JPH0795178A - Terminal equipment and network system using it - Google Patents

Abstract

PURPOSE:To enhance the response with respect to a transmission request of a motion picture signal and to prevent production of intermission of a signal to be sent. CONSTITUTION:Motion picture data sent on a wavelength multiplex transmission line 1 are divided into plural partial motion picture signals, they are coded and sent while placing priority to them. When lots of partial motion picture signals are relayed, a terminal equipment connecting to a transmission line selects properly a routing path depending on the data quantity. Furthermore, the signals are relayed according to the priority from higher priority to a lower priority to use the transmission band of the transmission line effectively. When a predetermined delay time elapses as to the partial motion picture signal with low priority, the motion picture data are aborted. Terminal equipments 6, 7 have plural transmission wavelengths to set the routing path freely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a video camera, a VTR.
The present invention relates to a plurality of terminal devices to which moving image signal sources such as the above and moving image output devices such as a monitor TV and a printer are connected, and a network system using the terminal devices.

[0002]

2. Description of the Related Art Conventionally, as a moving image network system, for example, an optical ring network having a configuration shown in FIG. 9 is a video camera 176 which is a moving image signal source.
It has a display 177 which is a moving image output device, and a terminal 178 to which a video camera and a display are connected. This terminal 178 encodes a moving image signal from the video camera into a desired digital signal and outputs it to a network interface 179. And a function of decoding the digital signal input from the network interface 179 and inputting it to the moving image output device.

In addition, the network interface 17
9 has a function of inspecting the slot circulating on the illustrated optical ring network and inserting a digital signal output from the terminal into a vacant channel, and a function of reading a digital signal from the channel addressed to the own terminal. Have The optical fiber 180 is used as a transmission path for an optical signal transmitted on the optical ring network.

Further, as another conventional example of this type of moving image network, a moving image network system having a wider transmission bandwidth is shown in FIG.
A plurality of terminals are connected to an optical fiber 181 which is a ring type optical transmission line for transmitting optical signals of a plurality of wavelengths. In FIG. 10, the branching device 183 includes a plurality of (m) fixed wavelength filters 1 to m (reference numeral 191) and a combiner 184 for the optical signal transmitted on the optical fiber 181.
Branch to. In addition, the confluence device 184 is the branch device 18
3 functions to combine the optical signals emitted from 3 and the optical signals emitted from a plurality (m) of fixed wavelength lasers 1 to m (reference numeral 193) and emit the combined signals onto the optical fiber 181. .

The fixed wavelength filters 1 to m transmit only one different wavelength from the wavelength-multiplexed optical signals of λ1 to λm in the configuration shown in the figure, and pass it through the O / E converters 1 to m. (Reference numeral 192) respectively. Then, the O / E converters 1 to m convert the incident optical signals into electric signals and output the electric signals to the SWI 194. SWI19
Of the electric signals output from the m O / E converters, 4 selects only the electric signal applied to its own terminal under the control of the control unit 188 described later and outputs it as a reception signal. . Further, the SWII 195 outputs a transmission signal to the fixed wavelength laser according to an instruction from the control unit 188.

A plurality (m) of fixed wavelength lasers 193
, Only the one to which the signal is transmitted from the SWII 195 emits the input signal as an optical signal of a predetermined wavelength. In the configuration shown, each fixed wavelength filter 1 to m transmits at one fixed wavelength different from each other among wavelength-multiplexed light wavelengths λ1 to λm. The control unit 188 controls which of the outputs from the plurality of O / E converters input to the SWI 194 is output as a reception signal according to the instruction of the server 190 output from the control communication unit 189. , Switching the fixed wavelength laser that should output the transmission signal.

The server 190 determines the transmission permission / non-permission and the wavelength used in the case of transmission permission from the transmission permission request sent from each terminal and the wavelength used on the network. Instruct the terminal. Each terminal is
To use the wavelength specified by the server 190,
It controls the SWI 194 and SWII 195 and operates to perform the desired communication.

Further, as a third conventional example of this type of moving image network, there is a system having a configuration as shown in FIG. 11, the same components as those of the system shown in FIG. 10 are designated by the same reference numerals. In FIG. 11, the branching device 183 outputs the optical signal transmitted on the optical fiber 181 to the tunable filter 185.
And branch to the confluence unit 184. In addition, the confluencer 184
Serves to combine the optical signal emitted from the branching device 183 and the optical signal emitted from the tunable laser 186, and emit the combined signal onto the optical fiber 181.

The tunable filter 185 is a filter that uses a change in refractive index due to current injection, and selects only a specific wavelength from the optical signals of a plurality of wavelengths emitted from the branching device 183 according to an instruction from the control unit 188. Through. The tunable laser 186 is a laser that uses a refractive index change due to current injection, and converts a transmission signal into an optical signal of a specific wavelength according to an instruction from the control unit 188.
Output to the combiner 184.

The control section 188 follows the transmission wavelength of the tunable filter 185 and the tunable laser 18 according to the instruction of the server 190 output from the control communication section 189.
The oscillation wavelength of 6 is controlled. The control communication unit 189 communicates control signals such as a transmission permission request to the server 190 and an allocation wavelength instruction from the server 190. The server 190 determines the transmission permission / non-permission and the wavelength to be used in the case of transmission permission from the transmission permission request sent from each terminal and the wavelength used on the network, and instructs them to each terminal. To do. Then, each terminal uses the server 19
The tunable filter 185 and the tunable laser 186 are controlled so as to use the wavelength designated by 0, and operate to perform desired communication.

[0011]

However, in the above-mentioned conventional optical ring network, all channels are in use because one channel on the slot is exclusively assigned to the transmission of one moving image signal. In this case, the transmission request of the newly generated moving image signal is kept waiting until the use of one of the channels ends. Therefore, this kind of optical ring network has poor responsiveness to a transmission request and is not suitable for transmitting a large amount of continuous data such as moving image data.

Therefore, in order to solve such a problem,
There is also a method in which the right to use a channel is sequentially changed in a predetermined time unit to realize transmission of a moving image signal more than the number of channels, but in this case, the moving image signal is cut off every time the right to use a channel is lost. The problem arises. Furthermore,
In the conventional moving image network shown in FIGS. 10 and 11, it is possible to increase the number of transmission channels of moving images, but there are the following problems.

That is, the wavelengths used by a pair of terminals for transmission and reception are assigned by the server from among the unused wavelengths in the network system at that time, so that the wavelengths are used every time depending on the operating status of the network system.
Different wavelengths will be used. Therefore, in order to realize communication between all terminals,
Since a transmission / reception function for all wavelengths used in the network system is required, the configuration of the transmission / reception unit in the terminal becomes complicated and the cost of the device increases.

Specifically, in the example shown in FIG. 10 among the above-mentioned conventional moving image networks, the fixed wavelength filters, the O / E converters, and the fixed wavelength lasers corresponding to all wavelengths are provided. In addition, in the example shown in FIG. 11, it is necessary to exactly match the transmission wavelength of the tunable laser of the terminal on the transmission side and the transmission wavelength of the tunable filter of the terminal on the reception side.

However, the transmission wavelength of the tunable laser has a large temperature dependency, and there is a wavelength variation of about 0.1 nm with a temperature change of about 1 deg. Therefore, it is necessary to suppress the temperature stability to 0.1 deg or less. There is a problem that the temperature control mechanism becomes large. Further, in each of the conventional moving image networks shown in FIGS. 10 and 11, in order to start communication, it is necessary to have the server specify the communication permission / non-permission and the wavelength to be used in the case of communication permission. is there. Therefore, there is a problem that the time required for communication with the server, determination of communication permission / non-permission at the server, and processing of wavelength allocation is delayed until the communication starts.

In addition, in any structure of the conventional moving image networks shown in FIGS. 10 and 11, an optical signal of one wavelength transmitted from one terminal is input to all terminals connected to the network. Therefore, there is a problem in that a plurality of terminals cannot simultaneously perform communication using the same wavelength, and the number of terminals that can simultaneously transmit cannot exceed the number of wavelengths multiplexed.

The present invention has been made in view of the above problems, and an object of the present invention is to effectively use a transmission band to enhance responsiveness to a transmission request of a moving image signal and a signal to be transmitted. It is an object of the present invention to provide a terminal device having a simple configuration that prevents the occurrence of fragmentation and an image network system that uses the terminal device.

[0018]

[Means for Solving the Problems] and

In order to achieve the above object, the invention according to claim 1 is a terminal device for transmitting and receiving an optical signal by connecting to a wavelength division multiplexing optical transmission line, wherein wavelength division multiplexing is performed on the wavelength division multiplexing optical transmission line. Storing means for capturing and blocking an optical signal of a pre-allocated reception wavelength among the optical signals, a receiving means for receiving the optical signal captured by the capturing means, and information to be transmitted. Storage means, first transmission means for transmitting predetermined information at a first transmission wavelength pre-assigned, and predetermined information at a second transmission wavelength pre-assigned and different from the first transmission wavelength. And a deciding means for deciding whether to transmit the information stored in the storage means at the first transmission wavelength or at the second transmission wavelength. Prepare

According to a sixth aspect of the present invention, there is provided a terminal device for transmitting and receiving an optical signal by connecting to a wavelength division multiplexing optical transmission line, wherein the wavelength division multiplexed optical signals among the optical signals are transmitted on the wavelength division multiplexing optical transmission line. , Storing means for capturing and blocking optical signals of a plurality of reception wavelengths assigned in advance, receiving means for individually receiving the plurality of optical signals captured by the capturing means, and storing information to be transmitted Storage means, transmission means for individually transmitting predetermined information at a plurality of transmission wavelengths assigned in advance, and transmission of information stored in the storage means at any transmission wavelength of the plurality of transmission wavelengths And a decision means for deciding whether or not to do so.

Further, in the invention as set forth in claim 12, a priority order for transmission is added to the information, and the information having the higher priority order is transmitted in order from the information. In the above configuration, the transmission band is effectively used, the responsiveness to the transmission request of the image signal is enhanced, and the interruption of the signal to be transmitted can be prevented, and the signals are relayed from the high priority order to the low priority order. By doing so, it is possible to further effectively use the transmission band of the transmission path.

Further, since each terminal device has a plurality of transmission wavelengths, the degree of freedom in setting the routing path is increased,
Moreover, since a tunable light source is not used, the configuration is simplified, and the trouble of switching the transmission wavelength can be saved. In the thirteenth aspect of the invention, the transmission allowable delay time relating to transmission is assigned to the information, and the information for which the transmission allowable delay time has elapsed is discarded without being transmitted.

As described above, by discarding the data, it is possible to reduce the occurrence of a waiting state for a request for transmitting a moving image signal. Further, in the network system according to claim 15, when the transmission wavelength of the first terminal device that transmits the predetermined information and the reception wavelength of the second terminal device that receives the information are different, the plurality of terminals Among the devices, one or more terminal devices other than the first terminal device and the second terminal device perform wavelength conversion so that the transmission wavelength matches the reception wavelength.

By adopting such a configuration, it becomes possible to improve the responsiveness and prevent the interruption of the moving image signal.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. [First Embodiment] FIG. 1 is a block diagram showing a configuration of a moving picture network system according to a first embodiment of the present invention. Here, 12 terminals (I to XII) are connected to four wavelengths. They are connected by a wavelength multiplexing ring type optical transmission line using λ1, λ2, λ3 and λ4.

In FIG. 1, reference numeral 1 is an optical fiber which is an optical transmission line of a wavelength multiplexing ring type and is connected to terminals I to XII via demultiplexers 2 and 4 and multiplexers 3 and 5. ing. As will be described later, the demultiplexers 2 and 4 extract only optical signals of a predetermined wavelength assigned to each terminal from optical signals of a plurality of wavelengths transmitted on the optical fiber 1 and receive them. While demultiplexing the optical signal into eight, the optical signal that is not demultiplexed is transmitted to the multiplexer 3. The multiplexers 3 and 5 combine the optical signal transmitted through the optical fiber 1 with the optical signal sent from the transmitter 9.

Since each of the terminals I ... XII (6, 7) has the same internal structure, only the internal structure of the terminal I 6 is shown in FIG. Further, reference numeral 8 is a receiving unit,
The optical signal output from the demultiplexer 2 is received and converted into an electric signal. Then, as will be described later, the transmitter I 9 and the transmitter II 10 transmit an optical signal at a wavelength assigned to each terminal, and a semiconductor laser diode (not shown) converts the electric signal from the storage unit into an optical signal. Change and send.

The allocating unit 11 reads the receiving terminal number in the header added to the beginning of the partial moving image data output from the receiving unit 8, and refers to the routing table built in the allocating unit 11, Find the wavelength to use when transmitting. Then, the storage unit in which the partial moving image data is to be stored is selected from the storage unit I 12 and the storage unit II 13.

The storage unit I 12 and the storage unit II 13 are the receiving unit 8
Data to be transferred in the partial moving image data received in
In addition, since data to be transmitted from the own terminal to another terminal is temporarily stored according to priority, a plurality of FIFO (First-in-Firs)
t-out) memory, and its internal structure is shown in FIG.
The control unit 14 checks the receiving terminal number, priority order, coding type, allowable delay time, etc. of the header added to the beginning of the partial moving image data input from the receiving unit 18, and determines that the receiving terminal number is the own terminal. When they match, the decoding unit 15 controls to input the partial moving image signal output from the receiving unit 18. The priority order, coding type, and allowable delay time will be described later.

If the receiving terminal number does not match the own terminal number, the partial moving image data is stored in the storage unit I 12 or a predetermined FI in the storage unit II 13 according to the priority order information.
Control is performed so as to write in the FO memory, and the priority order and the allowable delay time of the partial moving image signal are written in the management table 14a. The control unit 14 further searches the management table 14a, reads out the partial moving image packet signals stored in the storage unit I 12 and the storage unit II 13 that have not passed the allowable delay time according to the priority order, Output to the transmission unit I 9 and the transmission unit II 10.

The decoding unit 15 has a function of decoding the single or plural partial moving image signals sent to its own terminal and outputting it as a predetermined analog video signal.
The internal structure of the decoding unit 15 is shown in FIG. Reference numeral 17 is a display which is a moving image output device,
The analog video signal output from the decoding unit 15 is visually displayed.

The encoding unit 16 converts the analog video signal output from the video camera 18 which is a moving image information source into four partial moving image signals, adds a predetermined header to them and packetizes them. It is output to the storage unit I 12 or the storage unit II 13. Note that FIG. 3 shows the internal structure of the encoding unit 16. FIG. 2 is an internal block configuration diagram of the storage unit 13 in the terminal configuring the moving image network system according to the present embodiment. As shown in FIG.
Is composed of eight FIFO memories (I, II, III to VIII). Each FIFO memory is composed of a dual port memory 20 that can perform write and read operations independently, a write counter 21 that generates a write address, and a read counter 22 that generates a read address.

The wavelength used in the moving image network system according to this embodiment is λ1 = 1.50 μm, λ
2 = 1.52 μm, λ3 = 1.54 μm, λ4 = 1.5
It is 6 μm. Further, Table 1 shows wavelengths used by each terminal for reception and transmission.

[0033]

[Table 1]

The allocating unit 11 has a built-in routing table for selecting the transmission wavelength shown in Table 2 based on the transmission / reception wavelengths assigned to each terminal shown in Table 1 for receiving. The transmission wavelength is selected according to the destination terminal of the partial moving image signal, and the storage unit that stores the moving image signal is determined.

[0035]

[Table 2]

In the present embodiment, one of the transmission wavelengths and the reception wavelength are common wavelengths, and the routing table shown in Table 2 shows that the wavelength that the destination terminal can receive is the two wavelengths that the own terminal can transmit. Of these, the wavelength is transmitted only when the wavelength matches the wavelength that can be received by the own terminal, and in other cases, the wavelength is transmitted at the same wavelength as the wavelength received by the own terminal.

That is, as can be seen from Table 1, the terminal I performs reception at the wavelength λ1 and transmission at the wavelengths λ1 and λ2, so that only the terminals IV, V, and VI having the reception function at the wavelength λ2. , Wavelength λ2 is transmitted, and for other terminals, wavelength λ1 is transmitted. By using such a routing table, for example, the partial moving image signal transmitted from the terminal I to the terminal VII is transmitted at the wavelength λ1 at the terminal I, after being received at the terminal II, transmitted at the wavelength λ3, It is received at terminal VII.

Since this routing route is not uniquely determined, for example, from the above terminal I to terminal V
In the transmission to II, if there are a large number of partial moving image signals in the storage unit that are in the transmission waiting state and correspond to the wavelength λ1 of the terminal I, transmission is performed at the wavelength λ2. in this case,
The routing path is that the terminal IV receives the wavelength λ2 again, the terminal V receives the wavelength V, the terminal V transmits the wavelength λ3, and the terminal VII receives the wavelength λ3.

Next, a method for efficiently transmitting a moving image signal in the system according to this embodiment having the above-mentioned configuration will be described in detail. It should be noted that here, the moving image signal is divided into four, and the priority order and the allowable delay time are appropriately assigned and transmitted. FIG. 3 is a detailed block diagram of the encoding unit 16 in the terminal that constitutes the system according to the present embodiment, and employs a so-called filter configuration subband encoding method.

In FIG. 3, reference numeral 23 is an A / D converter for digitizing the moving image signal output from the video camera 18. Reference numeral 24 is a horizontal low-pass filter that transmits only low-frequency components in the horizontal direction of the video image. Further, reference numeral 25 is a horizontal high-pass filter that transmits only the high-frequency component in the horizontal direction of the video image.

Reference numeral 26 is a system clock generator which extracts a synchronizing signal from the moving image signal output from the video camera 18 to generate a sampling signal used in the terminal and various timing signals. Also, reference numeral 27,
28 is a decimator A, B, which is 1 / pixel in the horizontal direction.
Decimate (decimate) to 2. Reference numerals 29 and 31 denote vertical low-pass filters A and B, respectively, and reference numerals 30 and 32 denote vertical high-pass filters that transmit only the vertical low-frequency component of the video image and reference numerals 30 and 32 transmit only the high-frequency component of the video image in the vertical direction. is there.

Reference numerals 33 to 36 are decimators C,
D, E, and F, which decimates (decimates) the pixel in half in the vertical direction. Reference numerals 37 to 40 are quantizers, which compress the outputs from the decimators C, D, E, and F to a predetermined bit length. Reference numerals 41 to 44 are dual port memories A, B, C and D, reference numeral 45 is a header addition unit, reference numeral 46 is a write counter, and reference numeral 47 is a read counter.

The dual port memories A, B, C and D (reference numerals 41, 42, 43 and 44) have quantizers A, B and
The outputs from C and D are written according to the address value output from the write counter 46, and read out according to the address value output from the read counter 47. The write counter 46 and the read counter 47 perform counting operations according to the system clock output from the system clock generator 26.

The header adding unit 45 adds the destination terminal address, the sending terminal address, the priority order to the partial moving image data read from the dual port memories A, B, C and D.
Add headers such as allowable delay time. FIG. 4 is a block diagram of the decoding unit 1 in the terminal which constitutes the system according to the embodiment of the present invention.
5 is a detailed block diagram of FIG.

In FIG. 4, reference numeral 48 is a header removing section for removing the header information added to the partial moving image signal, and reference numerals 49, 50, 51 and 52 are for removing the header by the header removing section 48. Dual port memories A, B, C for synchronously reproducing a plurality of partial moving image signals
It is D. The write counter 53 outputs the partial moving image signal from which the header is removed to the dual port memories A, B,
A counter 58 generates an address for writing to a predetermined address of C and D, and reference numeral 58 denotes a partial moving image signal written in the dual port memories A, B, C and D.
It is a read counter that generates an address for reading based on a timing signal output from the system clock generation unit 63.

Reference numerals 54 to 57 are inverse quantizers A, B, C,
D, which expands the bit length compressed by the quantizers A, B, C, and D of the above-mentioned encoding unit to a predetermined length. Reference numerals 59 to 62 are interpolators A, B, C and D,
Pixels are doubled in the vertical direction. Reference numerals 64 and 66 denote vertical low-pass filters A and B, which transmit only the low-frequency component in the vertical direction of the partial moving image signal. Also, reference numeral 6
Reference numerals 5 and 67 are vertical high-pass filters A and B, which transmit only the high-frequency component in the vertical direction of the partial moving image signal.

Reference numerals 68 and 70 denote interpolators E and F, which double the pixels in the horizontal direction. Reference numeral 69 is a horizontal low-pass filter, which transmits only the low-frequency component in the horizontal direction of the partial moving image signal. Further, reference numeral 71 is a horizontal high-pass filter, which transmits only the high-frequency component in the horizontal direction of the partial moving image signal. Reference numeral 103 is a synthesizing unit, and 104 is a D / A converter.

In this embodiment, the operation performed by each terminal is roughly classified into the following three, and each terminal performs a necessary operation out of these three operations. That is, encoding: an operation of decomposing a moving image signal to be transmitted into partial moving image signals and encoding them. Relay: a partial moving image data code received from a transmission line,
Operation of transmitting the partial moving image signal generated from the own terminal on the transmission path with a predetermined procedure and a predetermined wavelength Decoding: This is the operation of decoding the partial moving image signal sent to the own terminal.

The above three operations will be described in detail below. <Encoding Operation> When a moving image signal is input from the video camera 18, a sampling signal having a period equal to the pixel period T is created. The A / D converter 23 A / D converts the moving image signal by the sampling clock output from the system clock generation unit 26, and outputs it to the horizontal low-pass filter 24 and the horizontal high-pass filter 25. The horizontal low-pass filter 24 removes high-frequency components in the horizontal direction, and then the decimator A27 decimates the pixels in the horizontal direction to 1/2.

On the other hand, the horizontal high-pass filter 25 removes low-frequency components in the horizontal direction, and the decimator B28 thins out pixels to 1/2 in the horizontal direction. Further, the output of the decimator A27 has a high frequency component in the vertical direction removed by a vertical low pass filter A29, is decimated to 1/2 in the vertical direction by a decimator C33, and is then compressed to a predetermined bit length by a quantizer A37. It In this way, the quantizer A37 outputs the partial moving image signal A containing only low frequency components in both the horizontal and vertical directions.

The output from the decimator A27 is also output to the vertical high-pass filter A30 at the same time, where the low frequency components in the vertical direction are removed, and the decimator D34 decimates the pixels in the vertical direction to 1/2, B3
At 8, it is compressed to a predetermined bit length. In this way, the quantizer B38 outputs the partial moving image signal B containing only low frequency components in the horizontal direction and high frequency components in the vertical direction.

On the other hand, output from the decimator B28,
The vertical low-pass filter B31 removes the high-frequency component in the vertical direction from the moving image signal containing only the high-frequency component in the horizontal direction, and the decimator E35 decimates the pixels in the vertical direction to 1/2, and then the quantizer C39. Is compressed to a predetermined bit length. Then, the partial moving image signal C including only the high frequency component in the horizontal direction and the low frequency component in the vertical direction is output to the dual port memory C43.

The output from the decimator B28 is also output to the vertical high-pass filter B32, where low-frequency components in the vertical direction are removed, and then the decimator F decimates the pixels to 1/2 in the vertical direction. Get burned. Then, after being compressed to a predetermined bit length by the quantizer D40, it is output to the dual port memory D44 as a partial moving image signal D containing only high frequency components in both the horizontal and vertical directions.

The partial moving image signals A, B, C, D input to the dual port memories A, B, C, D (reference numerals 41, 42, 43, 44) are predetermined according to the address generated by the write counter 46. Written in position. Further, the read counter 47 generates a read address at a predetermined timing for transmission and outputs it to the dual port memories A, B, C and D. In the dual port memories A, B, C and D, according to this read address,
Partial moving image signals are read out as serial signals one by one,
It is output to the header addition unit 45.

In the header adding section 45, for the output from the dual port memory A41, the receiving terminal address and the source terminal address of the transmission source, the encoding type A, the priority of 1, the transmission time as the encoding time, and , The header information is added with the allowable delay time of 4 msec, and the storage unit I 12 or the storage unit II 13 is designated by the assignment unit 11.
Write to the FIFO V of.

Similarly, for the output from the dual port memory B42, the coding type B and the priority are set to 2,
Other information is stored in the storage unit I 12 or the storage unit II 13 according to the instruction of the allocation unit 11 in the same manner as the above case.
Write to FIFO VI. Further, with respect to the output from the dual port memory C43, the encoding type C and the priority order are set to 3, and the storage unit I is instructed according to the instruction of the allocation unit 11.
12 or the FIFO VII of the storage unit II13, and with respect to the output from the dual port memory D44, the encoding type D, the priority order is set to 4, and the storage unit I12 or the storage unit II12 of the storage unit II12 is instructed according to the instruction of the allocation unit. FIF
Write in OVIII.

When writing from the header adding unit to the storage unit, the allocating unit 11 searches the routing table for the transmission wavelength corresponding to the receiving terminal address, and writes it in either the storage unit I12 or the storage unit II13. Instruct. In this way, the storage unit I 12 and the storage unit II 13 are
The data written in FIFO V to FIFO VIII of
It is appropriately processed in the operation of the relay processing described later. <Relay Processing> Partial video image signal data transmitted from another terminal (for example, terminal X) is transmitted through the optical transmission line 1 using the wavelength λ1, is received by the receiving unit 18 of the terminal I, and is controlled by the control unit 14. After the information in the header section is checked with, the output destination is controlled. When the receiving terminal address stored in the header section matches the terminal address of the self terminal (here, terminal I), the output of the receiving section 18 is sent to the decoding section 15.

On the other hand, when the receiving terminal address does not match the own terminal address, the allocating unit 11 searches the routing table for the transmission wavelength corresponding to the receiving terminal address and stores it in either the storage unit I 12 or the storage unit II 13. You will be prompted to write. Next, the priority order information is checked, and if the priority order is 1, the storage unit follows the above instruction.
It is output to the dual port memory of I12 or the FIFO I of the storage unit II13.

Similarly, when the priority is 2, the FIFO
It is sent to the dual port memory of II and to the dual port memories of FIFO III and IV when the priorities are 3 and 4, respectively. The partial moving image signal output to the storage unit I 12 or the storage unit II 13 is sequentially written to a predetermined address according to the write address output from the write counter 21. At this time, the control unit 14 registers the write start address, the write end address, the transmission time added to the header portion, and the allowable delay time in the management table.

In this way, the storage unit I 12 and the storage unit II
In 13, the partial moving image signal received by the receiving unit 8 is FIFO.
The partial moving image signals to be transmitted from the own terminal are written to FIFO V to FIFO VIII, as described in the above-mentioned encoding operation, to I to FIFO IV. Memory
The partial moving image data written in the I 12 and the storage unit II 13 are independently read out as described below by the control of the control unit and output to the transmission units I 1, II (9, 10), respectively. The control unit 14 then controls each FIFO in the storage unit.
The presence or absence of an untransmitted partial moving image data signal in the FIFO is checked by comparing the value of the read counter with the value of the write counter.

When the untransmitted partial moving image data remains in the FIFO I, the control unit 14 checks the transmission time and the allowable delay time from the management table, and adds the allowable delay time to the transmission time.
When the value obtained as a result is larger than the current time, it is used as valid data, the address to be read is output from the read counter 22, the dual port memory 20 is sequentially read, and it is output to the transmission unit I 9. Transmitter I
In 9, the input signal is converted into an optical signal of a predetermined wavelength,
It is transmitted to the optical fiber 1 which is an optical transmission line.

If the value obtained by adding the allowable delay time to the transmission time is smaller than the current time, it is regarded as invalid data,
By setting the value of the read counter 22 to the write start address of the subsequent partial moving image signal, the invalid partial moving image signal is discarded. In this way, the FIFO storing the partial moving image signal with the highest priority is stored.
When the OI untransmitted partial moving image data signal disappears, the control unit 14 transmits the FIFO II untransmitted partial moving image data signal in the same manner.

If a partial moving image signal is newly written in the FIFO I during the data transmission in the FIFO II, after the transmission of the partial moving image signal currently being transmitted is completed,
The partial moving image data signal of OI is transmitted. Here, as described above, the partial moving image signal having the higher priority is transmitted first, while the partial moving image signal having the lower priority is transmitted. In addition, the control unit 14 is a storage unit.
The partial moving image signals in II13 are sequentially read out and sent to the transmission unit II10. The control of the storage unit I and the storage unit II is simultaneously performed in parallel by the control unit 14.

In the transfer, the received partial moving image data is transmitted from the transmitter I 9 or the transmitter II 10 as an optical signal of a predetermined wavelength according to the routing table. In the case of transmission at a wavelength different from the reception wavelength in this embodiment, access competition for transmission occurs between a plurality of terminals. For example, terminals III, VI, and IX all have the function of transmitting at wavelength λ4, but the optical signals transmitted from these three terminals are all received at terminal X, causing interference. , Accurate transmission cannot be done. for that reason,
As shown in the timing chart of FIG. 5, each terminal performs time division multiplex transmission to avoid access contention.

On the other hand, in the case of transmission at the same wavelength as the reception wavelength, the optical signal transmitted from the terminal located upstream in the transmission direction is demultiplexed by the demultiplexer 2 and the entire amount is taken in and blocked. , It does not interfere with the optical signal transmitted from its own terminal. That is, since the optical signal of wavelength λ1 transmitted from terminal I is blocked by the demultiplexer 2 of terminal II, it does not reach terminal III beyond terminal II and the wavelength λ1 of wavelength λ1 transmitted from terminal II is transmitted. It does not interfere with optical signals. <Decoding Process> The partial moving image data signal input to the decoding unit 15 shown in FIG.
If the header portion is removed and the encoding type recorded in the header portion is A, the dual port memory A49
Further, when the coding type is B, C, D, the data is output to the dual port memories B, C, D, respectively, and writing is performed according to the write address output from the write counter 53.

The partial moving image data signal transmitted from the transmission side terminal is transmitted while being relayed by the terminal on the way to the reception side terminal. Then, when the transmission load on the terminal on the way is large and the transmission is awaited after the allowable delay time is exceeded, the partial moving image signal is abandoned as described above. Therefore, not all of the four partial moving image data signals sent from the transmitting unit reach the receiving unit. Also, the operation of the decoding unit 15 changes depending on the number of partial moving image signals that have arrived.

I) When the Number of Partial Moving Image Signals Reaches Four: The control unit 14 determines the number of partial moving image data signals reaching the decoding unit 15 for each frame period of the image output to the display 17. When the number is counted and the number is 4, the control is performed so that the data stored in the dual port memories A, B, C and D can be read. By the system clock generated from the system clock generator 63,
A read address signal is output from the read counter 58 and the dual port memories A, B, C and D are read.

The output from the dual port memory A49 is a partial moving image signal A containing only low frequency components in both horizontal and vertical directions, expanded by the inverse quantizer A54 to a predetermined bit length, and then by the interpolator A59. Pixels are doubled in the vertical direction, the high-frequency component noise component is removed by the interpolation by the vertical low-pass filter A64, and the interpolator E68 outputs the result.

The output from the dual port memory B50 is a partial moving image signal B including a low frequency component in the horizontal direction and a high frequency component in the vertical direction. The partial quantizer B55 decompresses the partial moving image signal B into a predetermined bit length and then the interpolator. At B60, the pixel is doubled in the vertical direction. Then, the vertical high-pass filter A65 removes low-frequency noise components due to interpolation, and then outputs to the interpolator E68.

In the interpolator E68, 2 in the horizontal direction.
After the pixels are doubled, the horizontal low-pass filter 10
When 0, horizontal low frequency noise due to interpolation is removed and output to the synthesis unit 72. The output from the dual port memory C51 is a partial moving image signal C containing a high frequency component in the horizontal direction and a low frequency component in the vertical direction, and after being decompressed to a predetermined bit length by the inverse quantizer C56. , After the pixel is doubled in the vertical direction by the interpolator C61,
The vertical low-pass filter B66 removes the noise of the high frequency component in the vertical direction due to the interpolation, and then the interpolator F
It is output to 70.

The output from the dual port memory D52 is a partial moving image signal D containing only high frequency components in both the horizontal and vertical directions. The interpolator D62 doubles the pixels in the vertical direction and then the vertical high-pass filter. B
The noise of the low frequency component in the vertical direction due to the interpolation is removed at 67, and then output to the interpolator F70. In the interpolator F70, the pixels are doubled in the horizontal direction, and then the horizontal high-pass filter 71 removes the noise of the low-frequency component in the horizontal direction, and the noise is then output to the combining unit 72. In the synthesizing unit 72, the signal output from the horizontal low-pass filter 69 in which the high frequency component in the horizontal direction is missing,
The signal output from the horizontal high-pass filter 71 and the signal lacking the low-frequency component in the horizontal direction are combined to reproduce the original moving image signal, which is then output to the D / A converter 73. D
The / A converter 73 converts the moving image signal into a predetermined analog video signal, and the output thereof is output to the display 17.

Ii) The number of partial moving image signals that have arrived is A,
In the case of three cases of B and C The control unit 14 prohibits reading of the dual port memory D52 and outputs pseudo data of 0 component (signal value is 0). Then, the other parts are operated in the same manner as in the case where there are four reaching partial moving image data, so that the D / A
The converter 73 outputs a moving image signal in which the high frequency component in the vertical direction is missing.

Iii) The arrived partial moving image signal is 2 of A and B.
In the case of the number, the control unit 14 controls the dual port memories C and D (51, 5).
Reading of 2) is prohibited, and pseudo data of 0 component is output. In this case, the D / A converter 73 outputs a moving image signal lacking high frequency components in both the vertical and horizontal directions. iv) When the Number of Partial Moving Image Signals that Arrived is One The control unit 14 prohibits reading of the dual port memories B, C, and D and outputs 0-component pseudo data. As a result, the D / A converter 73 outputs a moving image signal including only the low frequency component in the vertical direction.

If no partial moving image data arrives at the decoding unit 15, the partial moving image data that arrives before that remains in the dual port memory. A similar moving image signal is reproduced and output. As described above, according to the present embodiment, the moving image data transmitted on the ring type wavelength division multiplex transmission path is divided into a plurality of partial moving image signals, coded, and then prioritized. When the number of partial video signals to be transmitted and relayed at the terminal on the transmission path is large, not only the routing path is appropriately selected depending on the amount of data, but also the signal is relayed from high priority to low priority, Further effective use of the transmission band of the transmission line can be achieved.

Further, when a predetermined delay time has passed for the partial moving image signal of low priority, by discarding the moving image data, it is possible to reduce the occurrence of a waiting state for a moving image signal transmission request, and at the same time, When the receivable frequency of the receiving terminal is different, it is possible to improve the responsiveness and prevent the interruption of the moving image signal by changing the wavelength at the terminal on the transmission path.

Furthermore, since each terminal has a plurality of transmission wavelengths, the degree of freedom in setting routing routes is widened, and since no tunable light source is used, the configuration is simplified and the transmission wavelengths can be switched easily. Can be omitted. In the above embodiment, a common wavelength is assigned to the reception wavelength and one of the two transmission wavelengths, but the present invention is not limited to this, and the reception wavelength and the first transmission wavelength are not limited thereto. , Different wavelengths may be assigned to the respective second transmission wavelengths. At that time, if a problem such as access conflict occurs, an access conflict avoiding means such as the time division multiplexing described above is appropriately provided. [Second Embodiment] Next, a second embodiment according to the present invention will be described.

FIG. 6 is a block diagram showing the arrangement of a moving picture network system according to the second embodiment. Here, a configuration example in which the reception wavelength at the terminal I is two wavelengths is shown. In FIG. 6, the same components as those of the system according to the first embodiment shown in FIG. 1 are designated by the same reference numerals. In FIG. 6, the demultiplexer 2 demultiplexes the two wavelengths of light received by its own terminal into the receiving unit I and the receiving unit II, and outputs the demultiplexed light, while the other wavelengths are combined by the multiplexer 3
Make it transparent to the side. At this time, the reception wavelength of the own terminal is 2
The light of one wavelength is demultiplexed and the entire amount is taken in, so it is blocked there and is not output to the multiplexer 3 side.

In this embodiment, wavelengths are assigned as shown in Table 3. Here, a common wavelength is assigned as two reception wavelengths and two transmission wavelengths of each terminal device.

[0079]

[Table 3]

In FIG. 6, reference numeral 74 is a receiver I for receiving the optical signal of wavelength λ1 output from the demultiplexer 2.
And reference numeral 75 is the wavelength λ2 output from the demultiplexer 2.
2 is a receiver II for receiving the optical signal of. Of the partial moving image signals received by the receiving unit I and the receiving unit II, the one to be transferred is the assigning unit 11 as in the above-described embodiment.
The transmission wavelength is determined by referring to a routing table and a destination terminal address, which will be described later, which is built in the, and the signal is temporarily stored in the storage unit I 12 or the storage unit II 13 according to the transmission wavelength. . Then, the control unit 14 controls the reading as in the first embodiment, and the signals are transmitted from the transmitting unit I 9 and the transmitting unit II 10 as an optical signal.

Table 4 is a second routing table according to this embodiment and shows one embodiment in this embodiment. In this embodiment, for example, a partial moving image signal transmitted from the terminal I to the terminal IX is transmitted from the terminal I as an optical signal of wavelength λ1, received by the terminal II, and transmitted from there as an optical signal of wavelength λ3. It After that, the signals are respectively received by the terminals V, VII, and VIII, transmitted again as an optical signal of wavelength λ3, and finally received by the terminal IX.

[0082]

[Table 4]

As described above, in this embodiment, since the number of received wavelengths is two, the degree of freedom of the routing path is further increased, and the routing path can be changed according to the waiting status in the storage units I and II. The delay time can be reduced.
Further, in the present embodiment, the number of wavelengths to be transmitted and the wavelengths to be received at each terminal are the same and the same, and among the optical signals transmitted from the upstream side of the transmission path, the optical signal received by the own terminal is the demultiplexer. In 2, the signal is demultiplexed only to the receiving section of the own terminal,
It is blocked so as not to be transmitted to the downstream terminal beyond the multiplexer 3. Therefore, since interference with the optical signal transmitted from the own terminal does not occur, it is possible to suppress the occurrence of access competition, in which the optical signals transmitted from multiple terminals with the same optical wavelength interfere with each other at the receiving unit. , Time-division transmission and other access conflict avoidance measures are no longer required.

It is also possible to construct a moving image network system in which the two-wavelength receiving terminal of this embodiment and the one-wavelength receiving terminal of the first embodiment are mixed, and many high-performance terminals can be constructed. By assigning transmission / reception wavelengths and assigning fewer transmission / reception wavelengths to low-function terminals, a system configuration according to the function of the terminal becomes possible.

Further, in the first and second embodiments, the configuration is adopted in which the optical signal of the reception wavelength is taken in and blocked by using the demultiplexer, but the present invention is not limited to this and, for example,
As corresponding to the first embodiment, as shown in FIG.
Using the branching device 200, the optical signal on the wavelength multiplexing transmission line 230 is branched regardless of the wavelength, and only one of the branched optical signals is transmitted through the filter D20.
4 is used to extract and receive the optical signal of the reception wavelength.

Then, from the rest of the branched optical signals, the optical signals of the received wavelengths are obtained by using the filters A, B and C (201, 202, 203) which respectively transmit only one of the wavelengths other than the received wavelengths. It may be blocked. In addition,
Instead of the filters A, B and C, a cut filter that blocks only the reception wavelength may be used.

Further, as a case corresponding to the second embodiment, as shown in FIG. 8, the reception wavelength of its own terminal device sent from the terminal device upstream of the transmission line is adapted so as to be compatible with two reception wavelengths. The optical signal is blocked so as not to be output to the downstream terminal device. As described above, the cost of the system can be reduced by using the branching device and the filter, which are less expensive than the branching filter, instead of the branching filter.

Further, the encoding system to be adopted is not limited to the above-mentioned respective embodiments, and so-called DC is used.
It is also possible to use a hierarchical coding scheme such as a T-layer coding scheme. The present invention may be applied to a system including a plurality of devices or an apparatus including a single device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0089]

As described above, according to the first, sixth, and first aspects.
According to the invention described in 2, it is possible to effectively utilize the transmission band in the transmission path, enhance the responsiveness to the transmission request of the optical signal, and prevent the occurrence of fragmentation of the signal to be transmitted. By relaying the signals from the priority order to the low priority order, it is possible to further effectively use the transmission band.

Further, since each terminal device has a plurality of transmission wavelengths, the degree of freedom in setting the routing path is increased,
It is possible to save the trouble of switching the transmission wavelength. According to the thirteenth aspect of the present invention, it is possible to reduce the occurrence of a waiting state for an optical signal transmission request by discarding the information. Furthermore, according to the invention as set forth in claim 15, it is possible to improve the responsiveness and prevent the occurrence of fragmentation of the optical signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a moving image network system according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a storage unit in the system according to the first embodiment.

FIG. 3 is a block configuration diagram of an encoding unit configuring the system according to the first embodiment.

FIG. 4 is a block configuration diagram of a decoding unit included in the system according to the first embodiment.

FIG. 5 is a timing chart of time division multiplexing according to the first embodiment.

FIG. 6 is a block diagram showing a configuration of a moving image network system according to a second embodiment of the present invention.

FIG. 7 is a diagram illustrating another configuration example of the terminal device according to the first embodiment.

FIG. 8 is a diagram showing another configuration example of the terminal device according to the second embodiment.

FIG. 9 is a diagram showing a configuration of an optical ring network as a conventional moving image network system.

FIG. 10 is a diagram showing the configuration of another conventional moving image network system in which the transmission bandwidth is widened.

FIG. 11 is a diagram showing a configuration of a moving image network system according to a third conventional example.

[Explanation of symbols]

 1 Optical Fiber 8 Receiver 9 Transmitter I 10 Transmitter II 12 Storage I 13 Storage II 14 Control Unit 15 Decoding Unit 16 Encoding Unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H04L 12/42 H04N 7/22

Claims (16)

[Claims] 1. A terminal device for transmitting and receiving an optical signal by connecting to a wavelength division multiplexing optical transmission line, wherein an optical signal having a reception wavelength assigned in advance among the optical signals wavelength division multiplexed on the wavelength division multiplexing optical transmission line. A capturing unit that captures and blocks a signal, a receiving unit that receives the optical signal captured by the capturing unit, a storage unit that stores information to be transmitted, and a predetermined transmission wavelength that is assigned in advance. A first transmitting means for transmitting the information, a second transmitting means for transmitting the predetermined information at a second transmission wavelength, which is pre-assigned and different from the first transmission wavelength, and stored in the storage means. And a determining unit that determines whether the transmitted information is transmitted at the first transmission wavelength or at the second transmission wavelength. 2. The capturing means captures and blocks the optical signal of the reception wavelength by capturing all of the optical signal of the reception wavelength by a demultiplexer. Terminal device. 3. The taking-in means branches all optical signals on the wavelength-multiplexed optical transmission line into a plurality of paths by a branching device, and from the first optical signal among the branched optical signals, The optical signal of the reception wavelength is taken in, and the first
The terminal device according to claim 1, wherein an optical signal obtained by blocking an optical signal of the reception wavelength from an optical signal other than the optical signal of 1 is returned to the wavelength-multiplexed optical transmission line. 4. The at least one of the first transmission wavelength and the second transmission wavelength and the reception wavelength are different wavelengths from each other. Terminal equipment. 5. The one of the first transmission wavelength and the second transmission wavelength, and the reception wavelength are common wavelengths, according to any one of claims 1 to 3. The terminal device described. 6. A terminal device for transmitting and receiving an optical signal by connecting to a wavelength division multiplexing optical transmission line, wherein a plurality of reception wavelengths assigned in advance among optical signals wavelength division multiplexed on the wavelength division multiplexing optical transmission line. Capturing means for capturing and blocking the optical signal of, the receiving means for individually receiving the plurality of optical signals captured by the capturing means, the storing means for storing the information to be transmitted, and the plurality of pre-allocated Transmission means for individually transmitting predetermined information at the transmission wavelength of, and a determination means for determining which transmission wavelength among the plurality of transmission wavelengths the information stored in the storage means is to be transmitted, A terminal device comprising: 7. The capturing means captures and blocks the optical signals of the plurality of reception wavelengths by capturing all of the optical signals of the plurality of reception wavelengths by a demultiplexer. The terminal device according to item 6. 8. The take-in means branches all optical signals on the wavelength-multiplexed optical transmission line into a plurality of paths by a branching device, and outputs the first optical signal from the first optical signal among the branched optical signals. Taking in optical signals of a plurality of reception wavelengths, and of the optical signals after the branching,
7. The terminal device according to claim 6, wherein an optical signal obtained by blocking an optical signal of the plurality of reception wavelengths from an optical signal other than the first optical signal is returned to the wavelength multiplexing optical transmission line. 9. The terminal device according to claim 6, wherein the plurality of reception wavelengths and the plurality of transmission wavelengths have the same number and the same wavelength configuration. 10. The terminal device according to claim 1, wherein the storage unit stores the information separately for each transmission wavelength determined by the determination unit. 11. The determining means determines the transmission wavelength based on the amount of information for each transmission wavelength of the information stored in the storage means in a state where the transmission wavelength has already been determined. 10. The terminal device according to 10. 12. The information according to any one of claims 1 to 11, wherein a priority order for transmission is added to the information, and the information having higher priority order is transmitted in order of the information. Terminal equipment. 13. The transmission allowable delay time for transmission is assigned to the information, and the information after the transmission allowable delay time has elapsed is discarded without being transmitted. The terminal device described in. 14. A network system for connecting a plurality of terminal devices to a wavelength division multiplexing optical transmission line to transmit and receive an optical signal, wherein some or all of the plurality of terminal devices are any one of claims 1 to 13. A network system, which is the terminal device described in 1. 15. When the transmission wavelength of a first terminal device that transmits predetermined information and the reception wavelength of a second terminal device that receives the information are different, the first terminal device among the plurality of terminal devices
15. The network system according to claim 14, wherein wavelength conversion is performed in one or more terminal devices other than the terminal device and the second terminal device such that the transmission wavelength matches the reception wavelength. 16. The network system according to claim 14, wherein the wavelength division multiplexing optical transmission line is configured by a wavelength division multiplexing optical transmission line.