JP7038302B2 - Wireless microphone system and wireless communication method for wireless microphone system - Google Patents

Description

The present disclosure relates to a wireless microphone system and a wireless communication method of a wireless microphone system that receives an audio signal transmitted by time-division multiplex communication with each of a plurality of microphones.

In wireless communication of a wireless microphone system using a microphone (for example, a wireless microphone), a master unit (for example, a receiver) and each microphone slave unit (for example, a wireless microphone) are used in one frame period using, for example, 24 slots. Radio signals are sent and received between. Generally, slots S0 to S11 for downlink when viewed from a wireless microphone are used for communication from the master unit to the microphone slave unit. When viewed from the wireless microphone, the uplink slots S12 to S23 are used for communication from the microphone slave unit to the master unit. Further, one slot (for example, slot S0) is used to send a control signal from the master unit to the microphone slave unit.

Here, when wireless communication is performed by a general diversity method, the master unit has at least two master unit antennas. Similarly, the microphone slave unit has at least two microphone antennas. For example, when the master unit transmits a communication signal using one of the master unit antennas in slot S4 of the downlink slots S0 to S11 described above, the microphone slave unit uses each of the two microphone antennas to transmit the communication signal. Receives the communication signal from. The microphone slave unit selects a microphone antenna having good communication quality (for example, a microphone antenna having a higher reception level) from the two microphone antennas. The microphone slave unit uses the selected microphone antenna to transmit a communication signal in slot S16 of the above-mentioned uplink slots S12 to S23.

The master unit receives the communication signal from the microphone slave unit using the two master unit antennas. The master unit selects the master unit antenna having good communication quality (for example, the master unit antenna having the higher reception level) from the two master unit antennas. The master unit transmits a control signal and a communication signal in the next one frame period using the selected master unit antenna. The operation procedure in one frame period described above is repeated, and stable wireless communication is performed between the master unit and the microphone slave unit.

Patent Document 1 discloses a wireless communication system including one master unit and a plurality of microphone slave units, and the master unit performs wireless communication with each microphone slave unit by a time division multiplexing communication method. In this wireless communication system, the master unit suppresses the transmission power to the distant microphone slave unit to the extent that communication can be maintained in order to suppress radio wave interference with other wireless communication systems.

Japanese Unexamined Patent Publication No. 2015-50727

Here, symmetric communication in which the microphone slave unit receives a signal from the master unit in the downlink slot in the first half described above, and the microphone slave unit transmits a signal to the master unit in the uplink slot in the second half. In order to transmit a high-quality audio signal to the master unit instead of the method, the microphone slave unit transmits the audio signal (for example, the audio signal picked up by the wireless microphone) to the master unit even in the slot in the first half of the one frame period. Imagine a wireless microphone system. Then, in the one frame period, the slot S4 described above is used as a transmission slot for transmitting an audio signal from the microphone slave unit to the master unit. Therefore, since the microphone slave unit cannot receive the communication signal from the master unit before the slot S4, the process of selecting the microphone antenna having good communication quality (for example, the microphone antenna having a high reception level) from the two microphone antennas is performed. Cannot be executed.

Therefore, for example, in the slot S16 for uplink in the latter half, the microphone slave unit transmits an audio signal to the master unit using a microphone antenna whose reception level is indefinite. On the other hand, the master unit is two master units used at the time of slot S0 of the next frame based on the communication signal transmitted from the microphone slave unit using the microphone antenna whose reception level is indefinite in slot S16. You have to choose one of the antennas. In slot S0, the master unit needs to transmit a control signal that defines which microphone slave unit of each of the plurality of microphone slave units to communicate with, etc. to each microphone slave unit.

As a result, when the master unit transmits the control signal to each microphone slave unit at the time of slot S0, the master unit antenna selected after the antenna diversity cannot be executed (that is, adaptive according to the communication quality). A master antenna that was not determined to be the master antenna) was sometimes used. In other words, each microphone slave unit has a problem that it cannot stably receive the control signal from the master unit at the time of slot S0.

Further, Patent Document 1 described above discloses that when one master unit wirelessly communicates with a plurality of microphone slave units, the transmission power is reduced to suppress interference with other wireless communication systems. In the above-mentioned wireless communication by the diversity method, no particular consideration is given to the measures for stably receiving the control signal from the master unit in the microphone slave unit.

The present disclosure has been devised in view of the above-mentioned conventional situation, and supports stabilization of communication quality at the time of receiving a control signal transmitted from a receiver as a master unit of wireless communication to a wireless microphone as a slave unit. , A wireless microphone system that provides high quality audio signals, and a wireless communication method for a wireless microphone system .

In the present disclosure, a microphone having a first antenna and a second antenna different from the first antenna and capable of wireless communication according to a time-division multiplex communication method, and a third antenna and a third antenna different from the third antenna are disclosed. A receiver having four antennas and capable of the wireless communication is provided, and the microphone uses the first control signal transmitted from the third antenna in the first half period of one frame of the wireless communication. The first antenna selected by selecting the antenna received by the antenna and the second antenna and used for data transmission of the voice signal based on the reception quality of the first control signal from the first antenna or the second antenna. Alternatively, the data transmission from the microphone to the receiver is performed by asymmetric communication using the second antenna, and the second control signal transmitted from the fourth antenna is transmitted from the fourth antenna in the latter half period of one frame of the wireless communication. The second antenna selected by selecting the antenna received by the first antenna and the second antenna and used for data transmission of the voice signal based on the reception quality of the second control signal from the first antenna or the second antenna. Provided is a wireless microphone system in which the data transmission from the microphone to the receiver is performed by asymmetric communication using one antenna or the second antenna.

In the present disclosure, a microphone having a first antenna and a second antenna different from the first antenna and capable of wireless communication according to a time-division multiplex communication method, and a third antenna and a third antenna different from the third antenna are disclosed. A wireless communication method in a wireless microphone system including a receiver having four antennas and capable of wireless communication, wherein the microphone is used from the third antenna in the first half period of one frame of the wireless communication. The transmitted first control signal is received by the first antenna and the second antenna, and the antenna used for data transmission of the voice signal based on the reception quality of the first control signal is the first antenna or the second antenna. The data transmission from the microphone to the receiver is performed by asymmetric communication using the first antenna or the second antenna selected from the above, and in the latter half period of one frame of the wireless communication, the fourth. The second control signal transmitted from the antenna is received by the first antenna and the second antenna, and the antenna used for data transmission of the voice signal based on the reception quality of the second control signal is the first antenna or the first antenna. Provided is a wireless communication method in which the data is transmitted from the microphone to the receiver by asymmetric communication by selecting from two antennas and using the selected first antenna or the second antenna.

According to the present disclosure, it is possible to support stabilization of communication quality at the time of receiving a control signal transmitted from a receiver as a master unit of wireless communication to a wireless microphone as a slave unit, and to provide a high-quality audio signal.

A diagram schematically showing a system configuration example of the wireless microphone system according to the first embodiment. The figure explaining the frequency band of the carrier used in the communication of the DECT system. The figure which shows the time slot in which a wireless signal is transmitted and received between a receiver and a microphone slave unit. The figure which shows the frame structure of the signal in DECT communication Block diagram showing a hardware configuration example of a microphone slave unit Block diagram showing a hardware configuration example of the receiver It is a figure which shows the time slot in which a control signal is transmitted and received. The figure which shows the time slot which a communication signal is sent and received. Sequence diagram showing the procedure of wireless communication between the receiver and the microphone slave unit The figure which shows the time slot in which the control signal which concerns on Embodiment 2 is transmitted and received. The figure which shows the time slot in which the control signal which concerns on Embodiment 3 is transmitted and received. The figure which shows the time slot which a communication signal is sent and received. The figure which shows the time slot in which a control signal is transmitted and received in Embodiment 4. The figure which shows the time slot which a communication signal is sent and received. A flowchart showing the operation procedure of the microphone slave unit according to the fourth embodiment. A flowchart showing an operation procedure of the microphone slave unit in the modified example of the fourth embodiment.

Hereinafter, embodiments in which the wireless microphone system and the wireless communication method according to the present disclosure are specifically disclosed will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of already well-known matters and duplicate explanations for substantially the same configuration may be omitted. This is to avoid unnecessary redundancy of the following description and to facilitate the understanding of those skilled in the art. It should be noted that the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
FIG. 1 is a diagram schematically showing a system configuration example of the wireless microphone system 5 according to the first embodiment. The wireless microphone system 5 includes a plurality of (for example, m) microphone slave units (wireless microphones) 2, a plurality of receivers 3 as master units, and a mixer receiver 8. m is an integer of 2 or more. In the following description, when each of the plurality of microphone slave units 2C1, 2, C2, ..., 2Cm is not particularly distinguished, it is referred to as microphone slave unit 2. In FIG. 1, for example, the microphone slave unit 2C1 and the microphone slave unit 2C2 belong to the receiver 3w1 (that is, the receiver 3w1 is recognized as a wireless communication partner (that is, a master unit)). Further, the microphone slave unit 2C3 and the microphone slave unit 2C4 belong to the receiver 3w2 (that is, the receiver 3w2 is recognized as a wireless communication partner (that is, a master unit)). The microphone slave unit 2Cm-1 and the microphone slave unit 2Cm belong to the receiver 3wk (that is, the receiver 3wk is recognized as a wireless communication partner (that is, the master unit)). The number of microphone slave units belonging to one master unit may be any number. Further, each microphone slave unit 2 may belong to a plurality of receivers 3w1 to 3wk in an overlapping manner. For example, all microphone slave units 2 may belong to all receivers 3w1 to 3wk.

Between the microphone slave unit 2 and the receiver 3 to which the microphone slave unit 2 belongs, a wireless signal (for example, an audio signal or a control signal) becomes a communication standard of a time division multiple access system (for example, a time division multiple access system). It is transmitted and received through a conforming wireless line. When the user of the microphone slave unit 2 inputs voice to the microphone slave unit 2 (for example, makes a voice), the voice signal picked up by the microphone slave unit 2 is transmitted to the receiver 3 through the wireless line. To. In each embodiment, as the communication standard of the time division multiplexing communication method, for example, the DECT (Digital Enhanced Cordless Telecommunications) method having a frequency band of 1.9 GHz, which is a standard for digital cordless telephones established in 2011, is used.

The plurality of receivers 3 output the audio signal received from the microphone slave unit 2 belonging to each receiver 3 to the mixer receiver 8. A plurality of ports P (P1, P2, ..., Pm) to which signal lines 140 connected to each of the plurality of receivers 3 can be connected are arranged in the housing 8z of the mixer receiver 8. The mixer receiver 8 synthesizes one or more audio signals input from the plurality of receivers 3 connected to the plurality of ports P, and outputs the voice signal after the voice synthesis from the external speaker SPK1. In addition, each receiver 3 may transmit an audio signal to the mixer receiver 8 and may reproduce the audio by the speaker SPK (see FIG. 6) connected to the receiver 3.

FIG. 2 is a diagram illustrating a frequency band of a carrier used in DECT communication. For DECT communication, five frequency bands are used in the 1.9 GHz band (specifically, 1895, 616 MHz to 1902.528 MHz). Specifically, the five frequency bands include a carrier having f1 (1895.616 MHz) as a center frequency (that is, a carrier wave; the same applies hereinafter), a carrier having f2 (1897.344 MHz) as a center frequency, and f3 (that is, a carrier wave). A carrier having a center frequency of 1899.072 MHz), a carrier having a center frequency of f4 (1900.800 MHz), a carrier having a center frequency of f5 (1902.528 MHz), and a carrier having f6 (1904.256 MHz) as a center frequency. It is a carrier to do.

Since these frequency bands do not overlap, radio wave interference is unlikely to occur, and communication interference can be reduced. Further, since the DECT communication using the 1.9 GHz band does not interfere with the radio waves emitted by a device such as a wireless LAN (Local Area Network) or a microwave oven, the voice quality of the wireless microphone system can be maintained. In addition, the receiver 3 constantly monitors the usage status of channels in each frequency band (for example, the availability of resources such as carriers and slots) for each frame period of DECT communication, and channels in the optimum frequency band. By selecting, the 1.9 GHz band can be used efficiently.

FIG. 3 is a diagram showing a time slot in which a radio signal is transmitted / received between the receiver 3 and the microphone slave unit 2. Hereinafter, the time slot is abbreviated as "slot". FIG. 4 is a diagram showing a frame configuration of a signal in DECT communication. A wireless signal is transmitted and received between the receiver 3 and each microphone slave unit 2 using a predetermined number (for example, n) of slots determined according to a communication standard for each frame period. When the communication standard is the DECT system, one frame period corresponds to 10 ms, and is composed of, for example, n = 24 slots (that is, 12 slots for downlink and 12 slots for uplink).

In wireless communication using the DECT method (hereinafter referred to as "DECT communication"), the downlink slots S0 to S11 are generally used for communication from the receiver 3 to the microphone slave unit 2. The uplink slots S12 to S23 are used for communication from the microphone slave unit 2 to the receiver 3. In the communication between the receiver 3 and the microphone slave unit 2, slots having a positional relationship of 5 ms apart corresponding to 1/2 cycle, such as slot S0 and slot S12, slot S1 and slot S13, are combined ( Used (in pair slots). This pair slot constitutes one channel (for example, a control channel for transmitting and receiving control information, a communication channel for transmitting and receiving audio signals).

Further, of the 12 slots in which transmission is performed from the receiver 3 to the microphone slave unit 2, at least one slot (for example, slot S0) transmits a control signal including control information from the receiver 3 to the microphone slave unit 2. It is a control slot for. The control signal is transmitted from the receiver 3 to each microphone slave unit 2 using one of the predetermined number of slots constituting one frame period. If radio wave interference occurs during transmission of a control signal from the receiver 3 to the microphone slave unit 2, an empty slot (in other words, an unused slot) may be used as the control slot. For example, when radio wave interference or the like occurs in slot S0, the receiver 3 may switch the control slot from slot S0 to another vacant slot (for example, a slot for switching described later) for use. In conjunction with this, the response slot for the control slot (that is, the slot used for responding to the control slot and used for transmission from the microphone slave unit 2 to the receiver 3) is another empty slot from the slot S12. (For example, the slot for switching which will be described later in the same manner) is changed. In this way, the receiver 3 operates a slot used as a control channel or a communication channel for each frame period of DECT communication according to the radio wave condition between the receiver 3 and the microphone slave unit 2. To decide. For example, in a device such as a cordless phone, in slots S0 to S11 in the first half, the receiver is on the transmitting side and the microphone slave unit is on the receiving side, and in slots S12 to S23 in the latter half, the receiver is on the receiving side and the microphone slave unit is on the transmitting side. Is.

On the other hand, in the wireless microphone system 5, the receiver 3 receives audio signals transmitted from each of the plurality of microphone slave units 2. Further, the receiver 3 may transmit a control signal to each microphone slave unit 2 once during one frame period. Therefore, in the present embodiment, the receiver 3 uses slots S0 to S11 so that the slots S0 to S11 in the first half can be used as slots (communication slots) for uplink in which the microphone slave unit 2 is the transmission side. Determine dynamically.

For example, the receiver 3 determines slot S0 within one frame period as a control channel for transmitting a control signal, and transmits the control signal to the microphone slave unit 2 through this control channel. The control information included in the control signal includes, for example, system information, slot information, and carrier information. Specifically, the control information includes, for example, the identification information of the microphone slave unit 2 which is a carrier and the communication partner using the slot, the identification information of the carrier and the slot, the busy state of each slot, and the designation of available empty slots. , The number of connected microphone slave units, the radio error status of the receiver, slot switching due to wireless interference, etc. are included.

Each slot constituting one frame of DECT communication is defined by a time width of 416.67 μs (= 10 ms / 24), and specifically, a synchronization signal field, a control bit field, a CRC1 field, a data bit field, and a CRC2. Consists of fields. The synchronization signal field is composed of a preamble interval and a synchronization bit. The synchronization signal field contains fixed data composed of a data string for bit synchronization (preamble interval) and a data string for slot synchronization (synchronization bit). When performing wireless communication by the diversity method, two antennas are switched in the preamble section, an antenna having good communication quality (for example, a large reception level) is selected, and an operation of receiving a field after the synchronization bit is performed. The control bit field includes the control signals described above. When the amount of control information contained in the control signal is large, for example, not only the control bit field but also a part of the area of the data bit field may be used. The CRC1 field contains a CRC (Cyclic Redundancy Check) code calculated based on a data string of the control bit field, and is used for detecting a transmission error in the control bit field. Data bit fields are used for voice communication. The CRC2 field contains a CRC code calculated based on the data string of the data bit field and is used for detecting transmission errors in the data bit field.

FIG. 5 is a block diagram showing a hardware configuration example of the microphone slave unit 2. The microphone slave unit 2 as an example of the microphone has a configuration including a microphone control unit 10, a microphone radio unit 11, an antenna changeover switch 12, and two microphone antennas W1 and W2. The microphone slave unit 2 uses two microphone antennas W1 and W2 to perform wireless communication with the receiver 3 by a diversity method. The antenna changeover switch 12 selects either the microphone antenna W1 or the microphone antenna W2 according to the instruction from the microphone control unit 10, and selects the antenna connected to the microphone radio unit 11 as the selected microphone antenna W1 or the microphone antenna W2. Switch to.

Further, the microphone slave unit 2 includes an operation unit 13 including a sound quality setting button as a user interface and a switch for turning on / off the power, a display unit 14 for displaying the setting contents by the operation unit 13, and a non-volatile memory. It has a stored storage unit 15. The storage unit 15 stores a threshold value to be compared with the reception level of the signal and a predetermined number to be compared with the number of reception errors of the signal. The number of reception errors is counted using, for example, a CRC (Cyclic Redundancy Check) performed using the CRC1 field and the CRC2 field included in each slot. The threshold value is set to the lower limit value of the received signal strength (RSSI) in order to maintain the communication quality. The predetermined number is set to the upper limit of the number of reception errors in order to maintain the communication quality.

Further, the microphone slave unit 2 includes a battery 16 that supplies power to each part of the microphone slave unit 2, a memory 17 that is composed of a dual port RAM (Random Access Memory) and functions as a ring buffer, and a microphone sound processing unit 18. , And a microphone 19 for inputting voice.

The microphone control unit 10 includes a CPU (Central Processing Unit) that is coupled to the storage unit 15 by a bus or the like. The microphone control unit 10 controls the operation of each unit of the microphone slave unit 2, and detects, for example, that the sound quality setting button is pressed. Further, the microphone control unit 10 sets these operation timings for the microphone radio unit 11 and the microphone voice processing unit 18.

FIG. 6 is a block diagram showing a hardware configuration example of the receiver 3. The receiver 3 is a receiver that wirelessly communicates with the microphone slave unit 2, and is also referred to as a receiver. The receiver 3 includes a control unit 20 as an example of a control unit that controls each unit, a wireless control unit 31, a wireless unit 21, an antenna changeover switch 22, two antennas WA, WB, and a memory 27. It has a configuration including. The receiver 3 can perform wireless communication by the diversity method with the microphone slave unit 2 by using the two antennas WA and WB. The antenna changeover switch 22 selects either the antenna WA or the antenna WB according to the instruction from the control unit 20, and switches the antenna connected to the radio unit 21 to the selected antenna WA or the antenna WB.

Further, the receiver 3 has a configuration including an operation unit 23, a display unit 24, and a storage unit 25. The operation unit 23 includes a volume volume and a power switch as a user interface. The display unit 24 displays the setting contents and the like by the operation unit 23. The storage unit 25 is composed of a non-volatile memory. Further, the receiver 3 includes a power supply 26, a voice processing unit 28, a voice output unit 29, and a wired communication unit 30.

The power supply 26 supplies electric power to each part of the receiver 3. The power supply 26 receives a voltage supplied from the mixer receiver 8 through the signal line 140. Further, the power supply 26 may be configured from an external input such as a commercial power supply or an AC adapter. The audio output unit 29 connects to the external speaker SPK2 to reproduce audio. The wired communication unit 30 is connected to the mixer receiver 8 via the signal line 140, and transmits the voice signal from the microphone slave unit 2 voice-processed by the receiver 3 to the mixer receiver 8.

The control unit 20 is connected to the storage unit 25 by a bus or the like. The control unit 20 controls the operation of each unit of the receiver 3 and acquires the operation content input via the operation unit 23.

Further, the control unit 20 detects a transmission error of the compressed signal transmitted from the microphone slave unit 2. Specifically, when the wireless unit 21 receives the compressed signal transmitted from the microphone slave unit 2, the control unit 20 detects the presence or absence of a transmission error by referring to the CRC2 field 54, which is an error detection field. The control unit 20 supplies the clock for wireless communication to the wireless control unit 31. The wireless control unit 31 controls the wireless connection with the microphone slave unit 2, and instructs the wireless unit 21 of the carrier and the slot designated by the control unit 20. That is, the wireless control unit 31 controls the wireless unit 21 so as to communicate with the microphone slave unit 2 associated with the designated carrier and slot. The wireless unit 21 (an example of the wireless communication unit) communicates with the microphone slave unit 2 in a designated carrier and slot via the antenna WA or the antenna WB. In addition, the wireless unit 21 can generate a wireless control signal for controlling synchronization of the wireless microphone system and periodically transmit the signal. Further, the wireless control unit 31 stores the audio signal from the microphone slave unit 2 in the memory 27. The memory 27 is composed of dual port RAM and functions as a ring buffer.

Next, we show asymmetric communication in a high-quality wireless microphone system. FIG. 7 is a diagram showing time slots in which control signals are transmitted and received. FIG. 8 is a diagram showing a time slot in which a communication signal is transmitted / received.

The receiver 3 transmits a control signal using the antenna WA in slot S0 in one frame period. The microphone slave unit 2 receives a control signal from the microphone antennas W1 and W2 in the preamble section of the slot S0, and selects the microphone antenna having the higher reception level from the microphone antennas W1 and W2. For example, it is assumed that the microphone antenna W1 is selected.

The microphone slave unit (wireless microphone) 2 uses the microphone antenna W1 selected in slot S0 and transmits a communication signal in slot S4. The receiver 3 receives the communication signal at the antennas WA and WB in the preamble section of the slot S4, selects the antenna having the higher reception level from the antennas WA and WB, and acquires the communication signal. For example, assume that the antenna WB is selected. The receiver 3 may transmit a control signal by using the selected antenna WB in the slot S12 in the same one frame period.

Further, in the slot S12 in one frame period, the receiver 3 switches (replaces) the antenna used for transmission from the antenna WA to the antenna WB, and transmits the control signal using the antenna WB. The microphone slave unit 2 receives a control signal from the microphone antennas W1 and W2 in the preamble section of the slot S12, and selects the microphone antenna having the higher reception level from the microphone antennas W1 and W2. For example, assume that the microphone antenna W2 is selected.

The microphone slave unit 2 uses the microphone antenna W2 selected in the slot S12 and transmits a communication signal in the slot S16. The receiver 3 receives the communication signal at the antennas WA and WB in the preamble section of the slot S16, selects the antenna having the higher reception level from the antennas WA and WB, and acquires the communication signal. For example, assume that the antenna WA is selected. The receiver 3 may transmit the control signal by using the selected antenna WA in the slot S0 in the next one frame period.

FIG. 9 is a sequence diagram showing a procedure for wireless communication between the receiver 3 and the microphone slave unit 2. In the first half of the Nth frame, the receiver 3 transmits the control signal scA to the microphone slave unit 2 using the antenna WA in the slot S0. The microphone slave unit 2 receives the control signal scA transmitted from the antenna WA in the slot S0 by both the microphone antennas W1 and W2, and selects an antenna having good communication quality (T1). The antenna having good communication quality may be an antenna having a high reception level or an antenna having no communication error.

The microphone slave unit 2 uses one of the microphone antennas W1 and W2 selected in the slot S0, and transmits a communication signal in the slot S4 (T2). The receiver 3 receives the communication signal (call signal) transmitted by using one of the microphone antennas W1 and W2 in the slot S4 by both the antennas WA and WB.

In the latter half of the Nth frame, the receiver 3 transmits the control signal scB to the microphone slave unit 2 using the antenna WB in the slot S12. The microphone slave unit 2 receives the control signal scB transmitted from the antenna WB in the slot S12 by both the microphone antennas W1 and W2, and selects an antenna having good communication quality (T3). The antenna having good communication quality may be an antenna having a high reception level or an antenna having no communication error.

The microphone slave unit 2 uses one of the microphone antennas W1 and W2 selected in the slot S12, and transmits a communication signal in the slot S16 (T4). The receiver 3 receives the communication signal transmitted by using one of the microphone antennas W1 and W2 in the slot S16 by both the antennas WA and WB.

Even in the N + 1th frame, wireless communication is performed in the same procedures T5 to T8 as in the above procedures T1 to T4.

As described above, the receiver 3 has two antennas WA and WB, and is controlled by one of the two antennas WA and WB in slot S0 in order to eliminate the instability of receiving the control signal. The operation of transmitting a signal and transmitting a control signal at the other antenna in slot S12 is performed. By adding the transmission of the control signal in the slot S12, the microphone slave unit 2 can stably receive the control signal.

Further, the microphone slave unit 2 selects the microphone antennas W1 and W2 having a high reception level based on the reception level of the control signal received in the slots S0 and S12, and uses the selected microphone antenna to receive the communication signal. Send to machine 3. Therefore, even in the microphone slave unit of the high-quality wireless microphone system, diversity can be realized and a communication signal with good communication quality can be transmitted to the receiver.

Further, in the above example, the receiver 3 forcibly switches from the antenna WA to the antenna WB in the slot S12 of the two antennas WA and WB to transmit the control signal. Without this switching, the receiver 3 selects antennas WA and WB having a high reception level based on the reception level of the communication signal received in the slots S4 and S16, and uses the selected antenna to transmit the control signal. It is also possible to transmit to the microphone slave unit 2. In this case, the same antenna may be used in slots S4 and S12. As a result, diversity can be realized in both the receiver 3 and the microphone slave unit 2, an antenna having good communication quality can be used, and the control signal can be stably transmitted to the microphone slave unit 2.

As described above, the wireless microphone system 5 according to the first embodiment has a microphone antenna W1 (an example of a first antenna) and a microphone antenna W2 (an example of a second antenna), and wireless communication according to a time-divided multiplex communication method. It is provided with a microphone slave unit 2 (an example of a microphone) capable of enabling wireless communication, and a receiver 3 having an antenna WA (an example of a third antenna) and an antenna WB (an example of a fourth antenna). The microphone slave unit 2 receives the control signal scA (an example of the first control signal) transmitted from the antenna WA by the microphone antenna W1 and the microphone antenna W2 in one frame of wireless communication. The microphone slave unit 2 selects a microphone antenna to be used for transmitting a communication signal (an example of data transmission) from the microphone antenna W1 or the microphone antenna W2 based on the reception quality of the control signal scA. The microphone slave unit 2 transmits a communication signal using the selected microphone antenna W1 or microphone antenna W2. Further, the microphone slave unit 2 receives the control signal scB (an example of the second control signal) transmitted from the antenna WB by the microphone antenna W1 and the microphone antenna W2. The microphone slave unit 2 selects the microphone antenna used for transmitting the communication signal from the microphone antenna W1 or the microphone antenna W2 based on the reception quality of the control signal scB. The microphone slave unit 2 transmits a communication signal using the selected microphone antenna W1 or microphone antenna W2.

In this way, the microphone slave unit receives control signals from a plurality of antennas (here, two antennas) provided in the receiver in one frame period of the DECT wireless communication, so that the communication quality is good. Antenna diversity can be performed to select the antenna. As a result, the control signal from the receiver can be stably received by the wireless microphone, and stable wireless communication between the wireless microphone and the receiver is realized.

Further, in the wireless microphone system 5, the receiver 3 transmits the control signal scA from the antenna WA in the first half period of one frame of wireless communication. The receiver 3 transmits the control signal scB from the antenna WB in the latter half period of one frame of wireless communication. As a result, the microphone antennas used in the communication pair can be optimized for each half section of one frame.

(Embodiment 2)
In the first embodiment, the antenna used in the first half (slots S0 to S11) of one frame period is fixed to the antenna WA, and the antenna used in the second half (slots S12 to S23) is fixed to the antenna WB. It had been. In the second embodiment, the antennas used in the first half and the second half are switched, for example, at regular time intervals.

FIG. 10 is a diagram showing a time slot in which a control signal according to the second embodiment is transmitted / received. When a certain period of time elapses, the antenna used between slots S0 to S11 is switched from the antenna WA to the antenna WB, and when a certain time elapses again, the operation of switching from the antenna WB to the antenna WA is repeated. That is, in the slots S0 to S11, the receiver 3 uses the antenna WA to transmit the control signal scA to the microphone slave unit 2 at the Nth fixed time, and uses the antenna WB at the N + 1th fixed time. The control signal scA is transmitted to the microphone slave unit 2.

Similarly, when a certain time elapses, the antenna used between the slots S12 to S23 is switched from the antenna WB to the antenna WA, and when a certain time elapses again, the operation of switching from the antenna WA to the antenna WB is repeated. That is, in the slots S12 to S23, the receiver 3 uses the antenna WB to transmit the control signal scB to the microphone slave unit 2 at the Nth fixed time, and uses the antenna WA at the N + 1th fixed time. The control signal scB is transmitted to the microphone slave unit 2.

Here, the fixed time may be any time, for example, 200 msec corresponding to a period of 20 frames. The predetermined time may not be a fixed time, but may be a time corresponding to a random number that outputs an irregular value, that is, a time that is not particularly fixed.

As described above, in the wireless microphone system 5 according to the second embodiment, after the lapse of a predetermined time, the receiver 3 switches to one of the antenna WA and the antenna WB and transmits the control signal scA, and the other of the antenna WA and the antenna WB. Switch to and send the control signal scB, and repeat the operation. As a result, it is possible to absorb gentle fluctuations in the reception level between the antennas WA and WB, and it is possible to stabilize the communication of the wireless microphone system.

(Embodiment 3)
In the first embodiment, the slot in which the receiver transmits the second control signal is slot S12. The third embodiment shows a case where the receiver sets the slot for transmitting the second control signal before the first embodiment.

FIG. 11 is a diagram showing a time slot in which a control signal according to the third embodiment is transmitted / received. The receiver 3 transmits the control signal scA using the antenna WA in slot S0. The microphone slave unit 2 receives the control signal scA using the microphone antennas W1 and W2 in the slot S0, and selects the microphone antennas W1 and W2 having good communication quality.

Further, the receiver 3 switches from the antenna WA used in the slot S0 to the antenna WB, and transmits the second control signal scB in the slot S6. The microphone slave unit 2 receives the control signal scB using the microphone antennas W1 and W2 in the slot S6, and selects the microphone antennas W1 and W2 having good communication quality. The slot in which the receiver 3 transmits the second control signal is not limited to the slot S6, and may be any slot.

FIG. 12 is a diagram showing a time slot in which a communication signal is transmitted / received. The microphone slave unit 2 uses one of the microphone antennas W1 and W2 having good communication quality selected in slot S0, and transmits a communication signal in slot S4. Further, the microphone slave unit 2 uses one of the microphone antennas W1 and W2 having good communication quality selected in the slot S6, and transmits a communication signal in the slot S16.

As described above, in the wireless microphone system 5 according to the third embodiment, the receiver 3 transmits the control signal scA from the antenna WA in the first half period of one frame of wireless communication. The receiver 3 transmits the control signal scB from the antenna WB in the first half period of one frame of wireless communication.

As a result, the receiver 3 transmits the control signal from both of the antennas WA and WB in the first half period (transmission slot) of one frame. As a result, the receiver 3 can optimize the microphone antenna used in the communication pair in the section of one frame. Further, for example, even in a case where the first control signal scA is transmitted, the second control signal scB is immediately transmitted, and then the communication signal of the microphone is transmitted, the control signal is appropriately used according to the reception state of scA and scB. The antenna selected and used for transmission by the microphone slave unit 2 can obtain the same effect by transmitting with the antenna selected at the time of receiving the control signal immediately before the transmission slot, and the degree of design freedom is increased. ..

(Embodiment 4)
FIG. 13 is a diagram showing a time slot in which a control signal is transmitted / received according to the fourth embodiment. The receiver 3 transmits the control signal scA using the antenna WA in slot S0. The microphone slave unit 2 receives the control signal scA using the microphone antennas W1 and W2 in the slot S0, and selects the microphone antennas W1 and W2 having good communication quality.

Further, the receiver 3 switches from the antenna WA used in the slot S0 to the antenna WB, and transmits the second control signal scB in the slot S6. On the other hand, the microphone slave unit 2 measures the reception level of the control signal transmitted from the receiver 3 using the antenna WA in the slot S0 by the reception signal strength, and determines whether or not the reception level exceeds the threshold value. When the reception level exceeds the threshold value, the microphone slave unit 2 does not receive the second control signal scA transmitted by the receiver 3 using the antenna WB in the slot S6 (indicated by a broken line in the figure). ).

Further, when the reception level of the control signal transmitted from the receiver 3 using the antenna WA in the slot S0 is equal to or lower than the threshold value, the microphone slave unit 2 is transmitted using the antenna WB in the slot S6 for the second time. The control signal scB of is received. The microphone slave unit 2 selects one of the microphone antennas W1 and W2 used for transmission based on the reception level of the second control signal scB.

FIG. 14 is a diagram showing a time slot in which a communication signal is transmitted / received. The microphone slave unit 2 uses one of the microphone antennas W1 and W2 selected in slot S0, and transmits a communication signal in slot S4. Further, when the microphone slave unit 2 does not receive the second control signal scB in the slot S6, the microphone slave unit 2 uses one of the microphone antennas W1 and W2 selected in the slot S0 and transmits a communication signal in the slot S16.

FIG. 15 is a flowchart showing the operation procedure of the microphone slave unit 2 according to the fourth embodiment. The microphone control unit 10 of the microphone slave unit 2 determines whether or not the control signal scA was received in the previous frame during wireless communication with the receiver 3 (ST1). The control signal scA is a control signal transmitted using the antenna WA.

When the control signal scA is received in the previous frame, the microphone control unit 10 receives the control signal scA in the current frame (ST2). The microphone control unit 10 determines whether or not the reception level of the received control signal scA is equal to or lower than the threshold value stored in the storage unit 15 (ST3). When it is equal to or less than the threshold value, the microphone control unit 10 receives the control signal scB (ST4).

The microphone control unit 10 determines whether or not the reception level of the received control signal scB is higher than the reception level of the control signal scA (ST5). When the reception level of the control signal scB is higher than the reception level of the control signal scA, the microphone control unit 10 changes the control signal used for selecting the microphone antennas W1 and W2 to the control signal scB (ST6). After that, the microphone control unit 10 returns to the process of step ST1.

On the other hand, when the reception level of the control signal scB is equal to or lower than the reception level of the control signal scA in step ST5, or when the control signal scA exceeds the threshold value stored in the storage unit 15 in step ST3, the microphone slave unit 2 receives the control signal scB. The control signal used for selecting the microphone antennas W1 and W2 is defined as the control signal scA (ST7). After that, the microphone control unit 10 returns to the process of step ST1.

Further, when the control signal scA is not received in the previous frame in step ST1, the microphone control unit 10 receives the control signal scB in the current frame (ST8). The microphone control unit 10 determines whether or not the reception level of the received control signal scB is equal to or lower than the threshold value stored in the storage unit 15 (ST9). When it is equal to or less than the threshold value, the microphone control unit 10 receives the control signal scA (ST10).

The microphone control unit 10 determines whether or not the reception level of the received control signal scA is higher than the reception level of the control signal scB (ST11). When the reception level of the control signal scA is higher than the reception level of the control signal scB, the microphone control unit 10 changes the control signal used for selecting the microphone antennas W1 and W2 to the control signal scA (ST12). After that, the microphone control unit 10 returns to the process of step ST1.

On the other hand, when the reception level of the control signal scA is equal to or lower than the reception level of the control signal scB in step ST11, or when the reception level of the control signal scB exceeds the threshold value stored in the storage unit 15 in step ST9, the microphone slave unit In 2, the control signal used for selecting the microphone antennas W1 and W2 is the control signal scB (ST13). After that, the microphone control unit 10 returns to the process of step ST1.

As described above, in the wireless microphone system 5 according to the fourth embodiment, the microphone slave unit 2 does not receive the control signal scB when the reception level of the received control signal scA exceeds the threshold value. The microphone slave unit 2 receives the control signal scB when the reception level of the received control signal scA is equal to or less than the threshold value. The microphone slave unit 2 transmits a communication signal using the microphone antenna W1 or the microphone antenna W2 selected based on the reception quality of the control signal scB.

As described above, when the reception level of the first control signal exceeds the threshold value, the microphone slave unit does not receive the second control signal within one frame period. Therefore, the power consumption required for the microphone slave unit to receive the second control signal can be suppressed, which leads to a longer battery life.

(Modified Example of Embodiment 4)
FIG. 16 is a flowchart showing an operation procedure of the microphone slave unit 2 in the modified example of the fourth embodiment. The microphone control unit 10 of the microphone slave unit 2 determines whether or not the control signal scA was received in the previous frame during wireless communication with the receiver 3 (ST21).

When the control signal scA is received in the previous frame, the microphone control unit 10 receives the control signal scA in the current frame (ST22). The microphone control unit 10 determines whether or not the number of reception errors of the received control signal scA is equal to or greater than the predetermined number stored in the storage unit 15 (ST23). The number of reception errors of the control signal scA is obtained from the result of CRC (Cyclic Redundancy Check) in the CRC1 field and CRC2 field of the slot. When the number of reception errors is equal to or greater than a predetermined number, the microphone control unit 10 receives the control signal scB (ST24).

The microphone control unit 10 determines whether or not the number of reception errors of the received control signal scB is a predetermined number or less (ST25). When the number of reception errors of the control signal scB is not more than a predetermined number, the microphone control unit 10 changes the control signal used for selecting the microphone antennas W1 and W2 to the control signal scB (ST26). After that, the microphone control unit 10 returns to the process of step ST21.

On the other hand, when the number of reception errors of the control signal scB exceeds a predetermined number in step ST25, or when the number of reception errors of the control signal scA is less than a predetermined number in step ST23, the microphone slave unit 2 uses the microphone antennas W1 and W2. The control signal used for selection is the control signal scA (ST27). After that, the microphone control unit 10 returns to the process of step ST21.

Further, when the control signal scA is not received in the previous frame in step ST21, the microphone control unit 10 receives the control signal scB in the current frame (ST28). The microphone control unit 10 determines whether or not the number of reception errors of the received control signal scB is equal to or greater than the predetermined number stored in the storage unit 15 (ST29). When the number is equal to or more than a predetermined number, the microphone control unit 10 receives the control signal scA (ST30).

The microphone control unit 10 determines whether or not the number of reception errors of the received control signal scA is a predetermined number or less (ST31). When the number of reception errors of the control signal scA is not more than a predetermined number, the microphone control unit 10 changes the control signal used for selecting the microphone antennas W1 and W2 to the control signal scA (ST32). After that, the microphone control unit 10 returns to the process of step ST21.

On the other hand, when the number of reception errors of the control signal scA exceeds a predetermined number in step ST31 and the control signal scB is less than a predetermined number in step ST9, the microphone slave unit 2 is used for selecting the microphone antennas W1 and W2. The control signal to be used is defined as the control signal scB (ST33). After that, the microphone control unit 10 returns to the process of step ST21.

As described above, in the wireless microphone system 5 according to the modified example of the fourth embodiment, the microphone slave unit 2 does not receive the control signal scB when the number of reception errors of the received control signal scA is less than a predetermined number. The microphone slave unit 2 receives the control signal scB when the number of reception errors of the received control signal scA is equal to or greater than a predetermined number. The microphone slave unit 2 transmits a communication signal using the microphone antenna W1 or the microphone antenna W2 selected based on the reception quality of the control signal scB.

As described above, when the number of reception errors of the first control signal is less than a predetermined number, the microphone slave unit does not receive the second control signal within the one frame period. Therefore, the power consumption required for the microphone slave unit to receive the second control signal can be suppressed, which leads to a longer battery life.

Further, even when the reception level of the control signal is high, a reception error may occur in a noisy environment. Therefore, determining the reception of the second control signal based on the number of reception errors is suitable for the actual usage environment.

Although various embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can come up with various modifications, modifications, substitutions, additions, deletions, and even examples within the scope of the claims. It is understood that it belongs to the technical scope of the present disclosure. Further, each component in the various embodiments described above may be arbitrarily combined as long as the gist of the invention is not deviated.

For example, in the above embodiment, the receiver and the microphone slave unit each use two antennas for communication by the diversity method, but may use three or more antennas for communication by the diversity method.

The present disclosure is a wireless microphone system that supports stabilization of communication quality when receiving a control signal transmitted from a receiver as a master unit of wireless communication to a wireless microphone as a slave unit, and provides a high-quality audio signal. And useful as a wireless communication method.

2 Microphone handset 3 Receiver 5 Wireless microphone system 10 Microphone control unit 20 Control unit W1, W2 Microphone antenna WA, WB antenna

Claims (2)

A microphone that has a first antenna and a second antenna that is different from this first antenna and is capable of wireless communication according to the time division multiplexing communication method.
It has a third antenna and a fourth antenna different from the third antenna, and includes a receiver capable of wireless communication.
The microphone is used in the first half of one frame of the wireless communication.
The first antenna is an antenna that receives the first control signal transmitted from the third antenna by the first antenna and the second antenna and is used for data transmission of an audio signal based on the reception quality of the first control signal. Alternatively, the data can be transmitted from the microphone to the receiver by asymmetric communication by selecting from the second antenna and using the selected first antenna or the second antenna.
In the latter half of one frame of the wireless communication
The second control signal transmitted from the fourth antenna is received by the first antenna and the second antenna, and the antenna used for data transmission of the voice signal based on the reception quality of the second control signal is the first antenna. Alternatively, the data is transmitted from the microphone to the receiver by asymmetric communication by selecting from the second antenna and using the selected first antenna or the second antenna.
Wireless microphone system. A microphone that has a first antenna and a second antenna that is different from this first antenna and is capable of wireless communication according to the time division multiplexing communication method.
A wireless communication method in a wireless microphone system having a third antenna and a fourth antenna different from the third antenna and capable of wireless communication.
The microphone is used in the first half of one frame of the wireless communication.
The first antenna is an antenna that receives the first control signal transmitted from the third antenna by the first antenna and the second antenna and is used for data transmission of an audio signal based on the reception quality of the first control signal. Alternatively, a selection is made from the second antenna, and the data transmission from the microphone to the receiver is performed by asymmetric communication using the selected first antenna or the second antenna.
In the latter half of one frame of the wireless communication
The second control signal transmitted from the fourth antenna is received by the first antenna and the second antenna, and the antenna used for data transmission of the voice signal based on the reception quality of the second control signal is the first antenna. Alternatively, the data is transmitted from the microphone to the receiver by asymmetric communication by selecting from the second antenna and using the selected first antenna or the second antenna.
A wireless communication method for a wireless microphone system.

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