JPH0212299A - Automatic controller for sound field effect - Google Patents

Abstract

PURPOSE:To obtain different sound field effect between a musical sound program and a voice program part by discriminating between the musical sound program part and voice program part according to the number of variation parts of an envelope and outputting their decision signals respectively. CONSTITUTION:A logic circuit 3 performs counting operation and logical decision operation according to the binary signal from a syllable detector 2. Then when the musical sound program part is decided while the voice program part is already decided, the number of times of arrival of a 2nd decision signal indicating the musical sound program is counted and when the counted value exceeds a specific value, a control signal for switching the sound field effect from low to high is generated. When the voice program part is decided while the musical sound program part is already decided, on the other hand, the number of times of arrival of a 1st decision signal indicating the musical sound program is counted and when the counted value exceeds a specific value, a control signal for switching the sound field effect from low to high is generated. Consequently, different sound field effect is obtained automatically between the musical sound program part and voice program part.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention provides a sound field effect adding device that adds sound field effects such as presence (surround effect), reverberation, and echo to an audio program signal. The present invention relates to an automatic sound field effect control device that softens the sound field effect applied to an audio program section.

(Prior Art) Conventionally, a device for adding the above-mentioned sound field effect to an input audio program signal has one musical tone program section mainly containing musical tone signals and one audio program section mainly consisting of audio signals. A sound field effect is applied. If a sound field effect is applied without distinguishing between such signals with different properties, the sound quality of musical tone signals will be improved, but the clarity of audio signals such as announcements will be lost.

(Problems to be Solved by the Invention) The present invention eliminates the above-mentioned problems and provides a sound field effect self-tjJ that allows different sound field effects to be obtained in the musical tone program and the audio program section for the input audio program signal.
! , II control device.

[Structure of the Invention] Means for Solving the Problems) The present invention provides a sound field effect adding device for adding a sound field effect to an audio program signal, and provides a method for detecting a variable part and a flat part of an envelope in an input audio program signal. syllable detection means for outputting a value signal; and based on the output from the detection means, it is determined whether the input audio program signal is mainly a musical tone program signal or a voice program signal, and the input audio program signal is transmitted from the voice program section to the musical tone program section. When determining a switch to FJJ, the determination is made based on the number of arrivals of a signal indicating that it is a musical tone program, and when switching from a musical tone program section to an audio program section, it is determined by the number of arrivals of a signal indicating that it is an audio program section. Logic circuit means for making a determination is provided.

(Function) In the case of an audio signal, the fluctuation of the envelope related to the signal is greater than that of a musical tone signal. According to this invention, it is determined whether it is a musical tone program section or an audio program section based on the number of variation sections of the envelope, and first and second determination signals are output, respectively.

Then, when determining the musical tone program section from the state determined to be the sound block [] durum section, the musical tone program in the second determination signal is accepted, the number of arrivals of the signal is counted, and when the number of arrivals of the signal exceeds a predetermined value, the sound field Generates a control signal to switch the effect from weak to strong.

In addition, when determining the audio program section based on the state determined to be the musical tone program section, the number of arrivals of the signal indicating the audio program in the first determination signal is counted, and when the number of arrivals exceeds a predetermined value, the sound field effect is weakened. Generates a control signal to switch from to strong.

As a result, for example, when an audio program signal contains many audio signals, the sound field effect is relaxed, and when the opposite audio signal is the main component, the sound field effect can be fully applied.

(Example) The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 is a block diagram showing the basic configuration of an automatic sound field effect control device according to the present invention. In the figure, TP1 is an input terminal to which a previous input audio program signal to which a sound field effect has been added is introduced, and TP2 is an output terminal for the audio program signal to which a sound field effect has been added.

1 is a sound field effect circuit that adds sound field effects such as surround;
2 is a syllable detection circuit that outputs a binary signal indicating an envelope fluctuation part and a flat part in an audio program signal; 3 is a logic circuit according to the present invention; and 4 is an analog circuit having two signal paths whose conducting and non-conducting states can be controlled. This is a switch circuit composed of multiplexers and the like. Terminal TPI is connected to the sound field effect circuit 1. An audio amplifier signal is introduced into one of the signal paths of the syllable detection circuit 2 and the switch circuit 4. Further, the other signal path of the switch circuit 4 is led to an audio program signal to which a sound field effect has been added from the sound field effect circuit 1.

Therefore, the logic circuit 3 according to the present invention performs the counting operation and logic judgment operation described below based on the binary signal from the syllable detection 2, and controls each signal path of the switch circuit 4 to be conductive or non-conductive. A control signal is generated.

First, a specific example of the syllable detection circuit 2 will be explained with reference to FIG.

In FIG. 2, TP3 supplies an input audio program signal to one of the two input terminals of analog converter 5. In FIG. This analog comparator 5
At the other input terminal of the input audio program signal, a threshold voltage for detecting a fluctuating part of the envelope is set by a trimmer component such as a variable resistor in order to distinguish between a musical tone program part and a voice program part in the input audio program signal. is being applied. Thereby, a signal is obtained from the analog comparator 5 that distinguishes between a flat part where the amplitude of the input audio program signal is greater than the threshold voltage and a fluctuating part where the amplitude is small.

The output of the analog comparator 5 is input to a retrigger type monostable multivibrator 6. This monostable multivibrator 6 has two output terminals Q, ? ), one Q output is supplied to one input terminal of the Nandts gate 8 via a waveform shaping circuit 6a constituted by a diode, a capacitor, etc., and the ζ output is supplied to one input terminal of the Nandts gate 7. The output of the Nant gate 8 is fed to a retrigger monostable multivibrator 9 which supplies the ζ output to the Nant gate 8.
is fed back to the other input terminal of the With the monostable multivibrator 9 having this configuration, it is possible to obtain a binary signal in which all the fluctuation parts are detected, regardless of the time width of the fluctuation parts of the input audio program signal. Further, this binary signal enters the other input terminal of the Nandt gate 7 marked 11, and is logically compared with the output from the monostable multivibrator 6. The monostable multivibrator 9 is set to have a longer metastable period than the monostable multivibrator 6, so that the output of the Nant gate 7 represents a binary signal that picks up only the fluctuation part longer than a certain period of time. It turns out. The reason for picking up the variable portions of the binary signal that are longer than a certain time width lies in the nature of the h-return signal.

Next, the configuration of the logic circuit 3 will be explained.

In FIG. 3, terminal TP5- derives a binary signal from terminal TP4, which corresponds to J3 in FIG. Then, the binary signal from the terminal TP5 is transmitted to the flip-flop circuit 11a.
, 11b and an AND gate 11c, and is input to the fall detection circuit 11. This falling detection circuit 1
1, each of the 7 lip 70 tubes 11a and 11b are operated by a clock signal from a clock generator 10. The detection pulse indicating the falling of the binary Shintan is
Derived from AND gate 11C, (first) counter 1
Enter 3.

The counter 13 supplies the count output to the (first and second) comparators 15.1G via a flip-flop array 14 with a latch function. These comparators 15.1B each have a register 1 which has been set and operated in advance.
7. Resist value from 18 and the flip 70 tube row 1
Compare with the count value from 4.

As a result of these comparisons, the output of the comparator 15 is connected to the latch circuit 21 via the NOT gate 25.
and one end of the AND gate 24, and the output of the comparator 16 is input to the (second) counter 19 via the AND gate 23.

The counter 19 uses the register value set in the register 20 as an overflow value, and the ant gate 2
The output of comparator 16 via 3 is counted. Therefore, when the register value set in the output register 20 of the comparator 16 is exceeded, the counter 19
The output as a carry signal is sent to the latch circuit 21 and the ant gate 1-24 through the not gate 26, respectively.
to the other end of the

On the other hand, a counter 12a and a flip-flop 12b.

The circuit constituted by 12c is a timing signal generation circuit that operates based on the clock (rffi signal) from the clock generator 10. This timing signal generation circuit 12 is
Flip the signal to clear the force 1 kunter 13 7
A signal for causing the flip-flop 14 to perform a latch operation is outputted from the flip-flop 12C from the zero tube 12b, and is supplied to a predetermined circuit.

The audio program signal is divided into predetermined unit sections by the outputs of these flip 70 tabs 12b and 12c. Incidentally, the output of the flip-flop 12c is also supplied to the other input terminal of the AND gate 23. The clock generator 10 also drives counters 13 and 19.

Thus, the latch circuits 21 each have a comparator 15. The output based on the counter 19 is led out to the terminal TP6 via the flip-flop 22. This terminal TP6
The signal derived from this becomes a control signal for controlling the switch circuit 4 in FIG.

Next, the operation of the above configuration will be explained with reference to FIGS. 4 and 5.

FIG. 4 is a timing chart showing the operation of the syllable detection circuit 2. In the figure, the signal SO is the input audio program signal, Sl is the output of the comparator 5, Sl is the Q output of the monostable multivibrator 6, S 2' is the output of the waveform shaping circuit 6a, and S3 is the monostable multivibrator. S4 is the output of the vibrator 6, and S4 is the output of the Nantes gate 8.
S5 indicates the output of the monostable multivibrator 9, and SO indicates the output of the Nandt gate 7, which is a binary signal of the present invention.

As shown in SO, the input audio program signal has a waveform such as a part X where the amplitude is flat, a part Y where the amplitude is intermittently interrupted, and a part X' where the interruption interval is small but is more continuous than Y. exhibit the part. In this example, the X
and X' are determined to be the musical tone program section, and the Y section is determined to be the audio program section. Based on this,
Comparator 5 outputs a pulse every time the amplitude of the input audio program signal exceeds a predetermined level. Therefore, the signal S1 becomes a pulse train signal Y) that is continuous or interrupted in a burst shape corresponding to each cycle waveform of the input audio program signal. The pulse train portion corresponds to a portion where the input audio program signal has an amplitude greater than a predetermined level.

Next, since the monostable multivibrator 6 has a metastable period set based on the maximum frequency of the input audio program, it exhibits a high level during the period when the pulse train of the signal S1 continues, and during the period when no pulses occur. Shin 5 exhibiting low level? Derive S2 as the Q output. Then, the output signal S3 becomes a signal obtained by inverting Sl. Furthermore, signal 8
2' is a pulse train that detects the rising edge of the signal S2.

On the other hand, the output 84 of the Nandt gate 8 becomes the same signal as 82' if a fluctuation part whose amplitude is interrupted at an interval longer than the metastable period of the monostable multivibrator 9 occurs.
If it occurs at an interval shorter than the metastable period of the monostable multivibrator 9, as in the X' part, the monostable multivibrator 9 is reversed with the pulse corresponding to the first part, and the subsequent width strip and the intervening part are is not detected. In this way, a binary signal S6 is obtained from the Nant gate 7, which changes to a high level and a low level corresponding to an amplitude variation part longer than a certain time width and a continuous part of the amplitude.

Next, the binary signal generated as described above enters the fall detection circuit 11. In FIG. 5, the same signals as in FIG. 4 are given the same symbols. S7 is the output of the rising edge detection circuit 11, and 88 and 89 are the flip 70 knobs 12c, respectively.
, 12b, 810 the output value of the counter 13, 311 the output of the comparator 15, 812 the output of the comparator 16, 313 the output of the AND gate 23, 314 the output of the AND gate 824, S15 is the output of the knot gate 25, and 816 is the output of the knot gate 26.
and 317 indicate the control signal of the present invention output from the flip 70 tube 2, respectively.

Now, since the signal $7 outputted from the fall detection circuit 11 detects the fall of a binary signal, it becomes a signal that exhibits a pulse every time an amplitude variation portion occurs. This signal S7 is input to the counter 13 and counted. in this case,
Counter 13 receives the signal from flip-flop 12b@
Cleared by S9. Thereby, the counter 13 counts the number of amplitude fluctuation parts within a certain unit period. Counted in this way,
The count value is transferred to the 7-lip flop 14 and output at the timing of the signal S8.

Comparators 15 and 16 are connected to the flip-flop 14
The count value from and the register value set in each register 17 and 18 are compared. Here, the value set in the register 17 is determined based on the frequency of occurrence of an amplitude variation section that can be determined to be an audio program section. Also, register 1
8 is determined based on the frequency of occurrence of an amplitude variation section that can be determined to be a musical tone program section. Specifically, if the number of pulses in the signal S7 within a unit period is one or less, it is determined to be a Tomei program part, and if there are two or more pulses, it is determined to be an audio program. In the figure, O91 is used in the musical tone program section.
... is generated as 1,0, and in the audio program section, it is generated as 4°3.

Now, suppose we are inputting the musical tone program section and 1111
The story will proceed from a state where the suburban signal S17 is at a high level and a large sound field effect is applied.

In the musical tone program section, the signals 315 and 316 are at a high level, and the control signal 817 is at a high level earlier.

In the musical tone program section, since the amplitude fluctuation section occurs less frequently, the output 311 of the comparator 15 shows a low level, and the output 312 of the comparator 16 shows a high level. Changed from musical tone program section to audio program section,
When four pulses in the signal S7 are counted, the output 311 of the comparator 15 changes to high level and the output 812 of the comparator 16 changes to low level. Here, the pulse of the signal 811 is passed through the not gate 25 to the signal 81
5 and enters the latch circuit, so when changing from the musical tone program to the audio program section, the input signal 315 of the flip-flop 22 changes to low level while the signal 816 remains unchanged. Therefore, it is determined that the audio program section has inputted the signal, and the control signal 817 changes from high level to low level, so that the sound field effect is reduced.

Next, the switching operation from the audio program section to the musical tone program section will be explained.

The signal 812 is at a low level during the audio program section. Since the AND gate 23 derives the AND output of the signal 812 and the signal S8, the signal S
1° through the pulse at 8. Therefore, the AND gate 2
The signal 313 outputted by No. 3 supplies the counter 19 with pulses P1 in the signal 813 that are generated at a cycle of a unit period during the music & program section determination period based on the signal 812. Here, the counter 19 receives the signal 815 and the signal 81.
Since the AND output of 6 and C is put into the loading state by a certain signal qs1n, the counter 19 counts the pulse P1 in the period determined to be the musical tone program section, and when this count value exceeds the value of the register 20, a predetermined value is input. A carry signal is output to set the signal 316 to the mouth/flare level.

In this way, since the next time when the signal 316 switches to low level is delayed, even if the comparator 15 determines that it is a musical tone program section and the signal 815 indicates a high level, there is no change in the operation of the flip-flop 22, and the control signal S17 remains at low level. On the other hand, signal 316
When the signal S15 becomes low level, the flip-flop 22 performs an inverting operation, and the control signal 8
17 to high level. As a result, the sound field effect can be strongly applied again.In other words, even if the audio program section ends and the musical tone program section returns, instead of immediately switching to the musical tone program section's sound field effect, the sound field effect will be applied again. The control signal 817 is set to a high level after the unit period to be determined is detected a plurality of times (in this case, the 2I first period).

In this way, this embodiment switches the sound field effect from strong to weak immediately after switching from the musical sound program section to the audio program, and when switching from the audio program to the musical sound program section, after a predetermined period of time has elapsed, the sound field effect is You can automatically select the Hataba effect that suits each program.

In the above embodiment, after it is determined that it is an audio program section, it is determined that it is a musical tone program and the sound field effect is 1, IJB, but the number of amplitude fluctuation sections that are determined to be Tomei program sections is small. This method switches control from the audio program section to the musical tone program section by counting over a unit period of 10 times.

Such ideas suggest that the opposite behavior is also possible. In other words, a buffer period as described above is provided between when it is determined that it is a musical tone program section and when it is determined that it is an audio program section.

In the case of the above embodiment, the functions of the comparators 15 and 16 may be replaced, that is, the signal S11 may be supplied to the AND gate 23, and the signal j3s12 may be directly supplied to the latch circuit 21.

Incidentally, FIG. 6 shows a method for ensuring the operation of the comparator 5 in the syllable detection circuit 2.

In FIG. 6, the input signal ei is directly connected to the comparator 5.
', and also enters the comparator 5' via the envelope detection circuit 31 and the coefficient circuit 32. Such a configuration is convenient when the sound field is varied.

FIG. 7 shows the operation of the circuit of FIG. 6, and the input signal e
i is detected as an envelope signal E+ at a normalized level by an envelope detection circuit 31 that uses average value detection, peak value detection, etc. Thereafter, by multiplying the coefficient α by the coefficient circuit 32, a level comparison is performed using αEi as a reference voltage.

As a result, even if the input signal ei fluctuates, αEi follows it, making it possible to reliably detect the amplitude fluctuation portion. In FIG. 7, (A> shows the operating waveform of the envelope detection circuit 31, and (B) corresponds to the signal S1 in FIG. 4.

In addition, as a method of controlling the sound field effect, only the method using the switch circuit 4 is used, and it is also possible to switch the post field effect using an electronic volume etc. Also, by using a VCA (liquid pressure control amblifier), fade-in, It can also be faded out.

[Effects of the Invention] As described above, according to the present invention, different sound field effects can be automatically selected and applied to the audio program signal in the musical tone program section and the audio program section.

[Brief explanation of the drawing]

FIG. 1 shows a sound field effect automatic control v according to an embodiment of the present invention.
2 is a circuit diagram showing an example of a specific circuit of a syllable detection circuit, FIG. 3 is a circuit diagram showing an example of a logic circuit according to the present invention, and FIGS. 4 and 5 are a block diagram showing the basic configuration of the device. Timing chart for detailed explanation of this invention, No. 6
7 are explanatory diagrams for explaining a method for reliably detecting syllables. 1... Sound field effect circuit, 2... Syllable detection circuit, 3
... logic circuit, 4 ... switch circuit, 5 ...] comparator 6, 9 ... monostable multi-bi break, 7
, 8... Nant gate, 10... clock generator,
DESCRIPTION OF SYMBOLS 11... Fall detection circuit, 12... Timing signal generation circuit, 13... (first) counter, 14...
・Fritsubfu []tub, 15... (first) comparator, 16... (second) comparator, 17.18
...Register, 1o...(Second) counter, 2
0...Register, 21...Latch circuit, 22...
Flip-flop, S6...binary signal, 811...
First determination signal, 812...Second determination signal, S16
. . . third determination signal, 817 . . . control signal. Attorney Susumu Ito (Rei tJ-2; Figure 6)

Claims (2)

[Claims] (1) A sound field effect adding device for adding a sound field effect to an audio program signal, comprising: syllable detection means for outputting a binary signal indicating a fluctuating part and a flat part of an envelope in an input audio program signal; a first counting means for counting and inputting the output from the unit and counting the number of said variable parts within a preset unit period; and first and second counting means for presetting the output value of this counting means. Comparing with the respective register values, if the output value of the first counting means is larger than the first register value, outputting a first determination signal indicating that the input audio program signal is an audio program portion. a first comparator and a second determination signal that outputs a second determination signal indicating that the input program signal is a musical tone program when the output value of the first counting means is smaller than the second register value; a second comparator means; after the first comparator means determines that it is an audio program section, counts the number of times a signal indicating a determination result that it is a musical tone program arrives from the second comparator means; a second counting means that outputs a third judgment signal indicating whether the count value exceeds a preset number of times; a first judgment signal from the first comparator means; and a second judgment signal from the first comparator means; and control signal output means for outputting a control signal for controlling the strength of the sound field effect based on the third determination signal from the counting means. (2) A sound field effect adding device for adding a sound field effect to an audio program signal, comprising: syllable detection means for outputting a binary signal indicating a fluctuating part and a flat part of an envelope in an input audio program signal; a first counting means for counting and inputting the output from the unit and counting the number of said variable parts within a preset unit period; Comparing with the respective register values, if the output value of the first counting means is larger than the first register value, outputting a first determination signal indicating that the input audio program signal is an audio program portion. a first comparator and a second determination signal that outputs a second determination signal indicating that the input program signal is a musical tone program when the output value of the first counting means is smaller than the second register value; a second comparator means; after the second comparator means determines that it is a musical tone program part, counts the number of arrivals of a signal indicating a determination result that it is an audio program from the first comparator means; a second counting means for outputting a third judgment signal indicating whether or not the count value exceeds a preset number of times; a second judgment signal from the second comparator means; and control signal output means for outputting a control signal for controlling the strength of the sound field effect based on the third determination signal from the counting means.