Multiplexing apparatus

Abstract: A multiplexing apparatus in which plural digital data are written into a memory, stored in it, the data is read out in sequence by a clock to get a subsequent group of digital data, wherein memory means for storing digital data to be transferred from a certain high-speed circuit to another high-speed circuit and control means for performing a writing and reading-out control of the digital data for the memory means, the digital data to be relayed from a prescribed high-speed circuit of plural high-speed circuits to another high-speed circuit is stored, a writing of the digital data of another high-speed circuit card is allowed for the memory means by the control means when this desired high-speed circuit card is being used and in turn when another high-speed circuit card is being used, a writing of the digital data of the prescribed high-speed circuit card is allowed for the memory means through the control means to perform a high-speed relay of the digital data of plural high-speed circuits, resulting in that even if the number of high-speed circuits are increased, the number of ICs are not changed and a relay of the high-speed digital data can be performed.

Description: BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a multiplexing apparatus for multiplexing plural input data (digital signals) of 400 to 9600 PBS, for example, and plural data of 1.544 MBPS to plural data of 1.544 MBPS. Description of the Prior Art EP-A-O 186 141 discloses a multiplexing apparatus comprising a plurality of terminal cards connected to each of plural low-speed circuits, plural high-speed circuit cards connected to each of plural high-speed circuits, a memory means for writing and reading the transmitted digital data from said high-speed circuits through said high-speed circuit cards in case of performing data transfer between said plural high-speed circuits, and a control means for writing data from said high-speed circuits into said memory means through said high-speed circuit cards, reading out the data stored in said memory means at a time different from the case of said data transfer between said plural high-speed circuits and outputting the data to said high-speed circuit cards. In this known apparatus, data are transferred by units of 8 bit. Fig. 1 is a schematic diagram for showing a configuration of an internal arrangement of a further conventional type of multiplexing apparatus disclosed in JP-A-61-163741 wherein 1a-1n denote low-speed circuits, and each of these circuits is connected to each of terminal cards 2a to 2n. Reference numeral 3 designates an input bus and reference numeral 4 denotes an output bus and these are connected in common to the terminal cards 2a to 2n. Reference numeral 5a denotes a high-speed circuit card, reference numeral 5b denotes a second high-speed card, and reference numeral 7 designates a timing control circuit and each of them is connected to the input bus 3 and the output bus 4, respectively. Reference numeral 6a denotes a first high-speed circuit and reference numeral 6b designates a second high-speed circuit, and each of the high-speed circuits is connected to the high-speed circuit card 5a and the second high-speed circuit card 5b. To the timing control circuit 7 is connected an address bus 8 and from the timing control circuit 7 is outputted a synchronous clock 9. The address bus 8 is connected to the terminal cards 2a to 2n and the synchronous clock 9 is given to the first high-speed circuit card 5a and the second high-speed circuit card 5b. Within the second high-speed circuit card 5b are present a shift register 10 and a selector 11, and to the shift register 10 is inputted the synchronous clock 9 and the selector 11 is connected. In Fig. 3, reference numeral 13 denotes data on either input bus or output bus, reference numeral 14 denotes a synchronous clock 9, reference numeral 15 denotes the synchronous clock 9 after shifting, reference numeral 16 designates data on the first high-speed circuit, reference numeral 17 denotes data on the second high-speed circuit, respectively. Next, operation will be described. In Fig. 2 is illustrated a standard configuration of PCM (Pulse Code Modulation) signal. A configuration of bits consists of a synchronous bit of one bit and data bits of 192 bits and one frame is constructed by these bits. In this preferred embodiment, one bit of 192 bits is used to cause the synchronous bit to have a value of 2. If a symbol showing one cycle in 20 frames is applied to the synchronous bit, a period for every 20 frames can be detected. Since one frame is of 125 µsec, one multi-frame occupy 2.5 msec. Accordingly, since one bit on one multi-frame is one bit per 2.5 msec, information of 400 BPS can be transferred. Thus, if n bits in one multi-frame are assigned for a transmittance of 400*nBPS, data ranging from a low-speed to a high-speed can be directly multiplexed. On multi-frame contains data of 193*20 = 3860 bits. Then, in Fig. 1, the timing control circuit 7 has a counter cyclically operating at a period of this 3860 and transmits a synchronous clock 9 once per 3860 times. The timing control circuit 7 has memories corresponding to the addresses of the terminal cards 2a to 2n for every counter values of 3860 pieces, and the addresses outputted from the memories are transmitted to each of the terminal cards 2a to 2n through the address bus 8. The address values are compared with an address value of each of the cards by an address decoder in the terminal cards 2a to 2n and then the terminal cards 2a to 2n can use the input bus 3 and the output bus 4 only when a specified terminal card is selected. The first and second high-speed circuit cards 5a and 5b may detect at first a synchronizing bit from the bits inputted from the first and second high-speed circuits 6a and 6b and fetch the input data. The first high-speed circuit card 5a may transmit the input data to the input bus 3 in compliance with a synchronizing clock sent from the timing control circuit 7. Since all the data sent from the first high-speed circuit 6a are determined in advance for their bits to be assigned to what terminal, a length of data representing their sum is already known and thus the value of the selector 11 in the second high-speed circuit card 5b is set to be delayed by an amount corresponding to this data length. Since the second high-speed circuit card 5b may transmit the input data to the input bus 3 in synchronous with the shifted synchronous clock 15, the data from the first high-speed circuit 6a is not overlapped with the data from the second high-speed circuit 6b on the input bus 3 as indicated in the data on the input or output bus 13. As shown in data 16 on the first high-speed circuit, the output is made such that the first high-speed circuit card 5a may insert a synchronous bit in compliance with the synchronous clock 14 to transmit the data on the output bus 4 to the high-speed circuit 6a, and as shown by the data on the second high-speed circuit 17, the second high-speed circuit card 5b may insert a synchronous bit in compliance with the shifted synchronous clock 15 and transmit the data of the output bus 4 to the high-speed circuit 6b. Since the conventional type of multiplexing apparatus is constructed as described above, it had a problem that data could not be transmitted from one high-speed circuit to the other high-speed circuit through a multiplexing device. SUMMARY OF THE INVENTION It is an major object of the present invention to provide a multiplexing apparatus having a function of relay so as to enable data transmitted from one high-speed circuit to the other high-speed circuit through a multiplexing device to be performed. It is another object of the present invention to provide a multiplexing apparatus having a new performance which is more superior than the existing device and of which realization can be performed in a relative inexpensive cost. It is still another object of the present invention to provide a multiplexing apparatus in which a structure of this apparatus is not complex and even if the number of circuits is increased, a relay of high-speed data can be carried out without changing the number of IC. The above and other objects and features of the present invention will become more apparent by reading the following detailed description in compliance with the accompanying drawings. Provided that the drawings are only illustrative and they do not restrict a scope of the present invention. In order to accomplish the above objects, the multiplexing apparatus of the present invention comprises a plurality of terminal cards connected to each of plural low-speed circuits, plural high-speed circuit cards connected to each of plural high-speed circuits, a memory means for writing and reading the transmitted digital data from said high-speed circuits through said high-speed circuit cards in case of performing data transfer between said plural high-speed circuits, and a control means for writing data from said high-speed circuits into said memory means through said high-speed circuit cards, reading out the data stored in said memory means at a time different from the case of said data transfer between said plural high-speed circuits and outputting the data to said high-speed circuit cards, and is characterized in that a timing control circuit is provided for varying speed of data of said terminal cards by corresponding addresses of said high-speed circuit cards with those of said high-speed circuit cards, performing a timing control for multiplex transmittance to said high-speed circuit cards and performing a timing control for fetching data from said high-speed circuits to said high-speed circuit cards and a timing control over a writing and reading for said memory means in case of performing said data transfer, and said control means is provided for writing data from said high-speed circuits into said memory means on a bit by bit basis through said high-speed circuit cards under an order based on said timing control, reading out the data stored in said memory means on the basis of said timing control at a time different from the case of said data transfer between said plural high-speed circuits and outputting the data to said high-speed circuit cards on a bit by bit basis. The above-mentioned features result in the advantage that the multiplexing apparatus can be used for more general purposes, and that it can deal with more various types of data. Further advantageous embodiments are defined in the sub-claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram for showing a configuration of a multiplexing apparatus of the prior art. Fig. 2 is an explanatory view for showing a configuration of frame for explanating the multiplexing apparatus of Fig. 1. Fig. 3 is an explanatory view for showing operation of the multiplexing apparatus of Fig. 1. Fig. 4 is a block diagram for showing a configuration of a multiplexing apparatus of a first preferred embodiment of the present invention. Figs. 5 and 6 are an illustrative view for illustrating operation of the first preferred embodiment, respectively. Fig. 7 is a block diagram for showing a configuration of the multiplexing apparatus of the second preferred embodiment of the present invention. Fig. 8 is an explanatory view for showing operation of the second preferred embodiment of the present invention. Fig. 9 is a block diagram for showing a configuration of the multiplexing apparatus of the third preferred embodiment of the present invention. Fig. 10 is a block diagram for showing a configuration of the multiplexing apparatus of the fourth preferred embodiments of the present invention. Fig. 11 is an explanatory view for showing operation of the multiplexing apparatus of Fig. 10. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the accompanying drawings, the preferred embodiments of the present invention will be described in detail. In Fig. 4, the same portion as that of Fig. 1 are affixed only with the same reference symbols. That is, 1a to 1n, 2a to 2n, 3, 4, 5a to 5c, 6a to 6c and 7 to 9 are similar to that of Fig. 1. Reference numeral 40 denotes an address decoder to which an address bus 8 from the timing control circuit 7 is connected and also a cyclic clock 58 is inputted. Reference numeral 42 denotes a counter in which a clock 41 for a counter from the address decoder 40, and a synchronizing clock 9 are applied as an input signal. To the counter 42 is connected a data RAM writing address bus 43 and the data RAM writing address bus 43 is connected to the reading address memory 44 and R/W (reading/writing) selector 46. From the reading address memory 44 is connected the data RAM reading address bus 45, and the data RAM reading address bus 45 is connected to the R/W selector 46. To the R/W selector 46 is also inputted the cyclic clock 58. Reference numeral 50 designates a data RAM acting as memory means and to the address of the data RAM 50 is connected the data RAM address bus 47 from the R/W selector 46. To the R/W control terminal of the data RAM 50 is inputted the R/W control signal 48 from the R/W selector 46. Reference numeral 53 denotes an input bus gate and its input terminal is connected to an input bus 3 and its output terminal is connected to data RAM 50 through the data RAM data bus 51. The data bus 51 for data RAM is also connected to a latch 52. Reference numeral 49 denotes a latch clock from R/W selector 46 and inputted to the clock terminal of the latch 52. Reference numeral 54 denotes a latch output bus connected to the latch 52. This latch output bus 54 is connected to an input terminal of the output bus gate 57 and an output terminal of the output bus gate 57 is connected to an output bus 4. To a control terminal of the gate 53 for input bus is connected a gate allowable signal 56 for input bus from the R/W selector 46. To the control terminal of the gate 57 for output bus is inputted a gate allowable signal 55 for an output bus from the address decoder 40. Figs. 5 and 6 illustrate one preferred embodiment of the present invention. Reference numeral 31 in Fig. 5(a) denotes an input data from the first high-speed circuit 6a, reference numeral 32 in Fig. 5(b) denotes an input data from the second high-speed circuit 6b, reference numeral 33 in Fig. 5(c) denotes an input data from a third high-speed circuit 6c, reference numeral 37 in Fig. 5(d) denotes an output data for the first high-speed circuit 6a, reference numeral 38 in Fig. 5(e) denotes an output data for the second high-speed circuit 6b, and reference numeral 39 in Fig. 5(f) denotes an output data for the third high-speed circuit 6c, respectively. Reference numeral 60 in Fig. 6(a) denotes a writing address bus value for data RAM, reference numeral 61 in Fig. 6(b) denotes R/W control signal, reference numeral 62 in Fig. 6(c) denotes an address bus value of data RAM, reference numeral 63 in Fig. 6(d) denotes a gate allowable signal for input bus, reference numeral 64 in Fig. 6(e) designates a data bus value for data RAM, reference numeral 65 in Fig. 6(f) denotes a latch clock, reference numeral 66 in Fig. 6(g) designates a latch output bus value, reference numeral 67 in Fig. 6(h) designates a gate allowable signal for an output bus, and reference numeral 68 in Fig. 6(i) denotes an output bus value, respectively. The address decoder 40, the counter 42, the reading address memory 44, the R/W selector 46, the latch 52, the input bus gate 53 and the output bus gate 57 may constitute a controlling means for writing and reading of the data RAM 50 acting as the memory means. Next, operation of the above-mentioned arrangement will be described. In Fig. 5, in case that the first high-speed circuit 6a performs a transferring of data by every 10H bits between the second high-speed circuit 6b and the third high-speed circuit 6c, the data transmitted from the first high-speed circuit 6a to the second high-speed circuit 6b and the third high-speed circuit 6c is included in the input data from the first high-speed circuit 6a [Fig. 5(a)] and the timing control circuit 7 may output an address of the second high-speed circuit card 5b in order to fetch the data (indicated by A1 in Fig. 5) for the second high-speed circuit 6b and further output an address of the third high-speed circuit card 5c in order to take data (indicated by B1 in Fig. 5) for the third high-speed circuit 6c. The address decoder 40 may fetch a clock of the counter operating in synchronous with 3860 provided by the timing control circuit 7 as the cyclic clock 58 and output this cyclic clock 58 as the clock 41 for the counter only while the address of any one of the high-speed circuit cards 5a to 5c is selected, so that during a time in which data of a total of 20H bits of data 10H bits for the second high-speed circuit 6b and data 10H bits for the third high-speed circuit 6c are inputted, the address decoder 40 may transmit the clock 41 for the counter to the counter 42 by 20H times. Since the counter 42 is reset by the synchronous clock 9, an output value of the counter 42 is varied in compliance with the counter clock 41 from 0 to 20H. An output of the counter 42 is sent to the R/W selector 46 as a writing address bus 43 for data RAM and is used as an address when it is written into the data RAM 50. Although R/W control signal 48 is normally high (read), the R/W selector 46 may output 1 clock of the cyclic clock 58 to the R/W control signal 48 when a value of the writing address bus 43 for data RAM is varied. With this arrangement, as shown at 61 in Fig. 6(b), the R/W control signal 48 becomes low (write) for 1/2 clock period. Then, a value of the writing address bus 43 for data RAM is transmitted to the address bus 47 of data RAM. When a signal having the R/W control signal 61 reversed is transmitted as shown in 63 of Fig. 6(d) as the gate allowable signal 56 for the input bus, an allowable state is attained when a writing operation is carried out, the data of the input bus 3 passes through the input bus gate 53 and is written into the data RAM 50 through the data bus 51 for data RAM. Accordingly, when an output value of the counter 42 is varied up to 20H, the data sent from the first high-speed circuit 6a to the second high-speed circuit 6b and the third high-speed circuit 6c as shown at A2 and B2 in Fig. 5 is written at addresses of 1H to 20H of the data RAM 50. Similarly, the data sent from the high-speed circuit 6b to the first high-speed circuit 6a in Fig. 5 is written at addresses 21H to 30H as shown at C2 in Fig. 5, and the data sent from the third high-speed circuit 6c to the first high-speed circuit 6a is written at addresses 31H to 40H of the data RAM 50 as shown at D2 in Fig. 5. Again, in case that the data is transferred from the first high-speed circuit 6a to the second high-speed circuit 6b and the third high-speed circuit 6c, the counter 42 is reset by the synchronous clock 9, and an output value of the counter 42 is varied from 0H to 20H in compliance with the counter clock 41. It is assumed that RAM is used as the reading address memory 44 and further an output of the counter 42 is also inputted to the reading address memory 44. If 21H to 30H are written in the addresses 1H to 10H and 31H to 40H are written in the addresses 11H to 20H in the reading address memory 44 in advance, at first 21H is outputted to the reading bus 45 for data RAM, the addresses are incrementized in sequence in compliance with the counter clock 41 and then their contents of 22H to 30H are outputted in sequence. As the value of the writing address bus 43 for data RAM is varied, the R/W selector 46 causes the R/W control signal 48 to be alternatively varied as read/write, and as shown at 62 in Fig. 6(c), since the value of reading address bus 45 for data RAM is transmitted to the address bus 47 for data RAM in case of reading, the content of the address 21H of the data RAM 50 is outputted at first to the data bus 51 for data RAM. An initial 1 bit of the data 10H bits from the previous second high-speed circuit 6b to the first high-speed circuit 6a is written in the address 21H, and this value is outputted to the data bus 51 for data RAM as shown at 64 in Fig. 6(e). If it is assumed that the latch clock 49 may output only when the value of writing address bus 43 for data RAM shown in Fig. 6(e) is varied, the value of data bus 51 for data RAM is fetched into the latch 52 by the latch clock 49, and the value of latch output bus 54 is varied as shown at the latch output bus value 66 of Fig. 6(g). As shown at 67 in Fig. 6(h), if the gate allowable signal 55 for output bus is allowed while any one of the addresses of the first to third high-speed circuit cards 5a to 5c is being selected, the value of the latch output bus 54 which is the content of the previous address of 21H is outputted to the output bus 4 through the output bus gate 57. Similarly, although the contents ranging from 22H to 30H are also outputted, these are the data to be applied from the second high-speed circuit 6b to the first high-speed circuit 6a shown at C2 in Fig. 5 and the contents of 31H to 40H are also outputted. These contents are data fed from the third high-speed circuit 6c to the first high-speed circuit 6a shown at D2 in Fig. 5, and as shown by the output data 37 [Fig. 5(d)] for the first high-speed circuit, both data from the second high-speed circuit 6b (shown at C3 in Fig. 5) and data from the third high-speed circuit 6c (shown at D3 in Fig. 5) are transferred to the first high-speed circuit 6a. Then, if the second high-speed circuit card 5b is selected, data from the first high-speed circuit 6a to the second high-speed circuit 6b (shown at A2 in Fig. 5) are applied as contents of the addresses 21H to 30H of the reading address memory 44 and 1H to 10H are written in advance, thereby as shown at the output data 38 for the second high-speed circuit 6b [Fig. 5(e)], the data from the first high-speed circuit 6a (shown at A3 in Fig. 5) is transferred to the second high-speed circuit 6b. Then, if the third high-speed circuit card 5c is selected, similarly, the data from the first high-speed circuit 6a to the third high-speed circuit 6c (shown at B2 in Fig. 5) are applied as the contents of the addresses 31H to 40H of the reading address memory 44 and 11H to 20H are written, thereby as shown at the output data 39 for the third high-speed circuit [Fig. 5(f)], the data from the first high-speed circuit 6a (shown at B3 in Fig. 5) is transferred to the third high-speed circuit 6c. In Fig. 4, RAM is used as the reading address memory 44. It is more convenient to use ROM due to the fact that a bit assignment of data for the high-speed circuit is fixed, and so even if ROM is used, a similar effect can be attained. In the above-mentioned example, it has been indicated as if one block of the high-speed data is continuously relayed. However, another block which is not continuous may be processed similarly by dispersing the addresses for the address decoder 40. As described above, according to the first preferred embodiment of the present invention, even if the number of high-speed circuits are increased, the number of ICs are not varied in the multiplexing apparatus and so a relay of the high-speed data can be performed. Fig. 7 is a block diagram for showing a second preferred embodiment of the present invention. Fig. 7 shows a case in which two systems of the high-speed circuits 6a and 6b and the high-speed circuit cards 5a and 5b are applied, wherein the data RAM 50, latch 52, input bus gate 53, output bus gate 57, R/W selector 46, reading address memory 44 and address decoder 40 in Fig. 4 are not used. Alternatively, FIFO memories 120a and 120b and address decoder 118 for FIFO are used. To the address decoder 118 for FIFO is connected an address bus 8. From the address decoder 118 for FIFO are outputted FIFO control signals 119a and 119b. FIFO control signals 119a and 119b are connected to the first and second FIFO memories 120a and 120b. Next, operation of this system will be described. Fig. 8 is an explanatory view for showing operation of the preferred embodiment shown in Fig. 7. Reference numeral 121 in Fig. 8(a) denotes an input data from the first high-speed circuit 6a, reference numeral 122 in Fig. 8(b) designates an output data to the first high-speed circuit 6a, reference numeral 123 in Fig. 8(c) denotes an input data from the second high-speed circuit 6b, reference numeral 124 in Fig. 8(d) denotes an output data for the second high-speed circuit 6b, reference numeral 125 in Fig. 8(e) denotes data fed into the first FIFO memory 120a and reference numeral 126 in Fig. 8(f) denotes data to be fed into the second FIFO memory 120b. The timing control circuit 7 has memories to which the addresses of the terminal cards 2a to 2n and the first and second high-speed circuit cards 5a and 5b are corresponded for every counter values of 3860 pieces, and the address values outputted from these memories are transmitted to each of the terminal cards 2a to 2n and the address decoder 118 for FIFO through the address bus 8. Data transmitted from the first high-speed circuit 6a to the second high-speed circuit 6b are included in the input data 121 [Fig. 8(a)] from the first high-speed circuit 6a and the timing control circuit 7 may output an address of the second high-speed circuit card 5b in order to fetch the data (shown at A1 in Fig. 8) into the second high-speed circuit 6b. Address decoder 118 for FIFO may write data (indicated at A2 in Fig. 8) into the second FIFO memory 120b by turning OFF the control signal 119a and turning ON the control signal 119b as shown at data 126 to be fed to the second FIFO memory 120b. Then, data to be transmitted from the second high-speed circuit 6b to the first high-speed circuit 6a is included in the input data 123 [Fig. 8(c)] from the second high-speed circuit 6b, and the timing control circuit 7 may output an address of the first high-speed circuit card 5a in order to fetch the data (indicated at B1 in Fig. 8) for the first high-speed circuit 6a. Address decoder 118 for FIFO may write the data (indicated at B2 in Fig. 8) into the first FIFO memory 120a by turning ON the control signal 119a and turning OFF the control signal 119b as shown at data 125 [Fig. 8(e)] to be fed into the first FIFO memory 120a. At this time, a reading from the second FIFO memory 120b is allowed, the previous data (indicated at A2 in Fig. 8) is sent to the output bus 4, and then the data from the first high-speed circuit 6a is outputted to the second high-speed circuit 6b as shown at the output data 124 [Fig. 8(d)] for the second high-speed circuit 6b. Fig. 9 is a block diagram for showing a third preferred embodiment of the present invention. In Fig. 9, one FIFO memory 120 is used and reference numeral 127 in Fig. 8(g) denotes an input data for this FIFO memory 120. As shown in Fig. 9, even if there is one FIFO memory 120, a relay function can be applied to the multiplexing apparatus. Data transmitted from the first high-speed circuit 6a to the second high-speed circuit 6b is included in the input data 121 [ Fig. 8(a)] from the first high-speed circuit 6a. The timing control circuit 7 may output an address of the second high-speed circuit card 5b in order to fetch data (indicated at A1 in Fig. 8) for the second high-speed circuit 6b. Address decoder 118 for FIFO may write data (indicated at A3 in Fig. 8) into the FIFO memory 120 by turning ON the control signal 119 as shown at data 127 inputted to the FIFO memory 120 [Fig. 8(g)]. Then, data transmitted from the second high-speed circuit 6b to the first high-speed circuit 6a is included in the input data 123 [Fig. 8(c)] from the second high-speed circuit 6b, and the timing control circuit 7 may output an address of the first high-speed circuit card 5a in order to fetch data (indicated at B1 in Fig. 8) for the first high-speed circuit. Address decoder 118 for FIFO may write data (indicated at B3 in Fig. 8) into FIFO memory 120 by turning ON the control signal 119 as indicated by data 127 [Fig. 8(g)] to be fed into FIFO memory 120. At this time, a reading from the FIFO memory 120 is also allowed and the previous data (indicated at A3 in Fig. 8) is transmitted to the output bus 4, and data from the first high-speed circuit 6a is outputted to the second high-speed circuit 6b as shown at an output data 124 for the second high-speed circuit 6b. In Fig. 7, the FIFO memories 120a and 120b become memory means and the FIFO address decoder 118 may become a writing and reading control means for the memory means. In Fig. 9, FIFO memory 120 becomes memory means and address decoder 118 for FIFO becomes its writing and reading means. Although the examples shown in Figs. 7 and 9 indicate a system in which one block of high-speed data is continuously relayed. However, data which is not continuous can be processed similarly by dispersing the address for FIFO memory. As described above, according to the preferred embodiment shown in Figs. 7 and 9, application of FIFO memory and address decoder for FIFO enables data to be transmitted from one high-speed circuit to the other high-speed circuit. Fig. 10 is a block diagram for showing a fourth preferred embodiment of the present invention, wherein reference numeral 150 denotes an address decoder for FIFO writing to which an address bus 8 from the timing control circuit 7 is connected and then FIFO writing control signals 160a to 160c are outputted. FIFO writing control signals 160a to 160c are connected to the FIFO memories 140a to 140c. From the FIFO writing address decoder 150 are also outputted counter clock 170 and FIFO allowable signal 180. The counter clock 170 is connected to the counter 190 and a synchronizing clock 9 from the timing control circuit 7 is also connected to the counter 190. From the counter 190 is outputted a counted value and this is connected to the memory 210 as a memory address bus 200. Reference numeral 220 denotes FIFO reading address bus connected between the memory 210 and the FIFO reading address decoder 230. To the FIFO reading address decoder 230 is also inputted the FIFO allowable signal 180. Each of the FIFO reading control signals 240a to 240c is transmitted from the FIFO reading address decoder 230 to each of the FIFO memories 140a to 140c. In Fig. 10, FIFO memories 140a to 140c may constitute memory means, and FIFO writing address decoder 150, counter 190, memory 210 and FIFO reading address decoder 230 may constitute control means. In addition, reference numerals 1a to 1n, 2a to 2n, 3, 4, 5a to 5c, 6a to 6c and 7 to 9 are similar to that of the preferred embodiment shown in Fig. 4. Fig. 11 is an operative illustration for showing the preferred embodiment of Fig. 10. Reference numeral 310 in Fig. 11(a) denotes input data from the first high-speed circuit 6a, reference numeral 320 in Fig. 11(b) denotes an input data from the second high-speed circuit 6b and reference numeral 330 in Fig. 11(c) denotes an input data from the third high-speed circuit 6c. Reference numeral 340 in Fig. 11(d) denotes data to be fed into the first FIFO memory 140a, reference numeral 350 in Fig. 11(e) denotes data to be fed into the second FIFO memory 140b, reference numeral 360 in Fig. 11(f) denotes data to be fed into the third FIFO memory 140c and reference numeral 370 in Fig. 11(g) denotes an output data for the first high-speed circuit 6a. Reference numeral 380 in Fig. 11(h) denotes an output data for the second high-speed circuit 6b and reference numeral 390 in Fig. 11(i) denotes an output data for the third high-speed circuit 6c. Next, operation of this system will be described. In case that the first high-speed circuit 6a may perform a data transferring operation between the second high-speed circuit 6b and the third high-speed circuit 6c, data to be transmitted from the first high-speed circuit 6a to the second high-speed circuit 6b and the third high-speed circuit 6c is included in the input data 310 [Fig. 11(a)] from the first high-speed circuit 6a. The timing control circuit 7 may output an address of the second high-speed circuit card 5b in order to fetch data (indicated at A1 in Fig. 11) for the second high-speed circuit 6b. Address decoder 150 for FIFO writing may write data (indicated at A2 in Fig. 11) into the second FIFO 140b by turning ON the second FIFO writing control signal 160b and turning OFF other FIFO writing control signals 160a and 160c as indicated in data 350 [Fig. 11(e)] to be fed to the second FIFO memory 140b. Similarly, the timing control circuit 7 may output the address of the third high-speed circuit card 5c in order to fetch the data (indicated at B1 in Fig. 11) for the third high-speed circuit 6c. FIFO writing address decoder 150 may write data (indicated at B2 in Fig. 11) into the third FIFO memory 140c by turning ON the third FIFO writing control signal 160c and turning OFF other FIFO writing control signals 160a and 160b as indicated by data 360 [Fig. 11(f)] to be fed into the third FIFO memory 140c. Data to be transmitted from the second high-speed circuit 6b to the first high-speed circuit 6a is included in the input data 320 [Fig. 11(b)] from the second high-speed circuit 6b. The timing control circuit 7 may output an address of the first high-speed circuit card 5a in order to fetch data (indicated at C1 in Fig. 11) to the first high-speed circuit. FIFO writing address decoder 150 may write data (indicated at C2 in Fig. 11) into the first FIFO memory 140a by turning ON the first FIFO writing control signal 160a and turning OFF other FIFO writing control signals 160b and 160c as indicated in data 340 [Fig. 11(d)] to be fed to the first FIFO memory 140a. Data to be transmitted from the third high-speed circuit 6c to the first high-speed circuit 6a is included in the input data from the third high-speed circuit 6c [Fig. 11(c)]. The timing control circuit 7 may output an address of the first high-speed circuit card 5a in order to fetch data (indicated at D1 in Fig. 11) for the first high-speed circuit 6a. FIFO writing address decoder 150 may write data (indicated at D2 in Fig. 11) into the first FIFO memory 140a by turning ON the first FIFO writing control signal 160a and turning OFF other FIFO writing control signals 160b and 160c as indicated by data 340 [Fig. 11(d)] to be fed to the first FIFO memory 140a. In case that data is transmitted again from the first high-speed circuit 6a to the second high-speed circuit 6b and the third high-speed circuit 6c, the counter 190 is reset in compliance with the synchronizing clock 9. FIFO writing address decoder 150 may send the counter clock 170 every time any one of the first to third high-speed circuit cards 5a to 5c is selected. At first, the second high-speed circuit card 5b is selected, then the third high-speed circuit card 5c is selected, so that the clock is sent by two times. Accordingly, the counted value is increased, a value of the memory address bus 200 is varied from "0" to "1" and then from "1" to "2". RAM is used in the memory 210, an address of the first high-speed circuit card 5a is written to the memory address value "1" in the memory 210 in advance and an address of the first high-speed circuit card 5a is also written to the memory address value "2" in advance, this value is outputted to the FIFO reading address bus 220. FIFO writing address decoder 150 is operated such that if FIFO allowable signal 180 is allowed only when any one of the writing control signals 160a to 160c for the FIFO memory is turned ON, the FIFO reading address decoder 230 may interpret this value when the address of the first high-speed circuit card 5a is outputted to the previous FIFO reading address bus 220. Since the FIFO allowable signal 180 is allowed, the first FIFO reading control signal 240a is turned ON and other FIFO reading control signals 240b and 240c are turned OFF. With this arrangement, the previous data (indicated at C2 and D2 in Fig. 11) is transmitted to the output bus 4 and both data from the second high-speed circuit 6b (indicated at C3 in Fig. 11) and the data (indicated at D3 in Fig. 11) from the third high-speed circuit 6c are transmitted to the first high-speed circuit card 6a as shown by output data 370 [Fig. 11(g)] for the first high-speed circuit 6a. Then, if the second high-speed circuit card 5b is selected, similarly, the clock is sent by one time, so that the counted value is increased by one and the value of the memory address bus 200 is varied from 2 to 3. If the address of the second high-speed circuit card 5b is written into the memory address value 3 in the memory 210 in advance, this value is outputted to the FIFO reading address bus 220 and FIFO allowable signal 180 is also allowed. So, the FIFO reading address decoder 230 may interpret this value to turn ON the second FIFO reading control signal 240b and to turn OFF other FIFO reading control signals 240a and 240c. With this arrangement, the previous data (indicated at A2 in Fig. 11) is sent to the output bus 4 and the data from the first high-speed circuit 6a (indicated at A3 in Fig. 11) is transmitted to the second high-speed circuit 6b as indicated by the output data 380 for the second high-speed circuit 6b [Fig. 11(h)]. Then, if the third high-speed circuit card 5c is selected, similarly, a clock is sent once, so that the counted value is increased by one and a value of the memory address bus 200 is varied from "3" to "4". If an address of the third high-speed circuit card 5c is written into the memory address value 4 in the memory 210 in advance, this value is outputted to the FIFO reading address bus 220 and the FIFO allowable signal 180 is also allowed, so that the FIFO reading address decoder 230 may interpret this value to turn ON the third FIFO reading control signal 240c and to turn OFF other FIFO reading control signals 240a and 240b. With this arrangement, the previous data (indicated at B2 in Fig. 11) is transmitted to the output bus 4, and the data (indicated at B3 in Fig. 11) from the first high-speed circuit 6a is transmitted to the third high-speed circuit 6c as indicated at the output data 390 for the third high-speed circuit 6c [Fig. 11(i)]. In Fig. 10, RAM is used as the memory 210. In case that a bit assignment of data for the high-speed circuit is fixed, an application of ROM is more convenient and a similar effect may also be attained even if ROM is used. The example shown in Fig. 10 illustrates a case in which three high-speed circuits are applied. Even if the number of high-speed circuits are increased, a similar effect can be attained by using the FIFO memories of which numbers correspond to the number of high-speed circuits. In this way, even if the number of the high-speed circuits are more than three, a relay of the high-speed data can be carried out with the multiplexing apparatus. As described above, according to the present invention, data to be relayed from the prescribed high-speed circuit of plural high-speed circuits to another high-speed circuit is stored, a writing of data of the other high-speed circuit card is allowed for the memory means by a controlling means when this prescribed high-speed circuit card is being used, and in turn when this another high-speed circuit card is being used, data in the desired high-speed circuit card is allowed for the memory means by the controlling means so as to make a high-speed relaying of data of plural high-speed data, resulting in that even if the number of high-speed circuits are increased, the present invention may have an effect that the number of ICs in the multiplexing apparatus are not varied and a relay of high-speed data can be carried out.

Claims: A multiplexing apparatus for multiplexing plural digital data in time-sharing basis to get a subsequent group of different digital data comprising: a plurality of terminal cards (2a - 2n) connected to each of plural low-speed circuits (1a - 1n); plural high-speed circuit cards (5a - 5c) connected to each of plural high-speed circuits (6a - 6c); a memory means (50; 120; 140) for writing and reading the transmitted digital data from said high-speed circuits (6a - 6c) through said high-speed circuit cards (5a - 5c) in case of performing data transfer between said plural high-speed circuits (6a - 6c); and a control means (46) for writing data from said high-speed circuits (6a - 6c) into said memory means (50) through said high-speed circuit cards (5a - 5c), reading out the data stored in said memory means (50) at a time different from the case of said data transfer between said plural high-speed circuits (6a - 6c) and outputting the data to said high-speed circuit cards (5a - 5c); characterized in that a timing control circuit (7) is provided for varying speed of data of said terminal cards (2a - 2n) by corresponding addresses of said high-speed circuit cards (5a - 5c) with those of said high-speed circuit cards (5a - 5c), performing a timing control for multiplex transmittance to said high-speed circuit cards (5a - 5c) and performing a timing control for fetching data from said high-speed circuits (6a - 6c) to said high-speed circuit cards (5a - 5c) and a timing control over a writing and reading for said memory means (50) in case of performing said data transfer; and said control means (46) is provided for writing data from said high-speed circuits (6a - 6c) into said memory means (50) on a bit by bit basis through said high-speed circuit cards (5a - 5c) under an order based on said timing control, reading out the data stored in said memory means (50) on the basis of said timing control at a time different from the case of said data transfer between said plural high-speed circuits (6a - 6c) and outputting the data to said high-speed circuit cards (5a - 5c) on a bit by bit basis. A multiplexing apparatus according to claim 1 in which said memory means (50; 120; 140) is of RAM (Random Access Memory). A multiplexing apparatus according to claim 1 in which said memory means is a FIFO (First-In First-Out) memory and said control means is a FIFO address decoder (118; 150).

Inventors: YAMADA YOSHIKO MITSUBISHI DENK, YAMADA, YOSHIKO MITSUBISHI DENKI KABUSHIKI KAISHA
Applicants: MITSUBISHI ELECTRIC CORP, MITSUBISHI DENKI KABUSHIKI KAISHA
Application year: 1989
Main classification: H04J3
IPC codes: H04J3