KR100669820B1 - Directional sound receiving device - Google Patents

Abstract

The present invention relates to a sound wave receiving apparatus, comprising: a microphone array in which two or more microphones for converting sound waves into electric signals are spatially spaced apart from each other; And electric signal processing means for comparing the phase difference of each of the electrical signals received from the two or more microphones to output only a signal having a predetermined phase difference or less.

The sound wave receiver according to the present invention can receive the front sound wave with a high S / N ratio (Singal to Noise Ratio), and thus has an effect of showing high directivity in the front direction.

Microphone, phase, frontal, directivity

Description

Directional Sound Wave Receivers {DIRECTIONAL SOUND RECEIVING DEVICE}

1 is an overall configuration diagram of a directional sound wave reception device composed of two microphones in a directional sound wave reception device according to an embodiment of the present invention.

2 is an overall configuration diagram of a directional sound wave receiving device consisting of three microphones in the directional sound wave receiving device according to an embodiment of the present invention.

3 is a view showing that a difference occurs in the reach distance of the side sound waves to reach each microphone when receiving the side sound waves in the directional sound wave receiving apparatus according to the present invention.

4 is a view showing that there is no difference in the reach distance of the front sound waves that reach each microphone when receiving the front sound waves in the directional sound wave receiving apparatus according to the present invention.

5 is an overall configuration diagram of a directional radio wave receiving apparatus according to a first embodiment of the present invention.

FIG. 6 is a diagram illustrating that in the directional sound wave receiving apparatus according to the first embodiment of the present invention, the front sound waves are output from the DSP output due to no mutual reception phase difference, and the side sound waves are removed due to the mutual reception phase difference.

7 is an overall configuration diagram of a directional radio wave receiving apparatus according to a second embodiment of the present invention.

FIG. 8 is a view showing changed waveforms of side sound waves appearing on the output side of the coupling means due to different phases of the side sound waves received by each microphone when receiving the side sound waves in the directional sound wave receiving apparatus according to the second embodiment of the present invention; FIG. to be.

<Explanation of symbols for the main parts of the drawings>

30, 60: Directional acoustic wave receiver 1: microphone

61: selection means 75: filter

33: DSP

The present invention relates to a sound wave receiving apparatus, and in particular, by configuring a microphone array in which two or more microphones are arranged in a predetermined form, the sound wave received from the front side of the microphone array and the sound wave received from the side can be easily distinguished, The present invention relates to a sound wave receiving apparatus capable of selectively removing sound waves and exhibiting high directivity.

In general, in order to remove the ambient noise from the sound wave receiver, the sound wave with the strong signal strength is output from the output of the sound wave receiver and the ambient noise with the weak signal strength is generally removed to remove the ambient noise in the sound wave output.

However, in this method, when the desired sound wave is smaller or similar to the ambient noise, it is difficult to distinguish between the ambient noise component and the desired sound wave component, and thus it is not easy to remove the ambient noise. In addition, when amplifying the microphone output, the desired sound output and the ambient noise were amplified together, making it difficult to remove the ambient noise.

As another solution to this problem, two microphones are provided, the first microphone receives the ambient noise and the desired sound wave signal, and the second microphone receives only the ambient noise and passes the FFT (Fast Fourier Transform) process. After analyzing the noise component, a method of canceling the noise by canceling only the ambient noise at the first microphone output was presented.

However, this method is also inconvenient in removing noise components because it is difficult to distinguish between the ambient noise and the desired signal.

 The present invention has been made to solve the above-mentioned problems of the prior art, by selectively blocking the side sound waves that can act as noise components in the sound receiving element to remove noise at the input stage, the desired front sound wave signal is a side sound wave It is a technical object of the present invention to provide a highly directional sound wave receiver capable of obtaining a high signal / noise ratio even with a smaller signal size.

  In order to achieve the above technical problem, the present invention provides a microphone array in which two or more microphones for converting sound waves into electrical signals are arranged to be separated from each other by a predetermined distance, and the electrical signals of the microphone array are received and received from the two or more microphones. Provided is a directional sound wave receiving apparatus including electric signal processing means for controlling the blocking and output of the electric signal in accordance with the phase difference between the electric signals.

   As shown in Fig. 4, when two or more microphones (1) are arranged 15 away from each other, the phase of the front sound waves arriving in a straight line connecting the microphones or in the vertical direction in the center of the plane containing each microphone In Phase, the frontal wave reaches each microphone the same, so the phase is also received the same. But

In the case of the side acoustic waves transmitted in a direction other than the vertical direction from the center of the plane including the respective microphones or a straight line connecting the respective microphones as shown in FIG. Since it is different (13), the phase of the received side sound wave is different for each microphone. In the case of the sound wave received from the side surface, the phase difference is generated by comparing the phases of the electrical signals transmitted from the respective microphones by using the point that the phase difference occurs in the electrical signals of the microphones constituting the microphone array. If only the electric signal is output, the signal is generally received only in front of or near the microphone array of the sound wave receiver, so that a high-directional sound wave can be amplified even if the desired sound in the front direction is similar or smaller than the surrounding noise. A receiver can be obtained.

 According to an embodiment of the present invention, two or more microphones (1) for converting sound waves into electrical signals are spatially arranged in a microphone array 5 and phases of respective electrical signals received from the two or more microphones (1). A directional acoustic wave reception device comprising electric signal processing means for comparing the difference and outputting only a signal equal to or less than a preset phase difference value, wherein the electric signal processing means is configured to digitize an electric signal of the two or more microphones. Directional sound wave receiving means may be provided which comprises an analog-to-digital converter 31 and a digital signal processor (DSP) 33.

When the analog / digital converter 31 and the DSP 33 are used as the electrical signal processing means (3), the electrical signals, which are the respective microphone outputs, are digitized by the analog / digital converter 31 to the DSP 33. This allows the signal to be processed. The DSP detects the phase of each electric signal, compares the received phases with each other, and outputs sound waves having the same phase as an analog or digitized output through the DSP 33, and receives the phases differently. Only the front sound wave propagated from the front by blocking the sound wave is output through the DSP 33, and the side sound wave received from the side is cut off from the DSP to effectively block the side sound wave. At this time, the number of sound waves that are received in the same phase or less than a certain level can be several, so the DSP can select more than one of the sound waves of similar phase and receive a clearer output.

One of the phase comparison methods in DSP is the point of time when the magnitude of the electrical signal increases from the magnitude of the electrical signal to the magnitude of the amplitude of each received electrical signal (when the peak of the wave occurs) and the magnitude of the electrical signal. The phases of the electrical signals can be compared with each other by comparing the time point at which the magnitude of the electric signal changes from the smaller value to the time point when the low point of the wave occurs.

  In addition, if only the electrical signal of the phase difference is preset through the DSP can output only the sound wave transmitted in a certain direction.

 According to another aspect of the present invention, in the directional sound wave receiving apparatus, the electric signal processing means (3), the coupling means by selecting the electric signal received at each microphone for a predetermined time alternately with time Selecting means 61 to be connected to, provides a directional sound wave receiving device, characterized in that it comprises a coupling means (65) for combining and outputting the selected electrical signals alternately over time.

In addition, it can be configured by further adding a filter on the output side of the coupling means of the directional sound wave receiving apparatus.

   The selecting means of the directional sound wave receiving apparatus includes an oscillator for generating a clock, a counter for counting an oscillator output and outputting the result, a selector for controlling each switch according to the counter output result, and combining the electrical signal according to the output of the selector It may comprise a switch for connecting and disconnecting the means.

 When the output of two or more microphones spaced apart from each other by a switch including a switch to the output of one or more or less than the number of microphones in order to be connected to the coupler at a high speed, combiner output In this case, the effect of the microphone moving to the microphones on the microphone array and receiving sound waves is generated. As a result, the sound waves received from the side of the microphone array have different phases for each microphone. Due to the same effect as moving the sound wave and receiving sound waves, it is shifted to a frequency that can be blocked by the filter (85). The sound wave of the distorted frequency (85) is determined by an effect such that the frequency of the distorted frequency is moved to the microphones and receives sound waves, so that the clock frequency of the oscillator is increased to increase the effect of moving and receiving with the microphones. It can be removed by shifting it to a frequency that can be sufficiently removed by the filter. In addition, the front sound wave received by the sound waves of the same phase in each microphone moves to the microphones, and even if the same effect occurs as receiving sound waves, each microphone receives sound waves of the same phase, so that no frequency variation occurs and passes through the filter. Will print. Therefore, by selectively blocking the side sound waves that can act as noise components in the microphone to remove noise at the input stage, even if the desired front sound wave signal is smaller than the side sound waves, highly directional sound waves can be received with a high S / N ratio. A receiver can be obtained.

  By using the directional sound wave receiving apparatus, an electronic device for receiving sound waves by collecting only sound waves of a desired front or a predetermined direction in a place where ambient noise is severe in a voice or sound processing electronic device such as a voice transmission terminal or a voice recorder, etc. You can configure the device. In addition, by using the directional sound wave receiving apparatus can be configured a broadcast system that significantly reduces noise in the broadcast system.

  A microphone array consisting of two microphones can be used to construct a directional sound wave receiving device that is directional in a direction perpendicular to the center of a line segment connecting two microphones. When three or more microphones are used, the center of each microphone connecting surface is formed. It is possible to configure a directional sound wave receiver having directivity in the direction perpendicular to the.

 Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention. However, the following examples are merely examples and should not be construed as limiting the present invention.

(Preferred embodiment)

 In the directional sound wave receiving apparatus 30 according to the first embodiment of the present invention, as shown in FIG. 5, a microphone array in which two microphones 1 for converting sound waves into electrical signals are arranged at a predetermined distance apart from each other ( 5) and the interaction between the digitized microphone output electrical signals and the analog / digital converter 31 connected to each microphone 1 constituting the microphone array 5 and performing an analog / digital conversion function. Comparing the phases are made of a DSP 33 to pass through and output the electrical signal of a similar phase and cut off the electrical signal of more than a predetermined phase difference value.

According to the first embodiment of the present invention, as shown in FIG. 6, the front sound waves collected at the front of the microphone array 21 and the side sound waves 11 received at the side of the microphone array are the two microphones 1. By being spaced apart (15), the front sound waves (21) are received in the same phase at both microphones and the side sound waves (11) are received in different phases at the two microphones. In this case, when one of the two microphones is called A and the other is B, when the front sound wave 21 and the side sound wave 11 are received by the B microphone at the same time and converted into an electric signal, the waveform 45 of FIG. The same electrical signal is generated, and the electrical signal of the microphone A disposed at a predetermined distance from the microphone B is received as a waveform in which only the phase of the side sound wave is delayed as in the waveform 49. At this time, when each of these electrical signals are converted into digital signals through the analog-to-digital converter 31 (46), each of the electrical signals is converted into digital signals such as waveforms 47 and 49. At this time, the frequency for sampling is 2 ~ 3 times the maximum reception frequency (Nyquest Frequency). This digital signal is supplied to the DSP to compare 52 the phases of the digital signals 47 and 49 with respect to each other. At this time, the front sound waves received similarly in phase with each other (21) pass, and the side sound waves received in different phases (11) are blocked, so that the front sound waves propagated from the front (21) are passed through the DSP (33) and The side sound waves received at the side are blocked by the DSP. At this time, one of the phase comparison methods in the DSP is the time at which the size of the electrical signal increases from the increase of the magnitude of the electrical signal to the decrease of the magnitude of the electrical signal according to the amplitude of each received electrical signal (when the peak of the wave occurs) and the The mutual phases of the electrical signals may be compared by comparing the time at which the magnitude of the electrical signal is increased from the smaller size (the time at which the low point of the wave occurs) (hereinafter, referred to as the inflection point). Therefore, the directional sound wave receiving apparatus 30 according to the first embodiment of the present invention can effectively output only the front sound wave.

In addition, since the directional sound wave receiving apparatus 30 can compare the phases of the sound waves received by the respective microphones, only the sound waves propagated at a predetermined angle may be received.

Meanwhile, in the directional sound wave receiver 60 according to the second embodiment of the present invention, as shown in FIG. 7, two microphones 1 for converting sound waves into electric signals are arranged at a predetermined distance from each other. By means of selecting means 61 and selecting means for connecting only the output of the microphone array 5 and one of the microphones 1 of the microphone array 5 to the coupling means 65 alternately at a high speed for a certain time; Coupling means (65) for uniting the selected microphone output, and the filter 75 is connected to the output of the coupling means and removes unnecessary frequency bands and passes only the required frequency bands. At this time, the selecting means selects a switch 73 according to a counter 69 for outputting an oscillator 67 for generating a clock. And a switch 73 for connecting and disconnecting the signal output with the coupling means 65.

 In the directional sound wave receiving apparatus of the present invention as shown in FIG. 3, when the side sound waves 11 reach the microphone array 5 in which the microphones are arranged at a predetermined distance, the respective microphones 1 are mutually connected. Due to the distance 34 between them, the side acoustic wave 11 signals received at each of the microphones 1, A, and B have a distance difference 13 reaching each microphone, so that each microphone has a different phase. You receive side sound waves.

Therefore, as shown in Fig. 8, the phase 11 of the received side sound wave is different for each microphone 1 (A, B). At this time, the outputs of the microphones 1 receiving the side sound waves 11 in different phases are sequentially changed at only one microphone 1 output at high speed so as to be connected to the coupling means 65 so as to connect the coupling means 65. At (65) output, one microphone moves rapidly to the microphones forming the microphone array 5, and has the same effect as receiving side sound waves 32.

FIG. 8 shows a process 85 in which the frequency of the received side sound wave 11 is shifted at the output of the coupling means 65 by an effect such as receiving the side sound waves moving rapidly with the microphones described above. Coupling means (65) by sequentially changing only the output of one microphone (1) at a high speed according to the time the side acoustic wave (11) received in a different phase between each microphone (1; A, B) and the coupling means (65) If the connection is made during the connection time 81, the frequency of the side sound wave 11 is changed as shown in the graph below in FIG. 8 at the coupling means output.

The side sound wave 11 of the coupling means output frequency is thus removed by the filter (75).

Alternatively, the frequency-shifted signal may be changed into a signal that cannot be heard by the human ear because it is over an audible range, and thus may not be a problem in the processing of sound without removing the filter.

On the other hand, upon reception of the front sound waves 21 transmitted from the front of the microphone array 5, as shown in FIG. 4, the front sound waves 21 are arranged for each microphone even when each of the microphones 1 is separated from each other. There is no time difference 13 in sound wave reception. Therefore, each microphone 1 outputs the front sound wave 21 of the same phase, and even if only one microphone 1 output is sequentially changed at high speed and output, the front sound wave ( The reception frequency of 21 does not change. At this time, the front sound wave output is passed through the filter 75.

On the other hand, if the number of microphones 1 constituting the microphone array 5 is two or more, a predetermined purpose can be achieved, but as shown in FIG. 3, three or more microphones 1 on the microphone array 5 are provided. When configured, the microphones have directivity in the direction perpendicular to the center of the plane connecting them.

In addition, the selecting means 61 may include an oscillator 67, a counter 69, a data selector 71, and a switch 73. Here, the oscillator 67 generates a clock signal, causing the above-described "effect such that one microphone moves rapidly to the microphones constituting the microphone array 5 and receives the side sound waves 32" by the clock frequency. The degree of frequency shift at the output of the coupling means of the side sound waves 11 is determined. The counter 69 counts the clock of the oscillator 67, and the result is transmitted to the data selector 71 with binary bits corresponding to the number of the switches 73 so that the data selector 71 can control all the switches 73. Output According to the binary bit output of the counter 69, the data selector 71 changes only one microphone 1 output sequentially with time through a switch control line connected to each switch 73, and the coupling means ( Control the switch (73) to be connected to (65). As a result, according to the oscillation frequency of the oscillator 67, it is possible to adjust the speed at which the microphone 1 output is sequentially connected to the coupling means 65 by the data selector 71, and according to the oscillation frequency of the oscillator 67. The degree of frequency shift 85 at the output of the coupling means 65 of the side sound waves 11 is determined.

In addition, the configuration of the switch 73 may be mechanically or electrically configured to act as a connection and disconnection of the signal between the microphone 1 output and the coupling means (65).

In addition, by allowing the pass band and the pass frequency of the filter 75 to be arbitrarily adjusted, only the front sound wave 21 of a specific frequency may be received, and the filter of the side sound wave 11 according to the frequency variation of the side sound wave 11 ( 75) You can choose whether to pass.

With this configuration and action, it is possible to receive only the front sound wave with high reception sensitivity even if the signal strength is smaller than the lateral sound wave signal where the front sound wave signal strength may act as noise.

The sound wave receiving apparatus according to the present invention as described above can be applied to various fields, but for example, if the voice source of the sound source and the terminal is applied to the terminal where the ambient noise can be input to the terminal by a certain distance while talking on the screen, the call quality This can be particularly helpful in improving.

As described above, according to the directional sound wave receiving apparatus according to the present invention, the phase difference of each microphone output signal received in a microphone array composed of two or more microphones arranged at a predetermined distance from each other is compared to only a signal having a predetermined phase difference or less. Because of the output, it is easy to control and remove the ambient noise coming from the side of the sound wave receiving device, and also effectively remove various noises generated by each microphone itself. Accordingly, the present invention provides a high-directional sound wave receiver and a sound wave reception method capable of receiving a high S / N ratio even if the desired front sound wave signal is smaller in size than the side sound wave.

Claims (11)

And a microphone array in which two or more microphones for converting sound waves into electrical signals are arranged apart from each other, and electrical signal processing means for controlling the output according to the phase difference between the electrical signals. delete The electric signal processing means of claim 1, wherein the electric signal processing means compares the phase difference between the electric signals to block an electric signal above a set phase difference value, and outputs an electric signal below a set phase difference value through the electric signal processing means. Directional acoustic wave receiving device, characterized in that. delete delete delete According to claim 1, The electrical signal processing means is a selection means for alternately selecting each electrical signal received from each microphone in accordance with time to connect to the coupling means, the electrical signals selected for a predetermined time sequentially over time Directional acoustic wave receiving device comprising a coupling means for combining and outputting. 8. The directional sound wave receiving device according to claim 7, further comprising a filter on the output side of the coupling means. The electric signal of the sound wave of claim 8, wherein the electric signal of the sound wave arriving from the front side of the microphone array is output without changing the frequency output through the selection means, the coupling means and the filter, and the sound signal reaching from the side of the microphone array. The directional acoustic wave receiving device, characterized in that the frequency received through the selection means and coupling means is changed to be removed from the filter. 9. The apparatus according to any one of claims 7 and 8, wherein the selection means includes an oscillator for generating a signal, a counter for counting the oscillator output and outputting the result, a selector for controlling each switch according to the counter output result, and a selector. Directional acoustic wave receiving device comprising a switch for connecting and disconnecting the electrical signal from the microphone to the coupling means in accordance with the output of the. Electronic device for sound or speech processing comprising the directional sound wave receiving device of claim 1.

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