JP2006217088A - Auditory transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact auditory transmission system that can prolong the life of a battery and make it easier to hear a reproduced sound by modulating a voice entered to a microphone etc., into a digital signal and transmitting it, and reproducing the digital signal by a bone conduction speaker system. <P>SOLUTION: A voice signal entered from the microphone 1 is amplified by a voice signal amplification section 2 and outputted as a signal X. The signal X is converted by a ΔΣ modulation section 1 into a 1-bit signal Y. The output signal Y of the ΔΣ modulation section 1 is power-amplified by a digital amplifier 2 and outputted from an output terminal 5. The 1-bit signal outputted from the output terminal 5 is input to a control circuit section 17 of the bone conduction speaker system to drive a bone conduction speaker 9. The 1-bit signal Y is transmitted with a pulse signal, so deterioration in sound quality accompanying deterioration of the transmitted signal and noise mixture can be avoided and an ultrasonic component included in the bone conduction speaker output enables high-efficiency transmission of the voice to the sense of hearing and can make it easier to hear the reproduced sound, thereby simplifying constitution, specially, on a reception side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a sound source device, a transmission line, and a speaker device that receives a signal transmitted from the sound source device via the transmission line, and more particularly to an auditory transmission system that uses a bone conduction speaker for the speaker device. .

  Conventionally, bone conduction hearing aids have been used as hearing aids for assisting persons with hearing impairment. Further, it is known that bone conduction is effective for listening to sound in a noisy environment even for a normal hearing person. It is also effective when the sound cannot be heard by normal air conduction, such as when a mask or helmet is worn over the head.

  By the way, since bone conduction directly propagates to the auditory nerve after the cochlea, it is also effective for highly deaf people who cannot hear the sound due to air conduction. Japanese Patent Laid-Open No. 2001-320799 (Patent Document 1), etc. It is described in.

  According to the above-mentioned patent document 1, bone conduction can be heard even by a highly-impaired hearing person, particularly when a voice signal is subjected to DSB (Double Sideband) modulation or balanced modulation using an ultrasonic carrier wave of about 27 kHz. ing. The band of sound used for bone conduction is usually about 5 kHz as described in Japanese Patent Application Laid-Open No. 2002-199480 (Patent Document 2), Japanese Patent Application Laid-Open No. 8-195959 (Patent Document 3), and the like. The following are often used:

Also, according to Japanese Patent Laid-Open No. 2003-32768 (Patent Document 4), there is described a headphone using a piezoelectric transducer that converts a high frequency of about 10 kHz or more of an input signal into vibration and reproduces it by bone conduction. Yes.
JP 2001-320799 A JP 2002-199480 A Japanese Patent Laid-Open No. 8-195959 JP 2003-32768 A

  The prior art described in Patent Document 1 is effective in that the bone conduction sound can be heard even by a highly deaf person, but it must include an analog carrier generator and a modulation unit, and the configuration is Due to the complexity, size, and analog modulation, there is a problem that heat loss occurs particularly in a high frequency amplifier, the efficiency is poor, and the battery life is short.

  Further, when DSB modulation or balanced modulation is performed, the spectrum of the audio signal is distributed as a sideband component around the carrier frequency. In the prior art described in Patent Document 1, DSB modulation or balanced modulation is performed using an ultrasonic carrier wave of about 27 kHz, and the effective frequency band of sound is limited to about 5 kHz or less. There is a problem that can not be taken high.

  The prior art described in Patent Document 4 is effective in that the bone conduction sound is light and small and does not require an amplifier. However, the signal for driving the bone conduction speaker is included in a part of the voice band. Since the component is about 10 kHz or higher, there is a problem that clear hearing transmission cannot be performed for the hearing impaired.

In particular, in a system in which a sound source device and a speaker device are transmitted and received via a transmission line, the conventional analog method has a problem that noise due to transmission and sound quality are deteriorated due to attenuation, and clear auditory transmission cannot be performed.

  Accordingly, an object of the present invention is to provide an auditory transmission system that solves the above problems in an auditory transmission system that includes a sound source device, a transmission line, and a speaker device that receives a signal transmitted from the sound source device via the transmission line. There is to do.

The gist of the invention according to claim 1 of the present invention is an auditory transmission system comprising a sound source device, a transmission line, and a speaker device that receives a signal transmitted from the sound source device via the transmission line, the sound source The apparatus includes transmission means for outputting based on a 1-bit signal modulated into a binary pulse signal in response to a digital signal obtained by sampling a voice or acoustic signal at a predetermined period, and the speaker apparatus Is provided with a bone conduction speaker that is driven based on the 1-bit signal obtained by receiving the output signal of the transmitting means.
The gist of the invention according to claim 2 of the present invention is that the sound source device includes binary pulse modulation means, and the sound or the sound signal is input from a sound output unit of the audio device. An auditory transmission system according to claim 1.
The gist of the invention according to claim 3 of the present invention is that the sound source device includes binary pulse modulation means, and the sound or sound signal is input from a microphone. The auditory transmission system.
The gist of the invention according to claim 4 of the present invention is that the transmission path comprises a coaxial cable or a wired transmission path of an optical cable. 4. The auditory transmission system according to claim 1, Exist.
The gist of the invention according to claim 5 of the present invention is the auditory transmission system according to any one of claims 1 to 3, wherein the transmission path is a radio transmission path using radio waves or light. Exist.
The gist of the invention according to claim 6 of the present invention resides in the auditory transmission system according to any one of claims 1 to 3, wherein the transmitting means outputs via a lighting device.
The gist of the invention according to claim 7 of the present invention resides in the auditory transmission system according to claim 3, wherein the microphone is a bone conduction microphone.
The gist of the invention according to claim 8 of the present invention is the auditory transmission system according to any one of claims 1 to 7, wherein the modulation to the 1-bit signal is a ΔΣ modulation signal. Exist.
The gist of the invention according to claim 9 of the present invention is the auditory transmission system according to any one of claims 1 to 7, wherein the modulation to the 1-bit signal is a PWM modulation signal. Exist.

  According to the present invention, bone conduction sound can be transmitted with high efficiency by generating pulse vibration as a signal for driving a bone conduction speaker. In addition, it is not necessary to limit the sound band to about 5 kHz or less, and it is possible to perform easy-to-listen reproduction without deteriorating intelligibility.

Further, since the signal becomes a pulse signal and the digital amplifier only needs to be turned on and off, the efficiency is increased. The bone conduction speaker is also characterized by low power consumption when a piezoelectric ceramic type speaker is used, and when the battery is used, the battery has a long life.

Moreover, in the auditory transmission system of the present invention, it is possible to prevent deterioration of sound quality due to noise and attenuation due to transmission in particular, and the circuit configuration on the receiving side, that is, the bone conduction speaker device side is simplified. This is more suitable when a large number of receiving apparatuses are used.

  According to the present invention, in a system that generates a bone conduction sound component over an ultrasonic region and transmits an auditory signal, unlike a case where low-density air is vibrated, a human skin, muscle, or bone having a higher density is vibrated. In this case, since the pulse vibration is more easily transmitted than the periodic wave, the bone conduction sound can be transmitted with high efficiency by generating the pulse vibration.

  In the present invention, the 1-bit signal generated by the binary pulse modulator is turned on and off by a processing clock having a frequency exceeding the audible frequency, so that an ultrasonic pulse can be easily obtained. Therefore, if a 1-bit signal from a binary pulse modulator is used for driving a bone conduction speaker, a modulated voice or acoustic signal including an ultrasonic component can be obtained, and further, it is driven by a bone conduction because it is driven by a pulse signal. Sound transmission efficiency can be improved.

  Further, in the present invention, since a method of modulating a so-called 1-bit signal in response to a digital signal obtained by sampling at a predetermined period is used, about 27 kHz as in the conventional example of DSB modulation or balanced modulation. Unlike the case where analog modulation is performed using an ultrasonic carrier wave, it is not necessary to limit the sound band to about 5 kHz or less, and it is possible to perform easy-to-listen reproduction without causing a decrease in intelligibility.

  In addition, the reproduced sound generated by the 1-bit signal also includes the input sound or the spectral component of the sound itself, which is different from those using DSB modulation or balanced modulation. It is effective for listening to sound in a noisy environment.

In addition, there is a feature that a binary pulse modulator that can receive a binary pulse or that is suitable for integration can be configured without requiring an analog modulator or a carrier generator (complex circuit configuration for processing an analog signal). Therefore, the circuit configuration is simplified, and the size and cost can be reduced.

Also, since the 1-bit signal generated by the binary pulse modulator is a 0 or 1 pulse signal, a special amplifier is not required, or the operating point of the amplifier can be set in the saturation region, so that the heat loss in the element is suppressed. Therefore, high efficiency can be achieved, and therefore low power consumption can be achieved, so that the life can be extended when using a battery.

  In the present invention, a 1-bit signal generated by binary pulse modulation is used for transmission of bone conduction sound, and a 1-bit signal which is an output signal of binary pulse modulation is digitally transmitted to the bone conduction speaker device. Transmission is performed to prevent degradation of sound quality due to noise and attenuation due to transmission.

  Next, with reference to FIG. 2 and FIG. 3, the difference in the sound reproduction of the prior art described in Patent Document 1 and the present invention will be described. FIG. 2 shows a spectrum obtained by the modulation method according to the prior art described in Patent Document 1, and FIG. 3 shows a spectrum of a 1-bit signal generated by ΔΣ modulation according to the present invention.

  The above prior art uses DSB modulation or balanced modulation, which is an analog amplitude modulation system, and the modulated spectrum is a spectrum having sidebands vertically around the carrier frequency fc as shown in FIG.

  On the other hand, as can be seen from FIG. 3, the spectrum of the 1-bit signal generated by the ΔΣ modulation method has a quantization noise component that rises to the right and the spectrum component of the input speech itself. The quantization noise component contains a lot of ultrasonic components, and when the bone conduction speaker is driven with a signal that maintains the pulse shape after ΔΣ modulation, a large amount of ultrasonic components can be kept, and the sound due to bone conduction is effective. Can be used to tell In addition, since the spectral components of the input voice are different from those using the DSB modulation or the balanced modulation as in the prior art described in Patent Document 1, they are normal auditory persons. Can also be used as an effective means for listening to reproduced sound in a noisy environment.

Next, the best mode for carrying out the present invention will be specifically described with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram showing a first embodiment of the present invention.
The sound source device includes a microphone 1 and a 1-bit signal output circuit 16, and the 1-bit signal output circuit 16 inputs sound from the microphone and outputs it as a 1-bit signal. The 1-bit signal output circuit 16 includes an audio signal amplifier 2 that amplifies an analog audio signal from the microphone 1, a ΔΣ modulator 3 that modulates the analog signal X from the audio signal amplifier 2 into a 1-bit signal Y, and a ΔΣ modulator. 3 is a digital amplifier 4 that amplifies the 1-bit signal Y from 3 and outputs it from the output terminal 5.

  Reference numeral 17 denotes a control circuit unit of the bone conduction speaker device that receives the 1-bit signal output from the 1-bit signal output circuit 16 and reproduces sound by the bone conduction speaker 9. The control circuit unit 17 of the bone conduction speaker device amplifies the 1-bit signal pulse-formed by the receiving unit 7 that obtains the original 1-bit pulse signal by pulse-forming the signal from the input terminal 6. The bone conduction speaker 9 is driven by the output of the digital amplifier 8. The output terminal 5 and the input terminal 6 are connected by a wired transmission line 15 such as a coaxial cable or an optical cable.

  As described above, the analog signal X from the audio signal amplification unit 2 in FIG. 1 is ΔΣ modulated by the ΔΣ modulation unit 3 and output as a 1-bit signal Y, and this 1-bit signal Y is transmitted to the bone conduction speaker device. The bone conduction speaker 9 of the conduction speaker device is driven.

  As the bone conduction speaker 9, an electromagnetic induction type speaker (dynamic speaker) can be used. However, if a voltage driving type speaker such as a piezoelectric ceramic type speaker is used, power consumption can be reduced.

  FIG. 4 is a diagram for explaining the principle of the ΔΣ modulator 3. In FIG. 4, a ΔΣ modulation unit indicates a first-order ΔΣ modulation unit.

  In FIG. 4, 10 is an adder, 11 is an integrator, 12 is a quantizer, and 13 is a one-sample delay device. X represents an analog input signal, and Y represents a 1-bit signal. The quantizer 12 quantizes the analog signal output of the integrator 11 into a 1-bit signal, thereby adding a quantization error Nq. The quantization error Nq is uniformly distributed in the transmission band.

In FIG. 4, if 1-bit signal Y, analog input signal X, 1-sample delay is Z ⁻¹ , and quantization error is Nq, 1-bit signal Y is expressed by the equation Y = X + Nq (1−Z ⁻¹ ). expressed.

Here, although Nq (1-Z ⁻¹ ) is a noise component, the quantization error Nq uniformly distributed in the transmission band is shifted to the high frequency side due to the high-pass characteristic of the differentiation circuit of (1-Z ⁻¹ ). To do. This is known as the noise shaping effect of the ΔΣ modulator. FIG. 3 shows the frequency characteristics of the ΔΣ modulator, and the quantization error Nq included in the 1-bit signal of the ΔΣ modulator becomes a noise floor Nq ′ that rises to the right as shown in FIG. 3 due to the noise shaping effect. .

  FIG. 5 shows an example of the analog input signal X (upper signal in FIG. 5) and 1-bit signal Y (lower signal in FIG. 5). A 1-bit signal that is an output signal every sampling takes a value of 0 or 1 (the vertical dotted line indicates a 1-sampling break). A 1-bit signal by ΔΣ modulation is frequently encoded as 1 when the amplitude of the input signal is increased, and is frequently encoded as 0 when the amplitude of the input signal is decreased. Further, a 1-bit signal by ΔΣ modulation is oversampled by increasing the sampling frequency in order to ensure a dynamic range.

  As described above, in the present invention, by transmitting the signals for driving the bone conduction speaker 9 as individual pulse vibrations, the sound transmission efficiency by bone conduction can be improved and the speech sound can be effectively perceived by bone conduction. You can That is, the 1-bit signal generated by the ΔΣ modulation is a pulse having a peak value of the power supply voltage, and energy when transmitting sound to the bone is transmitted by the pulse. Therefore, the energy by the pulse can be effectively transmitted to the auditory nerve after the cochlea.

  FIG. 6 shows a specific configuration of the ΔΣ modulator. In FIG. 6, the ΔΣ modulation unit indicates a secondary ΔΣ modulation unit.

In FIG. 6, 20, 21, and 22 are adders, 23 is a quantizer, and 24 and 25 are 1 sampling delay elements having a function of delaying by 1 sampling. Reference numerals 26 and 27 denote coefficient units. These constituent elements constitute a second-order ΔΣ modulator. ΔΣ modulation increases the order of the differentiation circuit (1-Z ⁻¹ ) by increasing the order, and as illustrated in FIG. 3 as a noise floor Nq ″ by the second-order ΔΣ modulation, an effect of reducing quantization noise by noise shaping. Will increase.

  As described above, in the present embodiment, a bone conduction sound can be efficiently transmitted using an ultrasonic component of ΔΣ modulation using a 1-bit signal generated by ΔΣ modulation, and generated by ΔΣ modulation. The reproduced sound based on the 1-bit signal can be reproduced without being demodulated.

  Further, the analog sound input to the microphone 1 is ΔΣ modulated to generate a 1-bit signal. Since this 1-bit signal is a pulse signal of 0 or 1, it is not easily affected by noise or signal attenuation due to the transmission path when transmitting the signal from the microphone 1 to the bone conduction speaker 9, and the sound quality is improved. Can keep. Further, since this 1-bit signal is a pulse signal of 0 or 1 modulated by ultrasonic waves, the bone conduction sound can be efficiently transmitted from the bone conduction speaker 9 to the auditory nerve after the cochlea.

  Furthermore, since the 1-bit signal generated by ΔΣ modulation is a pulse signal of 0 and 1, the circuit configuration of the digital amplifiers 4 and 8 and the like can be simple and operate with high efficiency. If a voltage-driven speaker such as a piezoelectric ceramic speaker is used as the bone conduction speaker 9, the efficiency is further improved, and when a battery is used, the life can be extended.

  In addition, a 1-bit signal generated by ΔΣ modulation contains a high-frequency noise component and is usually attenuated by a low-pass filter. In the present invention, this high-frequency noise component is effectively used for bone conduction sound. Conversely, it can be used actively to communicate to.

(Second Embodiment)
FIG. 7 is a diagram illustrating a sound source device according to the second embodiment. FIG. 8 is a diagram showing a bone conduction speaker device according to the second embodiment.

  In FIG. 7, 31 is a microphone, 32 is an audio signal amplifier for amplifying an analog audio signal from the microphone 31, 33 is a ΔΣ modulator for modulating the analog signal from the audio signal amplifier 32 into a 1-bit signal, and outputting it. 34 modulates and amplifies the signal from the ΔΣ modulator 33 to a signal having a frequency bandwidth suitable for transmission as a radio wave, sends the signal to the transmission antenna 35, and transmits the signal from the transmission antenna 35 as a radio wave.

  In FIG. 8, reference numeral 36 denotes a reception antenna that receives radio waves from the transmission antenna 35. Reference numeral 37 denotes a receiving unit, 38 denotes a demodulating unit that demodulates the original 1-bit signal, 39 denotes a digital amplifier, and 40 denotes a bone conduction speaker. This embodiment is different from the first embodiment in that a 1-bit signal is transmitted wirelessly.

  According to this embodiment, since a 1-bit signal is transmitted wirelessly, bone conduction sounds can be heard simultaneously by a plurality of bone conduction speaker devices. Ideal for attending classroom lectures or lectures in the auditorium. In addition, in this case, the ΔΣ modulation unit 33 is on the transmission side, and the bone conduction speaker device on the reception side has a simple configuration and can be reduced in size. In addition, the power consumption on the bone conduction speaker device side is reduced, and when the battery is used, the battery life can be kept long.

  Further, since the signal transmitted wirelessly is a 1-bit signal, that is, a digital signal, it is strong against attenuation of the transmission signal, and it is easy to add a parity signal and the like, and it is possible to easily avoid deterioration of sound quality due to noise mixing. .

(Third embodiment)
FIG. 9 shows a third embodiment.
In FIG. 9, the sound source device includes an audio device 50. Reference numerals 51 to 53 denote circuit portions of the bone conduction speaker device, and 54 to 56 denote bone conduction speakers. In the first and second embodiments, sound is input from the microphone and is modulated and output to a 1-bit signal by the ΔΣ modulator, but in this embodiment, the sound from the sound signal amplifier 60 of the audio device 50 is output. The audio signal is input to the ΔΣ modulation unit 61, modulated into a 1-bit signal, and output.

  The output of the ΔΣ modulation unit 61 is radiated from the infrared light emitting unit 62 to the front surface of the audio device as a signal by the infrared light 66. Reference numeral 63 denotes an infrared light receiving unit which receives a signal from the infrared light emitting unit 62. Reference numeral 64 denotes a receiving unit that performs pulse shaping from the received signal into the original 1-bit signal and outputs it. A digital amplifier 65 amplifies the signal from the receiving unit 64 and outputs the amplified signal to the bone conduction speaker. The bone conduction speakers 54 to 56 reproduce bone conduction sound based on the input 1-bit signal.

  According to this embodiment, a plurality of listeners in front of the audio device wearing the bone conduction speaker device can simultaneously listen to voice, music, and the like. Further, according to the present embodiment, even a hearing-impaired person can hear the sound and music from the audio device as a 1-bit signal that is ΔΣ-modulated efficiently and with high sound quality by the bone conduction speaker device.

  Usually, it can be expected that the space between the infrared light emitting unit 62 and the infrared light receiving unit 63 is unobstructed, and the intensity of light received by the infrared light receiving unit 63 is simply binarized and the bone conduction speaker is driven through a digital amplifier. . It is possible to avoid the deterioration of the sound quality due to the attenuation of the transmission signal and the mixing of noise, and a simple configuration that does not require a data buffer often used in digital transmission. Furthermore, a 1-bit signal has a feature that a signal transmission delay is smaller than that of a multi-bit signal having the same amount of information. When the audio device is a device that simultaneously displays an image, the movement of a person's mouth in the image Therefore, it can be suitably used as an auditory transmission system in which there is no sense of incongruity between the voice and the voice.

In the above description, the infrared ray 66 is used to transmit a signal to the listener. However, visible light or radio waves may be used instead of the infrared ray 66.

(Fourth embodiment)
FIG. 10 is a diagram showing a fourth embodiment according to the present invention. The present invention transmits a 1-bit signal to a plurality of bone conduction speaker devices using lighting in a classroom or the like.

  In FIG. 10, 1 is a microphone, 2 is an audio signal amplifier, 3 is a ΔΣ modulator, 4 is a digital amplifier, and has the same configuration as that shown in the first embodiment. An illumination device 70 is attached to the ceiling 79 of the classroom, and an LED illumination device that can transmit a pulse signal can be used. An audio signal may be input from the audio output unit of the audio device instead of the microphone 1.

  Reference numerals 71 to 72 denote circuit portions of the bone conduction speaker device, and 73 to 74 denote bone conduction speakers. 75 is a light receiving element that receives the light 78, 76 is a receiving unit that receives a signal from the light receiving element 75 and performs pulse shaping, and 77 is a digital amplifier that amplifies the signal of the receiving unit 76. Students in the classroom can wear a bone conduction speaker device and listen to bone conduction.

  The illumination device controls the intensity of light emission by a 1-bit signal Y generated by ΔΣ modulation. Normally, it can be expected that the space between the LED illumination device 70 and the light receiving unit 75 is unobstructed, and the intensity of light received by the light receiving unit 75 is simply binarized and the bone conduction speaker is driven through a digital amplifier. It is possible to avoid the deterioration of the sound quality due to the attenuation of the transmission signal and the mixing of noise, and a simple configuration that does not require a data buffer often used in digital transmission. Furthermore, the 1-bit signal has a feature that the signal transmission delay is smaller than the information of the multi-bit signal having the same information amount, and can be suitably used as an auditory transmission system that does not feel uncomfortable with the movement of the teacher's mouth in the classroom.

The intensity of light emission may be controlled by the 1-bit signal Y itself. However, as shown in FIG. 5, the 1-bit signal Y has uneven pulse widths and intervals, so that the 1-bit signal Y itself emits light. When the intensity is controlled, there may be a feeling of discomfort due to flickering of illumination due to the length of the pulse width and pulse interval.

  11 and 12 show an example of improving the flicker of illumination. First, as shown in FIG. 11, the 1-bit signal output circuit includes a signal conversion circuit 85 between the ΔΣ modulator 3 and the digital amplifier 4 in FIG. The signal conversion circuit 85 switches the clock signal CLK and an inverted signal obtained by inverting the clock signal CLK by the NOT circuit 87 by the switch 86 based on the 1-bit signal Y to obtain the signal a.

  Further, as shown in FIG. 12, the circuit unit of the bone conduction speaker device includes a waveform restoration circuit 90 between the receiving unit 76 and the digital amplifier 77 in FIG. The waveform restoration circuit 90 receives the signal b from the receiving unit 76 and obtains a signal e obtained by restoring the 1-bit signal Y. As shown in FIG. 13, the pulse generator 91 constituting the waveform restoration circuit 90 outputs a pulse signal c when the b signal after time 3T / 4 is 1 from the rising edge of the signal b. Further, the pulse generator 92 outputs the pulse signal d when the b signal after time 3T / 4 is 0 after the falling edge of the signal b. Reference numeral 93 denotes a D-type lip flop that sets the output Q to 1 when the pulse signal c is input and resets the output Q to 0 when the pulse signal d is input. A signal e in FIG. 13 indicates the output Q of the flip-flop.

  As can be seen from FIG. 13, the signal c is a pulse for detecting a portion where the pulse width (1 interval) in the signal b is wider than T / 2, and the signal d is 0 interval in the signal b from T / 2. This is a pulse for detecting a wide part. Therefore, the timing for obtaining the pulse signals c and d is not limited to the time 3T / 4 after the rise / fall of the signal b, and if the portion wider than T / 2 can be detected stably, the rise / fall of the signal b. Between T / 2 and T / 2 to T.

  In FIG. 13, Y indicates a 1-bit signal Y. The signal CLK represents a clock signal having a period T that is ½ of the sampling time of ΔΣ modulation. The signal a is switched between the signal CLK and its inverted signal by the switch 86 of the signal conversion circuit 85 so that the signal CLK is output when the 1-bit signal Y is 1 and the inverted signal of the signal CLK is output when the 1-bit signal Y is 0. Is obtained.

  If the 1-bit signal e restored in this way is amplified by the digital amplifier 77 and the bone conduction speaker 73 is driven, the bone conduction sound can be reproduced in the same manner as that driven by the 1-bit signal from ΔΣ modulation.

  At this time, the light from the LED illumination device has the same average within the time T as can be seen from the signals a and b, so that flickering of illumination can be eliminated.

  As described above in the embodiment, the transmission path between the sound source device and the bone conduction speaker device includes a coaxial cable, an optical cable, radio waves, infrared rays, illumination light, as is apparent from the description of the embodiment. Etc. can be appropriately selected.

In addition, in the above-described embodiment, the 1-bit signal is an example of ΔΣ modulation. Further, the 1-bit signal may be a modulation including the spectral component itself of the input sound and the high frequency component, and for example, a PWM signal can be applied to the present invention.

  As is clear from the description of the above embodiment, the input to the binary pulse modulation unit may be from a microphone or an audio device. Further, in the case of a microphone, the sound transmission from the sound source to the microphones 1 and 31 may be either air conduction or bone conduction. In the case of bone conduction, the microphones 1 and 31 may be bone conduction microphones. In this case, since the spectrum of the audible component of the transmitted voice is a component suitable for bone conduction, auditory transmission is more efficient.

  In the above embodiment, the microphones 1 and 31, the audio signal amplifiers 2 and 32, the ΔΣ modulators 3 and 33, the digital amplifier 4, or the transmitter 34 are separated, but the audio signal amplifier 2 , 32, ΔΣ modulators 3 and 33, digital amplifier 4 or transmitter 34 may be incorporated in microphones 1 and 31.

Further, as is clear from the description of the above embodiment, the number of bone conduction speaker devices transmitted from the sound source device may be singular or plural.

In the above embodiment, transmission is shown only in one direction, but a bidirectional auditory transmission system may be used. In that case, the transmission paths may be the same or different combinations.

  Moreover, it cannot be overemphasized that this invention can be suitably changed in the range which does not change the summary, without being limited to these.

  The present invention relates to a bone conduction hearing aid for assisting deafness, a bone conduction mobile phone that can easily hear sound even under noise, a bone conduction speaker device for listening to both air conduction and bone conduction in an English conversation class, a mask, and a helmet It can be used widely, such as a bone conduction speaker device and an audio device that are used in a state where the earphone cannot be heard by air conduction.

It is the figure which showed the structure of 1st Embodiment by this invention. It is a figure explaining the spectrum characteristic of the signal modulated by DSB modulation or the balanced modulation system. It is a figure explaining the spectrum characteristic of 1 bit signal by a delta-sigma modulation system. It is the figure which showed the principle of delta-sigma modulation system. It is the figure which showed the operation | movement of (DELTA) (Sigma) modulation system. It is the figure which showed the specific structure of the delta-sigma modulation part applied to the 1st Embodiment of this invention. It is the figure which showed the structure of 2nd Embodiment of the 1-bit signal output circuit by this invention. It is the figure which showed the structure of 2nd Embodiment of the bone-conduction speaker apparatus by this invention. It is the figure which showed the structure of 3rd Embodiment by this invention. It is the figure which showed the structure of 4th Embodiment by this invention. It is the figure which showed the detailed structure of 4th Embodiment by this invention. It is the figure which showed the detailed structure of 4th Embodiment by this invention. It is a figure explaining the operation | movement of 4th Embodiment by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 31 ... Microphone 2, 32, 60 ... Audio | voice signal amplification part 3, 33, 61 ... ΔΣ modulation part 4, 8, 39, 65, 77 ... Digital amplifier 5 ... Output terminal 6 ... Input terminals 7, 37, 64, 76, ... Receivers 9, 40, 54 to 56, 73, 74 ... Bone conduction speakers 10, 20, 21, 22 ... Adder 11 ..Integrators 12, 23 ... Quantizers 13, 24, 25 ... Sampling delay 15 ... Wired transmission line 16 ... 1-bit signal output circuit 17 ... Control of bone conduction speaker device Circuit unit 26, 27 ... Coefficient unit 34 ... Transmitting unit 35 ... Transmitting antenna 36 ... Receiving antenna 38 ... Demodulating unit 50 ... Audio devices 51-53, 71, 72 ... Bone-conduction speaker device circuit unit 62... Infrared light emitting unit 63. Light part 66 ... Infrared light 70 ... LED illumination device 78 ... Light flux 75 ... Light receiving part 79 ... Ceiling 85 ... Signal conversion circuit 86 ... Changeover switch 87 ... NOT circuit 90 ... Wave restoration circuits 91, 92 ... Pulse generator 93 ... Lip flop

Claims (9)

An auditory transmission system comprising a sound source device, a transmission path, and a speaker device that receives a signal transmitted from the sound source apparatus via the transmission path,
The sound source device includes transmission means for outputting based on a 1-bit signal modulated into a binary pulse signal in response to a digital signal obtained by sampling a sound or an acoustic signal at a predetermined period,
The auditory transmission system, wherein the speaker device includes a bone conduction speaker that is driven based on the 1-bit signal obtained by receiving an output signal of the transmitting means. The sound source device includes binary pulse modulation means,
The auditory transmission system according to claim 1, wherein the voice or acoustic signal is input from a voice output unit of an audio device. The sound source device includes binary pulse modulation means,
The auditory transmission system according to claim 1, wherein the voice or acoustic signal is input from a microphone. The auditory transmission system according to claim 1, wherein the transmission path is a wired transmission path of a coaxial cable or an optical cable. The auditory transmission system according to claim 1, wherein the transmission path is a radio transmission path using radio waves or light. The auditory transmission system according to any one of claims 1 to 3, wherein the transmission means outputs via a lighting device. The auditory transmission system according to claim 3, wherein the microphone is a bone conduction microphone. The auditory transmission system according to any one of claims 1 to 7, wherein the modulation to the 1-bit signal is a ΔΣ modulation signal. The auditory transmission system according to any one of claims 1 to 7, wherein the modulation to the 1-bit signal is a PWM modulation signal.

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