volume switching time. The setting control unit sequentially switches the volume setting values up to the value of the volume setting data by the minimum step width at the step time intervals determined by the volume step time determining unit.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of an electronic volume circuit according to the present invention will be described in detail below with reference to the accompanying drawings.

Embodiment 1. The first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing the configuration of the electronic volume circuit according to the first embodiment. The electronic volume circuit according to the first embodiment is the MCU 40.
, MCU I / F 30, and volume change amount determination unit 60
A volume setting control unit 50, a decoding unit 20,
The electronic volume 10 is provided.

The MCU 40 is composed of a microcontroller and outputs volume setting data of an output signal to the MCU / I.
Output to F30.

The MCU I / F 30 reads the volume setting data set by the MCU 40, and decodes the volume setting data.
It has an interface function to output to.

The volume change amount determination unit 60 compares the current volume setting data with the newly set volume setting data and determines whether or not the change amount is a predetermined minimum change amount.

When the amount of change determined by the volume change amount determining unit 60 is greater than the minimum amount of change, the volume setting control unit 50 sets the volume newly set from the value of the current volume setting data. The volume setting value is sequentially changed in units of the minimum step width up to the value of the setting data.

The decoding unit 20 outputs the volume setting value designated by the volume setting control unit 50 to the electronic volume 10.

The electronic volume 10 outputs an output signal obtained by adjusting the input signal based on the designation of the decoding section 20.

The operation of the electronic volume circuit of the first embodiment will be described with reference to the flowchart of FIG. Here, the minimum change amount that is predetermined by the volume change amount determination unit 60 and the minimum step width that is changed by the volume setting control unit 50 are the same 1 dB.

The MCU 40 outputs the volume setting data to the MCU I / F 30 in order to switch the volume (step S100). When the volume setting data is output from the MCU 40, the MCU I / F 30
The volume setting data is read and output to the volume change amount determination unit 60. When the volume setting data is received from the MCU I / F 30, the volume change amount determination unit 60
Compares the current volume setting data with the volume setting data newly received from the MCUI / F30, and the change amount is determined to be a predetermined minimum change amount (in this case, 1d
B) is determined, and the determination result is output to the volume setting control unit 50.

If the determination result input from the volume change amount determination unit 60 is not the minimum change amount (No in step S110), the volume setting control unit 50 newly adds the volume setting data from the currently set volume setting data. The volume setting value is sequentially switched by the minimum step width up to the set volume setting data (step S12).
0). Specifically, as shown in FIG. 3, when the current volume setting data is 0 dB and the newly set volume setting data is −10 dB, the volume setting control unit 50 causes the volume setting control unit 50 to output −1 dB at regular time intervals t. -2 dB, -3d
The volume setting value is changed by 1 dB, which is the minimum step width, such as B, so that the volume setting value finally becomes -10 dB which is the value of the volume setting data set by the MCU 40.

The decoding unit 20 decodes the volume setting value input from the volume setting control unit 50 and sets the electronic volume 10 (step S130).
The electronic volume 10 outputs an output signal obtained by changing the input signal based on the volume setting value input from the decoding unit 20.

On the other hand, when the determination result input from the volume change amount determination unit 60 is the minimum change amount (step S1
10, Yes), it is not necessary to switch sequentially, so the volume setting control unit 50 outputs the volume setting data set by the MCU 40 to the decoding unit 20 as it is,
The decoding unit 20 sets the electronic volume 10,
Based on the setting, the electronic volume 10 outputs an output signal obtained by changing the input signal.

FIG. 4 shows a signal envelope in the electronic volume circuit of the first embodiment. Time t ₀
At, the volume setting data is output from the MCU 40. The volume setting control unit 50 changes the volume setting value from 0 dB by 1 dB, which is the minimum step width, at fixed time intervals t, and in this case, changes the volume setting value to −10 dB over a period of 10 t from the start of switching to the end of switching. That is, in the conventional technique shown in FIG. 12, when the volume setting data is output to switch the volume, the output signal instantaneously changes from −0 dB to −10 dB, so that the signal envelope shows a sharp change.
In the first embodiment, when the MCU 40 outputs the volume setting data at time t ₀ , the volume setting control unit 5
0 is changing the volume setting value by -1 dB at each step time t interval, and the volume is changed to -10 dB by 10t volume switching time until time t _1, so that the signal envelope smoothly changes.

As described above, in the first embodiment, the volume change amount determination unit 60 determines whether or not the change amount of the volume setting data is the minimum change amount, and when the determination result is larger than the minimum change amount. , Volume setting control unit 50
However, since the volume setting value is sequentially changed with the minimum step width at the constant time t, the signal level changes smoothly without abrupt change, and the shock noise at the time of volume switching can be reduced. You can

Embodiment 2. Second Embodiment A second embodiment of the present invention will be described with reference to FIGS. Originally, for volume switching, it is desirable that the volume setting value of the electronic volume 10 be switched at the same time when the volume setting data from the MCU 40 is taken in. However, in the first embodiment, when the change amount of the volume setting data is larger than the minimum change amount, the volume setting value is sequentially changed at the constant time interval with the minimum step width. If the amount is large, it will take time to switch the volume.

In order to solve such a problem, in the second embodiment, the step width for changing the volume setting value is changed according to the volume change amount, and the time required for volume switching is made constant. .

FIG. 5 is a block diagram showing the configuration of the electronic volume circuit according to the second embodiment. In the electronic volume circuit according to the second embodiment, the volume step width determination unit 7 is provided between the volume change amount determination unit 60 and the volume setting control unit 50 of the electronic volume circuit according to the first embodiment.
0 is added. The components having the same functions as those in the first embodiment are designated by the same reference numerals, and the duplicate description will be omitted.

The volume step width determination unit 70 determines the step width from the amount of change between the current volume setting data and the newly set volume setting data so that the volume switching is completed within a predetermined volume switching time T. decide.

The operation of the electronic volume circuit of the second embodiment will be described with reference to the flowchart of FIG. Here, the minimum change amount that is predetermined by the volume change amount determination unit 60 is 1 dB, and the volume switching time T is 10
The case of t will be described as an example.

The MCU 40 outputs the volume setting data to the MCU I / F 30 in order to switch the volume (step S100). When the volume setting data is output from the MCU 40, the MCU I / F 30
The volume setting data is read and output to the volume change amount determination unit 60. When the volume setting data is received from the MCU I / F 30, the volume change amount determination unit 60
Compares the current volume setting data with the volume setting data newly received from the MCUI / F30, and the change amount is determined to be a predetermined minimum change amount (in this case, 1d
It is determined whether or not it is B), and the determination result is output to the volume step width determination unit 70.

When the determination result input from the volume change amount determination unit 60 is not the minimum change amount (No in step S110), the volume step width determination unit 70 determines
The step width is determined so that the volume switching is completed within a predetermined volume switching time T, and the determined step width is output to the volume setting control unit 50 (step S200). Specifically, as shown in FIG. 7, assuming that the volume switching time T is 10 t, if the current volume setting data is 0 dB and the newly set volume setting data is -10 dB, the volume setting data changes. Since the amount is 10 dB, if the volume setting value is changed by 1 dB which is the minimum step width at every constant time t, the volume switching time becomes 10 t. However, the current volume setting data is 0 dB
Then, the newly set volume setting data is -20d.
In the case of B, when the volume setting value is changed by -1 dB which is the minimum step width, the volume switching time is 2
It takes 0t. Therefore, if the step width is set to -2 dB, the volume switching time becomes 10 t. As described above, when the volume step width determination unit 70 does not complete the volume switching within the volume switching time T when the volume setting value is changed with the minimum step width, the volume switching width is switched within the predetermined volume switching time T. The step width for changing the volume setting value is determined based on the change amount of the volume setting data and the volume switching time T so that the process ends.

The volume setting control unit 50 sequentially sets the volume setting values from the currently set volume setting value to the newly set volume setting value in steps of the step width input from the volume step width determining unit 70. It switches (step S210). Specifically, for example, as shown in FIG. 7, the volume setting value is −0 dB.
When changed from -20dB to -2dB, -4d
B, −6 dB, etc., the step width input from the volume step width determination unit 70 at regular time intervals t−
The volume setting value is changed by 2 dB and finally 10
At t, the volume setting value is set to −20 dB which is the value of the volume setting data set by the MCU 40.

The decoding unit 20 decodes the volume setting value input from the volume setting control unit 50 and sets the electronic volume 10 (step S130).
The electronic volume 10 outputs an output signal obtained by changing the input signal based on the set value input from the decoding unit 20.

On the other hand, when the determination result input from the volume change amount determination unit 60 is the minimum change amount (step S1
10, Yes), it is not necessary to switch sequentially, so the volume setting control unit 50 outputs the volume setting data set by the MCU 40 to the decoding unit 20 as it is,
The decoding unit 20 sets the electronic volume 10,
Based on the setting, the electronic volume 10 outputs an output signal obtained by changing the input signal.

As described above, in the second embodiment, the volume step width determining unit 70 changes the volume stepwise so that the volume switching is completed within the preset volume switching time T based on the change amount of the volume setting data. Since the step width to be changed is determined, the volume switching time can be kept constant.

Embodiment 3. A third embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the step width of the change amount of the volume setting data is determined so that the volume switching is completed within the predetermined volume switching time. However, when the change amount of the volume setting data is large, the step width also becomes large.

In order to solve such a problem, in the third embodiment, the volume is changed stepwise with the minimum step width, and the step time which is the change time is adjusted to adjust the volume according to the volume change amount. The time required for volume switching is made constant.

FIG. 8 is a block diagram showing the configuration of the electronic volume circuit of the third embodiment. In the electronic volume circuit according to the third embodiment, a volume step time determination unit 80 is added between the volume change amount determination unit 60 and the volume setting control unit 50 of the electronic volume circuit according to the first embodiment. The components having the same functions as those in the first embodiment are designated by the same reference numerals, and the duplicate description will be omitted.

The volume step time determination unit 80 has the current volume setting data and the newly set volume so that the volume switching is completed within a predetermined volume switching time T with a predetermined minimum step width. The step time is determined from the amount of change in the setting data.

The operation of the electronic volume circuit of the third embodiment will be described with reference to the flowchart of FIG. Here, an example will be described in which the minimum change amount predetermined in the volume change amount determination unit 60 and the minimum step width changed by the volume setting control unit 50 are the same 1 dB, and the volume switching time T is 10 t. .

The MCU 40 outputs the volume setting data to the MCU I / F 30 in order to switch the volume (step S100). When the volume setting data is output from the MCU 40, the MCU I / F 30
The volume setting data is read and output to the volume change amount determination unit 60. When the volume setting data is received from the MCU I / F 30, the volume change amount determination unit 60
Compares the current volume setting data with the volume setting data newly received from the MCUI / F30, and the change amount is determined to be a predetermined minimum change amount (in this case, 1d
It is determined whether or not it is B), and the determination result is output to the volume step time determination unit 80.

If the determination result input from the volume change amount determination unit 60 is not the minimum change amount, the volume step time determination unit 80 (step S110, N
o), the step time is determined so that the volume switching is completed within a predetermined volume switching time T, and the determined step time is set to the volume setting control unit 5
It is output to 0 (step S300). Specifically, FIG.
As shown in 0, when the volume switching time T is 10t, when the current volume setting data is 0 dB and the newly set volume setting data is -10 dB, it is the constant time interval and the minimum step width. When the volume setting value is changed by 1 dB, the volume switching time becomes 10t. However, if the current volume setting data is 0 dB and the newly set volume setting data is −20 dB, the current volume setting data is 0 dB and the newly set volume setting data is −0 dB.
In the case of 20 dB, if the volume setting value is changed by -1 dB, which is the minimum step width, the volume switching time will take 20 t. Therefore, the step time is t
When set to / 2, the volume switching time becomes 10t. In this way, the volume step time determination unit 80
If the volume switching is not completed within the volume switching time T when the volume setting value is changed with the minimum step width, the volume setting value is set so that the volume switching is completed within the predetermined volume switching time T. From the amount of change and the volume switching time T, the step time for changing the volume setting value is determined and output to the volume setting control unit 50.

The volume setting control unit 50 receives the minimum step width (in this case, from the currently set volume setting value to the newly set volume setting value at step time intervals input from the volume step time determining unit 80. The volume setting value is sequentially switched in steps of -1 dB) (step S310). Specifically, for example, FIG.
As shown in, the volume setting value is from −0 dB to −2.
When it is changed to 0 dB, the step time for changing the volume setting value is set to -1d every t / 2.
B, −2 dB, −3 dB, etc., and finally, at 10 t, the volume setting value becomes −20 dB which is the value of the volume setting data set by the MCU 40.

The decoding unit 20 decodes the volume setting value input from the volume setting control unit 50 and sets the electronic volume 10 (step S130).
The electronic volume 10 outputs an output signal obtained by changing the input signal based on the set value input from the decoding unit 20.

On the other hand, when the determination result input from the volume change amount determination unit 60 is the minimum step width (Yes at step S110), it is not necessary to switch sequentially,
The volume setting control unit 50 outputs the volume setting data set by the MCU 40 to the decoding unit 20 as it is, the decoding unit 20 sets the electronic volume 10, and the electronic volume 10 receives the input signal based on the setting. The changed output signal is output.

As described above, in the third embodiment, the volume step time determining unit 80 sets the volume in the minimum step width so that the volume switching is completed within the preset volume switching time based on the change amount of the volume setting data. Since the step time to be changed is determined, even if the amount of change in the volume setting data specified by the MCU 40 is different, the volume switching time is kept constant and the signal level changes smoothly without sudden changes. However, it is possible to reduce the shock noise when switching the volume.

Although the minimum change amount and the minimum step width of the volume setting value are the same value, they may be different values.

[0051]

As described above, according to the present invention, the volume change amount determination unit determines the change amount between the current volume setting data and the newly input volume setting data to be a predetermined minimum change amount. Determine if there is,
If the determination result is larger than the minimum change amount, the volume setting control unit sequentially switches the volume setting value up to the value of the newly input volume setting data by a predetermined minimum step width, so that the signal level changes. It is possible to reduce the shock noise at the time of volume switching, which changes smoothly without sudden changes.

According to the next invention, when the volume change amount determining unit determines that the change amount of the newly input volume setting data is larger than the minimum change amount, the volume step width determining unit determines in advance. In order to complete the volume switching within the volume switching time, the amount of change between the current volume setting data and the newly input volume setting data is equally divided to determine the step width. Since the volume setting value is sequentially switched up to the value of the input volume setting data by the step width determined by the volume step width determining unit, the volume switching time can be kept constant.

According to the next invention, when the volume change amount determining unit determines that the change amount of the newly input volume setting data is larger than the minimum change amount, the volume step time determining unit determines the current volume setting. When switching the amount of change between the data and the newly input volume setting data with the minimum step width, the step time for changing the volume setting value is determined so that the volume switching is completed within the predetermined volume switching time, The volume setting control unit sequentially switches the volume setting value up to the value of the volume setting data by the minimum step width at the step time intervals determined by the volume step time determination unit, so that the volume switching time is kept constant and the signal Glide without suddenly changing the level Is crab changed, it is possible to reduce the shock sound when the volume is switched.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an electronic volume circuit according to a first embodiment.

FIG. 2 is a flowchart for explaining the operation of the electronic volume circuit according to the first embodiment.

FIG. 3 is a diagram showing an operation state of volume switching according to the first embodiment.

FIG. 4 is a diagram showing a signal envelope of the electronic volume circuit of the first embodiment.

FIG. 5 is a block diagram showing a configuration of an electronic volume circuit according to a second embodiment.

FIG. 6 is a flowchart for explaining the operation of the electronic volume circuit of the second embodiment.

FIG. 7 is a diagram showing an operation state of volume switching according to the second embodiment.

FIG. 8 is a block diagram showing a configuration of an electronic volume circuit according to a third embodiment.

FIG. 9 is a flowchart for explaining the operation of the electronic volume circuit of the third embodiment.

FIG. 10 is a diagram showing an operation state of volume switching according to the third embodiment.

FIG. 11 is a block diagram showing a configuration of a conventional electronic volume circuit.

FIG. 12 is a diagram showing a signal envelope of a conventional electronic volume circuit.

[Explanation of symbols]

10 electronic volume, 20 decoding section, 30 MC
UI / F, 40 MCU, 50 volume setting control unit, 60 volume change amount determination unit, 70 volume step width determination unit, 80 volume step time determination unit.

Claims (3)

[Claims] 1. An electronic volume circuit for adjusting the volume of an input signal on the basis of input volume setting data, wherein whether or not a change amount of newly input volume setting data is larger than a predetermined minimum change amount. The volume change amount determination unit for determining and the volume change amount determination unit, when the change amount of the newly input volume setting data is determined to be larger than the minimum change amount, the volume setting value for the input signal is set to the current volume. An electronic volume circuit, comprising: a volume setting control unit that sequentially changes from a set value to a value of the newly input volume setting data by a predetermined minimum step width. 2. The volume setting control unit, when the volume change amount determination unit determines that the change amount of the newly input volume setting data is larger than the minimum change amount, within the predetermined volume switching time. A volume step width determination unit that evenly divides the amount of change between the current volume setting value and the setting value of the newly input volume setting data so that the volume switching is completed, and determines the step width, The electronic volume circuit according to claim 1, wherein a volume setting value for the input signal is changed by the determined step width. 3. The volume setting control unit uses the minimum step width and a predetermined volume when the volume change amount determination unit determines that the change amount of the volume setting data is larger than the minimum change amount. A volume step time determination unit that determines a step time for changing the volume setting value so that the volume switching is completed within the switching time is provided, and the volume setting for the input signal is performed by the minimum step width at the determined step time interval. The electronic volume circuit according to claim 1, wherein a value is changed.