JP4439383B2 - Wireless communication system - Google Patents

Description

  The present invention relates to a wireless communication system that wirelessly transmits a signal from a transmitting device to a receiving device (for example, a wireless audio system that wirelessly transmits an audio signal from an audio reproducing device to a wireless headphone or a wireless speaker).

  In recent years, with the spread of wireless local area networks (LAN), Bluetooth devices, microwave ovens, and the like, a large number of radio waves are flying in the same frequency band indoors. For this reason, when a wireless communication system is used in such an indoor environment, mutual interference with radio waves radiated from other electronic devices and reflection / absorption of radio waves by the ceiling, roof, surrounding metal parts, etc. As a result, normal wireless communication may not be performed.

  Therefore, a conventional wireless communication system is generally configured to be able to divide a specific frequency band assigned to each system into a plurality of channels and appropriately change the transmission / reception frequency.

  Also, in a conventional wireless communication system, a diversity antenna system (antenna) in which a plurality of receiving antennas are provided on the receiving device side and a reception error occurs due to the influence of an external signal or the like, switching to another receiving antenna and continuing reception. In many cases, the switching method was adopted.

  In addition, the result of having investigated the example by the past gazette regarding another radio | wireless communications system is as follows.

  Patent Document 1 discloses and proposes a connection control method in mobile communication. In the wireless communication system, a wireless device that has generated a communication request is configured to transmit that a certain wireless channel is used prior to the start of the communication. On the other hand, other wireless devices that are already communicating using the wireless channel compare the reception level from the communication partner of the local station with the reception level from the wireless device that generated the communication request, and the ratio between the two is When it is below a certain value, a notification signal to that effect is sent. The wireless device that has generated the communication request starts communication on the wireless channel only when the notification signal is not received from another wireless device, and selects another wireless channel when the wireless signal is received. It is said that.

  Patent Document 2 discloses and proposes a radio selective call receiver and a radio frequency channel search method thereof. In the wireless communication system, the receiving apparatus includes electric field detecting means for detecting the received electric field strength of the receiving channel, and receiving channel control means for controlling the search of the radio frequency channel and determining the target receiving channel. The reception channel control means is configured to immediately switch to the next reception channel when the reception electric field strength does not exceed a certain level.

Patent Document 3 discloses and proposes an antenna diversity receiver that receives spread spectrum signals with two receiving antennas and despreads and combines multipath signals with the same despreading timing. The antenna diversity receiving apparatus obtains a channel estimation value of each path, calculates a conversion coefficient that eliminates the correlation of interference signals between both antennas based on the channel estimation value, and converts the despread signal into the converted signal It is configured to include means for multiplying by a coefficient to convert to a signal having no correlation of the interference signal, and means for synthesizing the converted signal to a signal having no correlation of the interference signal.
JP-A-2-192330 JP-A-6-244777 JP 2002-198879 A

  Certainly, in the case of a conventional wireless communication system in which the transmission / reception frequency and the reception antenna can be appropriately changed, even if the wireless communication using a certain transmission / reception frequency or reception antenna is bad, By changing, it is possible to avoid the interference frequency and obtain a better reception state.

  However, in the conventional wireless communication system, when setting the transmission / reception frequency, the user must manually and sequentially switch both the transmission frequency of the transmission device and the reception frequency of the reception device. There was a problem that it was very complicated.

  In addition, the reception state of the wireless communication system may fluctuate only when a person approaches the transmitter or receiver, and when the diversity antenna system is adopted on the receiver side, the switching state of the antenna Since the reception state fluctuates depending on the condition, the setting operation further takes time.

  Further, in the conventional wireless communication system, when setting the transmission / reception frequency, the user compares and determines each reception state (for example, the quality of the received video and the received audio) at the transmission / reception frequency that is sequentially switched, with his / her own eyes and ears. When the user completes the transmission / reception frequency setting operation simply because it is difficult to give subtle superiority or inferiority in the reception state, and the reception state after change happens to be better than the reception state by chance. There is also a problem that it is not always possible to set a transmission / reception frequency at which the best reception state can be obtained.

  In particular, in recent wireless audio systems, abnormal sounds such as noises are easily generated due to high output of a power amplifier connected to a receiving device and high S / N of the system, and the above-described problems have become prominent.

  Note that the prior art disclosed in Patent Document 1 is merely a technique for eliminating co-channel interference that is a problem in a distributed control type radio communication system (such as a multi-channel cordless telephone), and can solve the above problems. It wasn't.

  In addition, the prior art of Patent Document 2 is based on the premise that a desired radio signal is transmitted in parallel at a plurality of transmission frequencies, and if the reception state at a certain reception frequency becomes poor, the reception device The search operation is automatically started, and when the reception frequency at which radio signals can be received normally is found, the search operation is only completed, and the search time for the reception frequency can be shortened. However, the above problem could not be solved.

  The prior art in Patent Document 3 is a technology related to an antenna diversity receiver that performs multipath combining in a mobile radio communication terminal device using a spread spectrum method, and considers the correlation of interference components between antennas. However, this is merely a technique for maximizing the ratio of signal power to interference power and cannot solve the above problem.

  In view of the above problems, an object of the present invention is to provide a wireless communication system capable of optimizing the transmission / reception frequency without requiring a complicated operation.

In order to achieve the above object, a wireless communication system according to the present invention extracts a broadcast receiving antenna for detecting a radio wave in the first frequency band and a signal component corresponding to the reception frequency of the apparatus from the detected radio wave. A broadcast receiving unit, an audio signal processing unit that receives an input of a surround signal and separates it into a plurality of analog audio signals, and an analog / digital conversion unit that converts at least one of the separated analog audio signals into a digital audio signal; A modulation signal generation unit that generates a modulation signal based on the digital audio signal, a digital transmission unit that modulates a carrier wave based on the modulation signal, and a modulated signal obtained by the modulation process at a second frequency Digital transmission antenna that emits to the space as radio waves in the band and variably controls the transmission frequency of the device A frequency control unit; a digital reception antenna that detects radio waves in the second frequency band; and a digital reception unit that extracts signal components according to the reception frequency of the device from the detected radio waves A demodulator that demodulates the digital audio signal from the extracted signal components, a digital / analog converter that converts the demodulated digital audio signal into the analog audio signal, and frequency control that variably controls the reception frequency of the device And a reception device comprising: a reception device comprising: a reception status data signal indicating a reception status of the demodulated digital audio signal as a radio wave in the first frequency band. Means for emitting to space, wherein the transmitter is a digital radio for the receiver Changing means for changing the transmission frequency of the device based on the received status data signal obtained by the broadcast receiving unit in signal, the reception frequency of the device when the received status data signal normally at the broadcast receiving unit can not be obtained And means for carrying out the above.

  By adopting such a configuration, it is possible to optimize the transmission / reception frequency used for digital wireless communication without requiring complicated operations, and to perform good digital wireless communication with less interference, that is, distortion and It becomes possible to perform high-quality sound reproduction with less noise. In addition, since the wireless communication system according to the present invention is configured to perform two-way communication using an existing broadcast receiving unit without newly installing a receiving unit in the transmission apparatus, a large-scale system modification (of a digital communication system) No increase in the number of parts and an increase in cost can be minimized.

In addition, with such a configuration, it is possible to optimize the transmission / reception frequency used for the communication of the reception status data signal without requiring a complicated operation, and the communication of the good reception status data signal with less interference In other words, it is possible to appropriately perform the transmission / reception frequency optimization process based on the reception status data signal.

In the wireless communication system configured as described above, the transmission device superimposes a first data signal indicating the changed transmission frequency on the modulated signal currently being transmitted before changing the transmission frequency of the device. The reception apparatus includes means for matching the reception frequency of the apparatus with the changed transmission frequency indicated by the first data signal if the demodulation result in the demodulation unit includes the first data signal. It is good to have a configuration comprising. By adopting such a configuration, it is possible to automatically optimize the transmission / reception frequency used for digital wireless communication, so the time required for the optimization process can be shortened and the operation burden on the user can be reduced. It becomes.

  Further, in the wireless communication system having the above-described configuration, the transmission device superimposes a second data signal indicating the changed reception frequency on the modulated signal currently being transmitted prior to changing the reception frequency of the device. And the receiving device includes means for matching the transmission frequency of the device with the changed receiving frequency indicated by the second data signal if the second data signal is included in the demodulation result of the demodulator. It is good to have a configuration comprising. By adopting such a configuration, it is possible to automatically optimize the transmission / reception frequency used for communication of the reception status data signal, so that it is possible to reduce the required time and reduce the operation burden on the user. .

  In the wireless communication system having the above-described configuration, the receiving apparatus includes a plurality of the digital receiving antennas, a means for sequentially selecting them, and a third data signal included in a demodulation result of the demodulating unit. Means for selecting a digital reception antenna indicated by the third data signal, and the transmission device receives a reception status obtained by the broadcast reception unit each time the digital reception antenna is sequentially selected. It may be configured to have means for superimposing a third data signal indicating a digital receiving antenna to be selected on the modulated signal currently being transmitted based on the data signal. By adopting such a configuration, it is possible to automatically perform optimum selection of the digital receiving antenna in conjunction with the optimization of the transmission / reception frequency used for digital wireless communication, so that even higher quality audio reproduction can be performed. It becomes.

  As described above, the radio communication system according to the present invention can optimize the transmission / reception frequency without requiring a complicated operation.

  Hereinafter, an embodiment of the present invention will be described in detail by taking as an example a case where the present invention is applied to a wireless audio system that wirelessly transmits an audio signal from an audio playback device to a wireless speaker.

  First, a first embodiment of a wireless audio system according to the present invention will be described in detail with reference to FIG. FIG. 1 is a block diagram showing a first embodiment of a wireless audio system according to the present invention.

  As shown in the figure, the wireless audio system of the present embodiment is constructed from an audio playback apparatus A that functions as an audio signal transmission apparatus and a wireless speaker B that functions as an audio signal reception apparatus. With such a wireless audio system, it is not necessary to consider the wiring between devices, and the degree of freedom of the layout can be increased.

  The audio reproduction apparatus A includes an FM [Frequency Modulation] broadcast receiving antenna A1, an FM broadcast receiving unit A2, an audio signal processing unit A3, a front speaker unit A4, and an analog / digital conversion unit A5 (hereinafter referred to as A / D [ Analog / Digital] conversion unit A5), modulation signal generation unit A6, digital transmission unit A7, digital transmission antenna A8, frequency control unit A9, central processing unit A10, and embedded signal generation unit A11 And an operation unit A12 and a display unit A13. Although not explicitly shown in the figure, transmission efficiency can be improved by adopting a configuration in which digital audio signals are compressed and wireless transmission is performed. However, when this configuration is adopted, it is necessary to perform a predetermined expansion process on the compressed signal demodulated on the wireless speaker B side.

  The FM broadcast receiving antenna A1 is means for detecting FM broadcast radio waves in the VHF [Very High Frequency] band (30 to 300 [MHz]).

  The FM broadcast receiving unit A2 is a tuner unit that generates a desired analog audio signal by extracting a signal component corresponding to the reception frequency of the apparatus from the FM broadcast radio wave detected by the FM broadcast receiving antenna A1.

  The audio signal processing unit A3 receives a surround signal (such as a 5.1CH surround signal) and separates it into a plurality of analog audio signals. The surround speaker means (front [L, C, R], rear [ L / R], subwoofer, etc.). The audio signal processing unit A3 also performs distribution and transmission control for the analog audio signal input from the FM broadcast receiving unit A2.

  The front speaker unit A4 is means for outputting an analog audio signal input from the audio signal processing unit A3 as audio. Although not explicitly shown in the figure, an amplifier for amplifying the analog audio signal with a predetermined gain is provided at the input stage of the front speaker unit A4.

  The A / D converter A5 outputs at least one of the analog audio signals separated by the audio signal processing unit A3 (in this embodiment, a rear system analog audio signal to be wirelessly transmitted to the wireless speaker B) by PCM [Pulse Code Modulation]. ] Means for converting into a digital audio signal by conversion.

  The modulation signal generation unit A6 is means for generating a modulation signal (a serial block data group shown in FIG. 5) based on the digital audio signal and an embedded signal described later.

  The digital transmitter A7 is an oscillating unit that performs a carrier wave modulation process based on the modulated signal.

  The digital transmission antenna A8 is a means for emitting the modulated signal obtained by the digital transmission unit A7 to the space as a radio wave in the ISM [Industry Science Medical] band (2.4 [GHz]), and whether or not there is directivity Does not matter.

  The frequency control unit A9 is means for variably controlling the transmission frequency of the audio reproduction device A (the carrier wave oscillation frequency in the digital transmission unit A7).

  The central processing unit A10 has functions for performing overall control of transmission frequency change signal generation control, input monitoring control of the operation unit A12, display control of the display unit A13, and the like, as will be described in detail later. It also has a monitoring function of a reception status data signal obtained by the FM broadcast receiving unit A2 during digital wireless transmission to the wireless speaker B, and an embedded signal generation control function in the embedded signal generating unit A11. Note that the above transmission frequency change signal is a control in which a specific frequency band assigned to each system is divided into a plurality of channels, and the frequency control unit A9 is instructed to change the transmission frequency in order to appropriately change the transmission / reception frequency. It is a signal.

  The embedded signal generation unit A11 is means for controlling generation of an embedded signal based on an instruction from the central processing unit A10. The embedded signal is a data signal superimposed on the modulated signal currently being transmitted to transmit various commands to the wireless speaker B, and is input to the modulation signal generation unit A6 together with the digital audio signal. Is done. In the audio playback device A of the present embodiment, as will be described in detail later, prior to changing the transmission frequency of the device, the first data signal indicating the changed transmission frequency is generated as an embedded signal. The

  The operation unit A12 is a user interface that accepts various operations, and includes a transmission / reception frequency change button that is pressed when changing the transmission / reception frequency of the system, in addition to keys and buttons that are pressed during general operations. It consists of

  The display unit A13 is a means for visually informing the operation state of the apparatus (for example, the currently set transmission frequency), and a liquid crystal display, an LED (Light Emitting Diode), or the like can be used.

  On the other hand, the wireless speaker B includes a digital reception antenna B1, a digital reception unit B2, a demodulation unit B3, a digital / analog conversion unit B4 (hereinafter referred to as D / A [Digital / Analog] conversion unit B4), and a rear speaker. Unit B5, frequency control unit B6, error detection unit B7, error counter unit B8, central processing unit B9, reception status data signal generation unit B10, FM transmission unit B11, FM transmission antenna B12, Display portion B13.

  The digital receiving antenna B1 is a means for detecting the radio wave emitted from the digital transmitting antenna A8 of the audio reproduction apparatus A, and it does not matter whether or not there is directivity.

  The digital reception unit B2 is a means for extracting a signal component corresponding to the reception frequency of the wireless speaker B from the radio wave detected by the digital reception antenna unit B1.

  The demodulator B3 demodulates the digital audio signal and the embedded signal from the signal component extracted by the digital receiver B2.

  The D / A converter B4 is means for converting the digital audio signal demodulated by the demodulator B3 into an analog audio signal.

  The rear speaker unit B5 is means for outputting the analog audio signal input from the D / A conversion unit B4. Although not clearly shown in the figure, an amplifier that amplifies the analog audio signal with a predetermined gain is provided at the input stage of the rear speaker unit B5.

  The frequency control unit B6 is means for performing tuning control of the digital reception unit B2 based on the reception frequency of the wireless speaker B determined according to a reception frequency change signal described later.

  The error detection unit B7 is a means for detecting whether or not the digital audio signal obtained by the demodulation unit B3 is a regular signal (that is, whether or not data abnormality has occurred), and detects the occurrence of data abnormality. If so, an error signal indicating that is generated and sent to the error counter B8.

  Although not clearly shown in FIG. 1, the error signal is also sent to the D / A converter B4, and the D / A converter B4 determines whether the error signal is input based on whether or not the error signal is input. It is determined whether an error has occurred in the digital audio signal obtained in B3. When the D / A conversion unit B4 determines that an error has occurred in the digital audio signal, the analog audio signal that is the output of the D / A conversion unit B4 performs a mute process (in order to suppress occurrence of abnormal sound in the rear speaker unit B5). Mute). In addition, since the error detection unit B7 transmits an error signal even when the wireless speaker B receives only static noise (that is, no signal state), the D / A conversion unit B4 transmits a signal from the audio reproduction device A. The above mute process is also performed when the transmission is stopped or when the transmission frequency and the reception frequency do not match.

  The error counter unit B8 is means for counting the number of error occurrences (error amount) per predetermined time in the digital audio signal obtained by the demodulation unit B3 by monitoring the error signal input from the error detection unit B7.

  The central processing unit B9 has a function as a general control means for controlling the entire wireless speaker B, a detection function of an embedded signal (first data signal), and a reception frequency change signal based on the embedded signal. It has a generation control function. The reception frequency change signal is a control signal for instructing the frequency control unit B6 to change the reception frequency so that the reception frequency of the wireless speaker B matches the transmission frequency of the audio reproduction device A. In addition to the above functions, the central processing unit B9 includes a reception status data signal generation control function in the reception status data signal generation unit B10.

  The reception status data signal generation unit B10 is means for generating the reception status data signal based on the error amount obtained by the error counter unit B8. The reception status data signal is a signal indicating the reception status (error amount) of the demodulated digital audio signal.

  The FM transmitter B11 is an oscillating unit that performs FM modulation processing of a carrier wave based on the reception status data signal.

  The FM transmission antenna B12 is means for emitting the modulated wave obtained by the FM transmission unit B11 to the space as an FM radio wave in the VHF band.

  The display unit B13 is a means for visually informing the operation state of the apparatus (for example, a currently set transmission frequency), and a liquid crystal display, an LED, or the like can be used.

  The digital transmission / reception frequency changing operation of the wireless audio system configured as described above will be described in detail.

  When the transmission frequency change button of the operation unit A12 is pressed in the audio playback device A, the central processing unit A10, prior to the transmission frequency change instruction, that is, the transmission of the transmission frequency change signal to the frequency control unit A9, An instruction is sent to the embedded signal generator A11 to generate an embedded signal (first data signal) indicating the changed transmission frequency. Receiving the instruction, the embedded signal generation unit A11 generates an embedded signal indicating the changed transmission frequency, and sends the embedded signal to the modulation signal generation unit A6. That is, in the audio reproduction device A of the present embodiment, the embedded signal indicating the change content is wirelessly transmitted to the wireless speaker B prior to the change of the transmission frequency. The central processing unit A10 changes the transmission frequency when a predetermined standby time (time required for changing the reception frequency of the wireless speaker B) has elapsed since the generation of the embedded signal was instructed. Is transmitted to the frequency control unit A9.

  On the other hand, in the wireless speaker B, the central processing unit B9 constantly monitors whether or not the embedded signal (first data signal) is included in the demodulation result obtained by the demodulating unit B3. If the reception frequency change signal is included, a reception frequency change signal is generated to the frequency control unit B6 so that the reception frequency of the wireless speaker B matches the transmission frequency after the change of the audio reproduction device A indicated by the embedded signal. Send it out.

  That is, in the wireless speaker B of the present embodiment, when the transmission frequency change operation is performed on the audio reproduction device A side, the reception frequency automatically matches the transmission frequency after the change of the audio reproduction device A. Accordingly, the wireless communication between both apparatuses A and B continues normally without being interrupted even after the transmission frequency of the audio reproducing apparatus A is changed.

  In addition, when the transmission / reception frequency change button of the operation unit A12 is pressed again, the transmission frequency of the audio reproduction device A is changed to another transmission frequency or the original transmission frequency. In the audio reproduction apparatus A and the wireless speaker B, the same signal processing as described above is performed.

  After the transmission / reception frequency of the system is changed by the above operation, the central processing unit B9 of the wireless speaker B receives the digital audio signal demodulated under the changed frequency condition based on the output of the error counter unit B8. (Error amount) is detected, and an instruction is sent to the reception status data signal generation unit B10 to generate a reception status data signal indicating the detection result. As a result, the reception status data signal is emitted into the space as an FM radio wave from the FM transmission antenna B12, and the FM radio wave is detected by the FM reception antenna A1 of the audio reproduction device A.

  On the other hand, the central processing unit A10 of the audio playback device A has a monitoring function of the reception status data signal obtained by the FM broadcast receiving unit A2, as described above, and is obtained during digital wireless transmission to the wireless speaker B. Based on the reception status data signal, the transmission frequency of the audio reproduction device A is variably controlled.

  More specifically, when it is determined that no reception error has occurred in the wireless speaker B based on the reception status data signal obtained by the FM broadcast receiving unit A2, the central processing unit A10 The transmission frequency of is fixed to the current value. As a result, the system is shifted to the stable mode. On the other hand, when it is determined that a reception error has occurred in the wireless speaker B, the central processing unit A10 indicates the transmission frequency after re-change in the same manner as described above in order to change the transmission / reception frequency of the system again. The embedded signal is sent to the wireless speaker B, and its own transmission frequency is changed again. On the wireless speaker B side as well, the reception status (error amount) is re-detected as described above, and a reception status data signal indicating the detection result is retransmitted. By repeating such bidirectional communication, transmission / reception signal optimization processing that does not cause a reception error proceeds, and finally a stable communication network is completed.

  As described above, in the wireless audio system of the present embodiment, the wireless speaker B has means (B7 to B12) for emitting a reception status data signal indicating the reception status of the demodulated digital audio signal to the space as FM radio waves. Thus, the audio reproduction apparatus A has means (A9, A10) for changing the transmission frequency of the apparatus based on the reception status data signal obtained by the FM broadcast receiving unit A2 during digital radio transmission to the wireless speaker B. It is set as the composition which consists of.

  By adopting such a configuration, it is possible to optimize the transmission / reception frequency used for digital wireless communication without requiring complicated operations, and to perform good digital wireless communication with less interference, that is, distortion and It becomes possible to perform high-quality sound reproduction with less noise. In addition, the wireless audio system according to the present invention is configured to perform bidirectional communication using the existing FM broadcast receiving unit A2 without newly installing a receiving unit in the audio playback device A. No additional digital communication system is required, and the increase in the number of parts and the increase in cost can be minimized.

  Also, in the wireless audio system of the present embodiment, the audio playback device A superimposes the first data signal indicating the changed transmission frequency on the modulated signal currently being transmitted prior to changing the transmission frequency of the device. (A10, A11), and the wireless speaker B, if the first data signal is included in the demodulation result in the demodulator B3, indicates the transmission frequency after the change that indicates the reception frequency of the device. It has the structure which has means (B6, B9) to match. By adopting such a configuration, it is possible to automatically optimize the transmission / reception frequency used for digital wireless communication, so the time required for the optimization process can be shortened and the operation burden on the user can be reduced. It becomes.

  In the above embodiment, prior to changing the transmission frequency of the audio playback device A, the description has been given by taking as an example a configuration that teaches the changed transmission frequency to the wireless speaker B side using an embedded signal. However, the configuration of the present invention is not limited to this. For example, the audio playback apparatus A is configured to generate an embedded signal that teaches the change timing in addition to the changed transmission frequency, and is a wireless speaker. About B, it is good also as a structure which changes own receiving frequency according to the change timing of the transmission frequency shown by an embedded signal. By adopting such a configuration, the transmission / reception frequency change timing can be controlled with higher accuracy, so that the wireless communication between the devices A and B is interrupted, and the accompanying noise generation of the wireless speaker B is caused. It is possible to prevent as much as possible.

  Next, a second embodiment of the wireless audio system according to the present invention will be described in detail with reference to FIG. FIG. 2 is a block diagram showing a second embodiment of the wireless audio system according to the present invention. As can be seen from the figure, the wireless audio system of the present embodiment has a configuration substantially similar to that of the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof will be omitted. Hereinafter, description will be given with emphasis on the characteristic portions of the present embodiment. .

  First, as a characteristic part on the audio playback device A side, the central processing unit A10 has the above-described functions, and during the digital radio transmission to the wireless speaker B, the FM broadcast receiving unit A2 receives a normal reception status data signal. The function as means for changing the FM reception frequency of the audio playback device A when it cannot be obtained, or the FM reception frequency after changing to the modulated signal currently being transmitted prior to changing the FM reception frequency of the audio playback device A The function as a means to superimpose the 2nd data signal which showed is newly provided. The embedded signal generator A11 has a function of generating the second data signal as an embedded signal in addition to the first data signal described in the previous embodiment, based on an instruction from the central processing unit A10. I have.

  On the other hand, as a characteristic part on the wireless speaker B side, the central processing unit B9 has the above-described functions, and if the second data signal is included in the demodulation result in the demodulation unit B3, the FM of the wireless speaker B A function is newly provided as means for matching the transmission frequency to the FM reception frequency after the change of the audio reproduction apparatus A indicated by the second data signal.

  The FM transmission / reception frequency changing operation of the wireless audio system configured as described above will be described in detail.

  During digital wireless transmission to the wireless speaker B, the central processing unit A10 of the audio playback device A monitors the reception status data signal obtained by the FM broadcast reception unit A2, as described above, and based on the reception status data signal. The transmission frequency of the audio playback device A is variably controlled. At this time, if a normal reception status data signal cannot be obtained by the FM broadcast receiving unit A2, the central processing unit A10 is affected by an external FM broadcast radio wave or the like, and the FM communication with the wireless speaker B is hindered. It judges that it has occurred, and instructs the FM broadcast receiving unit A2 to change the FM reception frequency.

  At this time, prior to the instruction to change the FM reception frequency, the central processing unit A10 instructs the embedded signal generation unit A11 to generate an embedded signal (second data signal) indicating the FM reception frequency after the change. Send instructions. Receiving the instruction, the embedded signal generation unit A11 generates an embedded signal indicating the FM reception frequency after the change, and sends the embedded signal to the modulation signal generation unit A6. That is, in the audio reproduction device A of the present embodiment, the embedded signal indicating the change content is wirelessly transmitted to the wireless speaker B prior to the change of the FM reception frequency. The central processing unit A10 receives the FM reception broadcast when a predetermined standby time (time required for changing the FM transmission frequency of the wireless speaker B) has elapsed since the generation of the embedded signal was instructed. The reception A2 is instructed to change the FM reception frequency.

  On the other hand, in the wireless speaker B, the central processing unit B9 constantly monitors whether or not the embedded signal (second data signal) is included in the demodulation result obtained by the demodulating unit B3. If an embedded signal is included, an instruction is sent to the FM transmitter B11 so that the FM transmission frequency of the wireless speaker B matches the FM reception frequency after the change of the audio reproduction apparatus A indicated by the embedded signal.

  That is, in the wireless speaker B of the present embodiment, the FM transmission frequency automatically matches the FM reception frequency after the change of the audio reproduction device A in accordance with the FM reception frequency change processing on the audio reproduction device A side. . Therefore, FM communication between both devices A and B continues normally without being interrupted even after the FM reception frequency of the audio playback device A is changed.

  After the FM transmission / reception frequency of the system is changed by the above operation, the central processing unit A10 of the audio reproduction device A determines whether or not a normal reception status data signal is obtained by the FM broadcast receiving unit A2. Here, when it is determined that the reception status data signal is normal, the central processing unit A10 fixes the FM reception frequency of the audio playback device A to the current value. As a result, the system is shifted to the stable mode. On the other hand, when it is determined that the reception status data signal is still not normal, the central processing unit A10 indicates the FM reception frequency after re-change in the same manner as described above in order to change the FM transmission / reception frequency of the system again. The embedded signal is sent to the wireless speaker B, and its own FM reception frequency is changed again. On the wireless speaker B side, the FM transmission frequency is changed again as described above. By repeating such bi-directional communication, an FM transmission / reception signal optimization process in which no reception error occurs is advanced, and finally a stable communication network is completed.

  As described above, in the wireless audio system of the present embodiment, the audio playback device A changes the FM reception frequency of the audio playback device A when the FM broadcast receiving unit A2 cannot obtain a normal reception status data signal. (A9, A10). By adopting such a configuration, it is possible to optimize the FM transmission / reception frequency used for the communication of the reception status data signal without requiring a complicated operation, and it is possible to perform a good communication of the reception status data signal with less interference. It is possible to appropriately perform the digital transmission / reception frequency optimization process based on the reception status data signal.

  Also, in the wireless audio system of the present embodiment, the audio playback device A superimposes the second data signal indicating the changed FM reception frequency on the modulated signal currently being transmitted prior to changing the FM reception frequency. Means (A10, A11), and the wireless speaker B is an audio reproducing apparatus in which the second data signal indicates the FM transmission frequency of the apparatus if the second data signal is included in the demodulation result in the demodulator B3. A means (B9, B11) for matching the FM reception frequency after the change of A is provided. By adopting such a configuration, it is possible to automatically optimize the FM transmission / reception frequency used for communication of the reception status data signal, so that it is possible to reduce the required time and the operation burden on the user. Become.

  Next, a third embodiment of the wireless audio system according to the present invention will be described in detail with reference to FIG. FIG. 3 is a block diagram showing a third embodiment of the wireless audio system according to the present invention. As can be seen from the figure, the wireless audio system of the present embodiment has a configuration substantially similar to that of the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof will be omitted. Hereinafter, description will be given with emphasis on the characteristic portions of the present embodiment. .

  First, as a characteristic part on the audio playback apparatus A side, the central processing unit A10 has the above-described functions, and at the FM broadcast receiving unit A2 every time digital receiving antennas B1a and B1b described later are sequentially selected. A function as a means for superimposing a third data signal indicating a digital reception antenna to be selected on a modulated signal currently being transmitted based on the obtained reception status data signal is newly provided. Further, the embedded signal generation unit A11 has a function of generating the third data signal as an embedded signal in addition to the first data signal described in the previous embodiment based on an instruction from the central processing unit A10. I have.

  On the other hand, as a characteristic part on the wireless speaker B side, the wireless speaker B has a configuration employing a diversity antenna system, that is, a configuration having a plurality of digital receiving antennas B1a and B1b as means for detecting radio waves. . The wireless speaker B receives an antenna switching signal based on an instruction from the central processing unit B9 and an antenna switching unit B14 that selects one of the digital receiving antennas B1a and B1b and connects to the digital receiving unit B2. A switching control unit B15 to be generated is additionally provided. The antenna switching signal is a control signal that instructs the antenna switching unit B14 to switch the signal system.

  Further, the central processing unit B9 of the wireless speaker B has a function as a means for sequentially selecting the digital receiving antennas B1a and B1b at the time of digital radio reception from the audio reproducing apparatus A in addition to the above-described functions, and a demodulating unit B3. If the third data signal is included in the demodulation result in, a function as means for selecting a digital receiving antenna indicated by the third data signal is newly provided.

  The diversity antenna switching operation of the wireless audio system configured as described above will be described in detail.

  In the wireless speaker B, the central processing unit B9 sends an instruction to the switching control unit B15 to sequentially select the digital reception antennas B1a and B1b at the time of digital radio reception from the audio reproduction device A. The switching control unit B15 generates an antenna switching signal based on an instruction from the central processing unit B9, and the antenna switching unit B14 sequentially switches a signal system based on the antenna switching signal.

  The central processing unit B9 detects the reception status (error amount) of the demodulated digital audio signal based on the output of the error counter unit B8 every time the digital reception antennas B1a and B1b are sequentially selected. The reception status data signal generation unit B10 is instructed to generate a reception status data signal indicating the detection result. As a result, the FM transmission antenna B12 emits reception status data signals for the digital reception antennas B1a and B1b to the space as FM radio waves, and the FM reception antennas A1 of the audio reproduction apparatus A detect the FM radio waves. It will be.

  On the other hand, the central processing unit A10 of the audio playback apparatus A has a monitoring function of the reception status data signal obtained by the FM broadcast receiving unit A2, as described above, and the digital receiving antennas B1a and B1b are sequentially selected. The digital reception antenna to be selected (that is, the digital reception antenna that can obtain the best reception state) is determined based on the reception status data signal obtained by the FM broadcast reception unit A2. Then, the central processing unit A10 sends an instruction to the embedded signal generation unit A11 so as to generate an embedded signal (third data signal) indicating the determination result. The embedded signal generation unit A11 generates the instructed embedded signal and sends it to the modulation signal generation unit A6. As a result, the embedded signal is superimposed on the modulated wave currently being transmitted and wirelessly transmitted to the wireless speaker B.

  In the wireless speaker B, the central processing unit B9 constantly monitors whether or not an embedded signal (third data signal) is included in the demodulation result obtained by the demodulation unit B3, and the third data is included in the demodulation result. If a signal is included, an instruction is sent to the switching control unit B15 to select the digital reception antenna indicated by the third data signal. The switching control unit B15 generates an antenna switching signal based on an instruction from the central processing unit B9, and the antenna switching unit B14 switches a signal system based on the antenna switching signal. Thereby, the wireless speaker B is shifted to the stable mode.

  As described above, in the wireless audio system of the present embodiment, the wireless speaker B has a plurality of digital receiving antennas B1a and B1b, means (B9, B14, B15) for sequentially selecting them, and a demodulator B3. Means (B9, B14, B15) for selecting a digital reception antenna indicated by the third data signal if the third data signal is included in the demodulation result of A third data signal indicating a digital reception antenna to be selected as a modulated signal currently being transmitted based on the reception status data signal obtained by the FM broadcast reception unit A2 every time the digital reception antennas B1a and B1b are sequentially selected. It has the structure which has the means (A10, A11) to superimpose. By adopting such a configuration, it is possible to automatically select the digital receiving antennas B1a and B1b together with the optimization of the transmission / reception frequency used for digital wireless communication, so that higher-quality sound reproduction can be performed. Is possible.

  In the description of the present embodiment, the above-described optimization control of the digital transmission / reception frequency and the FM transmission / reception frequency is not particularly mentioned. However, the optimization control of the transmission / reception frequency is performed in accordance with the diversity antenna selection control of the present embodiment. It goes without saying that it should be done.

  Next, a fourth embodiment of the wireless audio system according to the present invention will be described in detail with reference to FIG. FIG. 4 is a block diagram showing a fourth embodiment of the wireless audio system according to the present invention. As can be seen from the figure, the wireless audio system of the present embodiment has a configuration substantially similar to that of the third embodiment. Therefore, the same components as those in the third embodiment are denoted by the same reference numerals as those in FIG. 3, and detailed description thereof will be omitted. Hereinafter, the features of the present embodiment will be described with emphasis. .

  First, as a characteristic part on the audio playback device A side, the central processing unit A10 has the above-described functions, functions as means for sequentially changing the transmission frequency of the audio playback device A, and the sequential change processing. A function as means for changing the transmission frequency of the apparatus is newly provided based on an optimum frequency data signal (to be described later) obtained by the FM broadcast receiving unit A2 after completion.

  On the other hand, as a characteristic part on the wireless speaker B side, the wireless speaker B includes a memory unit B16 for storing the reception status of the digital audio signal as information, and instead of the reception status data signal generation unit B10 described above, The optimum frequency data signal generation unit B17 is included. The central processing unit B9 has the above-described functions, and also functions as means for sequentially selecting the digital reception antennas B1a and B1b for each reception frequency of the apparatus, and the digital reception antennas B1a and B1b are sequentially selected. A function as means for sequentially storing the reception status of the digital audio signal as information in the memory unit B16 each time the reception status of the apparatus having the best reception status by comparing the stored information and the digital reception antenna; As a means for determining the combination of the receiver, a function as a means for selecting the reception frequency and digital receiving antenna of the device determined to be the best combination, and a device determined to be the best combination A function as a means for emitting the optimum frequency data signal indicating the reception frequency of the radio wave to the space as FM radio waves is newly provided There.

  The digital transmission / reception frequency changing operation of the wireless audio system configured as described above will be described in detail.

  When the transmission frequency change button of the operation unit A12 is pressed in the audio playback device A, the system is shifted to an operation mode for automatically searching for the best transmission / reception frequency, and the central processing unit A10 is connected to the audio playback device A. The transmission frequency is sequentially changed at predetermined time intervals. At this time, prior to the change of the transmission frequency, the embedded signal (first data signal) indicating the change content is wirelessly transmitted to the wireless speaker B side, as in the first embodiment. Such a transmission frequency sequential change process is continued until a plurality of transmission frequencies as selection candidates are made at least once.

  On the other hand, in the wireless speaker B, while the transmission frequency is sequentially changed on the audio playback device A side, the reception frequency is automatically changed to the transmission frequency after the change by the same signal processing as in the first embodiment. Matched sequentially. At this time, the central processing unit B9 sends an instruction to the switching control unit B15 to sequentially select the digital reception antennas B1a and B1b for each reception frequency of the wireless speaker B.

  Specifically, the central processing unit B9 first sends an instruction to the switching control unit B15 to select the digital receiving antenna B1a. When the digital reception antenna B1a is selected and a radio wave is detected, the error detection unit B7 and the error counter B8 detect the error amount of the digital audio signal obtained by the demodulation unit B3. The central processing unit B9 detects the reception state of the wireless speaker B based on the error amount, and stores the reception state in the memory unit B16 as electronic information. Next, the central processing unit B9 sends an instruction to the switching control unit B15 to select the digital reception antenna B1b, and stores the reception state at that time in the memory unit B16 as electronic information as described above. Such an operation of selecting the digital reception antenna and a detection operation of the reception state are repeated every time the reception frequency of the wireless speaker B is sequentially changed.

  That is, the wireless speaker B according to the present embodiment performs the above-described sequential change control of the reception frequency and the sequential selection control of the digital reception antenna units B1a and B1b for each combination of the reception frequency and the digital reception antennas B1a and B1b. It can be said that each reception state is sequentially stored as electronic information.

  In this way, when all the reception state information is stored for the combination of the reception frequency as a selection candidate and the digital reception antennas B1a and B1b, the central processing unit B9 compares the stored electronic information. The best combination (that is, the combination with the smallest error amount) is determined. Then, the central processing unit B9 sends an instruction to the frequency control unit B6 and the switching control unit B15 so as to select the reception frequency and digital reception antenna determined to be the best combination. Further, the central processing unit B9 sends an instruction to the optimum frequency data signal generation unit B17 so as to generate an optimum frequency data signal indicating the reception frequency of the device determined to be the best combination. As a result, the optimum frequency data signal is emitted to the space as an FM radio wave from the FM transmission antenna B12, and the FM radio wave is detected by the FM reception antenna A1 of the audio reproduction apparatus A.

  On the other hand, as described above, the central processing unit A10 of the audio playback device A has a monitoring function of the optimum frequency data signal obtained by the FM broadcast receiving unit A2, and receives FM broadcasts after the transmission frequency sequential change processing is completed. Based on the optimum frequency data signal obtained by the unit A2, an instruction is sent to the frequency control unit A9 so that the transmission frequency of the audio reproduction device A matches the reception frequency after the change of the wireless speaker B indicated by the optimum frequency data signal. .

  As described above, in the wireless audio system of this embodiment, the audio playback device A obtains the means (A9, A10) for sequentially changing the transmission frequency of the device and the FM broadcast receiving unit A2 after the completion of the sequential change processing. Means (A9, A10) for changing the transmission frequency of the apparatus based on the optimum frequency data signal to be generated, and the wireless speaker B sequentially selects the digital reception antennas B1a, B1b for each reception frequency of the apparatus. Means (B9, B14, B15), means (B9, B16) for sequentially storing the reception status of the digital audio signal as information each time the digital receiving antennas B1a, B1b are sequentially selected, and the stored information Compare the reception frequency of the equipment with the best reception compared with the digital reception antenna to determine the combination Means (B9), means (B6, B9, B14, B15) for selecting the receiving frequency and digital receiving antenna of the apparatus determined to be the best combination, and the apparatus determined to be the best combination Means (B9, B11, B12, B17) for emitting an optimum frequency data signal indicating the received frequency to the space as FM radio waves.

  By adopting such a configuration, it is possible to easily set a combination of a transmission / reception frequency and a diversity antenna that can obtain the best reception state without requiring a complicated operation, and high-quality audio with less distortion and noise. Playback can be performed. In addition, since there is no possibility that the user may complete the sequential change operation of the transmission / reception frequency halfway and the subtle superiority or inferiority of the reception state is accurately determined without depending on the user's subjectivity, the best transmission / reception frequency is determined. It becomes possible to search appropriately.

  In the description of the present embodiment, the FM transmission / reception frequency optimization control described above is not specifically mentioned. However, the FM transmission / reception frequency optimization control should be performed in accordance with the diversity antenna selection control of the present embodiment. Needless to say.

  In the first to fourth embodiments, the description has been given by taking as an example a configuration for performing bidirectional communication using radio waves in the ISM band or VHF band, but the configuration of the present invention is not limited thereto. However, the configuration may be such that bidirectional communication is performed using radio waves in other frequency bands.

  In addition to the above-described embodiment, the configuration of the present invention can be variously modified without departing from the spirit of the invention.

  The present invention is a technique useful for improving reception quality (that is, reproduction quality of received sound) in a wireless audio system, for example.

These are block diagrams which show 1st Embodiment of the wireless audio system which concerns on this invention. These are block diagrams which show 2nd Embodiment of the wireless audio system which concerns on this invention. These are block diagrams which show 3rd Embodiment of the wireless audio system which concerns on this invention. These are block diagrams which show 4th Embodiment of the wireless audio system which concerns on this invention. FIG. 3 is a conceptual diagram showing a block data group.

Explanation of symbols

A Audio playback device (transmitting device)
A1 FM broadcast reception antenna A2 FM broadcast reception unit A3 Audio signal processing unit A4 Front speaker unit A5 Analog / digital conversion unit A6 Modulation signal generation unit A7 Digital transmission unit A8 Digital transmission antenna A9 Frequency control unit A10 Central processing unit A11 Embedding Signal generation unit A12 Operation unit A13 Display unit B Wireless speaker (receiving device)
B1 (B1a, B1b) Digital reception antenna B2 Digital reception unit B3 Demodulation unit B4 Digital / analog conversion unit B5 Rear speaker unit B6 Frequency control unit B7 Error detection unit B8 Error counter unit B9 Central processing unit B10 Reception status data signal generation unit B11 FM transmission unit B12 FM transmission antenna B13 Display unit B14 Antenna switching unit B15 Switching control unit B16 Memory unit B17 Optimal frequency data signal generation unit

Claims (4)

A broadcast receiving antenna for detecting radio waves in the first frequency band, a broadcast receiving unit for extracting signal components corresponding to the reception frequency of the apparatus from the detected radio waves, and a plurality of systems of analog audio upon receiving a surround signal input An audio signal processing unit that separates the signal, an analog / digital conversion unit that converts at least one of the separated analog audio signals into a digital audio signal, and a modulation signal generation unit that generates a modulation signal based on the digital audio signal; A digital transmission unit that modulates a carrier wave based on the modulation signal, a digital transmission antenna that emits a modulated signal obtained by the modulation process as a radio wave of the second frequency band, and a transmission frequency of the device A frequency control unit that variably controls the transmission device; and a second frequency band A digital receiving antenna for detecting radio waves; a digital receiving unit for extracting signal components corresponding to the received frequency of the device from the detected radio waves; a demodulating unit for demodulating the digital audio signals from the extracted signal components; In a wireless communication system constructed by: a receiver comprising: a digital / analog converter that converts the digital audio signal converted into the analog audio signal; and a frequency controller that variably controls the reception frequency of the device ,
The receiver comprises means for emitting a reception status data signal indicating a reception status of a demodulated digital audio signal to space as a radio wave of the first frequency band,
The transmission device includes means for changing a transmission frequency of the device based on a reception status data signal obtained by the broadcast reception unit during digital wireless transmission to the reception device, and a normal reception status data signal at the broadcast reception unit. Means for changing the reception frequency of the apparatus when it cannot be obtained . The transmission device comprises means for superimposing a first data signal indicating the changed transmission frequency on the modulated signal currently being transmitted prior to changing the transmission frequency of the device,
The receiving device comprises means for matching the reception frequency of the device with the changed transmission frequency indicated by the first data signal if the first data signal is included in the demodulation result in the demodulator. The wireless communication system according to claim 1. The transmission device comprises means for superimposing a second data signal indicating the changed reception frequency on the modulated signal currently being transmitted prior to changing the reception frequency of the device,
The receiving device includes means for matching the transmission frequency of the device with the changed reception frequency indicated by the second data signal if the second data signal is included in the demodulation result of the demodulator. The wireless communication system according to claim 1 or 2, characterized in that The receiving apparatus includes a plurality of the digital receiving antennas, a means for sequentially selecting them, and a digital reception indicated by the third data signal if the third data signal is included in the demodulation result of the demodulator. Means for selecting an antenna, and
The transmission device includes third data indicating a digital reception antenna to be selected as a modulated signal currently being transmitted based on a reception status data signal obtained by the broadcast reception unit each time the digital reception antenna is sequentially selected. 4. The wireless communication system according to claim 1, further comprising means for superimposing signals.

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