KR20050024049A - Super-directional zoom microphone - Google Patents

Abstract

PURPOSE: A super-directional zoom microphone is provided to reduce a directional angle and to stabilize a low band operation by adjusting an output gain by mixing audio signals outputted from directional microphones having preset sensitivity levels. CONSTITUTION: A microphone has a specific direction characteristic to an audio signal with a specific direction. At least one omni-directional microphone unit has the same sensitivity in audio signals with all directions. A phase of at least one directional microphone unit is changed between positive and negative values according to the direction. An amplification converter adjusts a gain of the audio signal which is received according to a preset sensitivity level of each of the microphone unit. A mixer mixes the audio signals from the amplification converter to increase or decrease the output level of the mixed signal.

Description

Super-Directional Zoom Microphone {SUPER-DIRECTIONAL ZOOM MICROPHONE}

The present invention relates to a super directional microphone that catches only a sound in a specific direction, and more particularly, sets a sensitivity level of a plurality of directional microphones and mixes acoustic signals output according to a set sensitivity level to differentially sensitive super directionality. A superdirectional zoom microphone for implementing.

In general, a super-directional microphone refers to a microphone designed to pick up sound only at a specific narrow angle, such as a shot-gun microphone or a microphone equipped with a sound collecting plate such as a parabola antenna behind the shotgun microphone. And as shown in FIG. 2.

1 is a view showing the shape of a superdirectional microphone according to the prior art, Figure 2 is a conceptual diagram showing the operation principle of a conventional superdirectional microphone.

As shown in FIG. 1, the superdirectional microphone 1 according to the related art is a rod-shaped rod having a long rod shape, in which a plurality of slits 11 are periodically drilled. . Therefore, the sound waves interfere with each other while passing through the slot 11, and the sound waves coming from the side are canceled and the sound waves coming from the front are reinforced to reach the microphone diaphragm to pick up only the sound waves coming from the front.

That is, as shown in FIG. 2 (a), the sound waves coming in through the slots 11 at regular intervals from the side or the rear side have the wavelength λ of each sound wave by the slots 11 formed periodically (or at regular intervals). Phases are mutually canceled by mutual multiples (2λ, 3λ, 4λ ...) and canceled, and the sound coming from the front (axial direction) reaches and outputs the diaphragm 12 without any obstacle, thereby minimizing ambient noise. In addition, it implements super-directional characteristics with sensitive directivity for specific ranges.

As shown in Fig. 2 (b), the hyperdirectionality generally shows a sensitive response only within a narrow angle (more specifically, within 30 degrees) by reducing the directional angle of the side. It has a weak polarity.

Therefore, the conventional super-directional microphone 1 is mainly used in the case of picking up the sound of a specific animal for an interview or a natural documentary at the time of photographing. There is an advantage that can be attenuated to a negative wavelength has a relatively sensitive directivity.

However, in the conventional superdirectional microphone 1 using the slot 11, the size of the superdirectional microphone mechanism as well as the number of the slots 11 necessary to receive the incident low frequency voice band can be increased. There is a problem that there is a limit in reducing the size, and furthermore, there is a problem that is difficult to apply to the external linkage.

Accordingly, the present invention has been made to solve the above-mentioned problems, to improve the shortcomings of the super-directional microphone using the slot, using a plurality of directional microphones, but sets the sensitivity level of each directional microphone, respectively, and outputs according to the set sensitivity level The purpose of this invention is to provide an ultra-compact zoom microphone that can stably operate on low-frequency sound waves while reducing the direct angle of the sound signal by differentially adjusting the gain of the final output signal by mixing the sound signals. have.

It is another object of the present invention to maximize the characteristics of a personal portable wireless terminal by enabling the communication in a video communication or a noise environment by applying the above-mentioned papermaking zoom microphone to a personal portable wireless terminal such as a mobile phone. have.

Super-directional zoom microphone of the present invention for achieving the above object, at least one non-directional microphone unit having the same sensitivity to the acoustic signal in all directions; One or more directional microphone units; And an amplifying converter for adjusting the gain of the incident acoustic signal according to the set sensitivity level by setting the sensitivity level of each microphone unit, and mixing a plurality of acoustic signals output through the amplifying converter to differentially output the output signal. It is characterized by consisting of a circuit portion consisting of a mixing portion to raise or cancel.

The phase is changed in a positive (+) direction with respect to the directing direction and in a reverse (-) direction with respect to a direction other than the directing direction, so that an acoustic signal corresponding to the positive (+) direction is added to increase the output signal. The sound signal corresponding to the reverse (-) direction is subtracted to cancel the output signal.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention;

3 is an embodiment of a super directional zoom microphone according to the present invention, Figure 4 is a conceptual diagram showing the operation principle of the super directional zoom microphone according to the present invention, Figure 5a is a block diagram of a super directional zoom microphone according to the present invention 5B is a detailed circuit diagram of the mixing part shown in FIG. 5A.

The superdirectional zoom microphone 100 according to the present invention implements sensitive directivity (that is, superdirectional) by using a plurality of directional microphones 121-1 and 121-2, and more preferably at least one omnidirectional microphone. Use at least one directional microphone. Thus, by setting the sensitivity level of the plurality of directional microphones provided, by mixing the acoustic signals output according to the set sensitivity level to differentially adjust the gain of the final output signal to implement the super-directional pattern that was implemented through the slot, It is characterized by smaller size than microphone.

Hereinafter, as shown in the accompanying drawings, for convenience of description, an embodiment implemented by a combination of two directional microphones 121-1 and 121-2, that is, one omnidirectional microphone and one directional microphone, will be described. The present invention is not limited thereto, and a plurality of sound signals may be selectively mixed by using a plurality of directional microphones.

First, referring to Figure 3, the super-directional zoom microphone 100 according to the present invention is largely divided into the upper body 12 and the lower body 14, and the lower body 10 is installed with other means of use Consists of a connection plug 20 to be linked, the body 10 is connected by a joint 13 between the upper body 12 and the lower body 14 to enable the direction of the upper body 12 to be switched. The upper body 10 has two directional microphones 121-1 and 121-2, that is, an omnidirectional microphone and a directional microphone, and is closed with a grill net 122, and the lower body 14 is a directional microphone of the upper body 12. A circuit section for setting the sensitivity levels corresponding to (121-1, 121-2) and mixing the sound signals output in accordance with the set sensitivity level is incorporated.

On the other hand, the appearance of the super-directional zoom microphone 100 made as shown is only one embodiment, it is not limited to the appearance shown in FIG. 3 and having ordinary skill in the art within the technical spirit to which the present invention belongs. Of course, many variations are possible by the ruler.

Next, referring to FIG. 4, an operation principle of implementing superdirectionality by applying two microphones 121-1 and 121-2 as described above is illustrated.

At this time, one omni-directional microphone applied has an omni-directional pattern that captures sound with the same sensitivity in all directions as in the P pattern shown, and the other directional microphone is shown as the Q pattern shown. It has an eight-character cardioid pattern that captures sounds with varying sensitivity at maximum at 0 and 180 degrees, minimum at 90 degrees, and at an angle between the two points.

Therefore, in the front and rear of the directional microphone, the phases are reversed from each other in the (+) phase and the (-) phase by an 8-character cardioid pattern. Therefore, when these two directional microphones 121-1 and 121-2 are combined, Like the pattern, the directivity at which the maximum sensitivity is obtained in the 0 degree direction and the output sensitivity is 0 in the 180 degree direction can be obtained.

For example, when one acoustic signal is radiated at the same angle in front, the omnidirectional microphone corresponding to the P pattern accepts the OA linear sensitivity, and the bidirectional microphone corresponding to the Q pattern accepts the acoustic signal with the sensitivity of the + OB linear magnitude. do. When these two sound signals are mixed, the output sensitivity is increased by the sensitivity of the OC linear size, which is equivalent to the addition of the OA straight line and the OB straight line.

On the contrary, when another acoustic signal is radiated at the same rearward angle, the omnidirectional microphone corresponding to the P pattern is taken as the sensitivity of OA 'linear size, and the bidirectional microphone corresponding to the Q pattern is measured at the sensitivity of the (-) OB' linear size. It is accepted. When the two acoustic signals output from the two directional microphones 121-1 and 121-2 are mixed, the output sensitivity is canceled by the sensitivity of the OC 'linear size corresponding to the subtracted OB straight line from the OA straight line.

As such, in order to realize sensitive hyperdirectionality by the combination of the two microphones 121-1 and 121-2, the sensitivity levels of the omnidirectional and directional microphones to be provided should be adjusted. In addition, if the sensitivity level of the directional microphone is set in a direction that increases, the overall output sensitivity is changed from the R pattern shown in the drawing to a pattern having sensitive directivity, thereby effectively achieving the object of the present invention.

The superdirectional zoom microphone 100 of the present invention adjusts the gain of the incident sound signal by setting the sensitivity levels of the two directional microphones 121-1 and 121-2, as shown in FIGS. 5A and 5B. It is composed of a circuit for combining the sound signals output according to the set sensitivity level.

That is, the first amplification converter 141-1 which sets the sensitivity level of the omnidirectional microphone 121-1 so that the acoustic signals incident from all directions are equally picked up by the set sensitivity, and the incident of the incident acoustic signals A second amplifying converter 141-2 for setting the sensitivity level of the directional microphone 121-2 that is reversed in the normal phase and the reverse phase in the direction to be picked up with various sensitivity according to the phase, and the omnidirectional microphone 121- 1) mixes and adds an acoustic signal output through the first amplification converter 141-1 and an acoustic signal output from the directional microphone 121-2 through the second amplification converter 141-2. Or it consists of a mixing part 143 subtracted.

At this time, the first amplification converter 141-1 and the second amplification converter 141-2 reduce the sensitivity level of the omnidirectional microphone 121-1 to achieve more sensitive directivity and reduce the directional microphone 121-2. It is preferable to adjust the sensitivity level using the amplifier in the direction to enlarge. And, a manipulator for easily manipulating the adjustment of such an amplifier may be provided separately.

On the other hand, the mixing unit 143 adds or mixes the sound signals output from the first amplifying converter 141-1 and the second amplifying converter 141-2 through the IC element as shown in FIG. 5B. It is configured to perform subtraction and to adjust and output the level by the variable resistor VR. The output signal may be connected to an external means through an ENC terminal to record or dub a sound signal or to reproduce the sound.

This configuration of the present invention is characterized by the omni-directional microphone that the phase oscillates in the positive (+) direction with respect to the incident sound in all directions, and the phase is inverse to the (+) direction in accordance with the negative incident direction. It uses the characteristics of the directional microphone that changes in the direction of), and when the characteristics of these two microphones are mixed with each other, the signal in the positive direction is positive to increase the output sensitivity, and the reverse direction is negative. The signal at E is negative and cancels output sensitivity.

Therefore, the acoustic signal incident through the omnidirectional microphone 121-1 is output by being positively added according to the sensitivity level set by the first amplifying converter 141-1, and is output through the directional microphone 121-2. The incident signal is output by being positive (+) or negative (-) according to the sensitivity level set in the second amplification converter 141-2 and the incident direction (for example, front or rear). When the sound signals are mixed with each other in the mixing unit 143, the output signals may be increased or canceled according to the phase of the sound signals incident through the directional microphone 121-2 and output.

At this time, it is preferable that the directing direction of the directional microphone 121-2 is set to the positive (+) direction, and the direction other than the directing direction is set to the reverse (-) direction.

Accordingly, a signal having a positive phase in the directional microphone 121-2 is positive (+) to the sensitivity level set in the second amplifying converter 141-2 and is incident through the non-directional microphone 121-1. By adding with, the sensitivity of the final output signal is increased and output. On the contrary, the signal having the reverse phase is negative (-) to the sensitivity level set by the second amplification converter 141-2, so that the sensitivity of the output signal is canceled and output. do.

Therefore, the superdirectional zoom microphone 100 according to the present invention can be significantly reduced than the size of the existing microphone by using at least one omnidirectional microphone 121-1 and the directional microphone 121-2, and furthermore, each directional microphone Sensitivity levels of (121-1, 121-2) can be arbitrarily set, so that low-frequency voice bands can be picked up by a long distance or a noise environment. In addition, when recording, the surrounding signal, that is, noise can be minimized and only an acoustic signal incident from a predetermined direction can be increased, and in some cases, a dubbing operation can be performed with a background effect sound.

On the other hand, the super-directional zoom microphone 100 of the present invention can arbitrarily set the direction angle of the microphone 121-2 so that the sound signal in any particular direction can be raised and outputted, and the sound signal in other directions can be attenuated. have.

Looking at an embodiment in which the super-directional zoom microphone 100 of the present invention is applied to a personal portable radio terminal such as a mobile phone 5, two housings of the mobile phone 5 are opposed to each other as shown in FIG. 6. The directional microphones 51 and 52 are mounted, and as described above, a circuit section for combining and outputting the acoustic signals incident from the two directional microphones 51 and 52 as described above is provided, even in a video communication or noise environment. Communication can be enabled. Furthermore, not only a personal portable wireless terminal but also a walkman, a CD player, and an MP3 player may be applied to multimedia such as high quality voice recording.

Although described above with reference to the preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. I can understand that you can.

As described above, according to the present invention, it is possible to implement a high quality superdirectional image even when using two directional microphones, and to reduce the size significantly compared to a conventional superdirectional microphone, and to realize a compact design. have. Furthermore, there is an effect that can operate stably to the low frequency voice band.

In addition, the present invention has an effect of enabling voice recording and calling even in a noisy environment by applying variously to multimedia such as a mobile phone, a camcorder, a walkman, a CD player, and an MP3 player.

1 is a view showing the form of a superdirectional microphone according to the prior art,

2 is a conceptual diagram showing the operation principle of a conventional superdirectional microphone;

3 is an embodiment of a superdirectional zoom microphone according to the present invention;

4 is a conceptual diagram showing an operating principle of the superdirectional zoom microphone according to the present invention;

5A is a block diagram of a superdirectional zoom microphone according to the present invention;

5B is a detailed circuit diagram of the mixing part shown in FIG. 5A;

6 is an example of using a super-directional zoom microphone according to the invention mounted on a mobile phone.

** Explanation of symbols for main parts of drawings **

100; superdirectional zoom microphone 10; body

20; plug 12; upper body

13; joint 14; lower body

121-1,121-2; Omnidirectional microphone 122; Grill network

141-1,141-2; first and second amplification conversion unit 143; mixing unit

Claims (4)

In a microphone having a directivity to the acoustic signal in a specific direction, At least one omnidirectional microphone unit having the same sensitivity to acoustic signals in all directions; and At least one directional microphone unit whose phase changes in a positive or inverse direction depending on the directing direction; And By setting the sensitivity level of each microphone unit, each of the amplification converter which adjusts the gain of the incident acoustic signal according to the set sensitivity level, and a plurality of acoustic signals output through the amplification converter are mixed to increase the output signal differentially. Or a circuit section comprising a mixing section for canceling. The method of claim 1, wherein the phase is A superdirectional zoom microphone, characterized by changing in a positive (+) direction with respect to the directing direction and in a reverse (-) direction with respect to a direction other than the directing direction. The method according to claim 1 or 2, And a sound signal corresponding to the positive (+) direction is added to increase the output signal, and a sound signal corresponding to the reverse (-) direction is subtracted to cancel the output signal. The method of claim 1, Super-directional zoom microphone, which can be used in connection with external multimedia such as mobile phones, camcorders, walkman, CD player, and MP3 player.