JPS5841718B2 - 4 channel pan pot stake position detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stick position detection method for a 4-channel panpot, and relates to the inclination angle and direction of a stick that is rotatable with one end as a fulcrum and the other end tracing a hemispherical trajectory. The amount of change corresponding to the stick is detected and extracted as the change in the distance from the origin in two-dimensional orthogonal coordinates where the origin is defined when the stick is perpendicular to the horizontal plane, and the angle with respect to a certain direction. We developed a stick position detection method for a four-channel panpot that extracts the mechanical movement of the sound source as an electrical signal expressed as a change in position within two-dimensional orthogonal coordinates, and uses this signal to move or fix the sound source to any location in the sound field. The purpose is to provide.

Conventionally, it has been known that a four-channel stereo reproduction device localizes a sound image at a position corresponding to the movement of a stick of a four-channel panpot.

However, the conventional method for localizing a sound image is called a level difference localization method in which the sound image is localized by relatively varying only the levels of the audio signals supplied to the four speakers.

Therefore, the output signal of the 4-channel panpot is only a univariate parameter signal for relatively varying the level of the 4-channel audio signal and distributing it to the front left and right or the rear left and right.

However, in the level difference localization method described above, the position of the sound image is limited to the range between each speaker, and it is not possible to localize the sound image outside of each speaker.

On the other hand, in recent years, as a method for obtaining clear and natural sound images outside each speaker, for example,
Pages 455 to 46 of the NHK Technology Monthly Report, December 2009 issue
On page 1, a method called the so-called ΔP-Δφ method was proposed.

According to this ΔP-Δφ method, for example, in the case of two-channel stereo, a natural sound image can be created even right next to the listener using the natural sound image localization device shown in FIG.

In FIG. 5, the audio signal entering the input terminal IN is supplied to a low-pass filter 22, bandpass filters 23, 24, and 25, respectively, and divided into four bands, and is then divided into four bands, followed by a phase shifter 26,
27, 28 and 29 are provided with husbands.

The phase shifter 26 converts the band-divided signal from the low-pass filter 23 into 2
The desired phase difference θ for the branched and supplied signals
For example, one input signal is set to θ1 so that 1 is given relatively.
Shift phase slightly.

Of the two output signals of the phase shifter 26, one output signal whose phase is shifted is adjusted to a desired level by a variable resistor 31a and supplied to the mixer 33, and the other output signal whose phase is not shifted is supplied to a variable resistor 30a. The signal is adjusted to a desired level and supplied to the mixer 34.

Here, the variable resistor 31a provides a signal level lower than Xl relative to the variable resistor 30a.

Similarly, by phase shifters 27, 28 and 29, θ θ
The two output signals each given a phase difference of 3 and θ4 are connected to variable resistors 30b and 31b, 30c and 31e,
and is supplied to mixers 32 and 33 via 30d and 31d.

The output signal of the mixer 32 is sent to the right speaker R of the listener 34.
The output signal of the mixer 33 is supplied to the left speaker L.
supplied to

Here, if the signal applied to speaker L is xejθ and the signal applied to speaker R is 1.0, or the level ratio expressed as (level of input signal of speaker L)/(level of input signal of speaker R) , and θ is the relative phase difference between both speaker input signals.

Now, there is a sound pressure P at the left and right ear canal entrances of the listener 34.
L tPR is expressed as .

However, in the above equation, τ is the delay time due to head diffraction, γ is the attenuation coefficient due to head diffraction, and Po is the reference sound pressure.

Also, the interaural level difference △P is 2010g1PR/PL1
The interaural phase difference △φ is Arg (PR) Arg
It is expressed as (PL).

According to the ΔP-Δφ method, a natural sound image that is equal in quality to the actual sound source can be created outside the two speakers.

In the case of 4-channel stereo, one more system of the apparatus shown in FIG. 5 is sufficient.

Here, the phase shifters 26, 27, 28, and 29 need to be varied in phase shift according to the desired sound image localization position, and for this purpose, the amount of phase shift is varied by the angle identification signal and the quadrant determination signal. It is considered to be a composition.

On the other hand, the resistance values of the variable resistors 30a to 30d and 31a to 31d must be varied according to the desired sound image localization position, and for this purpose, the resistance values are configured to be varied by the distance identification signal.

The present invention particularly relates to a stick position detection system capable of generating the above-mentioned angle identification signal, quadrant judgment signal, and distance identification signal in accordance with the stick position of a four-channel panpot.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic side view of an example of a four-channel panpot to which the method of the present invention can be applied.

Reference numeral 1 denotes a stick, one end 1a of which is rotatably supported, and by freely rotating the stick using this one end 1a as a fulcrum, the other end 1b draws a hemispherical locus.

The resistance values of the rotary variable resistors VR1 and vR2 are configured to change in accordance with the amount of change in the movement of the stick 1.

By the way, in the method of the present invention, the resistance value of the variable resistor is changed in response to the movement of the stick 1 in order to express the mapping of the stick 1 to the horizontal plane as a position within coordinates with this horizontal plane as two-dimensional orthogonal coordinates. Furthermore, the rotary variable resistors vR1 and vR2 are constructed as shown in FIG.

In the figure, vRl is stick 1 at the X coordinate of the horizontal plane.
VR2 is a rotary variable resistor that indicates the position of the stick 1 in the Y coordinate of the horizontal plane.

One ends of the rotary variable resistors VR1 and VR2 are commonly connected and connected to the positive DC power supply voltage B input terminal, while the other ends are respectively connected to the negative DC power supply voltage -B input terminal.

The origin (0, O) of the above two-dimensional orthogonal coordinates of
The slider of 1°VR is set to be at the midpoint position of each.

Therefore, when the stick 1 is perpendicular to the horizontal plane, the DC voltages led to the output terminals 2 and 3 from the sliders of the rotary variable resistors VR, VR2 are both Ov.

Movements other than the vertical position of stick 1 are as described in X and Y above.
The resistance values of the rotary variable resistors VR□ and vR2 are changed to be expressed as a change in the mapping position in the dimensional orthogonal coordinates,
A signal with a corresponding level and polarity is extracted.

From this signal, the movement of stick 1 is determined by the distance r (= J-] u0) from the origin of the mapping of stick 1 in the above X, Y two-dimensional orthogonal coordinates, and the angle θ (= tan ') with respect to a certain direction. --) is detected.

FIG. 3 shows a circuit diagram of an embodiment of the method of the present invention.

In this figure, the same parts as in FIG. 2 are given the same reference numerals.

The DC voltage from the output terminals 2 and 3 is applied to rotary variable resistors VR1 and V whose sliders are varied according to the movement of the stick 1.
By changing the resistance value of R2, the level and polarity will correspond to the movement of the mapping of stick 1 in the X and Y coordinates, and the
, represents the point (x, y) of the Y coordinate.

The output DC voltages of the output terminals 2 and 3 representing the x and y points of the X and Y coordinates are supplied to squarers 4 and 5, where X2, y2
After being converted into a signal representing X2+y2, the signals are supplied to an adder 6, where they are added and converted into a signal representing X2+y2.

The output signal of this adder 6 is sent to n voltage comparators 7□ to Tn as an analog signal representing the square r2 of the distance r.
are supplied respectively.

Here, n is any positive integer.

A voltage corresponding to the square of the distance from the origin of the coordinates measured in advance is applied as a reference voltage to the voltage comparators 71 to In from terminals 81 to 8n.

Therefore, the DC analog signal representing r2 and the reference voltage are compared in level by the voltage comparators 71 to In, respectively, and a signal is output from the voltage comparator corresponding to the distance.

That is, each output r of the voltage comparators 71 to 7rl.

-rn (represents each distance.

On the other hand, the DC voltage from terminals 2 and 3 is applied to the absolute value amplifier 9.
, 10, where it is converted into a signal representing IXl, Iyl, and the DC voltage, which is always positive or
It is output as an l signal.

These IX1 signal and lyl signal are divided by a resistor lL12 at a predetermined ratio, and then divided by m voltage comparators 13.
□~13m respectively.

However, m is any positive integer.

Here, a method of detecting the angle θ using the 1×1, lyl signal will be explained.

Now, suppose that (Xo, yo) are given as shown in FIG.

In this case, only the case of the first quadrant will be considered.

Letting θ be the angle formed by the line segment (mapping of stick 1) connecting the origin and (Xo, yo) and the y-axis, it is given by:

Then, by configuring, for example, θ-300 to operate, the voltage comparator 13i
By sending out the output signal, it is possible to determine that θ-30°.

Similarly, if the relationship between X and y corresponding to each angle is given to each voltage comparator 131 to 13m, the angle θ can be determined from the output thereof.

In this way, the angle can be determined without using a divider.

By the way, since the output signals of the absolute value amplifiers 9 and 100 always represent positions within the coordinates of the first quadrant, angles in the range of 0° to 900 can only be determined by the output signals of the voltage comparators 13□ to 13m. Therefore, it is necessary to determine where the X signal and y signal corresponding to the stick 1 are located in the coordinates and convert it from 0° to 360° with respect to the angle reference point.

Therefore, a quadrant determination circuit is required.

For this quadrant determination, the output DC voltage of terminal 2 is supplied to voltage comparators 14 and 15, and the output DC voltage of terminal 3 is supplied to voltage comparators 16 and 17.

When the output DC voltage of terminals 2 and 3 is positive or O, a signal is output from voltage comparators 14 and 16, and when this DC voltage is negative, a signal is output from voltage comparators 15 and 17.

The output signal of the voltage comparator 14 is processed by a two-man AND circuit (AN
D circuit) 18, 21, the output signal of the voltage comparator 15 is applied to two-man AND circuits 19, 20, the output signal of the voltage comparator 16 is applied to AND circuits 18, 19,
The output signal of the voltage comparator 17 is output from AND circuits 20 and 2.
1.

Therefore, for example, when the stick 1 is in the first quadrant of the coordinates, a signal is output only from the AND circuit 18 because X≧O and y≧0.

Similarly, the output signals of the AND circuits 19, 20, and 210 are output only when the stick is in the second, third, and fourth coordinate quadrants.

In this way, by determining each quadrant, 0
Can detect angles of ~36,000°.

Each output distance identification signal r of the voltage comparators 71 to In shown in FIG.

-rn-1, the output angle identification signals of the voltage comparators 13□ to 13m, and the output quadrant determination signals of the AND circuits 18 to 21 are as described in the above-mentioned NHK Giken Monthly Report December 1975 issue, respectively. It is used to control ΔP and Δφ of a natural sound image localization device that takes into consideration the correlation between the signal level difference (ΔP) and phase difference (Δφ) at the positions of both ears of a person.

Thereby, it is possible to move the sound image particularly in the four-channel sound field to an arbitrary location according to the movement of the stick 1, and to localize a natural sound image at an arbitrary location determined by the stick 1.

As described above, the stick position detection method of the 4-channel pan pot according to the present invention uses a 4-channel pan pot stick that is configured to be rotatable with one end of the stick as a fulcrum and the other end drawing a hemispherical trajectory. In order to represent the origin as a change in the stick mapping position within the two-dimensional orthogonal coordinates defined when the point is perpendicular to the horizontal plane, a variable resistor whose resistance value changes in response to the movement of the stick, and this variable resistor are used. a first conversion circuit that is supplied with a signal representing the point (x, y) of the orthogonal coordinates taken out from the resistor and converts it into a signal representing X2+y2; and a first conversion circuit that is supplied with the signal taken out from the variable resistor and converts it into a signal representing A second conversion circuit that converts the IX1 signal and Iyl signal representing the absolute value of the point (x, y) and the output signal of the first conversion circuit and the reference signal are compared at the husband level and the orthogonal coordinates are calculated. From the origin to the point (
A first comparator circuit that detects the distance to A second comparison circuit detects the angle based on a certain direction and compares the levels of the signal taken out from the variable resistor to determine in which quadrant of the orthogonal coordinates the map of the stick is located. Because it consists of a judgment circuit, the mechanical movement of the stick can be extracted as an electrical signal expressed as a change in position within two-dimensional orthogonal coordinates, and this electrical signal can be used to move the sound source to any location in the sound field. Alternatively, it can be fixed, and the means for detecting the distance from the origin in the two-dimensional orthogonal coordinates and the angle based on a certain direction can have an extremely simple circuit configuration without using a divider. It is something.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of an example of a 4-channel panpot to which the method of the present invention can be applied, FIG. 2 is a circuit diagram of an example of a rotary variable resistor used in the method of the present invention, and FIG. 3 is a schematic side view of an example of a rotary variable resistor used in the method of the present invention. FIG. 4 is a diagram for explaining angle detection according to the method of the present invention, and FIG. 5 is a block diagram showing an example of a natural sound image localization device. 1...stick, 4,5...squarer, 7□~~7n, 131~13m, 14,15,16°17...voltage comparator, 9, 10... Absolute value amplifier, 18-21... AND circuit.

Claims (1)

[Claims] 1. When the stick of a 4-channel pan pot is rotatable with one end of the stick as a fulcrum and the other end draws a hemispherical trajectory, it is defined as the origin when it is perpendicular to the horizontal plane.2 A variable resistor whose resistance value changes in response to the movement of the stick, and (x, y) of the orthogonal coordinate taken out from the variable resistor, in order to express it as a change in the mapped position of the stick in the dimensional orthogonal coordinates. a first conversion circuit that is supplied with a signal representing the point (X2+y2) and converts it into a signal that represents the point (X2+y2);
A second conversion circuit that converts the 1 signal and the Iyl signal, and the output signal of the first conversion circuit and the reference signal are compared in level, respectively, and the distance from the origin of the orthogonal coordinates to the point (x, y) is calculated. The output I of the first comparison circuit to detect and the second conversion circuit
a second comparison circuit that compares the levels of the Xl signal and the Iyl signal, determines whether these signals have a predetermined level relationship, and detects an angle with respect to a certain direction;
A stick position detection method for a four-channel panpot, comprising a circuit that compares the levels of signals taken out from the variable resistor to determine in which quadrant of orthogonal coordinates the map of the stick is located.