KR20100020098A - A bracelet-type bluetooth handsfree - Google Patents

Abstract

The present invention relates to a bracelet-type Bluetooth hands-free that can be worn like a bracelet on a user's wrist or arm.

The bracelet-type Bluetooth hands-free according to the present invention transmits / receives a Bluetooth signal with a mobile phone, and outputs a voice signal received from the mobile phone to a speaker and transmits a voice signal of a user input through a microphone to the mobile phone. In the wrist-shaped case, wearable on the user's wrist, Kalimba digital signal processor for removing the howling noise and echo of the voice signal transmitted and received with the mobile phone, and the incoming call received signal received from the mobile phone It further includes a vibrator for applying vibration to the case.

Description

Bracelet-type bluetooth handsfree {a bracelet-type bluetooth handsfree}

The present invention relates to a Bluetooth handsfree, and more particularly to a bracelet-type Bluetooth handsfree that can be worn like a bracelet on a user's wrist or arm.

Bluetooth refers to a wireless transmission technology for wirelessly transferring files such as pictures, voices, and ringtones between a mobile phone and a mobile phone or a mobile phone and a personal computer or a mobile phone and a handsfree product. Recently, hands-free products have been developed using the Bluetooth wireless transmission technology so that a user can make a call without holding a mobile phone in his hand. A representative type of handsfree product is a Bluetooth headset.

1 is a block diagram of a general Bluetooth headset. The Bluetooth-enabled mobile phone and the Bluetooth headset can be paired and connected, and then the mobile phone call can be made through the Bluetooth headset.

The Bluetooth headset includes a Balun Filter 112 connected to the antenna 111, a Bluetooth control unit 120, a power supply 113, a power monitoring unit 114, a microphone 115, and a speaker 116. ), A volume control unit 117, a call input button 118, and a plurality of indicator light (119). The Bluetooth controller 120 includes a Bluetooth wireless unit 121, a ROM 122, a RAM 123, a microcontroller unit (MCU) 124, and a digital signal processor (DSP). a digital signal processor 125, an audio codec 126, and an input / output unit 127.

Looking at the process of receiving a voice signal from the mobile phone to the Bluetooth headset, the high-frequency signal received by the antenna 111 is filtered by the balun filter 112, the digital signal processor 125 and the audio codec of the central controller 120 ( 126 is converted into a voice signal. This audio signal is amplified by the internal amplifier and then output to the speaker 116.

Looking at the process of transmitting a voice signal from the Bluetooth headset to the mobile phone, the user's voice signal is converted into an electrical signal through the microphone 115 and amplified in the internal amplifier of the Bluetooth controller 120 and then the audio codec 126 and After converting into a high frequency signal through the digital signal processor 125 and outputs through the balun filter 112 and the antenna 111.

At this time, the Bluetooth wireless unit 121 performs communication according to the Bluetooth protocol with respect to the signal transmitted and received between the Bluetooth headset and the mobile phone. The power supply unit 113 supplies driving power to the Bluetooth control unit 120, and the power monitoring unit 114 monitors whether the charging voltage of the power supply unit 113 is lower than the threshold value. The volume control unit 117 is used to adjust the volume of the voice output to the speaker 116, the call input button 118 is used when the user wants to talk on the mobile phone through the Bluetooth headset. Indicator light 119 indicates to the user the status of the Bluetooth headset.

In general, since a Bluetooth headset is directly plugged into a user's ear like an earphone, the impedance of the speaker 116 is about 16 to 32 ohm, and the output of the speaker is as low as several tens of mW. The microphone 115 has a sensitivity of -44 to -45 dB.

These Bluetooth headsets are small and light, but they don't feel comfortable to wear for long periods of time because they need to be worn over your ears like earphones. In addition, since the Bluetooth headset does not detect the incoming call of the mobile phone, the user must continuously monitor whether the signal is received by the mobile phone even when wearing the Bluetooth headset. Sometimes you do not receive incoming calls on your mobile phone.

On the other hand, to solve the problem of difficult to wear a Bluetooth headset for a long time, a Bluetooth car kit (car kit) has been developed, which is equipped with a higher performance microphone and speaker than a Bluetooth headset, so that the user can Allow them to talk. The sensitivity of the microphones that make up the Bluetooth car kit is -35 to -42dB, the speaker impedance is 4 to 8 ohms, and the speaker output is 1 to 2 watts (W).

The Bluetooth car kit is convenient for the user but has a disadvantage of being large and inconvenient to carry.

However, if the speaker output and the microphone sensitivity are kept high while reducing the size of the Bluetooth car kit, howling noise and echo are generated, in which the sound output from the speaker is fed back to the microphone.

In other words, to reduce the size of the Bluetooth kit for portability, the speaker output and microphone sensitivity should be designed low and manufactured in the form of a Bluetooth headset. For the convenience of use, the size of the speakerphone should be increased to increase the distance between the speaker and the microphone. Must be spaced apart.

The present invention has been made to solve the above-mentioned problems of the prior art, to provide a bracelet-type Bluetooth hands-free excellent in portability and ease of use because howling noise and echo does not occur even if the speaker output and microphone sensitivity are high. There is this.

Bracelet type Bluetooth hands free according to the present invention for achieving the above object,

In the Bluetooth hands-free to transmit and receive a Bluetooth signal to and from the mobile phone to output the voice signal received from the mobile phone to the speaker and the user's voice signal input through the microphone to the mobile phone,

Bracelet-shaped case that can be worn on the user's wrist,

Kalimba digital signal processor for removing the howling noise and echo of the voice signal transmitted and received with the mobile phone,

When the incoming call reception signal is transmitted from the mobile phone is characterized in that it further comprises a vibrator for applying vibration to the bracelet-type case.

According to the present invention, a high sensitivity microphone and a high output speaker are adopted to be mounted on the wrist, and the portability and convenience of use are excellent. In particular, it is convenient because it can be worn on the wrist during exercise, and the incoming state of the mobile phone can be delivered through the bracelet-type Bluetooth handsfree according to the present invention, so that the incoming call can be missed. In addition, the bracelet-type Bluetooth hands-free according to the present invention has an effect of improving the call quality by blocking howling noise and echo even when the distance between the microphone and the speaker is close.

Hereinafter, with reference to the accompanying drawings will be described in more detail the bracelet-type Bluetooth hands-free according to an embodiment of the present invention.

Figure 2 is a block diagram of the overall configuration of the bracelet-type Bluetooth hands-free according to an embodiment of the present invention.

The bracelet-type Bluetooth handsfree has a bracelet-shaped outer case that can be mounted on a user's wrist. In the bracelet-shaped outer case, the components as shown in FIG. 2 are mounted.

The bracelet-type Bluetooth hands-free device includes an antenna 211, a balun filter 212, a power supply unit 213, a vibrator 214, a status indicator 215, a volume control unit 216, an audio amplifier ( 217, a microphone 218, a speaker 219, and a Bluetooth controller 220.

The Bluetooth controller 220 includes a Bluetooth wireless unit 221, a ROM 222, a RAM 223, an MCU 224, a baseband digital signal processor (DSP) 225, and a knife. A Limba digital signal processor (Kalimba DSP) 226, an audio codec 227, and an input / output unit (I / O) 228.

In the configuration of FIG. 2, the antenna 211, the balun filter 212, the power supply unit 213, the status indicator 215, the volume control unit 216, the microphone 218, and the speaker 219 are illustrated in FIG. 1. The antenna 111, the balun filter 112, the power supply 113, the indicator 119, the volume control unit 117, the microphone 115 and the speaker 116 of the general Bluetooth headset functions the same.

However, the bracelet-type Bluetooth hands-free of the present invention uses a high-sensitivity microphone of -40 dB to recognize the user even if the distance between the user's mouth and the microphone is far away or the user makes a small sound. In addition, high-power speakers with an impedance of 8 ohms and an output of 1 watt or more are used so that a user can accurately hear the received voice signal even in a noisy place.

In addition, the Bluetooth wireless unit 221, the ROM 222, the RAM 223, the baseband digital signal processor 225, the audio codec 227, and the input / output unit 228 of the Bluetooth controller 220 of FIG. The Bluetooth wireless controller 121, the ROM 122, the RAM 123, the digital signal processor 125, the audio codec 126, and the input / output unit 127 of the Bluetooth controller 120 of FIG. .

When the incoming call is received, the mobile phone transmits the incoming call reception signal to the bracelet-type Bluetooth handsfree of the present invention. The bracelet-type Bluetooth hands-free of the present invention receives an incoming call reception signal, and the MC-U 224 of the Bluetooth controller 220 operates the vibrator 214 to cause the bracelet-type Bluetooth hands-free to vibrate.

The function of the Bluetooth controller 220 for the Bluetooth wireless signal transmitted and received with the mobile phone will be described with reference to FIG. 3.

3 is a diagram illustrating a voice signal processing process of the bracelet-type Bluetooth hands-free according to the present invention.

First, the voice signal transmitted by the bracelet-type Bluetooth hands-free to the mobile phone is input to the microphone 218, and the audio codec 227, the Kalimba digital signal processor 226, the baseband digital signal processor 225, and the Bluetooth wireless unit are input. It is output through the antenna 211 through the 221 and the balun filter 212.

Next, the voice signal transmitted from the mobile phone to the bracelet-type Bluetooth hands-free is input to the antenna 211 and the balun filter 212, the Bluetooth wireless unit 221, the baseband digital signal processor 225 and the Kalimba digital signal processor The speaker 219 is output through the audio codec 227 and the audio amplifier 217.

The audio amplifier 217 amplifies the analog voice signal. The analog voice signal received from the microphone 218 contains noise, and amplifying the microphone received signal also amplifies the noise and adversely affects the system. Therefore, the analog voice signal received from the microphone 218 is directly amplified without amplification. The audio codec 227 is transmitted.

The audio codec 227 converts analog voice signals into digital and digital voice signals into analog. That is, the digital voice signal is received from the Kalimba digital signal processor 226, converted to analog, and output to the audio amplifier 217, and the analog voice signal input from the microphone 218 is received and converted into digital, Output to the limb digital signal processor 226.

The Kalimba digital signal processor 226 improves sound quality by removing howling noise and echo on digital voice signals transmitted and received. The baseband digital signal processor 225 performs signal processing for the microphone channel and the speaker channel, and the Bluetooth wireless unit 221 converts the voice signal to be transmitted and received by applying the Bluetooth protocol.

4 is a block diagram illustrating an internal configuration of the Kalimba digital signal processor 226 according to the present invention. The signal input from the audio codec 227 is an acoustic echo canceller 301, a noise suppressor 302, an equalizer 303, and a noise gate. The signal is processed through the 304, an automatic gain controller 305, and a dynamic range compressor 306, and then transmitted to the baseband digital signal processor 225.

The signal input from the baseband digital signal processor 225 is an equalizer 311, a noise gate 312, an automatic gain controller 313, and an operating range compressor. The signal is processed by the dynamic range compressor 314 and the double torque gain controller 315 and then transmitted to the audio codec 227. The signal passing through the double torque gain controller 315 is output through the speaker and provided to the acoustic echo canceller 301.

5 is a block diagram illustrating an internal configuration of the acoustic echo remover 301. The acoustic echo canceller 301 inputs the microphone 218 to divide the digitally converted signal from the audio codec 227 into a plurality of frequency bands and outputs a plurality of subbands (subbands M1 to subband MN). The first analyzer 401 and the double torque gain controller 315 process the signal and output the speaker 219 into a plurality of frequency bands to output a plurality of subbands (subbands S1 to subband SN). Subband Mk and subband Sk (where k is a natural number of 1 ≦ k ≦ N) for each subband output from the second analyzer 402 and the first analyzer 401 and the second analyzer 402. A plurality of adaptive filters 411 and 412 for removing the acoustic echo of the subband Mk, and the subband Mk and the subband Sk (where k is a natural number of 1 ≦ k ≦ N) and the kth adaptive filter. And a plurality of residual echo suppressors for receiving residual signals, respectively, to remove residual echo.

The residual echo suppression apparatus includes residual echo suppressors 412 and 422, comfort noises 413 and 423, and adders 414 and 424. The residual echo suppressors 412 and 422 receive a signal from which the acoustic echo is removed from the adaptive filter in the subband Mk, the subband Sk, and the kth adaptive filter, respectively. The ratio is obtained. If the ratio is greater than the threshold, the adaptive filter output signal is output to the adders 414 and 424. If the ratio is smaller than the threshold, the comfort noise is generated in the comfort noise 413 and 423. Comfort noise generates stationary noise for each subband. The adders 414 and 424 selectively output the signal output from the residual echo suppressor 422 or the signal output from the comfort noise 413 and 423 to the noise suppressor 302.

That is, the adaptive filter removes acoustic echo using a signal input to the microphone and a signal output to the speaker for each subband. To this end, the in-band pass loss of the adaptive filter is set to -5 dB and the sub-band attenuation is set to -12 dB. However, using adaptive filters does not reduce all acoustic echoes. The residual echo suppressor removes residual echo from the adaptive filter output signal. That is, if the ratio of the signal to the residual echo remaining in the output signal of the adaptive filter for each subband is greater than the threshold using the shielding characteristic of the human auditory system, the output signal of the adaptive filter is output, and the ratio is smaller than the threshold. If it is, the output signal of the adaptive filter is cut off and comfort noise is output.

The noise suppressor 302 determines whether noise suppression is applied by checking a noise level at a predetermined time for each subband in which the echo echo canceller 301 is removed, and performs noise suppression according to the determination result. . The noise level check for each subband is performed based on a signal envelope operation for each subband. When the signal envelope decreases, the noise level decreases. When a large change in the signal envelope is detected for a predetermined time, the noise level increases. Increases. In addition, the noise suppression is performed by applying the noise suppression gain for each subband according to the signal of the subband and the noise level measured for each subband. If the signal of the subband is greater than the measured noise level, the signal of the subband is output to the equalizer 303. If the signal of the subband is smaller than the measured noise level, the noise suppression gain according to the noise level is applied to the signal of the subband. Apply attenuation.

At this time, the noise suppression gain is determined by two parameters, SNS (dB) and BNL (dB). If the noise level of the subband is less than BNL, the noise suppression gain is set to SNS, and the noise level of the subband is If it is larger than BNL, the noise suppression gain is set to noise level / 2. However, this noise suppression gain does not exceed | SNS | + 18dB. In this invention, SNS is set to -6dB and BNL is set to -36dB. When the noise suppression gain is set in this manner, the static noise always suppresses all signals determined as noise by the SNS value, and the dynamic noise determines the noise suppression gain according to the noise level.

Equalizers 303 and 311 then compensate for signal distortion.

Next, the noise gates 304 and 312 block a low level noise by blocking a signal whose input signal has a predetermined level or less.

Next, the automatic gain controllers 305 and 313 detect a change in the amplitude of the input signal and automatically adjust the gain so that the amplitude of the output signal is kept constant at all times. The operating range compressors 306 and 314 control the operating level of the input signal. (Difference between strong signal level and weak signal level) is compressed.

In general, the acoustic characteristics of the voice output from the speaker depends on the signal level of the speaker. The larger the signal level, the more the sound output from the speaker is distorted. In the bracelet-type Bluetooth hands-free of the present invention, the double talk gain controller 315 is used to increase the duplex.

When the voice signal is detected by the microphone, the double talk gain controller 315 reduces the volume of the voice output by the speaker. This can reduce the amount of echo captured by the microphone and improve double talk performance.

In the present invention, when the microphone detects a voice signal, it reduces the gain of the voice output to the speaker to -6dB, and the time taken to reduce the signal is 50ms, the time to maintain the decrease is 500ms, and the time to return to the original state is Design to be 200ms.

The technical idea of the electromagnetic wave absorber according to the present invention has been described above with reference to the accompanying drawings, but this is by way of example and not by way of limitation. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

1 is a block diagram of a typical Bluetooth headset,

Figure 2 is a block diagram of the overall configuration of the bracelet-type Bluetooth hands-free according to an embodiment of the present invention,

3 is a view showing a voice signal processing process of the bracelet-type Bluetooth handsfree according to the present invention;

4 is a block diagram illustrating an internal configuration of a Kalimba digital signal processor according to the present invention;

5 is a block diagram illustrating an internal configuration of the acoustic echo canceller according to the present invention.

      <Brief description of symbols for the main parts of the drawings>

211: antenna 212: balun filter

213: power supply section 214: vibrator

215: status indicator 216: volume control

217: audio amplifier 218: microphone

219: speaker 220: Bluetooth control unit

221: Bluetooth wireless unit 222: ROM

223: RAM 224: MCU

225: baseband digital signal processor 226: kalimba digital signal processor

227: audio codec 228: input and output unit

Claims (5)

In the Bluetooth hands-free to transmit and receive a Bluetooth signal to and from the mobile phone to output the voice signal received from the mobile phone to the speaker and the user's voice signal input through the microphone to the mobile phone, Bracelet-shaped case that can be worn on the user's wrist, Kalimba digital signal processor for removing the howling noise and echo of the voice signal transmitted and received with the mobile phone, Bracelet-type Bluetooth hands-free characterized in that it further comprises a vibrator for applying vibration to the bracelet-type case when the incoming call reception signal from the mobile phone. The method of claim 1, wherein the Kalimba digital signal processor, An acoustic echo remover for dividing a user's voice signal input through the microphone into a plurality of subbands to remove acoustic echo for each subband, and a noise at a predetermined time for each subband from which acoustic echo is removed from the acoustic echo remover A noise suppressor that determines whether noise suppression is applied by checking a noise level, and performs noise suppression according to the determination result, an equalizer which compensates for distortion of a signal output from the noise suppressor, and an output of the equalizer A noise gate for blocking a signal below a threshold value among the signals, an automatic gain controller for automatically adjusting a gain to maintain a constant amplitude of the output signal by detecting an amplitude change of the signal output from the noise gate; A motion range compressor that compresses the operation level of the signal output from the automatic gain controller. Bracelet Bluetooth hands free, characterized in that, including. The method of claim 1, wherein the Kalimba digital signal processor, An equalizer for compensating for distortion of the voice signal received from the mobile phone, a noise gate blocking a signal below a threshold value among the signals output from the equalizer, and detecting and outputting an amplitude variation of a signal output from the noise gate An automatic gain controller for automatically adjusting the gain so that the amplitude of the signal is kept constant, an operating range compressor for compressing the operating level of the signal output from the automatic gain controller, and a user's voice signal input through the microphone Wristlet type Bluetooth hands-free characterized in that it comprises a double torque gain controller for reducing the gain of the signal output to the speaker. The method of claim 2, wherein the acoustic echo canceller, A first analyzer for dividing a user's voice signal input through the microphone into a plurality of frequency bands and outputting a plurality of subbands (subbands M1 to subband MN); A second analyzer for dividing the voice signal output to the speaker into the plurality of frequency bands and outputting a plurality of subbands (subbands S1 to subband SN); A plurality of sub-band Mk acoustic echoes are removed using subband Mk and subband Sk (where k is an arbitrary natural number of 1 ≦ k ≦ N) for each subband output from the first analyzer and the second analyzer. With adaptive filter, Bracelet-type Bluetooth hands-free, characterized in that it comprises a plurality of residual echo suppression apparatus for receiving residual echoes from the subband Mk, subband Sk, and k-th adaptive filter, respectively, to remove residual echoes. The method of claim 4, wherein the residual eco-suppression device, The output signal of the subband Mk, the subband Sk, and the kth adaptive filter is respectively input, and the ratio of the signal to the residual echo remaining in the output signal of the kth adaptive filter is obtained. A wristband type Bluetooth hands-free, characterized by outputting an output signal of the adaptive filter, and outputting comfort noise if the ratio is smaller than a threshold.

Images