Data transmission device

Abstract

One aspect of the data transmission apparatus disclosed herein includes: a data transmitting unit having a transmitting port; and a data receiving group having n receiving units from a first receiving unit to an nth receiving unit (n ≥ 2), wherein the transmitting port of the data transmitting unit is configured to serially transmit data to be acquired by each of the n receiving units, the i-th receiving unit (2 ≤ i ≤ n-1) having an input port and a data port, and configured such that the input port of the i-th receiving unit receives data from the data port of the (i-1)-th receiving unit, and the data port of the i-th receiving unit transmits data received from the input port of the i-th receiving unit after removing the data that should only be received by the i-th receiving unit.

Description

Technical Field

[0001] This disclosure relates to a data transmission apparatus. Background Technology

[0002] In recent years, high-definition displays such as 4K or 8K have been put into practical use. Because these displays have a large number of pixels, if signals were to be sent directly to each pixel independently, the number of wiring between the display and the semiconductor chip that controls the image would become extremely large.

[0003] Therefore, various solutions have been introduced to reduce the number of wirings: for example, making the clock signals for transmitting data of each pixel share the same signal (see Japanese Patent Application Publication No. 2011-128535), and serializing the data to reduce the number of data signals (see Japanese Patent Application Publication No. Hei 8-10166).

[0004] [Existing technical documents]

[0005] [Patent Literature]

[0006] Patent Document 1: Japanese Patent Application Publication No. 2011-128535

[0007] Patent Document 2: Japanese Patent Application Publication No. 8-10166 Summary of the Invention

[0008] [The problem the invention aims to solve]

[0009] Since the number of signals that can be reduced even when sharing a clock signal is limited, serialization is usually used alone or in combination to reduce the number of data signals in most cases. For example, to maintain the data transmission speed after serializing the data of four signal wires, the data needs to be transmitted at four times the frequency. With such high-speed data transmission, power consumption tends to increase significantly.

[0010] This disclosure is based on the situation described above, and its objective is to provide a data transmission device that reduces the number of data signals while suppressing an increase in power consumption.

[0011] [Technical means to solve the problem]

[0012] One aspect of the data transmission apparatus disclosed herein includes: a data transmitting unit having a transmitting port; and a data receiving group having n receiving units from a first receiving unit to an nth receiving unit (n ≥ 2), wherein the transmitting port of the data transmitting unit is configured to serially transmit data to be acquired by each of the n receiving units, the first receiving unit having an input port and a data port, and configured such that the input port of the first receiving unit receives data from the transmitting port of the data transmitting unit, and the data port of the first receiving unit transmits data from the data received from the input port of the first receiving unit after removing data that should only be received by the first receiving unit, the i-th receiving unit (2 ≤ i ≤ n-1) having an input port and a data port, and configured such that the input port of the i-th receiving unit receives data from the data port of the (i-1)-th receiving unit, and the data port of the i-th receiving unit transmits data from the data received from the input port of the i-th receiving unit after removing data that should only be received by the i-th receiving unit, and the nth receiving unit having an input port, and configured such that the input port of the nth receiving unit receives data from the data port of the (n-1)-th receiving unit.

[0013] [The effects of the invention]

[0014] The data transmission apparatus disclosed herein can suppress the increase in power consumption while reducing the number of data signals. Attached Figure Description

[0015] [ Figure 1 ] Figure 1 This is a block diagram illustrating the modular structure of a data transmission apparatus according to one aspect of the present disclosure.

[0016] [ Figure 2 ] Figure 2 It is shown Figure 1 A block diagram illustrating the data transmission and reception relationship of the receiving unit.

[0017] [ Figure 3 ] Figure 3 yes Figure 2 An example of a timing diagram for data transmission and reception.

[0018] [ Figure 4 ] Figure 4 It is shown Figure 1 A block diagram of the automatic discrimination mechanism of the receiving unit.

[0019] [ Figure 5 ] Figure 5 It shows the use Figure 1 A block diagram illustrating the structure of a data transmission system of a data transmission device. Detailed Implementation

[0020] [Description of Implementation Forms of this Disclosure]

[0021] (1) One aspect of the data transmission apparatus of this disclosure includes: a data transmitting unit having a transmitting port; and a data receiving group having n receiving units from a first receiving unit to an nth receiving unit (n ≥ 2), wherein the transmitting port of the data transmitting unit is configured to serially transmit data to be acquired by each of the n receiving units, the first receiving unit having an input port and a data port, and configured such that the input port of the first receiving unit receives data from the transmitting port of the data transmitting unit, and the data port of the first receiving unit transmits data received from the input port of the first receiving unit after removing data consisting only of... The first receiving unit should receive the data after the data received. The i-th receiving unit (2≦i≦n-1) has an input port and a data port, and is configured such that the input port of the i-th receiving unit receives the data from the data port of the (i-1)-th receiving unit. The data port of the i-th receiving unit transmits the data after removing only the data that should be received by the i-th receiving unit from the data received from the input port of the i-th receiving unit. The n-th receiving unit has an input port, and is configured such that the input port of the n-th receiving unit receives the data from the data port of the (n-1)-th receiving unit.

[0022] The data transmission device serially outputs data transmitted from the transmitting port to n receiving units, thus reducing the number of data signals between the data transmitting unit and the data receiving group. Furthermore, in this data transmission device, the data port of the i-th receiving unit transmits data received from the input port of the i-th receiving unit after removing data that should only be received by the i-th receiving unit. Therefore, compared to the case where this data is not removed, the signal change at the data port of the i-th receiving unit is less than the signal change at the input port of the i-th receiving unit, thereby suppressing an increase in power consumption. Here, "data that should only be received by the i-th receiving unit" refers to data received by the i-th receiving unit that does not need to be transmitted to the (i+1)-th receiving unit.

[0023] (2) According to the data transmission apparatus of (1), it is preferable that the data transmission at the transmitting port is performed at a constant data rate, and the data transmission rate at the data port of the j-th receiving unit (1≦j≦n-1) is less than the data reception rate at the input port of the j-th receiving unit. By reducing the data reception rate at the data port of the j-th receiving unit in this way, power consumption caused by data signal changes can be reduced. Here, "data rate" refers to the number of bits of data transmitted and received per unit time (e.g., 1 second).

[0024] (3) According to the data transmission apparatus of (2), it is preferable that the data lengths of the data to be acquired by each of the n receiving units are equal, and the data transmission of the data port of the j-th receiving unit is performed at a rate of (nj) / n times the data transmission rate of the transmitting port. By configuring the data port of the j-th receiving unit in this way, power consumption can be reduced while data is acquired stably. Here, the term "acquired data" is synonymous with data received only by the corresponding receiving unit.

[0025] (4) A data transmission apparatus according to any one of (1) to (3), wherein the data at the transmitting port is data arranged in descending order of the data to be acquired by each of the n receiving units according to the number i of the receiving unit. With this configuration, it is easy to unify the timing of the data to be acquired by each of the n receiving units.

[0026] (5) The data transmission apparatus according to any one of (1) to (4) preferably has an automatic discrimination mechanism that can identify its own number i for each of the n receiving units. By having the n receiving units have an automatic discrimination mechanism that can identify its own number i in this way, initial setup can be easily performed.

[0027] (6) According to the data transmission apparatus of (5), the automatic discrimination mechanism preferably includes: a transmission start signal indicating the start of transmission to itself; a number input signal indicating the number i of the receiving unit to be received; a number register latching the number input signal when the transmission start signal 41 indicates the start of transmission; a transmission output signal indicating the start of transmission to the next segment; and a number output signal indicating the number (i+1) of the receiving unit to be received in the next segment, and the automatic discrimination mechanism is controlled such that the transmission output signal indicates the start of transmission after receiving the transmission start signal. By configuring the automatic discrimination mechanism in this way, especially in systems performing high-speed communication, a stable communication state can be ensured early on.

[0028] [Details of the implementation of this disclosure]

[0029] The following describes a data transmission apparatus according to one embodiment of the present disclosure.

[0030] Figure 1 The data transmission device 1 shown includes a data transmitting unit 10 and a data receiving unit 20. The data transmission device 1 may be constructed, for example, from circuits such as large-scale integrated circuits (LSI).

[0031] <Data Transmission Department>

[0032] The data transmission unit 10 has three input ports 11 and one transmission port 12.

[0033] Input the data to be received by the three receiving units 30 (described later) into the three input ports 11 respectively.

[0034] The data transmitting unit 10 is configured to serially transmit the data to be acquired by each of the three receiving units 30 from the transmitting port 12. Specifically, the transmitting port 12 transmits the data after parallel-to-serial conversion of the input data input from the three input ports 11. In this case, it is preferable to set the data rate of the transmitting port 12 to 3p when the data rate of the input data is set to p, so as not to reduce the data transmission rate. That is, to multiply the frequency of data transmission.

[0035] Especially when the data rate is high (the frequency of data transmission is high), it is advisable to further implement clock data recovery (CDR) transmission, in which the clock used as the data transmission reference is embedded into the data signal. The data transmission device 1 is preferably used for signal transmission in the CDR manner.

[0036] Here, since the circuits for parallel-to-serial conversion, frequency multiplication of data transmission, and signal conversion to CDR mode are known, detailed descriptions are omitted.

[0037] <Data Receiving Group>

[0038] The data receiving group 20 has three receiving units 30 (first receiving unit 31, second receiving unit 32, and third receiving unit 33). The three receiving units 30 have an input port 34, a data port 35, and an output port 36.

[0039] like Figure 2 As shown, the configuration is as follows: the input port 34 of the first receiving unit 31 receives data from the transmission port 12 of the data transmitting unit 10, and the data port 35 of the first receiving unit 31 transmits data from the data received from the input port 34 of the first receiving unit 31, after removing only the data that the first receiving unit 31 should receive. Furthermore, the data that the first receiving unit 31 should receive is output to the output port 36 of the first receiving unit 31.

[0040] The configuration is as follows: the input port 34 of the second receiving unit 32 receives data from the data port 35 of the first receiving unit 31, and the data port 35 of the second receiving unit 32 transmits data from the data received from the input port 34 of the second receiving unit 32, after removing only the data that the second receiving unit 32 should receive. Furthermore, the data that the second receiving unit 32 should receive is output to the output port 36 of the second receiving unit 32.

[0041] The input port 34 of the third receiving unit 33 receives data from the data port 35 of the second receiving unit 32. Additionally, the data that the third receiving unit 33 is supposed to receive is output to the output port 36 of the third receiving unit 33.

[0042] This section details the data processing of data receiving group 20.

[0043] As described above, the data received by the input port 34 of the first receiving unit 31 from the transmission port 12 of the data transmitting unit 10 (the data of the transmission port 12) is data serialized from the data to be acquired by each of the three receiving units 30 (the first receiving unit 31, the second receiving unit 32, and the third receiving unit 33). The data to be acquired by each of the three receiving units 30 can be 1 bit or multiple bits.

[0044] The data transmitted through port 12 may contain an identifier inserted into the data indicating which receiving unit 30 should receive the data. In this case, each receiving unit 30 can determine which data should be received based on the identifier.

[0045] Alternatively, the data at the transmitting port 12 can be arranged in a predetermined order. In this case, each receiving unit 30 can determine the data to be received based on the data's arrangement. Since no additional identifier is required in this method, data transmission can be performed efficiently. The data in this case should preferably be the data to be acquired by each of the three receiving units 30, arranged in descending order of the receiving unit 30's number i.

[0046] Furthermore, data transmission at the transmitting port 12 should preferably be performed at a constant data rate, and more preferably, the data lengths to be acquired by the three receiving units 30 should be equal. Hereinafter, as... Figure 3 As shown in R1-IN (DR3), the following case will be used as an example for further explanation: the data transmission rate of the transmitting port 12 is P (period T=1 / P) and remains constant, the data length of each receiving unit 30 is 3 bits, and the data is arranged in descending order of number i (the order of data of the third receiving unit 33, data of the second receiving unit 32, and data of the first receiving unit 31). However, this does not mean that the data of the transmitting port 12 of the data transmission device 1 is limited to the above conditions.

[0047] In the data transmission device 1, the data transmission rate at the data port 35 of the j-th receiving unit (1≦j≦2) is lower than the data reception rate at the input port 34 of the j-th receiving unit. By reducing the data reception rate at the data port 35 of the j-th receiving unit, power consumption caused by data signal variations can be reduced. Furthermore, when the data transmission device 1 is constructed as a circuit, the circuit area can be designed to be smaller for the receiving unit with the reduced data rate, thereby achieving cost reduction for the data transmission device 1.

[0048] In this configuration, with n receiving units 30, the data transmission of the data port 35 of the j-th receiving unit is performed at a rate of (nj) / n times the data transmission rate P of the transmitting port 12. By configuring the data transmission of the data port 35 of the j-th receiving unit in this way, power consumption can be reduced while ensuring stable data acquisition. Figure 1 In the data transmission device 1 shown, since n=3, therefore... Figure 3 As shown, the data rate at data port 35 of the first receiving unit 31 (j=1) is 2 / 3P (=(3-1) / 3×P; period is 1.5T), and the data rate at data port 35 of the second receiving unit 32 (j=2) is 1 / 3P (=(3-2) / 3×P; period is 3T). For example, when the data transmission rate of the transmitting port 12 is 4.5 Gbps, the data rate at data port 35 of the first receiving unit 31 is 3.0 GBps, and the data rate at data port 35 of the second receiving unit 32 (j=2) is 1.5 GBps. The following explanation will continue with an example of the aforementioned data rate relationship.

[0049] Furthermore, data transmission cycles determined by the data rate are often subject to periodic fluctuations such as delays or jitter, making transmission between different data rates prone to instability. To ensure stable transmission between different data rates, a margin of at least 20% should be allowed relative to (nj) / n times the data rate. Specifically, the data rate should be set to at least (nj) / n times and less than (nj) / n times × 1.2 relative to the data rate.

[0050] As described above, the input port 34 of the first receiving unit 31 receives data synchronously with period T. Figure 3 The data shown in R1-IN is illustrated. Furthermore, in... Figure 3 In the diagram, the parentheses in each signal contain a label indicating the data rate. DR3 is a data group with a period of 4.5 Gbps (period T), DR2 is a data group with a period of 3.0 Gbps (period 1.5T), and DR1 is a data group with a period of 1.5 Gbps (period 3T).

[0051] The first receiving unit 31 outputs the data R1-OUT that it should receive from R1-IN to its output port 36. R1-OUT can be synchronized with the period 3T of DR1. The data #1 that the first receiving unit 31 should receive in R1-IN is received in the last three periods. Therefore, as... Figure 3 As shown, after receiving data #1, R1-OUT and DR1's period 3T are output synchronously.

[0052] Additionally, the first receiving unit 31 sends data R1-D, which is the data R1-IN received from the input port 34 of the first receiving unit 31 after removing the data that should only be received by the first receiving unit 31, to the data port 35. R1-D is output synchronously with the period 1.5T of DR2. Since the data sent to the data port 35 in R1-IN is the data from the first 6 cycles, R1-D is output synchronously with the period 1.5T of DR2 after the first receiving unit 31's input port 34 has just begun receiving data.

[0053] Since the input port 34 of the second receiving unit 32 receives data from the data port 35 of the first receiving unit 31, R2-IN becomes the same signal as R1-D and is synchronized with the period 1.5T of DR2.

[0054] The second receiving unit 32 outputs the data R2-OUT that it should receive from R2-IN to its output port 36. R2-OUT can be synchronized with the period 3T of DR1. The data #2 that the second receiving unit 32 should receive in R2-IN is received in the latter three periods. Therefore, as... Figure 3 As shown, after receiving data #2, R2-OUT is output synchronously with the period 3T of DR1.

[0055] Additionally, the second receiving unit 32 sends data R2-D, which is the data R2-IN received from the input port 34 of the second receiving unit 32 after removing the data that should only be received by the second receiving unit 32, to the data port 35. R2-D is output synchronously with the period 3T of DR1. Since the data sent to the data port 35 in R2-IN is the first three periods of data, R2-D is output synchronously with the period 3T of DR1 after the second receiving unit 32's input port 34 has just begun receiving data.

[0056] Since the input port 34 of the third receiving unit 33 receives data from the data port 35 of the second receiving unit 32, R3-IN becomes the same signal as R2-D and is synchronized with the period 3T of DR1.

[0057] During this stage, since only the third receiving unit 33 should receive data in R3-IN, it is sufficient to output the R3-IN signal synchronously with the period 3T of DR1 as R3-OUT to the output port 36. Figure 3 In the middle, it is advisable to adjust the cycle to synchronize the output with the output port 36 of the first receiving unit 31 or the second receiving unit 32.

[0058] <Automatic discrimination mechanism>

[0059] The three receiving units 30 should preferably have an automatic discrimination mechanism capable of recognizing their own number i. By equipping the three receiving units 30 with such an automatic discrimination mechanism, initial setup can be easily performed.

[0060] For example, the automatic identification mechanism can be implemented by: providing a read-only memory (ROM) in each receiving unit 30, and determining its own number i based on the data written to the ROM during system startup; or by assigning the number i to the port for number identification provided in each receiving unit 30 during system startup. However, especially in the CDR method that transmits data at high speed and with an embedded clock, the processing may be difficult, or the manufacturing cost of the LSI, etc., including the data transmission device 1, may increase.

[0061] Furthermore, the manufacturing cost may increase in the aforementioned method. Specifically, for example, if a ROM is provided in each receiving section 30, the area of ​​the receiving section 30 may increase. Even if the ROM is mounted on a printed wiring board, for example, outside the receiving section 30, the size of the printed wiring board will increase. This increase in area leads to an increase in manufacturing cost. Additionally, if the external pins of the receiving section 30 are fixed to assign a number i to the port provided in the receiving section 30 for identification, a dedicated printed wiring board matching the pattern fixed as number i will be provided, for example, thereby increasing the manufacturing cost of the printed wiring board.

[0062] In contrast, for example, when using the CDR method, such as Figure 4 As shown, the automatic discrimination mechanism 40 includes: a transmission start signal 41 indicating the start of transmission to itself; a number input signal 42 indicating the number i of the receiving unit 30 to be received; a number register 43 latching the number input signal 42 when the transmission start signal 41 indicates the start of transmission; a transmission output signal 44 indicating the start of transmission to the next segment; and a number output signal 45 indicating the number (i+1) of the receiving unit 30 to be received in the next segment, and the automatic discrimination mechanism 40 is controlled such that after receiving the transmission start signal 41, the transmission output signal 44 indicates the start of transmission.

[0063] If explained Figure 4 The automatic discrimination mechanism 40 operates as follows: In the initial state, the transmission output signal 44 of the first receiving unit 31 is inactive, and the number output signal 45 outputs the value incremented by 1 in the number register 43. In this state, the first receiving unit 31 is activated when it receives a transmission start signal 41 from the outside, and the number input signal 42 is 1. Furthermore, when receiving from the outside, the number input signal 42 is always 1. The transmission start signal 41 signifies the activation of the automatic discrimination mechanism 40, and it is activated only during one cycle.

[0064] When the transmission start signal 41 becomes active, the first receiving unit 31 latches the value of the number input signal 42 into the number register 43. That is, the number register 43 becomes 1, and the number output signal 45 becomes 2, which is the value of the number input signal 42 plus 1. After that, the transmission output signal 44 is made active only for one cycle.

[0065] The transmission start signal 41 of the second receiving unit 32 is connected to the transmission output signal 44 of the first receiving unit 31, and the number input signal 42 of the second receiving unit 32 is connected to the number output signal 45 of the first receiving unit 31. At this time, the second receiving unit 32 operates in the same way as the first receiving unit 31. After receiving the transmission output signal 44 of the first receiving unit 31 and becoming active, it latches 2 in the number register 43, sets its own number output signal 45 to 3, and simultaneously activates the transmission output signal 44.

[0066] The third receiving unit 33 is configured similarly, with 3 latched in its number register 43.

[0067] As described above, each receiving unit 30 can identify its own number i. Furthermore, by configuring the automatic discrimination mechanism 40 in this way, a stable communication state can be ensured early on, especially in high-speed communication systems. Additionally, in the automatic discrimination mechanism 40, each receiving unit 30 can have the same structure, which can also reduce manufacturing costs.

[0068] <Advantages>

[0069] The data transmission device 1 serially outputs data transmitted from the transmitting port 12 to the three receiving units 30, thus reducing the number of data signals between the data transmitting unit 10 and the data receiving group 20. Furthermore, in the data transmission device 1, the data port 35 of the i-th receiving unit 30 transmits data received from the input port 34 of the i-th receiving unit 30 after removing the data that should only be received by the i-th receiving unit 30. Therefore, compared to the case where this data is not removed, the signal change at the data port 35 of the i-th receiving unit 30 is less than the signal change at the input port 34 of the i-th receiving unit 30, thereby suppressing an increase in power consumption.

[0070] [Other Implementation Forms]

[0071] The embodiments described do not limit the structure of this disclosure. Therefore, based on the description in this specification and common technical knowledge, the constituent parts of each embodiment may be omitted, replaced, or added, and all such omissions or additions should be interpreted as falling within the scope of this disclosure.

[0072] In the described embodiment, a receiving group with three receiving units is illustrated, but the number of receiving units is not limited to three; it can also be two or four or more. When the number of receiving units is n (n ≥ 2), each of the n receiving units has an input port and a data port. The data transmitting unit is configured to serially transmit the data to be acquired by each of the n receiving units from the transmitting port. Furthermore, the input port of the first receiving unit receives data from the transmitting port, and the data port of the first receiving unit transmits data received from the input port of the first receiving unit after removing the data that should only be received by the first receiving unit. Additionally, the input port of the i-th receiving unit (2 ≤ i ≤ n-1) receives data from the data port of the (i-1)-th receiving unit, and the data port of the i-th receiving unit transmits data received from the input port of the i-th receiving unit after removing the data that should only be received by the i-th receiving unit. Finally, the input port of the n-th receiving unit receives data from the data port of the (n-1)-th receiving unit.

[0073] Furthermore, the number of receiving units is preferably three or more and eight or less. If the number of receiving units is less than the lower limit, it may not be possible to sufficiently reduce the number of data signals between the transmitting unit and the receiving group. Conversely, if the number of receiving units exceeds the upper limit, the data transmission cycle between the transmitting unit and the receiving group becomes too short, which may make stable communication difficult.

[0074] In the described embodiment, the third receiving unit, which is the final segment among the three receiving units, is shown to have a data port, but the data port of the final segment can be omitted. On the other hand, when the third receiving unit has a data port, since each receiving unit can have the same structure, it has the advantage of being easy to design or expand the data transmission apparatus of this disclosure.

[0075] In the described embodiment, it is shown that each of the three receiving parts has an output port. However, the output port is not an essential component, and omitting some or all of the data transmission device is also within the scope of this disclosure.

[0076] In the described embodiment, the number of input ports of the transmitting unit is the same as the number of receiving units. However, the number of input ports of the transmitting unit and the number of receiving units do not necessarily need to be the same, and may differ. For example, the transmitting unit may have 4 input ports, and the receiving unit may have 3. In this case, regarding the data rate, when data rate D1 is input to each input port of the transmitting unit and data rate D2 is output from the transmitting port of the transmitting unit, the data rate can be determined, for example, by making D1×4=D2.

[0077] The data transmission devices can be used in parallel. That is, a data transmission system can be constructed that includes multiple data transmission devices configured in parallel. For example, Figure 5 As shown, there are two parallel configurations. Figure 1 In the case of the data transmission system 100 of the data transmission device 1, six data items can be transmitted through two signal lines.

[0078] [Industry availability]

[0079] The data transmission apparatus disclosed herein can suppress the increase in power consumption while reducing the number of data signals.

[0080] Explanation of icon numbers

[0081] 1: Data transmission device

[0082] 10: Data Transmission Department

[0083] 11: Input Port

[0084] 12: Sending port

[0085] 20: Data Receiving Group

[0086] 30: Receiving Department

[0087] 31: First Receiving Unit

[0088] 32: Second Receiving Unit

[0089] 33: Third Receiving Unit

[0090] 34: Input Port

[0091] 35: Data Port

[0092] 36: Output Port

[0093] 40: Automatic discrimination mechanism

[0094] 41: Transmission start signal

[0095] 42: Number Input Signal

[0096] 43: Number Register

[0097] 44: Transmit output signal

[0098] 45: Numbered output signal

[0099] 100: Data transmission system

Claims

1. A data transmission device, comprising: A data transmission unit with a transmission port; as well as The data receiving group has n receiving units, from the first receiving unit to the nth receiving unit (n ≥ 2). The transmitting port of the data transmitting unit is configured to serially transmit the data to be acquired by each of the n receiving units. The first receiving unit has an input port and a data port, and is configured such that the input port of the first receiving unit receives data from the transmission port of the data transmitting unit, and the data port of the first receiving unit transmits data from the data received from the input port of the first receiving unit after removing the data that should only be received by the first receiving unit. The i-th receiving unit (2≦i≦n-1) has an input port and a data port, and is configured such that the input port of the i-th receiving unit receives data from the data port of the (i-1)-th receiving unit, and the data port of the i-th receiving unit transmits data received from the input port of the i-th receiving unit after removing the data that should only be received by the i-th receiving unit. The nth receiving unit has an input port, and is configured such that the input port of the nth receiving unit receives data from the data port of the (n-1)th receiving unit.

2. The data transmission apparatus according to claim 1, wherein, The data transmission port transmits data at a constant data rate. The data transmission rate at the data port of the j-th receiving unit (1≦j≦n-1) is less than the data reception rate at the input port of the j-th receiving unit.

3. The data transmission device according to claim 2, wherein, The configuration is such that the data length to be acquired by each of the n receiving units is equal. The data transmission of the data port of the j-th receiving unit is performed at a rate of (nj) / n times the data transmission rate of the transmitting port.

4. The data transmission apparatus according to any one of claims 1 to 3, wherein, The data at the transmitting port is data that is arranged in descending order of the data to be acquired by each of the n receiving units according to the number i of the receiving unit.

5. The data transmission apparatus according to any one of claims 1 to 3, wherein, The n receiving units have an automatic discrimination mechanism that can identify their own number i.

6. The data transmission apparatus according to claim 5, wherein, The automatic discrimination mechanism has the following features: The transmission start signal indicates that transmission to itself has begun. The input signal indicates the number i of the receiving unit that should be received; The number register latches the number input signal when the transmission start signal indicates the start of transmission; The transmission output signal indicates the start of the next transmission segment; and The output signal indicates the number (i+1) of the receiving unit that should be received next. Furthermore, the automatic discrimination mechanism is controlled such that upon receiving the transmission start signal, the transmission output signal indicates the start of transmission.

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