JP2009065239A - Wireless headphone apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless headphone apparatus without the need of a battery. <P>SOLUTION: A coil 10 drives a speaker and generates sound on the basis of input sound signals. A power generation part 20 takes out power to be supplied to respective parts of the wireless headphone apparatus from high frequency signals guided to the coil 10 when the coil 10 receives radio waves. A sound signal generation part 30 generates sound signals from the high frequency signals guided to the coil 10 when the coil 10 receives the radio waves and supplies them to the coil 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless headphone device that wirelessly receives an audio signal such as music from an electronic device such as a mobile phone or a portable audio player and emits the sound from a speaker.

An example of this type of wireless headphone device is disclosed in Patent Document 1. The headphone device disclosed in Patent Document 1 includes a receiving device that is wirelessly connected to an audio player. The receiving device receives and demodulates music data that is digital data from the audio player, and music from a speaker. Sounds out. Since this type of wireless headphones device does not need to be connected to an audio player by a cord when used, there are few restrictions on the user's behavior and it has the advantage of being easy to use.
JP 2002-112383 A

  By the way, the conventional wireless headphone device as disclosed in Patent Document 1 needs to incorporate a battery in the headphone device as a power source for a circuit that receives an audio signal from an audio player or the like and drives a speaker. There was a problem that when it was worn out, it had to be replaced.

  The present invention has been made in view of the circumstances described above, and an object thereof is to provide a wireless headphone device that does not require a battery.

The present invention relates to a coil that generates sound by driving a speaker based on an input audio signal, and power that is supplied to each part of the wireless headphone device from a high-frequency signal that is induced in the coil when the coil receives radio waves. And a power generation unit for generating a sound signal from a high-frequency signal induced in the coil when the coil receives a radio wave and supplying the sound signal to the coil. A headphone device is provided.
Such a wireless headphone device operates with electric power obtained from radio waves received by the coil, extracts an audio signal from the radio wave received by the coil, applies it to the coil, and outputs a sound corresponding to the audio signal from the speaker. That is, it can serve as a wireless headphone device without using a battery.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a wireless audio transmission system including a wireless headphone device 1 and a portable electronic device 100 according to an embodiment of the present invention. In FIG. 1, a portable electronic device 100 is a mobile phone provided with an audio playback function such as music. In the portable electronic device 100, the audio transmission unit 101 modulates a carrier having a predetermined frequency f1 with a sample sequence (for example, a PCM sample sequence) of an audio signal to be transmitted to the wireless headphone device 1, and transmits an antenna as a transmission signal S1. 110 is a circuit that outputs to 110. The method of carrier modulation is arbitrary, but it is preferable that it does not generate noise in the voice frequency band in the transmission signal S1. The power transmission unit 102 is a circuit that outputs a power wave signal S2 that is a sine wave signal having a predetermined frequency f2 to the antenna 110. The transmission signal S1 output from the audio transmission unit 101 is superimposed on the power wave signal S2 in the antenna 110, and is radiated from the antenna 110 as a radio wave together with the power wave signal S2. The wireless headphone device 1 according to the present embodiment receives radio waves radiated from the portable electronic device 100 in this manner, and operates by acquiring power from the received radio waves.

  In a preferred embodiment, the carrier frequency f1 in the voice transmitting unit 101 is about 5 MHz. The frequency of the power wave signal S2 is about 500 kHz to 1 MHz. The power wave signal S2 is set to such a frequency f2 so long as the power wave is maintained at a sufficient frequency even when the wireless headphone device 1 is at a distance of about 1 to 5 m. This is because the signal S2 can reach the wireless headphone device 1.

  Various modes of transmission of the power wave signal S2 are conceivable, and two examples are shown in FIG. The first mode is a mode in which the power wave signal S2 is continuously transmitted regardless of the presence or absence of the transmission signal S1, as shown in FIG. In this aspect, for example, an audio signal such as music is reproduced in the portable electronic device 100, and the operation of transmitting a sample sequence of the audio signal as the transmission signal S1 to the wireless headphone device 1 is continued for a relatively long time. Suitable for the case. In the second mode, as shown in FIG. 1B, transmission of the power wave signal S2 is started a predetermined time before transmission of the transmission signal S1, and transmission of the power wave signal S2 is completed after transmission of the transmission signal S1 is completed. Is a mode of ending. This mode is relatively short, for example, when the portable electronic device 100, which is a mobile phone, receives an incoming call and sends the ringtone or a single buzzer sound instead thereof to the wireless headphone device 1 as the transmission signal S1 for playback. This is suitable for the case where an audio signal generated once in a continuous time is sent to the wireless headphone device 1. In any aspect, the transmission of the power wave signal S2 is started a predetermined time before the transmission start of the transmission signal S1. This is because the wireless headphone device 1 receives the power wave signal S2, acquires power from the received signal, and after the transmission signal S1 is received and reproduced as sound, the transmission signal S1 is This is so that the wireless headphone device 1 can receive the data.

  The wireless headphone device 1 includes a left ear portion 1L that provides sound to the user's left ear and a right ear portion 1R that provides sound to the user's right ear, as in a normal headphone device. FIG. 1 is a block diagram showing an electrical configuration of a circuit mounted in the left ear portion 1L of the wireless headphone device 1. As shown in FIG. Although not shown, a circuit having the same configuration as that shown in FIG. 1 is also incorporated in the right ear 1R.

  In FIG. 1, a coil 10 is a coil that drives a speaker (not shown) of the left ear 1L based on an input audio signal. The coil 10 in this embodiment has a role of receiving the transmission signal S1 and the power wave signal S2 radiated as radio waves from the portable electronic device 100 in addition to the role as a normal speaker driving coil. Fulfill.

  The power generation unit 20 is a circuit that extracts power to be supplied to each part in the left ear 1L from a high-frequency signal induced in the coil 10 when the coil 10 receives radio waves. Specifically, the power generation unit 20 rectifies a high-frequency signal induced in the coil 10 and converts it into a DC voltage with pulsation, and a pulsating component of the DC voltage obtained from the rectifier 21. A smoothing capacitor 22 and a regulator 23 that stabilizes the DC voltage smoothed by the capacitor 22 and supplies it as a power supply voltage to each part in the left ear 1L.

  The audio signal generation unit 30 is a circuit that operates by receiving a power supply voltage from the power generation unit 20. The audio signal generation unit 30 generates an audio signal from a high-frequency signal that is induced in the coil 10 when the coil 10 receives a radio wave to generate a coil. 10 is a circuit to be supplied. Specifically, the audio signal generation unit 30 includes an HPF (High Pass Filter) 31, a demodulator 32, and a D / A converter 33.

  Here, the HPF 31 is a filter that passes a signal in a higher frequency range than the audio frequency band among the high frequency signals induced in the coil 10. The HPF 31 only needs to pass the transmission signal S <b> 1 modulated by the audio signal among the signals received from the portable electronic device 100. Therefore, as in the present embodiment, when the frequency band of the transmission signal S1 modulated by the audio signal is higher than the audio frequency band (<20 kHz), the cutoff frequency of the HPF 31 is set to the lower limit of the frequency band of the transmission signal S1. The frequency may be slightly lower than the frequency.

  The demodulator 32 is a circuit that demodulates a signal that has passed through the HPF 31 and outputs a sample of an audio signal used for carrier modulation. Note that when the audio transmission unit 101 of the portable electronic device 100 modulates and outputs a carrier with a sample of a stereo audio signal composed of two channels, L and R, the demodulator 32 of the left ear unit 1L is connected to the HPF 31. The sample of the L channel audio signal is extracted from the output signal and output, and the demodulator 32 in the right ear 1R extracts the sample of the R channel audio signal from the output signal of the HPF 31 and outputs the sample.

  The D / A converter 33 converts the sample sequence (digital audio signal) of the audio signal output from the demodulator 32 into an analog audio signal in the audio frequency band, and provides it to the coil 10 as an input audio signal.

In a preferred embodiment, among the circuits described above, the power generation unit 20 and the audio signal generation unit 30 are one IC (Integrated).
Circuit) formed on the chip and built in the left ear 1L or the right ear 1R.

  According to the above configuration, when the power wave signal S <b> 2 from the portable electronic device 100 is transmitted, the wireless headphone device 1 receives the power wave signal S <b> 2 by the coil 10. In the wireless headphone device 1, a power supply voltage is extracted from the high-frequency signal (in this case, corresponding to the power wave signal S <b> 2) induced in the coil 10 by the power generation unit 20, and is supplied to each part in the wireless headphone device 1. Supplied. Thus, when receiving power supply from the portable electronic device 100 via the coil 10, the wireless headphone device 1 is about 10 mW necessary for operation even when the wireless headphone device 1 is at a distance of 1 to 5 m from the portable electronic device 100. Can be obtained.

In the portable electronic device 100, after a predetermined time or more has elapsed from the start of transmission of the power wave signal S2, the transmission signal S1 modulated by the audio signal is transmitted. In the wireless headphone device 1, when the transmission signal S 1 modulated by the audio signal is received by the coil 10, the transmission signal S 1 passes through the HPF 31 and is given to the demodulator 32. In the demodulator 32, a sample sequence of the audio signal is extracted from the transmission signal S1, and this audio signal sample sequence is converted into an analog audio signal in the audio frequency band by the D / A converter 33, and input to the coil 10 as an input audio signal. Given. The coil 10 drives the movable part of the speaker based on the input audio signal, and outputs the input audio signal as sound. Here, since the input audio signal applied to the coil 10 is a signal in the audio frequency band, the HPF 31 prevents passage to the demodulator 32 side. Therefore, the operation of the audio signal generation unit 30 is not hindered by the input audio signal to the coil 10.
As described above, according to the present embodiment, the wireless headphone device 1 that does not require a battery is realized.

  Although one embodiment of the present invention has been described above, the present invention may have other embodiments. For example:

(1) In the above embodiment, the power transmission unit 102 that transmits the power wave signal S2 is provided in the portable electronic device 100 prior to transmission of the transmission signal S1 modulated by the audio signal. However, when the head portion of the audio signal transmitted from the portable electronic device 100 does not have to be normally received and reproduced by the wireless headphone device 1, the power transmission unit 102 is connected to the portable electronic device 100. There is no need to provide it. This is because in this case, in the wireless headphone device 1, power is acquired from the transmission signal S <b> 1 transmitted by the audio transmission unit 101 by the power generation unit 20 and supplied to each unit.

(2) An error correction technique may be applied to transmission of an audio signal between the portable electronic device 100 and the wireless headphone device 1. That is, the audio transmission unit 101 of the portable electronic device 100 performs error correction coding on the digital audio signal to be transmitted and uses it for carrier modulation, and the demodulator 32 of the wireless headphone device 1 demodulates the output signal from the HPF 31. The digital signal is subjected to error correction decoding processing and a digital audio signal is output. According to this aspect, there is an advantage that high-quality audio transmission is possible.

(3) In the above embodiment, the transmission signal S1 modulated by the digital audio signal is transmitted from the portable electronic device 100 to the wireless headphone device 1. However, the transmission signal S1 modulated by the analog audio signal may be transmitted from the portable electronic device 100 to the wireless headphone device 1. In this aspect, the D / A converter 33 in the audio signal generation unit 30 is not necessary.

1 is a diagram illustrating a configuration of a wireless audio transmission system including a wireless headphone device 1 and a portable electronic device 100 according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wireless headphone apparatus, 1L ... Left ear part, 1R ... Right ear part, 100 ... Portable electronic device, 10 ... Coil, 20 ... Electric power generation part, 21 ... Rectifier, 22 ... Capacitor , 23... Regulator, 30... Audio signal generator, 31... HPF, 32.

Claims (3)

A coil that generates sound by driving a speaker based on an input audio signal;
Power generating means for extracting power to be supplied to each part of the wireless headphone device from a high-frequency signal induced in the coil when the coil receives radio waves;
A wireless headphone device comprising: audio signal generating means for generating an audio signal from a high-frequency signal induced in the coil when the coil receives radio waves and supplying the audio signal to the coil.   The audio signal generation means has a high-pass filter connected to the coil, and generates an audio signal by demodulating a signal that has passed through the high-pass filter among high-frequency signals induced in the coil, The wireless headphone device according to claim 1, wherein a pass band of the high pal filter is in a frequency band higher than an audio frequency band. The wireless headphone device according to claim 1, wherein the power generation unit includes a rectifier that rectifies a high-frequency signal induced in the coil and generates power to be supplied to each unit of the wireless headphone device.

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