JP2011035886A - Apparatus and method for reproducing sound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound reproducing apparatus and sound reproducing method which achieve high-quality sound reproduction with a simple configuration. <P>SOLUTION: A first channel sound output signal and a second channel sound output signal output from a first output circuit and a second output circuit respectively, both of which constitute the sound reproducing apparatus, are made to be in a mutually reversed phase relation. A first sound output means and a second sound output means for outputting the sounds by receiving the sound output signals are connected to the first output circuit and the second output circuit respectively with cables that make the output sounds in a same phase relation. As for the sound reproducing method, the sound output signals of the first and second channels output respectively from the first output circuit and the second output circuit are made to be in a mutually reversed relation, while the sound output means for outputting the sounds by receiving the sound output signals are connected to the first output circuit and the second output circuit respectively with two pairs of cables, in one of which the polarity is reversed with respect to that of the other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an audio reproduction device and an audio reproduction method, and relates to a technique effective when applied to, for example, a portable audio device capable of stereo reproduction.

  Japanese Laid-Open Patent Publication No. 2006-311097 is available as an audio signal amplifying device for portable devices and a cable for connecting portable devices. This portable device audio signal amplifying apparatus is provided with a model discriminating means, and performs high-quality sound reproduction through a component according to the model of the portable device. As an audio player assembly including an MP3 player, there is JP-T-2007-523433. It has an audio player unit that receives an audio signal from an MP3 player and outputs it from a speaker.

JP 2006-311097 A Special table 2007-523433 gazette

  The portable music players such as Patent Documents 1 and 2 operate with a built-in battery. Since the internal battery has a relatively large internal impedance or a small current supply capability, the reproduced sound is deteriorated due to power supply noise or the like generated in response to the operation of the output circuit. That is, it is well known in high-grade audio devices and the like that it is effective to enhance the power supply circuit for improving the sound quality in audio devices.

  An object of the present invention is to provide an audio reproducing apparatus and an audio reproducing method that realize high-quality audio reproduction with a simple configuration. The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  One embodiment disclosed in the present application is as follows. The first channel audio output signal and the second channel audio output signal output from the first output circuit and the second output circuit constituting the audio reproduction apparatus are in opposite phase relation to each other. The first audio output means and the second audio output means for receiving the audio output signal and outputting the audio are connected to the first output circuit and the second output by a cable in which the output audio has the same phase. Connected with the circuit.

  Other embodiments disclosed in the present application are as follows. A storage circuit storing digital audio signals of the first channel and the second channel, a digital audio signal of the first channel and a second channel stored in the storage circuit, an audio signal of the first channel, and an audio of the second channel Portable having a digital / analog signal conversion circuit for converting each into a signal, and a first output circuit and a second output circuit for forming an audio output signal corresponding to the first channel audio signal and the second channel audio signal As an audio playback method of the audio player, the first channel audio output signal and the second channel audio output signal output from the first output circuit and the second output circuit are in opposite phase to each other. The first earphone and the second earphone that receive the audio output signal and output the audio are polar in one of the two pairs of cables connected to the first output circuit and the second output circuit, respectively. Is reversed from the other cable.

  The two output circuits corresponding to the two channels form audio output signals that are in opposite phases to each other, so that the load current viewed from the power supply circuit is reduced by half, and crosstalk is generated between the two channels. Therefore, the power supply circuit is substantially strengthened, and high-quality sound reproduction can be realized.

1 is a block diagram of an embodiment of a portable audio device according to the present invention. It is a block diagram of another Example of the portable audio apparatus which concerns on this invention. It is a block diagram of further another embodiment of the portable audio device according to the present invention. FIG. 6 is a waveform diagram for explaining the operation of the portable audio device according to the present invention. It is a wave form diagram for operation | movement description of the portable audio apparatus of a conventional system. It is a block diagram of further another embodiment of the portable audio device according to the present invention. It is a block diagram of another example of this invention.

  A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing an embodiment of a portable audio device according to the present invention. The portable audio device of this embodiment is divided into a digital circuit portion and an analog circuit portion. The digital circuit unit is composed of the following circuits. The memory circuit MEM stores a digital audio signal. As the storage device MEM, for example, a flash memory which is one of nonvolatile storage devices is used. The control circuit CNT includes a control device such as a microcomputer unit (MCU), for example, and performs various control operations necessary for storage / reproduction of the portable audio device. The control circuit CNT instructs the storage device MEM to write the digital audio signal DI by a control signal R / W or the like. The writing operation of the digital audio signal DI in the storage device MEM includes a rewriting operation. That is, an operation of erasing an already stored digital audio signal and writing another digital audio signal is also included.

  Similarly to the above, the control circuit CNT instructs the storage device MEM to perform a read operation, outputs a digital audio signal DO, and inputs the signal to a signal conversion circuit DAC including a digital / analog conversion circuit. The analog audio signals RS and LS for the channel are formed. When the digital audio signal (DI, DO) stored in the memory circuit MEM is a digital signal that is data-compressed like MP3 as described in Patent Documents 1 and 2, the signal conversion is performed. The circuit DAC includes a signal expansion circuit that expands the compressed digital signal DO. Then, the analog audio signals RS and LS for the right channel and the left channel are formed by the digital / analog conversion circuit. This digital / analog conversion circuit is divided into a digital circuit section and an analog circuit section.

  The analog circuit section includes preamplifiers PAR and PAL that receive the analog audio signals RS and LS for the right channel and the left channel, respectively, and output circuits PWR and PWL as power amplifiers. In the preamplifiers PAR and PAL, voltage gain control of the analog audio signals RS and LS for the right channel and the left channel input by the volume control signal VC formed by the control circuit CNT is performed.

  In this embodiment, although there is no particular limitation for high-quality sound reproduction, the left channel preamplifier PAL inverts the input analog sound signal LS in addition to the voltage gain control as described above. This is transmitted to the input of the output circuit PWL for the left channel. On the other hand, the preamplifier PAR for the right channel transmits the input analog audio signal RS to the input of the output circuit PWR for the right channel while maintaining the same phase only by controlling the voltage gain as described above. Thereby, in the output circuit PWR and the output circuit PWL, the analog audio output signals to be output are in an opposite phase relationship to each other.

  The output terminals of the output circuit PWR and the output circuit PWL are not particularly limited, but are omitted in the figure, but an earphone jack (stereo mini type), an earphone plug (stereo mini type) and a cable are omitted. To the right earphone EHR and the left earphone EHL. As described above, the analog audio output signals from the output circuits PWR and PWL are in antiphase relations, so if they are connected as in a conventional portable music player, the left and right audio outputs remain in antiphase. Stereo playback sound is not localized. Therefore, for example, in the right channel, the + side input of the earphone EHR is connected to the + side output of the output circuit PWR as in the conventional case. On the other hand, the left channel connects the negative side input of the earphone EHL to the positive side output of the output circuit PWR, contrary to the conventional case.

  That is, the earphone jack (stereo mini type) has three electrodes respectively corresponding to the tip, ring, and sleeve of the earphone plug (stereo mini type). The electrode corresponding to the chip is connected to the output terminal of the output circuit PWL for the left channel, and the electrode corresponding to the ring is connected to the output terminal of the output circuit PWR for the right channel. The electrode corresponding to the sleeve is commonly connected to the ground potential of the circuit which is the middle point between the output circuits PWL and PWR. The + side of the right earphone EHR is connected to the + side output of the output circuit PWR via the earphone plug (stereo mini type) and cable, and the − side of the right earphone EHR is shared. It is connected to the negative side (midpoint) via a cable. In the figure, ○ corresponds to the above-mentioned earphone jack and earphone plug, the symbol + attached to ○ corresponds to the above + side output, and the symbol − attached to ○ is the above-mentioned common − side ( (Midpoint).

  The − side of the left earphone EHL is connected to the + side output of the output circuit PWL via an earphone plug (stereo mini type) and a cable, and the + side of the right earphone EHR is the common − The cable is connected to the side (midpoint). As a result, the left earphone EHL that receives the analog audio output signal of the left channel whose phase has been inverted outputs the audio whose phase is inverted with respect to the analog audio output signal. Stereo playback sound corresponding to the sound source is localized. When the original sound is monaural, the reproduced sound can be correctly heard from the center. The positive side of the earphones EHR and EHL is, for example, a coil winding start side, and the negative side of the earphones EHR and EHL is a coil winding end side.

  Although not particularly limited, the preamplifiers PAR, PAL and PWR, PWL which are analog circuit portions of this embodiment are a positive voltage + V formed by the charge pump circuit CPG1 and a negative voltage -V formed by the charge pump circuit CPG2. Operate. The charge pump circuits CPG1 and CPG2 receive the clock signal CK used for the operation of the control circuit CNT, and form the positive voltage + V and the negative voltage −V as described above based on the built-in battery voltage.

  In the analog circuit section, only the output circuits PWR and PWL operate with the two positive voltages + V and −V, and the analog output sections of the preamplifiers PAR and PAL and the digital / analog conversion circuit DAC operate only with the + V. It may be. In this case, since the load current of + V becomes larger than −V, a dedicated charge pump circuit may be provided in the analog output portions of the preamplifiers PAR and PAL and the digital / analog conversion circuit DAC. In this case, since the output signals of the preamplifiers PAR and PAL are analog signals that change in the positive voltage range, the output signal is level-shifted to match the midpoint voltage of the output circuits PWR and PWL, or coupled. A capacitor may be provided to remove the output direct current components of the preamplifiers PAR and PAL. When the power supplies on the output circuit side and the preamplifier side are formed by separate charge pump circuits as described above, it is possible to prevent deterioration in sound quality due to the power supply noise due to the operation of the output circuit returning to the preamplifier side.

  In order to stabilize the power supply, the charge pump circuits CPG1 and CPG2 receive the charge pump circuit unit and the voltage formed thereby, and output the positive voltage + V and the negative voltage −V corresponding to the reference voltage, respectively. You may comprise from the stabilization voltage circuit part. That is, a voltage having an absolute value larger than the above + V or −V is formed by the charge pump circuits CPG1 and CPG2, and the + V or −V voltage is stabilized through the stabilizing voltage circuit. The same applies to the case where a dedicated charge pump circuit is provided on the preamplifier side.

  The control circuit CNT performs the various operation controls in response to a plurality of operation signals CS formed by switches or the like. When the portable music player has a display device, the control circuit CNT takes charge of the control. The control circuit CNT also performs signal processing such as classification and search for a plurality of music programs stored in the memory circuit MEM and display control for the music program stored in the memory circuit MEM using the display device.

  FIG. 2 is a block diagram showing another embodiment of the portable audio device according to the present invention. In this embodiment, buffer amplifiers are provided on the input side of the preamplifiers PAR and PAL so that the analog audio output signals output from the output circuit PWR and the output circuit PWL have an opposite phase relationship with each other. For example, the buffer amplifier BAR on the right channel side forms an RS with an output signal in phase with the input signal, and the buffer amplifier BAL on the left channel side forms an output signal / RL with a phase opposite to that of the input signal. In this way, when the two analog audio signals RS and / LS are in opposite phases on the input sides of the preamplifiers PAR and PAL, the preamplifiers PAR and PAL are controlled by the volume control signal VC formed by the control circuit CNT. Only the control of the voltage gain of the input right channel and left channel analog audio signals RS and / LS is performed. That is, the preamplifiers PAR and PAL form an output signal that is in phase with or out of phase with the input signal.

  FIG. 3 is a block diagram showing still another embodiment of the portable audio apparatus according to the present invention. In this embodiment, in the digital / analog conversion circuit DAC, analog audio signals RS and / LS are formed such that the analog audio output signals output from the output circuit PWR and the output circuit PWL are in opposite phases to each other. In this way, when the two analog audio signals RS and / LS are in opposite phases on the input sides of the preamplifiers PAR and PAL, the preamplifiers PAR and PAL are controlled by the volume control signal VC formed by the control circuit CNT. Only the control of the voltage gain of the input right channel and left channel analog audio signals RS and / LS is performed. That is, as in the embodiment of FIG. 2, the preamplifiers PAR and PAL respectively form an output signal that is in phase or opposite in phase to the input signal.

  In the analog / digital conversion circuit DAC, in which a digital audio signal having a positive cycle and a negative cycle is expressed by a sign bit and a sound signal, for example, the sign bit of the digital audio signal of the left channel stored in the memory circuit MEM is inverted. . For the left channel, a digital / analog conversion operation is performed using the sign bit thus inverted. By such digital signal processing, the analog audio signals RS and / LS are made to have an opposite phase relationship in relation to the original audio.

  FIG. 4 is a waveform diagram for explaining the operation of the portable audio device according to the present invention. In the figure, a waveform diagram of an output circuit in the case of outputting a monaural audio signal is exemplarily shown. The monaural audio signal has the same signal waveform on both the left and right channels. In the output circuit of this embodiment, since the left and right channels are in opposite phases as described above, when the right channel output circuit PWR forms the positive output voltage VR, the left channel output circuit In PWL, a negative output voltage / VL opposite to that is formed.

  In the above case, the output circuit PWR on the right channel side forms the positive output voltage VR by the voltage from the positive voltage + V formed by the charge pump circuit CPG1. When such an output voltage VR is formed, the power supply noise included in the positive voltage + V is generated due to the power supply impedance included in the charge pump circuit CPG1, and the power supply noise + nv1 is generated by inverting the output voltage VR. Although not shown in the figure because it is difficult to express in the drawing, the power supply noise + nv1 as described above causes signal distortion in the output voltage VR that is actually output as shown by the arrow indicated by the solid line. That is, since the power supply noise + nv1 is a voltage obtained by inverting the output voltage VR as described above, the substantial output voltage VR in consideration of the power supply noise + nv1 is roughly represented by a dotted line by the power supply impedance. It is changed by a route such as an arrow shown and an arrow shown by a solid line.

  At this time, the output circuit PWL on the left channel side forms the negative output voltage / VL by the voltage from the negative voltage −V formed by the charge pump circuit CPG2 different from the charge pump circuit CPG1. When such an output voltage / VL is formed, a power supply noise -nv1 is generated in the negative voltage -V by inverting the output voltage / VL due to the power supply impedance included in the charge pump circuit CPG2. The power supply noise −nv1 as described above is omitted because it is difficult to express in the drawing in the drawing, but the above-described power supply noise −nv1 causes signal distortion in the output voltage / VL that is actually output as indicated by an arrow indicated by a solid line. . That is, since the power supply noise -nv1 is a voltage obtained by inverting the output voltage / VL as described above, the substantial output voltage / VL in consideration of the power supply noise -nv1 is roughly described above. The impedance is changed by a path such as an arrow indicated by a dotted line and an arrow indicated by a solid line.

  In the next half cycle, the output circuit PWR on the right channel side forms a negative output voltage VR by the voltage from the negative voltage −V formed by the charge pump circuit CPG2. When such an output voltage VR is formed, a power supply noise -nv2 is generated in the negative voltage -V by inverting the output voltage VR due to the power supply impedance included in the charge pump circuit CPG2. As a result, the substantial output voltage VR in consideration of the power supply noise -nv2 as described above is roughly changed by a path such as an arrow indicated by a dotted line and an arrow indicated by a solid line depending on the power supply impedance.

  At this time, the output circuit PWL on the left channel side forms a positive output voltage / VL by a voltage from the positive voltage + V formed by the charge pump circuit CPG1 different from the charge pump circuit CPG2. When such an output voltage / VL is formed, a power supply noise + nv2 is generated in the positive voltage + V by inverting the output voltage / VL due to the power supply impedance included in the charge pump circuit CPG1. As a result, the substantial output voltage / VL in consideration of the noise + nv2 as described above is roughly changed by a path such as an arrow indicated by a dotted line and an arrow indicated by a solid line depending on the power source impedance.

  In the output operation as described above, since the charge pump circuit CPG1 only supplies the operating current of one output circuit PWR, the positive output voltages VR and VL are simultaneously output from the output circuits PWR and PWL. Half of it is fine. Similarly, since the charge pump circuit CPG2 only supplies the operating current of one output circuit PWL, the charge pump circuit CPG2 may be half of the case where the negative output voltages VR and VL are simultaneously output from the output circuits PWR and PWL. As a result, when viewed from the output circuits PWR and PWL, this is equivalent to doubling the power supply circuit capacity or reducing the power supply impedance by half. That is, the power supply noise + nv1, + nv2, + nv3, + nv4... And the power supply noise -nv1, -nv2, -nv3, -nv4... Are reduced to half the level when the output circuits PWR and PWL are operated in the same phase. Can do. Thereby, high-quality sound reproduction with a simple configuration can be realized by the sound reproduction apparatus and the sound reproduction method according to the present invention.

  Incidentally, FIG. 5 shows a waveform diagram for explaining the operation of the conventional portable audio apparatus. In this case as well, the waveform diagram of the output circuit when outputting a monaural audio signal in the same manner as described above is exemplarily shown. The monaural audio signal has the same signal waveform on the left and right channels as described above. In the conventional output circuit, the left and right channels are set to the same phase analog output voltages VR and VL. Therefore, when the right channel output circuit PWR forms a positive output voltage VR, the left channel output circuit PWL is also positive. Output voltage VL.

  In the above case, the output circuits PWR and PWL of both channels form the positive output voltages VR and VL by the voltage from the positive voltage + V formed by the charge pump circuit CPG1. When such output voltages VR and VL are formed, power supply noise + nv1 is generated in the positive voltage + V by inverting the output voltage VR + VL due to the power supply impedance included in the charge pump circuit CPG1. This power supply noise + nv1 is twice as large as in the case of FIG. The power supply noise + nv1 causes signal distortion in the output voltages VR and VL that are actually output as shown by the arrows shown by the solid lines. That is, since the power supply noise + nv1 is a large voltage obtained by inverting the output voltages VR and VL as described above, the substantial output voltages VR and VL in consideration of the power supply noise + nv1 are roughly described above. Depending on the power source impedance, it is greatly changed by a path such as an arrow indicated by a dotted line and an arrow indicated by a solid line. At this time, no noise is generated in the charge pump circuit CPG2 that forms the negative voltage −V because no load current flows.

  In the next half cycle, the output circuits PWR and PWL of both channels form negative output voltages VR and VL by the voltage from the negative voltage −V formed by the charge pump circuit CPG2. When the output voltages VR and VL are formed, the power supply noise -nv1 is generated in the negative voltage -V by inverting the output voltage VR + VL due to the power supply impedance included in the charge pump circuit CPG2. This power supply noise -nv1 is twice as large as in the case of FIG. The power supply noise -nv1 causes signal distortion in the output voltages VR and VL that are actually output as indicated by arrows indicated by solid lines. That is, since the power supply noise -nv1 is a large voltage obtained by inverting the output voltages VR and VL as described above, the substantial output voltages VR and VR in consideration of the power supply noise -nv1 are roughly described. Depending on the power source impedance, it is greatly changed by a path such as an arrow indicated by a dotted line and an arrow indicated by a solid line. At this time, no noise is generated in the charge pump circuit CPG1 that forms the positive voltage + V because no load current flows.

  Unlike the case of the analog audio signal, when outputting a stereo audio signal, the output voltage VR and the output voltage VL have different waveforms. For this reason, in the positive half cycle, power supply noise + nv1 is generated on the positive voltage + V side, which is a combination of the output voltages VR and VL, and in the negative half cycle, the output voltage VR and VL are on the negative voltage -V side. The power supply noise -nv1 is generated. That is, the power supply noise + nv1 and -nv1 has a waveform with a large amplitude as if the output currents of both the left and right channels are combined, and affects both the output voltages VR and VL. Accordingly, the output voltage VR on the right channel side that is actually output causes a noise component corresponding to the output voltage VL on the left channel side, that is, crosstalk, and generates distortion that is different from the original speech waveform. Similarly, in the output voltage VL on the left channel side that is actually output, a noise component corresponding to the output voltage VR on the right channel side is so-called crosstalk, and distortion that differs from the original speech waveform is generated. In other words, in the case of stereo reproduction output, not only simple signal distortion as in the case of monaural reproduction output, but crosstalk between the left and right channels occurs with each other, increasing the distortion for each original audio waveform. .

  In the embodiment of FIGS. 2 and 3, the analog audio signals of the left and right channels are in opposite phases on the front stage side of the preamplifiers PAR and PAL. It is thought that the same thing as described above also occurs in the preamplifier, and the influence of the power supply noise and the crosstalk in the preamplifiers PAR and PAL performing the amplification operation with a large voltage gain can be reduced, so that a higher quality output can be achieved. Voice can be obtained.

  FIG. 6 is a block diagram showing still another embodiment of the portable audio apparatus according to the present invention. This embodiment is a modification of the embodiment of FIG. In this embodiment, the operating voltage is, for example, a positive voltage + V formed by the charge pump circuit CPG1. In this case, the output circuits PWR and PWL form an output waveform of a positive half cycle and a negative half cycle, with + V / 2 being the midpoint voltage. Since such an output waveform includes a direct current component as described above, the output of the output circuits PWL and PWR, the earphone plug (stereo mini type), and the earphone Between the two electrodes of the jack, coupling capacitors C2 and C1 for blocking a direct current component and transmitting only an audio signal are provided. The coupling capacitors C2 and C1 need to have a large capacitance value. Therefore, in the portable music player, it is preferable that the coupling capacitors C2 and C1 are not provided in order to reduce the size or to output to a low frequency.

  In the embodiment shown in FIGS. 1 to 3, the above-described coupling capacitors C1 and C2 are not required by using the positive voltage + V and the negative voltage −V and setting 0V as the midpoint voltage. As in the embodiment of FIG. 6, even when the analog circuit section operates with one power supply voltage (for example, + V), noise similar to the waveform diagram of FIG. 4 is generated. That is, in the portable audio device that operates with one power supply voltage, the midpoint 0 shown in FIGS. 4 and 5 is + V / 2, and the negative voltage −V corresponds to 0V. By applying this, a high-quality sound output operation can be performed as described above. In this case, the noise on the power supply voltage side is determined by the power supply impedance, but the ground potential side is determined by the parasitic resistance of the ground line.

  2 and 3 can be operated by one operating voltage + V or the like as in the embodiment of FIG. In this case, of course, the coupling capacitors C1 and C2 as described above are required. The operating voltage + V does not need to be boosted by the charge pump circuit, and may be one that uses the battery voltage as it is, or one that outputs the battery voltage through the stabilization voltage circuit.

  FIG. 7 is a block diagram showing still another embodiment of the present invention. This embodiment is directed to a stationary audio apparatus called a so-called component. The component of this embodiment includes a CD player, a preamplifier, a power amplifier, and a speaker. The CD player, the preamplifier, and the power amplifier are connected to each other by a RAC audio cable. Since such an RCA audio cable is composed of a signal line and a ground line, in order to perform output voltage operations in mutually opposite phases at the output part of the power amplifier as shown in FIGS. Even if the cable is reversely connected, the signal output is short-circuited to the ground potential, and the signal polarity of either the left or right channel cannot be reversed.

  In this embodiment, a line transformer is provided between the CD player and the preamplifier. This line transformer includes a right channel transformer TR and a left channel transformer TL. The voltage gain is set to approximately unity. The line transformer separates the CD player and the preamplifier in a DC manner. High frequency noise that exceeds the voice band is cut off by using the frequency characteristics of the transformer. The line transformer is provided as an audio accessory that brings the sound reproduction from the CD player closer to the analog sound reproduction from the analog record player. Here, the preamplifier includes a preamplifier A3 for the right channel and a preamplifier A4 for the left channel. The power amplifier includes a power amplifier A5 for the right channel and a power amplifier A6 for the left channel. The speaker includes a right channel speaker SPR and a left channel speaker SPL.

  In this embodiment, since the line transformer is a transformer coupled to the CD player and the preamplifier, attention is paid to the fact that phase inversion can be easily performed by selecting the coil connection. For example, the right channel transformer TR is connected to the input side. Connect so that the output side is in phase. On the other hand, the left channel transformer TL connects the coils so that the output side is inverted with respect to the input side. Then, the output terminals Ro and Lo of the CD player are connected to the input sides of the line transformers TR and TL using the RCA audio cables L1 and L2. The output side of the line transformers TR and TL and the input side of the preamplifiers A3 and A4 are connected using RCA audio cables L3 and L4. The output side of preamplifiers A3 and A4 and the input side of power amplifiers A5 and A6 are connected using RCA audio cables L5 and L6. The output terminals of the power amplifiers A5 and A6 and the speakers SPR and SPL are connected using the speaker cables L7 and L8.

  With the above connection, in the preamplifier and the power amplifier, the audio signals of both channels are in opposite phases as described above, and the power supply enhancement and the crosstalk between the channels as described above can be prevented. In order to make the sound of both channels output from the speaker have the same phase relationship as the original sound, for example, the input polarity of the left-channel speaker SPL is reversely connected between the power amplifier A6 and the polarity of the output terminal. . That is, the positive output of the power amplifier A6 is reversely connected to the negative input of the speaker, and the negative output of the power amplifier A6 is reversely connected to the positive input of the speaker. In contrast, the + output of the right channel power amplifier A5 is reversely connected to the + input of the speaker, and the-output of the power amplifier A5 is reversely connected to the-input of the speaker. By using a line transformer in which one of the right and left transformers is reversely connected as described above and by connecting one of the right and left speakers as described above in reverse, high-quality audio can be obtained even in a component. Playback is possible. In addition to the CD player, the line transformer can also be used between an FM tuner, a conventional MP player, and the like and the preamplifier constituting the component.

  Although the invention made by the inventor has been specifically described based on the above embodiment, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above embodiment, the phase of the left channel is inverted, but the phase of the right channel may be inverted instead. Instead of the audio output means on the phase-inverted side as in the above embodiment, the connection of the audio output means on the non-phase-inverted side may be reversed. The earphone jack adopts various embodiments such as an earphone jack having four electrodes in addition to the standard stereo mini-type and a plug connected to the left and right earphones by two pairs of cables. be able to. As the sound output means, headphones can be used in addition to the earphones. In the component, a speaker serves as an audio output means. In the embodiment shown in FIGS. 1 to 3 and FIG. 6, the phase-inverted output operation is selectively performed to enable audio output using a general earphone such as a stereo mini type or a headphone. It is also possible to provide a function to be performed.

  The means or method for inverting the phase of either the left or right channel may be formed when generating a digital audio signal. Alternatively, the phase of either one of the left and right channels may be reversed when the digital sound source is stored in the storage circuit MEM. Such a storage operation can be performed by, for example, processing the digital audio signal DI by the control circuit CNT. As described above, when the left channel and the right channel of the digital audio signal DO stored and output in the memory circuit MEM are in an opposite phase relationship, at least the reproduction system circuit uses the conventional MP player itself as it is. The audio output means may output the sound by inverting the phase of one of the left and right channels as described above.

  The present invention can be widely used for an audio reproducing apparatus such as a portable audio apparatus and an audio reproducing method.

  MEM: storage device, CNT (MCU): control circuit, DAC: signal conversion circuit, PAR, PAL ... preamplifier, PWR, PWL ... output circuit, EHR, EHL ... earphone, CPG1, CPG2 ... charge pump circuit, TR, TL ... Transformer, A3, A4 ... amplifier, A5, A6 ... power amplifier, SPR, SPL ... speaker, L1-L6 ... RCA audio cable, L7, L8 ... speaker cable.

Claims (6)

A first output circuit for outputting a first channel audio output signal;
A second output circuit for outputting an audio output signal of the second channel,
The first output circuit and the second output circuit are the first channel audio output signal output from the output terminal of the first output circuit and the second channel audio output from the output terminal of the second output circuit. Operates so that the output signal is in an antiphase relationship with each other,
The first channel audio output signal and the second channel audio output signal are received and output to the first audio output means and the second audio output means for outputting the first audio and the second audio, respectively. Connecting the first sound output means and the second sound output means to the first output circuit and the second output circuit, respectively, so that the sound is in phase with each other;
Audio playback device. In claim 1,
The first output circuit and the second output circuit are mounted on a portable audio player,
The portable audio player is
A storage circuit storing the digital audio signals of the first channel and the second channel;
A digital / analog signal conversion circuit for converting the first channel and second channel digital audio signals stored in the storage circuit into the first channel audio signal and the second channel audio signal, respectively;
The first audio output means and the second audio output means are earphones,
Audio playback device. In claim 2,
The first channel is the right channel;
The second channel is the left channel,
The portable audio player is
A right channel preamplifier for amplifying a right channel audio signal transmitted to the first output circuit and a left channel preamplifier for amplifying a left channel audio signal transmitted to the second output circuit;
The right channel preamplifier and the left channel preamplifier perform an amplification operation for a volume adjustment function and an amplification operation that makes the right channel audio signal and the left channel audio signal have an antiphase relationship.
Audio playback device. In claim 2,
The first channel is the right channel;
The second channel is the left channel,
The portable audio player is
A right channel preamplifier for amplifying a right channel audio signal transmitted to the first output circuit according to a volume control signal;
A left channel preamplifier for amplifying a left channel audio signal transmitted to the second output circuit in accordance with the volume control signal;
A first amplifier for amplifying a right channel audio signal supplied to an input of the right channel preamplifier;
A second amplifier that amplifies the left channel audio signal supplied to the input of the left channel preamplifier,
The first amplifier and the second amplifier are set to the same gain, one outputs the input signal in phase, and the other inverts and outputs the input signal.
Audio playback device. In claim 2,
The first channel is the right channel;
The second channel is the left channel,
The portable audio player is
A right channel preamplifier for amplifying a right channel audio signal transmitted to the first output circuit according to a volume control signal;
A left channel preamplifier for amplifying a left channel audio signal transmitted to the second output circuit according to the volume control signal;
At the input of the digital / analog signal conversion circuit, the digital audio signals of the first channel and the second channel are in antiphase relation to each other.
Audio playback device. A storage circuit storing digital audio signals of the first channel and the second channel;
A digital / analog signal conversion circuit for converting the first channel and second channel digital audio signals stored in the memory circuit into a first channel audio signal and a second channel audio signal, respectively;
An audio reproduction method for a portable audio player having a first output circuit and a second output circuit for forming an audio output signal corresponding to the first channel audio signal and the second channel audio signal,
The first channel audio signal and the second channel audio signal input to the first output circuit and the second output circuit are oppositely phased to form the first channel audio signal and the second channel audio output signal. And
In the first earphone and the second earphone that receive the first channel sound signal and the second channel sound output signal and output sound, the first output circuit and the first output circuit so that the two sounds to be output have the same phase. The polarity of one of the two pairs of cables for connecting the second output circuit, the first earphone, and the second earphone is opposite to that of the other cable and the first earphone and the second earphone are connected.
Audio playback method.

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