JPH0131725B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an electronic volume in which a plurality of variable impedance circuits are operated by a single variable resistor.

Generally, audio equipment uses a large number of variable impedance circuits such as bass control, treble control, balance control, and volume control. These variable impedance circuits usually have a variable resistor connected directly to the signal transmission line, but some of them do not connect the variable resistor directly to the signal transmission line, but instead use a transistor connected to the signal transmission line. Electronic volume controllers are also used in which impedance circuits such as the following are controlled by corresponding variable resistors. When such variable impedance circuits are used, variable resistors corresponding to the number of variable impedance circuits are required, and the number of operation knobs for the variable resistors increases. This was a major design constraint for equipment.

In order to improve this problem, variable impedance circuits A ₁ , A ₂ , and A ₃ for bass control, balance control, and volume control are controlled by a single variable resistor 1 as shown in Figure 1. Something like this was recently proposed. This supplies a hold signal and a through signal to each control terminal of hold-through circuits H ₁ , H ₂ , H ₃ placed between the output terminal of variable resistor 1 and each variable impedance circuit A ₁ , A ₂ , A ₃ Selection switch S ₁ , S ₂ , S ₃
By operating switches S ₁ , S ₂ , S ₃ and variable resistor 1, desired control can be performed freely. However, with this electronic volume control, for example, after maximizing the output voltage of variable resistor 1 using balance control, if switch S ₃ is closed and switched to volume control, hold-through gate H ₃ immediately enters through mode, and the variable The large output voltage of resistor 1 is applied directly to the control terminal of variable impedance circuit A ₃ . As a result, there is a problem in that the volume suddenly becomes louder and the operator becomes frightened.
Furthermore, if the volume suddenly increases, there are problems such as damage to the speaker.

The present invention is a further improvement of such an electronic volume, and even if the selection switch is closed, a through signal is not output until the output of the variable resistor matches a predetermined value, and the hold through gate remains in the hold mode. This will be explained below using examples.

Figure 2 is a circuit diagram of the main parts of an audio device that is an embodiment of the present invention. In the figure, 2 is a slide or rotary type variable resistor, and 3 is a converter for converting the output voltage of the variable resistor 2 into digital data. A to do
-D converter, H ₄ and H ₅ are control terminals respectively
Hold-through gates hold or pass the output data of the A-D converter 3 according to control signals applied to G ₄ and G ₅ , and 4 and 5 convert the output data of the hold-through gates H ₄ and H ₅ into analog signals. DA converters to be converted, A ₄ and A ₅ are impedance circuits for balance control and volume control whose transfer impedance changes according to the output level of the DA converters 4 and 5; 6;
7 supplies control signals to the hold-through gates H ₄ and H _5, respectively, and is a control circuit consisting of a flip-flop circuit, etc. S ₄ and S ₅ select the hold-through gate H ₄ or H ₅ to be set to through mode. Switches 8 and 9 are hold-through gates H ₄ ,
Variable resistors 10 and 11 are used to set the level at which the supply of the through signal starts to _H5 , and check whether the level set by the variable resistors 8 and 9 matches the output of variable resistor 2. Coincidence detection circuits S ₁₁ and S ₁₂ are switches that open and close in conjunction with the switches S ₄ and S ₅ , respectively, and 14 is supplied from a hold-through gate H ₆ or H ₇ via the switch S ₁₁ or S ₁₂ . A pattern converter 15 is a display device that displays respective control levels in accordance with the output of the pattern converter 14. Next, we will explain the operation of this audio equipment, starting with the balance control. In this case, switch _S4 is closed and switch _S5 is left open. When the switch _S4 is closed, the control circuit 6 comes to accept the output of the coincidence detection circuit 8. Subsequently, the operating knob (not shown) of the variable resistor 2 is operated to change the voltage at the output terminal of the variable resistor 2. During this operation, when the output of the variable resistor 2 matches the preset level of the variable resistor 8, a match signal is output from the match detection circuit 10.
Upon receiving the match signal, the control circuit 6 outputs a through signal to put the hold through circuit _H4 into the through mode. After switching to the through mode, the transfer impedance of the impedance circuit _A4 changes in accordance with the voltage at the output terminal of the variable resistor 2, and balance control is performed. Note that the hold-through gates H ₄ and H ₅ maintain the hold mode when there is no through signal, and each continues to hold the data immediately before switching from the through mode to the hold mode. Therefore, impedance circuit A ₄ , A ₅
The transfer impedance of is constant.

Next, let's talk about volume control. In this case, switch _S5 is closed and switch _S4 is left open. When the switch _S5 is closed, the control circuit 7 comes to receive the output of the coincidence detection circuit 11. Next, the operating knob (not shown) of the variable resistor 2 is operated to change the voltage at the output terminal of the variable resistor 2. During this operation, when the output of the variable resistor 2 matches the preset level of the variable resistor 9, a match signal is output from the match detection circuit 11. Upon receiving the match signal, the control circuit 7 outputs a through signal to put the hold through circuit _H5 into the through mode.
After switching to the through mode, the transfer impedance of the impedance circuit _A5 changes in accordance with the voltage at the output terminal of the variable resistor 2, and the volume is controlled. By operating variable resistor 2 and switches S ₄ and S ₅ in this way, it is possible to appropriately control the balance and volume of audio equipment, and also to prevent sudden loud noises even if switches S ₄ and S ₅ are opened or closed. There are no problems such as high volume. Note that it is convenient if the setting levels of the variable resistors 8 and 9 are near the center value.

Next, the display device 13 will be explained. First, switch _S4 is closed to perform balance control, and when switch _S5 is opened, switch _S11 is closed and switch _S12 is opened. The output data of the hold-through gate H ₄ is then supplied to the pattern converter 12 . The pattern converter 12 converts the data to display a display suitable for balance control, and the level of balance control is displayed on the display device 13 in accordance with the data. Do the same with the volume control level and close the switch _S5 to activate the hold-through gate.
An appropriate pattern is displayed on the display device 13 according to the output data of _H5 .

FIG. 3 is a circuit diagram of a main part of another embodiment of the present invention, in which 2 is a variable resistor, H ₆ and H ₇ correspond to control signals applied to respective control terminals G ₆ and G ₇ . A hold-through gate that holds or passes the output of the variable resistor 2, A ₄ , A ₅ , 6, 7,
S ₄ , S ₅ , 8, 9, 10, and 11 are the same impedance circuits for balance control and volume control, control circuits, selection switches, variable resistors for level setting, and coincidence detection as in the embodiment shown in FIG. It is a circuit. Further, S ₁₁ and S ₁₂ are also switches that open and close in conjunction with the switches S ₄ and S ₅ , as in the previous embodiment, and 14 is a hold-through gate H ₆ ,
A pattern converter converts the data supplied from H ₇ via switches S ₁₁ and S ₁₂ to suit a desired display; 15 is a display device that displays each control level according to the output of the pattern converter 14; It is. The feature _of this embodiment, compared to the embodiment of _FIG . Since it is the same as the embodiment shown in the figure, its explanation will be omitted. In the embodiments shown in FIGS. 2 and 3, each control circuit is selected by the selection switch and outputs a through signal after the output of the variable resistor matches a predetermined value. In either case, just configuring one control circuit in this manner will have sufficient effects.

As described above, according to the present invention, a variable resistor, a plurality of hold-through gates capable of holding and passing the output of the variable resistor, and a plurality of hold-through gates each connected to the output side of the plurality of hold-through gates are provided. , an impedance circuit in which the transfer impedance of the signal transmission path changes according to the respective outputs, a control means for supplying a hold signal or a through signal to the control terminals of the plurality of hold-through gates, and a hold circuit for supplying the through signal. and a selection means for selecting a through gate, wherein the through signal supplied to at least one hold-through gate is selected by the selection means, and the output of the variable resistor matches a predetermined value. After that, the signal is supplied to the control terminal of the selected hold-through gate, so the drawbacks such as the operator being confused by a sudden loud volume even when the electronic volume is switched are eliminated, and the practical effect is Remarkable.

[Brief explanation of drawings]

FIG. 1 is a conventional circuit diagram, FIG. 2 is a circuit diagram of a main part of an audio device according to an embodiment of the present invention, and FIG. 3 is a circuit diagram of a main part of another embodiment of the present invention. 2... Variable resistor, 3... A-D converter,
4, 5...D-A converter, 6,7...Control circuit, 8,9...Variable resistor, 10,11...Coincidence detection circuit, _S4 , _S5 ...Switch, _H4 , _H5 ...Hold-through gate, A ₄ , A ₅ ... Impedance circuit.

Claims (1)

[Claims] 1. A variable resistor, a plurality of hold-through gates connected to the output terminal of the variable resistor and capable of holding and passing the output of the variable resistor, each connected to the output side of the plurality of hold-through gates, an impedance circuit in which the transfer impedance of a signal transmission path changes according to each output; a control means for supplying a hold signal or a through signal to the control terminals of the plurality of hold-through gates; and a hold-through circuit to supply the through signal. and a selection means for selecting a gate, the through signal supplied to at least one hold-through gate is selected by the selection means, and the output of the variable resistor matches a predetermined value. An electronic volume that is later supplied to a control terminal of the selected hold-through gate.