JPH04200106A - Zero cross changeover circuit - Google Patents

Abstract

PURPOSE:To prevent production of noise sound when sound volume and sound quality or the like are changed by providing a flip-flop and an exclusive OR to the circuit and obtaining a storage control signal to store logic data given surely by a register even when an input voice signal is inverted. CONSTITUTION:New logic data is stored in a register 1 by a change control instruction at a time t1. An input voice signal is at a positive level simultaneously this time and the new logic data is not stored in a register 2. Since the input voice signal changes from a positive potential into a negative potential at a time t1, an output of a voltage comparator 3 changes from an H level to an L level. However, since a data output of a flip-flop 6 keeps a state at the time t0 when a change control instruction is given, the level is at an H level even at the time t1. Thus, an output of an exclusive OR 7 rises from an L level to an H level, the register 2 stores a new logic data, and a control circuit 5 changes the sound volume and the sound quality or the like according to the content of the new logic data.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention can generate sound using logical data. -Relates to an audio signal processing device that controls sound quality, etc.

[Prior Art] A block diagram of a conventional zero-cross switching circuit is shown in Fig. 3. In the figure, (1) and (2) are registers that latch data, (3) is a voltage comparator, and (4) is a base*f4 pressure,
(5) Sounds the audio signal according to the given logical data■
・This is a control circuit for volume, sound quality, etc. that changes the sound quality, etc.

Next, the operation will be explained with reference to FIG. FIG. 4 is a waveform diagram showing the waveform changes of the a-r signal lines shown in FIG. 3 over time.

An audio signal is input to signal &Ia. register(
1) includes logic data for controlling volume, sound quality, etc. (hereinafter referred to as logic data) for changing the sound quality, etc. of the input audio signal in a control circuit for controlling volume, sound quality, etc. (hereinafter referred to as control circuit) (5) ) is entered. If a change control command is input to the signal Bb at time to to change the training camp, sound quality, etc., logical data is immediately stored in the register (1). Here, if at the same time as the change control command, that is, at time L
In O, when changing the sound FI4, sound quality, etc., the audio waveform suddenly changes at the moment of the change, which may result in an audible abnormal sound.

FIG. 5 is a waveform diagram of a high-pitched voice waveform when the volume is decreased at the time of the clock.

In order to prevent this abnormal noise, a register (2) is provided to detect the moment when the audio signal reaches the AC zero level, that is, the reference voltage value, and at that time, the logical data is sent to the register (2).
At the same time, the control circuit (5) changes the volume, tone quality, etc. of the voice A word according to the logical data.

Next, a method for detecting the zero level will be described.

The input audio signal is always compared with the reference voltage 4 by the voltage comparator (3), and in the figure, when the instantaneous voltage value of the input audio signal is higher than the reference voltage (4) (hereinafter referred to as positive potential), the voltage comparator (3) ) is set to output an H level, and conversely to output an L level when the potential is low (hereinafter referred to as negative potential), and has a waveform like the d waveform of the fourth UA.

The register (2) is of a type that stores data at the rising edge of the storage control signal, and since the output of the voltage comparator (3) is supplied as the storage control signal, the voltage n! Comparator (
When the output of 3) goes from the L level to 1 level, that is, at the moment when the input audio signal goes from the 021st position to the positive potential, the register (2) stores the given logic data.

After the change control command was given, rt voice (No. 73 Masah;
・If you follow the process until the sound quality etc. is changed in chronological order with reference to Figure 4, at time LO, register (1) is changed to new logical data (shaded part of waveform C in Figure 4) by the change control command. is stored. However, at this time, since the input audio signal is at a positive potential, the output of the voltage comparator (3) is I
(The level is maintained, and the register (2) is not supplied with the rising pulse necessary to store the new logical data, and the logical data before the change is still stored.) The control circuit (5) is connected to the register (2). Since the volume, tone quality, etc. of the input audio signal is controlled according to the logical data stored in the ``G'' tone quality, etc., the tone quality, etc. is not changed.

Next, the time L when the input audio signal changes from positive potential to negative potential
1, the output of the voltage comparator (3) changes from H level to L level, but since it is not a rising pulse, at time t
Similar to o, the volume, sound quality, etc. are not changed.

At time t2, the input audio signal changes from a negative potential to a positive potential, so the output of the voltage comparator (3) changes from L level to H level, a rising pulse is supplied to the register (2), and the signal line C is The logical data of is stored in the register (2), and new logical data is output to the signal line e.
The control circuit (5) changes the volume, sound quality, etc. according to the contents of the new logical data.

[Problems to be Solved by the Invention] Since the conventional zero-cross switching circuit is configured as described above, it takes a maximum of 2T input from when a change control command is given until the volume, sound quality, etc. is changed. No. 1
There was a problem in that it required time equal to the wavelength.

The present invention has been made to solve the above-mentioned problems, and is a zero-cross switching method that reduces the time from when a change control command is given until the volume, sound quality, etc. is changed within half a wavelength of the input audio signal. The purpose is to obtain a circuit.

[Means for Solving the Problems] The zero-cross switching circuit according to the present invention is provided with a flip-flop and an exclusive OR, so that even when the input audio signal changes from a negative potential to a positive potential or vice versa, the control circuit can This is designed to obtain a storage control signal that allows a register that provides logical data to reliably store the given logical data.

[Function] The zero cross switching circuit in the present invention stores the logic level of the output of the voltage comparator that detects the zero level at the moment when the change control command is given by the change control command, and uses the stored logic level and the voltage. By taking the exclusive OR of the logic level of the comparator output, it is stored in a register that provides logic data to the control circuit at the time when the logic level of the voltage comparator output first inverts after a change control command is given. A control signal is provided.

[Example code] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a zero-cross switching circuit which is an embodiment of the present invention. This embodiment differs from the conventional one shown in FIG. (7), the output of the voltage comparator (3) is connected to the data input of the flip-flop (6) and the input of the exclusive OR (7), and the output of the voltage comparator (3) is connected to the input of the exclusive OR (7).
The other inputs are connected to the data output of the flip-flop (6), and the output of the exclusive OR (7) is connected to the register (
2) is connected to the storage control input of the flip-flop (6
) is such that a change control command is input to the storage control input. The other symbols are the same as those of the conventional device, and the explanation thereof will be omitted.

Also, like FIG. 4, FIG. 2 shows the time of the signal lines a to f shown in FIG. FIG. 3 is a waveform diagram showing waveform changes due to excess yen.

Next, the operation will be explained with reference to FIG. In order to prevent abnormal noises that occur when changing the volume, quality, etc., the moment when the input 0 voice signal becomes the same potential as the j, c * voltage, that is, when it is at zero level: This? The means for changing the volume, sound quality, etc. and the means for detecting the zero level are the same as those of the conventional method, so their explanation will be omitted.

If we follow the time sequence from when the change control command is given to when the sound quality etc. of the voice Dr.
At o, the register (11) stores new logic data (shaded part of the waveform C in Fig. 2) according to the change control command.At the same time, the input sound 11. The output of is H level, the H level is stored in the flip-flop (6) by the change control command, and the H level is output as the data output of the flip-flop (6). The output of 7) becomes I, level, but since the register (2) is stored by the rising pulse, the new logic data is not stored in the register (2) at this time, but the logic data before the change is stored. Therefore, changes in volume, sound quality, etc. will not be made.

At the time, the input audio signal changes from positive potential to negative potential, so the output of the voltage comparator (3) changes from l(level to I- level.However, the flip-flop (
6) The data output is the time when the change control command was given.

Since the state of 1. It is also 1 lebel. Therefore, the output of the exclusive OR (7) (waveform C in FIG. 2) rises from the 17th level to the II level, the register (2) stores new logical data, and the control circuit (5) stores the new logical data. Change the volume, sound quality, etc. according to the contents.

Time. As shown in 1', even if a change control command is input when the input audio signal is at a negative potential, the polarity of some signal lines will be different, but the volume, sound quality, etc. will be changed in the same way at 1'. .

[Effects of the Invention] As described above, according to the present invention, by adding a small number of logic elements, the time for changing the volume, sound quality, etc. after giving a change control command can be adjusted to a half wave of the input r2 voice signal. It can be made within good condition and has the same volume and volume as the conventional one.
The effect of preventing abnormal noise from occurring when the pawn book is changed can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a zero-cross switching circuit that is an embodiment of the present invention, and FIG. 2M is a waveform diagram of signal waveforms at various parts in FIG. 1.
Figure 3 is a block diagram of a conventional zero-cross switching circuit;
The figure shows the waveforms of the various signal waveforms of the 3rd
．． ．． 34 is a waveform diagram of 34 waveforms. In the figure, (1) is the first register, (2) is the second register, (3) is the voltage comparator, (4) is the reference voltage, (
6) is a flip-flop, and (7) is an exclusive OR. In addition, in the figures, the same numbers indicate the same or corresponding parts.

Claims (1)

[Claims] A first register stores logic data for controlling sound quality, etc. from an external source, and a first register stores logical data for controlling sound quality, etc. when the input audio signal reaches approximately the same voltage value as the reference voltage. In a device that includes a second register for storing stored logic data and controls the volume, sound quality, etc. according to the logic data stored in the second register, the input audio signal and the reference voltage are controlled. A voltage comparator that compares voltages, and a flip-flop that stores the logic level given to the data input by the change control command from the outside like the first register, and a flip-flop that stores the logic level given to the data input by the above-mentioned external change control command, and the logic level given to the two inputs matches. The output of the voltage comparator is connected to the data input of the flip-flop and the exclusive logic to output a signal with a polarity that causes the second register to store at the moment the state changes from one state to a different state. The data output of the flip-flop is connected to the other input of the exclusive OR, and the output of the exclusive OR is connected to the storage control input of the second register. A zero-cross switching circuit characterized by: