JP2005057409A - Data receiving system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data receiving system capable of synchronizing data reading timings between a plurality of devices for receiving data. <P>SOLUTION: Each sync device for receiving data transmitted from a source device is provided with an interface section 210 for receiving the data transmitted from the source device; an FIFO memory 220 for storing the received data; an FIFO control quantity setting section 244 for transmitting/receiving information about the storing capacity of the FIFO memory 220 to/from other sync devices, and for setting a permissible width of the data storing capacity of the FIFO memory 220 provided in its own device on the basis of the storing capacity of the FIFO memory 220 provided in each sync device; and an FIFO data quantity control unit 240 for controlling the reading/writing of the data from/into the FIFO memory 220 so that the data are stored in the set permissible width. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a data receiving system that transmits and receives audio data and the like.

Conventionally, when audio data sent from a computer or the like is received and played back by a player or the like, the audio data is temporarily stored in a FIFO, and the audio data is controlled to be read while monitoring the free space of the FIFO. A control device is known (see, for example, Patent Document 1). By using this synchronization control device, audio data sent from a computer or the like can be synchronously controlled with a clock having an appropriate frequency without overflow or underflow in a player or the like.
JP 2001-320351 A (page 3-10, FIG. 1-13)

  Incidentally, in the above-described synchronization control device disclosed in Patent Document 1, a reception clock used in a player as a data reception device can be synchronized with a transmission clock used in a computer as a transmission device. Since attention is paid to the receiving device, when there are a plurality of receiving devices, there is a problem that the timing of reading data cannot be synchronized between the receiving devices. Even if the timing of data read from the FIFO included in each of the plurality of receiving apparatuses is to be matched, if the capacity of each FIFO is different or the configuration of each receiving apparatus is not the same, the data before being stored and read in the FIFO Since the data capacities are not the same, it is difficult to match the time from storage to reading in the FIFO of each receiving device. For example, considering a sink device that inputs audio signals to speakers included in an audio system as a plurality of receiving devices, the transmission timing of audio sound corresponding to audio data transmitted from the source device to each sink device is shifted. As a result, the phase of the audio sound output from each speaker does not match, causing the sound quality of the entire audio sound to deteriorate.

  The present invention was created in view of the above points, and an object of the present invention is to provide a data receiving system capable of matching the data read timing among a plurality of devices that receive data.

  In order to solve the above-described problem, a data reception system of the present invention includes a plurality of reception devices that receive data transmitted from a transmission device, and the reception device receives data transmitted from the transmission device. Data receiving means, storage means for storing data received by the data receiving means, information communication means for transmitting / receiving information on the storage capacity of the storing means to / from other receiving devices, and the own device A control amount setting means for setting an allowable width of the storage data amount of the storage means provided in the own device based on the storage capacity of the storage means and the storage capacity of the storage means provided in the other receiving device received by the information communication means; The data is stored in the storage means in a first-in first-out manner, and the storage data amount of the storage means is controlled so as to fall within the allowable range of the storage data amount set by the control amount setting means. And a control unit. Each receiving device acquires information on the storage capacity of the storage means provided in the other receiving devices, and considers the storage capacity of the storage means of each receiving device including the own device, and the data control amount in the storing means of the own device Since (allowable width of stored data amount) can be set, it is possible to make the stored data amount before reading in each of a plurality of receiving devices receiving data the same, and the data is stored in the storage means. Thereafter, the timing for reading out this data can be adjusted between the receiving apparatuses.

  Further, the data described above is audio data, and it is preferable that the receiving device further includes an audio reproducing unit that reproduces an audio sound based on the audio data read from the storage unit. When audio data is transmitted from a transmission device and received by each reception device and audio sound is reproduced, the audio data is stored in the storage means in each reception device and read out in order to prevent sound quality degradation. It is necessary to make the time until the time constant. In the present invention, since the amount of data stored in the storage means can be made the same between the receiving devices, it is possible to match the timing of reading out audio data from the storage means, thereby preventing the sound quality of the audio sound from deteriorating. be able to.

  The audio data described above is preferably encoded at a fixed bit rate. For audio data encoded at a fixed bit rate, the amount of data is proportional to the playback time. Therefore, the timing of reading audio data necessary for playback can be set by making the storage data amount of the storage means of each receiving device the same. It is possible to easily adjust each receiving apparatus.

  Further, the control amount setting means described above determines whether or not the storage capacities of all the storage means included in the plurality of receiving devices are the same, and when they are the same, a predetermined range including 50% of the storage capacity It is desirable to set the allowable range of the stored data amount so that the stored data amount is within the range. As a result, it is possible to effectively avoid the situation where the storage means provided in each receiving apparatus overflows and underflows.

  Further, the control amount setting means described above specifies the smallest storage capacity among the storage capacities of all the storage means included in the plurality of receiving apparatuses, and includes a data amount corresponding to half of the specified storage capacity. It is desirable to set the allowable range of the stored data amount so that the stored data amount falls within a predetermined range. As a result, it is possible to prevent the storage unit of the receiving apparatus having the least amount of stored data from overflowing. For example, when considering an audio system, it is possible to avoid failure of the audio sound reproduction operation. it can.

  Further, the storage control means described above sets a wide allowable range of the stored data amount immediately after the start of the operation, and monitors the relationship between the actual stored data amount and the allowable width to thereby read the data from the storage means. It is desirable to set Thereby, control which changes the speed of the clock in a receiving device can be performed easily.

  Hereinafter, a data receiving system according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating an overall configuration of a data receiving system according to an embodiment. As shown in FIG. 1, the data receiving system according to the present embodiment includes one source device 100 and three sink devices 200, 300, and 400. The source device 100 includes an interface unit (IF) 110 as a communication control unit that transmits and receives data to and from the sink devices 200, 300, and 400. In addition, the sink device 200 includes an interface unit (IF) 210 as a communication control unit that transmits and receives data to and from the source device 100 and the other sink devices 300 and 400. Similarly, the sink device 300 includes an interface unit (IF) 310 as a communication control unit that transmits and receives data to and from the source device 100 and the other sink devices 200 and 400. The sink device 400 includes an interface unit (IF) 410 as a communication control unit that transmits and receives data to and from the source device 100 and the other sink devices 200 and 300.

  The source device 100 and the sink devices 200, 300, and 400 are connected via a predetermined cable. For example, the interface units 110, 210, 310, and 410 included in each device support communication operations compliant with the IEEE 1394 standard, and as illustrated in FIG. 1, the source devices 100, sink devices 200, 300, and 400 A daisy chain type connection is made in sequence using an IEEE1394 cable. As a connection form in conformity with the IEEE 1394 standard, a star type can be adopted in addition to the daisy chain type, and either of them may be used. Further, in the data receiving system of this embodiment, it is only necessary to transmit data from the source device 100 to each of the sink devices 200, 300, and 400. Therefore, other serial bus connections and parallel bus connections may be employed. .

  Next, the detailed configuration of each sink device 200, 300, 400 will be described. Hereinafter, details of the sink device 200 when the data receiving system shown in FIG. 1 is applied to an in-vehicle audio system will be described. The basic configurations of the other sink devices 300 and 400 are the same, and detailed description thereof is omitted.

  FIG. 2 is a diagram illustrating a detailed configuration of the sink device 200. The sink device 200 includes an interface unit 210, a first-in first-out (FIFO) memory 220, an audio processing unit 222, an amplifier 224, a reproduction clock generation unit 230, a reference signal generation unit 232, a FIFO data amount control unit 240, a clock relative A speed determination unit 242 and a FIFO control amount setting unit 244 are included.

  The FIFO memory 220 is a memory that writes and reads data by a first-in first-out method. When the audio data for the sink device 200 transmitted from the source device 100 is received by the interface unit 210, the audio data is written in the FIFO memory 220 in the order of reception.

  The audio processing unit 222 reads audio data from the FIFO memory 220 in synchronization with a reproduction clock signal (described later), performs a predetermined reproduction operation using the read audio data, and outputs an audio sound signal. For example, the audio processing unit 222 has a digital-analog converter (DAC), takes audio data of a predetermined number of bits in synchronization with a reproduction clock, and converts it into an audio signal. In the present embodiment, audio data encoded at a fixed bit rate is used. The audio signal output from the sound processing unit 222 is amplified by the amplifier 224, and the audio sound is output from the speaker 250 set at a predetermined position (for example, the front right side) from the speaker 250.

  The reproduction clock generation unit 230 generates a reproduction clock used for reading audio data from the FIFO memory 220 and capturing data by the audio processing unit 222. In order for the audio data stored in the FIFO memory 220 not to overflow or underflow, the frequency of the transmission clock used for transmission of the audio data by the source device 100 and the frequency of the reproduction clock must be matched exactly. Although there is a slight deviation between these even when setting to match exactly, the frequency of the recovered clock can be varied within a predetermined control width while actually monitoring the amount of data stored in the FIFO memory 220. Control.

  The reference signal generator 232 generates a highly accurate reference signal. For example, a crystal resonator is used, and a reference signal that matches or divides the natural vibration frequency of the crystal resonator is generated. The reproduction clock generation unit 230 described above has a PLL (phase-locked loop) configuration that operates using the reference signal as a reference signal, and by changing the frequency division ratio of the variable period provided in the loop, The frequency of the recovered clock is changed.

  The FIFO data amount control unit 240 monitors the amount of data stored in the FIFO memory 220 and sets an allowable width of this stored data amount. For example, immediately after the power is turned on, 30 to 70% of the storage capacity of the FIFO memory 220 is set as the allowable width. If the tolerance is not within the allowable range, the FIFO data amount control unit 240 performs control to change the frequency of the reproduction clock generated by the reproduction clock generation unit 230.

  The clock relative speed determination unit 242 is based on the amount of data stored in the FIFO memory 220 monitored by the FIFO data amount control unit 240, and the relative speed between the transmission clock in the source device 100 and the reproduction clock output from the reproduction clock generation unit 230. Determine.

  The FIFO control amount setting unit 244 communicates with the FIFO control amount setting unit 244 included in the other sink devices 300 and 400 and information on the storage capacity of the FIFO memory 220 provided in the other sink devices 300 and 400 And the allowable width of the amount of data stored in the FIFO memory 220 is set based on the acquired information and the storage capacity of the FIFO memory 220 provided in the own apparatus.

  The source device 100 described above is a transmission device, the sink devices 200, 300, and 400 are reception devices, the interface units 210, 310, and 410 are data reception units, the FIFO memory 220 is a storage unit, a FIFO data amount control unit 240, The clock relative speed determination unit 242 corresponds to the storage control unit, the FIFO control amount setting unit 244 corresponds to the control amount setting unit and the information communication unit, and the audio processing unit 222 corresponds to the audio reproduction unit.

  The audio system of the present embodiment has such a configuration, and the operation thereof will be described next.

  FIG. 3 is a flowchart showing an operation procedure in the sink device 200. When the power is turned on, first, the FIFO control amount setting unit 244 sets the allowable range of the data amount stored in the FIFO memory 220 to a default value of 30 to 70% (step 100). This setting is performed in each sink device regardless of the storage capacity of the FIFO memory 220 provided in each sink device.

  Next, an audio data read / write operation using the FIFO memory 220 is started (step 101). Thereafter, after a predetermined time has elapsed, the clock relative speed determination unit 242 determines the transmission clock used for audio data transmission in the source device 100 and the reproduction clock output from the reproduction clock generation unit 230 based on the amount of data stored in the FIFO memory 220. The relative speed is determined, and relative speed information based on the determination result is created (step 102). The relative speed is preferably determined after a predetermined time required for the amount of data stored in the FIFO memory 220 to stabilize after the audio data read / write operation is started in step 101. Generally, since the frequency of the transmission clock and the frequency of the recovered clock are different, the amount of data stored in the FIFO memory 220 increases or decreases in one direction with the passage of time. For example, when the frequency of the reproduction clock is higher than the frequency of the transmission clock, the reading speed of the audio data stored in the FIFO memory 220 is faster than the writing speed. The amount of stored data becomes stable near 30%. On the other hand, when the frequency of the reproduction clock is lower than the frequency of the transmission clock, the reading speed of the audio data stored in the FIFO memory 220 is slower than the writing speed. The amount of stored data becomes stable in the vicinity of 70%. The clock relative speed determination unit 242 checks whether the amount of data stored in the FIFO memory 220 is stable in the vicinity of 30% or stable in the vicinity of 70% after a predetermined time has elapsed, and generates a reproduction clock at that time. It is determined whether the frequency of the reproduction clock output from the unit 230 is higher or lower than the frequency of the transmission clock.

  The FIFO control amount setting unit 244 communicates with the FIFO control amount setting unit 244 included in the other sink devices 300 and 400 to store the storage capacity of the FIFO memory 220 included in the other sink devices 300 and 400. The information regarding is acquired (step 103). Next, the FIFO control amount setting unit 244 sets an allowable width of the stored data amount of the FIFO memory 220 based on the acquired information regarding the storage capacity and the storage capacity of the FIFO memory 220 provided in the own apparatus (step 104). The allowable width is set so that the amount of data stored in each FIFO memory 220 provided in all the sink devices 200, 300, and 400 is substantially constant. A specific example of the setting will be described later. Thereafter, an audio data read / write operation using the FIFO memory 220 is performed so as to satisfy the allowable width of the newly set stored data amount (step 105).

  FIG. 4 is a diagram showing the transition of the stored data capacity of the FIFO memory 220 provided in each sink device. 4A and 4B show changes in the amount of data stored in the FIFO memory 220 provided in the sink device 200, and FIGS. 4C and 4D show the storage in the FIFO memory 220 provided in the sink device 300. FIG. FIGS. 4E and 4F show changes in the amount of data stored in the FIFO memory 220 provided in the sink device 400, respectively.

  For example, in the initial state after the power is turned on, the frequency of the recovered clock of the sink device 200 is set faster than the frequency of the transmission clock, and the recovered clocks of the sink devices 300 and 400 are set slower. Also, let us consider a case where the storage capacities of the FIFO memories 220 provided in the sink devices are all the same.

  In the sink device 200, when a predetermined time elapses after the power is turned on, the amount of data stored in the FIFO memory 220 stabilizes in the vicinity of 30%, which is the lower limit of the allowable width in the initial state (FIG. 4A). Further, in the sink device 300, when a predetermined time elapses after the power is turned on, the amount of data stored in the FIFO memory 220 stabilizes in the vicinity of 70%, which is the upper limit of the allowable width in the initial state (FIG. 4C). Similarly, in the sink device 400, when a predetermined time elapses after the power is turned on, the amount of data stored in the FIFO memory 220 stabilizes in the vicinity of 70%, which is the upper limit of the allowable width in the initial state (FIG. 4E).

  The clock relative speed determination unit 242 of the sink device 200 confirms that the frequency of the reproduction clock of its own device is higher than the frequency of the transmission clock because the amount of data stored in the FIFO memory 220 is close to 30% of the storage capacity. Create the relative speed information shown. Also, the FIFO control amount setting unit 244 determines that the storage capacity of each FIFO memory 220 of the sink devices 300 and 400 is the same as the storage capacity of the FIFO memory 220 of its own device through communication performed with the other sink devices 300 and 400. If it is known that the same, the narrow range (for example, within ± several%) including 50% of the storage capacity is set as the allowable width of the stored data amount of the FIFO memory 220. Thereafter, the FIFO data amount control unit 240 performs control to slow down the frequency of the reproduction clock so that the amount of data stored in the FIFO memory 220 falls within the set allowable range near 50% (FIG. 4B). .

  On the other hand, the clock relative speed determination unit 242 of the sink devices 300 and 400 has the stored data amount in the FIFO memory 220 close to 70% of the storage capacity, so that the frequency of the reproduction clock of the own device is higher than the frequency of the transmission clock. The relative speed information indicating that the speed is low is also created. Further, the FIFO control amount setting unit 244 determines that the storage capacity of each FIFO memory 220 of the sink device 200 or the like is the same as the storage capacity of the FIFO memory 220 of its own device by communication performed with other sink devices 200 or the like. If it is known, a narrow range (for example, within ± several%) including 50% of the storage capacity is set as the allowable width of the stored data amount of the FIFO memory 220. Thereafter, the FIFO data amount control unit 240 increases the frequency of the reproduction clock so that the amount of data stored in the FIFO memory 220 falls within the set allowable range near 50% (FIGS. 4D and 4F). Control.

  FIG. 5 is a diagram showing another example of the transition of the stored data capacity of the FIFO memory 220 provided in each sink device. 5A and 5B show changes in the amount of data stored in the FIFO memory 220 provided in the sink device 200, and FIGS. 5C and 5D show the storage in the FIFO memory 220 provided in the sink device 300. FIG. Changes in the amount of data are shown in FIGS. 5E and 5F, respectively. Changes in the amount of data stored in the FIFO memory 220 provided in the sink device 400 are shown.

  For example, in the initial state after the power is turned on, the frequency of the recovered clock of the sink device 200 is set faster than the frequency of the transmission clock, and the recovered clocks of the sink devices 300 and 400 are set slower. The storage capacity of each FIFO memory 220 provided in each sink device is assumed to be the smallest storage capacity of the FIFO memory 220 provided in the sink device 200.

  In the sink device 200, when a predetermined time elapses after the power is turned on, the amount of data stored in the FIFO memory 220 stabilizes in the vicinity of 30%, which is the lower limit of the allowable width in the initial state (FIG. 5A). Further, in the sink device 300, when a predetermined time elapses after the power is turned on, the amount of data stored in the FIFO memory 220 stabilizes in the vicinity of 70%, which is the upper limit of the allowable width in the initial state (FIG. 5C). Similarly, in the sink device 400, when a predetermined time elapses after the power is turned on, the amount of data stored in the FIFO memory 220 stabilizes in the vicinity of 70%, which is the upper limit of the allowable width in the initial state (FIG. 5E). The allowable width of the stored data amount in these initial states is uniformly set regardless of the storage capacity of each FIFO memory 220.

  The clock relative speed determination unit 242 of the sink device 200 confirms that the frequency of the reproduction clock of its own device is higher than the frequency of the transmission clock because the amount of data stored in the FIFO memory 220 is close to 30% of the storage capacity. Create the relative speed information shown. Further, the FIFO control amount setting unit 244 stores the storage capacity of the FIFO memory 220 of the own device rather than the storage capacity of each FIFO memory 220 of the sink devices 300 and 400 through communication performed with the other sink devices 300 and 400. If it is found that the smaller is smaller, a narrow range including 50% of the storage capacity (for example, within ± several%) is set as the allowable width of the amount of data stored in the FIFO memory 220. Thereafter, the FIFO data amount control unit 240 performs control to slow down the frequency of the reproduction clock so that the amount of data stored in the FIFO memory 220 falls within the set allowable range near 50% (FIG. 5B). .

  On the other hand, the clock relative speed determination unit 242 of the sink devices 300 and 400 has the stored data amount in the FIFO memory 220 close to 70% of the storage capacity, so that the frequency of the reproduction clock of the own device is higher than the frequency of the transmission clock. The relative speed information indicating that the speed is low is also created. Also, the FIFO control amount setting unit 244 determines that the storage capacity of each FIFO memory 220 of the sink device 200 is smaller than the storage capacity of the FIFO memory 220 of its own device by communication performed with the other sink devices 200 and the like. As a result, a narrow range (for example, within ± several percent) including the storage data amount corresponding to 50% of the storage capacity of the FIFO memory 220 of the sink device 200 is set as the allowable width of the storage data amount of the FIFO memory 220. Thereafter, the FIFO data amount control unit 240 performs control to increase the frequency of the reproduction clock so that the amount of data stored in the FIFO memory 220 falls within the set allowable range (FIGS. 5D and 5F). .

  As described above, each sink device 200, 300, 400 included in the audio system according to the present embodiment acquires information on the storage capacity of the FIFO memory 220 provided in the other sink devices, and stores the storage capacity of all the FIFO memories 220. In consideration of this, the data control amount (allowable width of the stored data amount) in the FIFO memory 220 of the own device can be set, so that the stored data amount before reading in each of the plurality of sink devices that receive data is the same. Thus, the timing of reading out the data after storing the data in the FIFO memory 220 can be matched between the sink devices.

  In particular, the allowable width of the stored data amount of the FIFO memory 220 in each sink device 200, 300, 400 can be set as a ratio or absolute amount with respect to the storage capacity while considering the storage capacity of the FIFO memory 220 of the other sink device. Therefore, even if the frequency of the recovered clock changes with changes in temperature and power supply voltage, audio data can be controlled by controlling the amount of data stored in the FIFO memory 220 in each sink device so that this allowable range is entered. Can be prevented from being dispersed.

  In addition, when audio data is transmitted from the source device 100 and received by each sink device 200, 300, 400 to reproduce audio sound, the FIFO memory 220 in each sink device is used in order to prevent deterioration in sound quality. It is necessary to make the time from storing audio data to reading data constant. In the audio system of the present embodiment, the amount of data stored in the FIFO memory 220 can be made the same between the sink devices, so that the timing for reading audio data from the FIFO memory 220 can be matched. Therefore, it is possible to prevent a delay in the audio sound output from the speakers connected to some of the sink devices, and to avoid a deterioration in the sound quality of the audio sound.

  Also, since audio data encoded at a fixed bit rate is used and the amount of data stored in the FIFO memory 220 is proportional to the playback time of the audio sound, the amount of data stored in the FIFO memory 220 of each sink device is the same. By doing so, it becomes possible to easily match the timing of reading out the audio data necessary for reproduction in each sink device.

  Further, when the storage capacities of the FIFO memories 220 included in the plurality of sink devices are all the same, each data control amount is set by setting a predetermined range including 50% of the storage capacity as an allowable width of the stored data amount. The situation where the FIFO memory 220 provided in the sink device overflows and underflows can be effectively avoided.

  Alternatively, when the storage capacities of the FIFO memories 220 provided in the plurality of sink devices are not the same, a predetermined range including a storage data amount (for example, specified in bytes) corresponding to half of the smallest storage capacity is set. By setting the data control amount as the allowable range, it is possible to prevent the FIFO memory 220 of the sink device having the least storage data amount from overflowing.

  Also, the FIFO control amount setting unit 244 sets the allowable range of the data control amount (allowable width of the stored data amount) immediately after the operation is started after the power is turned on, and shows the relationship between the actual stored data amount and this allowable range. By monitoring, the speed of the reproduction clock for reading data from the FIFO memory 220 is set. This facilitates determination of the direction (frequency increase / decrease direction) in which the speed of the recovered clock in each sink device is changed, and control for this can be easily performed.

  Further, in this embodiment, each sink device automatically obtains information on the storage capacity of the FIFO memory 220 with other sink devices and sets an allowable width of the stored data amount. The user does not need to grasp the storage capacity of the FIFO memory 220 provided in each sink device or perform special settings. Even when a sink device is added, an optimum allowable range of the stored data amount is always set, so that optimum performance of an audio system or the like can be extracted.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. In the above-described embodiment, the case where the present invention is applied to an audio system has been described. However, the present invention can be applied to a data receiving system used for other purposes.

  In the above-described embodiment, each sink device stores data in the FIFO memory 220. However, a dual port RAM or the like may be used as long as it has a similar function.

  In the above-described embodiment, three sink devices 200, 300, and 400 are connected to one source device 100. However, the number of sink devices connected is not limited, and the storage capacity of the FIFO memory 220 is not limited. You can combine multiple sink devices without having to

It is a figure showing the whole data receiving system composition of one embodiment. It is a figure which shows the detailed structure of a sink device. It is a flowchart which shows the operation | movement procedure in a sink device. It is a figure which shows transition of the storage data capacity | capacitance of the FIFO memory with which each sink device is equipped. It is a figure which shows the other example of transition of the storage data capacity | capacitance of the FIFO memory with which each sink device is equipped.

Explanation of symbols

100 Source device 110, 210, 310, 410 Interface unit (IF)
200, 300, 400 Sink device 220 FIFO memory 222 Audio processing unit 224 Amplifier 230 Reproduction clock generation unit 232 Reference signal generation unit 240 FIFO data amount control unit 242 Clock relative speed determination unit 244 FIFO control amount setting unit 250 Speaker

Claims (6)

A data receiving system including a plurality of receiving devices for receiving data transmitted from a transmitting device,
The receiving device is:
Data receiving means for receiving the data transmitted from the transmitting device;
Storage means for storing the data received by the data receiving means;
Information communication means for transmitting and receiving information on the storage capacity of the storage means to and from the other receiving device;
Based on the storage capacity of the storage means provided in the own device and the storage capacity of the storage means provided in the other receiving device received by the information communication means, the amount of data stored in the storage means provided in the own device Control amount setting means for setting the allowable width of
Storage control means for controlling the storage data amount of the storage means so as to be within an allowable width of the storage data amount set by the control amount setting means, in addition to first-in first-out the data in the storage means;
A data receiving system comprising: In claim 1,
The data is audio data;
The data receiving system according to claim 1, wherein the receiving apparatus further comprises audio reproducing means for reproducing audio sound based on the audio data read from the storage means. In claim 2,
A data receiving system, wherein the audio data is encoded at a fixed bit rate. In any one of Claims 1-3,
The control amount setting means determines whether or not the storage capacities of all the storage means included in the plurality of receiving devices are the same, and when they are the same, a predetermined range including 50% of the storage capacity A data receiving system, wherein an allowable width of the stored data amount is set so that the stored data amount falls within the range. In any one of Claims 1-3,
The control amount setting means specifies the smallest storage capacity among the storage capacities of all the storage means included in the plurality of receiving devices, and includes a predetermined amount including a data amount corresponding to half of the specified storage capacity A data receiving system, wherein an allowable range of the stored data amount is set so that the stored data amount falls within a range. In any one of Claims 1-5,
The storage control unit sets the allowable range of the stored data amount wide immediately after the operation starts, and monitors the relationship between the actual stored data amount and the allowable range to thereby increase the clock speed for reading data from the storage unit. A data receiving system characterized by changing.

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