JPH05137127A - Transmission system - Google Patents

Abstract

PURPOSE:To improve the utilization efficiency of a multi-channel transmission line. CONSTITUTION:A dynamic image signal from a dynamic image signal source 110 in a transmission part 1 (1) is divided into plural partial dynamic image signals by a dynamic image dividing part I 11 and modulated by a desired modulation frequency in (k) pieces of modulation frequencies by modulators IA-ID (12-15). Subsequently, a multiplexer 16 synthesizes output signals from the modulators IAID and it is sent out to a coaxial cable 9. Also, a reception control part 118 in a reception part 1 (5) determines a modulation frequency used for the transmission of the partial dynamic image signal in accordance with the utilization state of a modulation frequency on a transmission line and simultaneously, controls a demultiplexer 20, demodulators IA-ID (21-24) and a dynamic image restoring part 25 and restores the original dynamic image signal from the partial dynamic image signal transmitted by a prescribed modulation frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission system for transmitting a plurality of moving image information via a multi-channel transmission line.

[0002]

2. Description of the Related Art Conventionally, various transmission systems of this type have been proposed. For example, there is one that constructs a multi-channel transmission path using a coaxial cable, a plurality of modulators, and a demodulator to transmit a plurality of moving image information.

[0003]

However, in the above-described conventional transmission system, when all the transmission channels of the multi-channel transmission line are in use, the transmission request of the newly generated moving image information is Since it is necessary to wait until the use of the transmission channel is completed, there is a problem that the response to the transmission request is poor.

Therefore, as one method for solving the above problem, the right of use of the transmission channels is sequentially changed in a predetermined time unit, and the transmission of moving image information of the number of transmission channels of the multi-channel transmission path or more is realized. However, in this case, there is a problem that moving image information is cut off every time the right to use the transmission channel is lost. Further, in the above-mentioned conventional transmission system, since the transmission capacity per one transmission channel is uniformly and fixedly allocated, the amount of information to be transmitted is small, for example, when performing reduced display on the receiving side. In the transmission of moving image information, since the transmission capacity is not fully utilized, a part of it is wasted, and there is a problem that the utilization efficiency of the transmission path is poor in the entire network.

[0005]

The present invention has been made for the purpose of solving the above-mentioned problems, and has the following constitution as one means for solving the above-mentioned problems. That is,
A transmission system for transmitting a plurality of moving image information using a plurality of channels, wherein allocation of the plurality of channels is changed according to a transmission request for other moving image information.

[0006]

In the above structure, it functions to improve the utilization efficiency of the multi-channel transmission line.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram showing the overall configuration of a moving image network system according to an embodiment of the present invention. In the moving picture network system shown in the figure, a plurality (n) of transmitting units 1 to n (1 to 4) for transmitting a moving picture signal from a built-in moving picture signal source and a receiving unit for receiving the moving picture signal. Multiple (m) receiving units 1 to m (5
8 to 8) are connected via a coaxial cable 9 which is a transmission line.

The transmitter 1 (1) divides the moving picture signal from the moving picture signal source into a plurality (up to four) or one partial moving picture signal and modulates it at a desired modulation frequency. Send to coaxial cable. Since the transmitters 2, 3, and n have the same configuration as the transmitter 1, their internal configurations are not shown here. The receiving unit 1 (5) receives and demodulates the modulated partial moving image signal from the transmitting unit, restores the transmitted moving image signal, and outputs it to the moving image output device. The receivers 2, 3 and m also have the same internal configuration as the receiver 1, and therefore are not shown here.

The coaxial cable 9 is a signal transmission path, and when the transmission path length becomes long, an amplifying means for relay amplification of the signal is inserted in the middle of the coaxial cable and the
And two coaxial cables dedicated for downlink are used. Incidentally, FIG.
Then, the amplification means for relay amplification is not shown,
Also, there is only one coaxial cable. Transmitter 1 (1)
In the above, as the moving image signal source I10, for example, a VTR, a video camera, or the like is used, and the moving image dividing unit I11 uses the moving image signal source I10 according to the control signal from the transmission control unit 17.
The divided moving image signal is divided into a single or a plurality of partial moving image signals and output to the modulators IA to ID (12 to 15). These modulators IA, IB, IC, and ID use the partial moving image signal from the moving image division unit I11 at a desired modulation frequency f _i (i = 1, ... K) of k modulation frequencies. Modulate.

The multiplexer 16 includes modulators IA, IB, IC,
The output signals from the IDs are combined and sent to the coaxial cable 9. In addition, the transmission control unit 17 includes a reception unit 1 described later.
It receives the control baseband signal from .about.m and controls the moving image division unit I11, the modulators IA, IB, IC, ID and the like. In the reception unit 1 (5), the reception control unit I18 performs channel allocation control. That is, according to the instruction from the MMI unit 19, the modulation frequency used for transmission of the partial moving image signal is determined according to the usage state of the modulation frequency on the transmission path, and the determined moving frequency is used as the moving image signal using the baseband signal. Notify the sender or other receiver of for that reason,
The reception control unit I18 has a necessary channel usage management table and usage level management table. Also, the reception controller I
Reference numeral 18 denotes a duplexer 20 and demodulators IA to ID (21 to 21 at the same time).
24) The moving picture restoration unit 25 is controlled to restore the original moving picture signal from the partial moving picture signal transmitted at a predetermined modulation frequency.

The demultiplexer 20 selectively receives the signal instructed by the reception control section I18 from the modulated partial moving image signals from the coaxial cable 9 and outputs it to a predetermined demodulator. Further, the demodulators IA to ID (21 to 24) demodulate a desired partial moving image signal according to the instruction of the reception control unit 18 and output it to the moving image restoration unit 25. The moving image restoration unit 25 restores the moving image signal using the partial moving image signal from the demodulator according to the instruction from the reception control unit 18. If a part of the partial image signal divided by the moving image signal transmitting unit is not transmitted, this is supplemented according to the instruction of the reception control unit I18. The moving image signal output from the moving image restoring unit 25 is output by the moving image output device I26 such as a display or a printer.

FIG. 2 is a detailed block diagram of the moving picture division unit I11 of FIG. In the figure, a system clock generating unit 31 extracts a synchronizing signal from a moving image signal from a moving image signal source I10 and generates various timing signals used in the moving image network system. A / D converter A to
D (32, 33, 34, 35) performs A / D conversion on the input moving image signal based on the sampling signal from the system clock generating unit 31. Further, the internal connection unit 36 outputs the outputs of the A / D converters A to D to the encoders A to D.
It is a connecting portion for inputting to D (37, 38, 39, 40). The encoders A to D encode the outputs of the A / D converters A to D into four partial moving images based on a predetermined conversion formula described later.

FIG. 3 is a detailed block diagram of the moving picture restoration section. In the figure, the system clock extraction section 41 extracts a necessary clock in the reception section from the transmitted image signal. Also, decoders A to D (43, 44, 45, 46)
Decodes the image signal encoded by the transmitter. The internal connection unit 42 is a connection unit for inputting the outputs of the demodulators IA to ID to the decoders A to D.

The synthesizing unit 47 synthesizes the outputs of the decoders A to D and outputs the synthesized output to the D / A converter 48. D
The / A converter 48 converts the input digital signal into an analog signal and outputs the converted signal to the moving image output device I26. FIG. 4 is a diagram showing a configuration of a pixel unit of a moving image signal transmitted in the moving image network system according to this embodiment. As shown in the figure, in the present embodiment, the pixel unit is divided into four pixel units a, b, c and d which are adjacent in the scanning line direction, and the divided pixel unit is transmitted. The coding conversion formula is as follows for each encoder: encoder A: k ₀₁ = (a + b + c + d) / 4 (1) encoder B: k ₁₁ = (a + b) / 2- (a + b + c + d) / 4 (2) Encoder C: k ₂₁ = a- (a + b) / 2 (3) Encoder D: k ₂₂ = c- (c + d) / 2 (4) The decoding conversion formula is as follows: Decoder A: a = k ₀₁ + k ₁₁ + k ₂₁ (5) Decoder B: b = k ₀₁ + k ₁₁ −k ₂₁ (6) Decoder C: c = k ₀₁ − _{k 11 + k 22 ... (7} ) decoder D: a _{d = k 01 -k 11 -k 22} ... (8).

[Description of System Operation] The operation of the moving image network system according to this embodiment will be described below. In the receiving unit 1 (5) of FIG. 1, the transmitting unit 1
When the transmission request of the moving picture signal source I10 of (1) is input through the MMI 19, the reception control unit I18 searches the channel use management table for an empty channel, and according to the number of empty channels, the following is performed. Operate.

<When the number of empty channels is four or more> The reception control unit I18 selects four desired channels from the empty channels, and uses the terminal number (not shown) in the corresponding channel column of the channel use management table. Although not shown, the terminals having the transmitting unit and the receiving unit in FIG. 1 are hereinafter referred to as the transmitting terminal and the receiving terminal, respectively, and the coding levels (A, B, C, D) used in the channel are recorded. ..
Then, using the baseband signal, the reception control units and transmission control units of all the transmission terminals and the reception terminals connected to the coaxial cable 9 start using the corresponding channel, the coding level, and the transmission terminal number. To report. Receiving this notification, the transmitting and receiving terminals modify the channel use management table.

On the other hand, when the transmitter 1 (1) receives this notification, it transmits the moving image signal of the moving image signal source I10 as follows. That is, when the moving picture signal from the moving picture signal source I10 is input, the system clock generator 31 in the moving picture division unit I11 separates the horizontal and vertical synchronization signals from the signal, and the A / D converter A ~ D (32, 33, 34,
35), the sampling signals φ ₁ , φ ₂ , φ ₃ , φ ₄ are interleaved in quadruple as shown in FIG.
To occur.

The A / D converters A to D use the above sampling signals to convert the moving image from the moving image signal source I10 to
A / b is obtained by sampling the pixel series a, b, c, d described above.
Perform D conversion. Then, the signals from the A / D converters A to D are latched so that they are simultaneously output at the clock φ ₀ , and then the encoders A to D (37) via the internal connection section 36 functioning as an internal bus. , 38, 39, 40).

In the encoder A37, A / B which is the image signal of the pixel series a, b, c, d is calculated based on the above equation (1).
The outputs of the D converters A to D are averaged in a cycle of 4T and converted into a serial signal, which is then output to the modulator IA12. In addition, the encoder B38 calculates the difference between the average value of the A / D converters A and B and the average value of the A / D converters A, B, C and D based on the above equation (2). It is obtained by 4T, converted into a serial signal, and output to the modulator IB13.

In the encoder C39, the output of the A / D converter A and the A / D converters A and B are calculated based on the above equation (3).
The difference from the average value of the output of is calculated in a cycle of 4T, converted into a serial signal, and output to the modulator IC14. Similarly, in the encoder D40, the difference between the output of the A / D converter C and the average value of the outputs of the A / D converters C and D is calculated in the cycle 4T based on the equation (4), and the serial value is calculated. Convert to signal, modulator ID15
Output to.

The modulators IA, IB, IC and ID transmit the serial signals output from the encoders A, B, C and D, respectively, to the frequency f corresponding to the channel and the encoding level reported from the receiving section 1. _The signals are modulated by _A , f _B , f _C and f _D and output to the multiplexer 16. Then, the multiplexer 16 has the modulator I
The modulated signals from A, IB, IC, and ID are combined and output to the coaxial cable 9.

In the receiving section 1 (5), the modulated signal input via the coaxial cable 9 is demultiplexed by the demultiplexer 20, and then demodulated by the demodulators IA, IB, IC, and ID, respectively, with the frequency f _A. , F _B , f _C , f _D signals are demodulated and output to the decoders A, B, C, D. At the same time, demodulator IA
From the output from, a synchronization signal is extracted by the system clock extraction unit 41, and system signals φ ₁ , φ ₂ , φ ₃ , and φ ₄ interleaved four times with a period of 4T are created.

The signals from the demodulators IA, IB, IC and ID are output to the decoders A, B, C and D via the internal connection section 42. Among them, in the decoder A, the above equation (5) is used. Based on the above, by adding the output signals of the demodulators IA, IB, and IC, the partial moving image signal corresponding to the pixel series a is decoded in the cycle 4T, and the partial moving image signal is decoded at the timing of the system signal φ _1. Output to. Further, in the decoder B, the signal of the demodulator IC is subtracted from the sum of the outputs of the demodulator IA and the demodulator IB based on the above equation (6), so that the partial moving image signal corresponding to the pixel series b has a period of 4T. And outputs to the synthesis processing unit 47 at the timing of the system signal φ ₂ .

Similarly, the decoder C subtracts the signal of the demodulator IB from the sum of the output signals of the demodulator IA and the demodulator ID on the basis of the above equation (7) to obtain the portion corresponding to the pixel series C. The moving image signal is decoded in the cycle 4T and output to the synthesis processing unit 47 at the timing of the system signal φ ₃ . Further, the decoder D subtracts the outputs of the demodulator IB and the demodulator ID from the output of the demodulator IA based on the equation (8), thereby decoding the partial moving image signal corresponding to the pixel series d in the cycle 4T. Then, the signal is output to the synthesis processing unit 47 at the timing of the system signal φ ₄ . Then, the decoders A, B,
The partial moving image signals corresponding to the image sequences a, b, c, d output from C and D are system signals φ ₁ , φ ₂ , φ ₃ ,
With φ _4, it is restored to one moving image signal, and the D / A converter 48
Are sequentially converted into analog signals by the moving image output apparatus I.
26 is output.

<When the number of free channels is 3>
A case where there are three free channels will be described. In this case, the reception control unit I18 records the used terminal number and the coding level (A, B, C) used in that channel in the three channel columns of the channel use management table. further,
The terminal number is registered at the end of the queue of the level D waiting order management table. Then, the reception controller 18
Using the baseband signal, all the transmissions connected to the coaxial cable 9 and the transmissions of the reception terminal, and the reception control unit, start of use of the corresponding channel and management of the encoding level, the transmission terminal number, and the waiting order of the level D Report registration to the end of the queue in the table. Then, the transmitting and receiving terminals receive the notification and modify the channel use management table and the waiting order management table.

On the other hand, the transmitter 1 (1) receives this notification.
If you do this, you will receive a notification except for encoder D40 and modulator ID15.
Frequency based on the three channels and the coding level
Number f _A', F_B', F_COutput of encoders A, B, and C using
To send. Further, in the receiving unit 1 (5), the demodulator ID2
No. 4 stops the demodulation operation, and in the above equations (7) and (8),
K_{twenty two}The pseudo output is output so that the value of becomes 0. this
In the receiving unit 1 (5), k_{twenty two}Put 0 as the value of
Then, the moving image signal is output.

<When the number of vacant channels is 2> Even when the number of vacant channels is 2, as in the case of 3, the terminal numbers used and the codes used for the channels are stored in the two channel columns of the channel use management table. Record the activation level (A, B). Further, the terminal number is registered at the end of the queue of the queue management table of level D and level C. continue,
The reception control unit 18 uses the baseband signal to transmit all the transmissions connected to the coaxial cable 9 and the transmission of the reception terminal, and the reception control unit uses the corresponding channel to start the use and the coding level, the transmission terminal number, Notification of registration at the end of the queue of the queue management table for level D and level C is reported. Upon receiving this notification, the transmitting and receiving terminals modify the channel use management table and the waiting order management table.

In response to this notification, the transmission unit 1 receives the notification and, except for the encoder C39, the encoder D40, the modulator IC14, and the modulator ID15, transmits the frequency f based on the two channels and the encoding level. The outputs of encoders A and B are transmitted at _A ″ and f _B ″. In the receiving unit 1,
Demodulator IC 23, and demodulator ID24 stops demodulation operation, the above equation (5), (6), (7), a pseudo output such that k _21, the value of k ₂₂ is 0 in (8) Output.
In this way, in the receiving unit 1, the values of k ₂₁ and k ₂₂ are reset to 0, and the moving image signal is output.

<When the Number of Free Channels is 1> When the number of free channels is 1, the used terminal number and the coding level (A) used in that channel are recorded in one channel column of the channel use management table. To do. Further, the terminal number is registered at the end of the queue of the waiting order management table of level B, level C, and level D. Then, the reception controller I18
Uses the baseband signal to transmit all the transmissions connected to the coaxial cable 9 and the transmission of the reception terminal, and the reception control unit starts the use of the corresponding channel and the coding level, the transmission terminal number, the level B, and the level. Report the registration at the end of the queue of the queue management table of C and level D. Upon receiving this notification, the transmitting and receiving terminals modify the channel use management table and the waiting order management table.

The transmitter 1 receives the notification and then the encoder B
38, encoder C39, encoder D40, and modulator IB
Other than 13, the modulator IC 14, and the modulator ID 15, the output of the encoder A is transmitted using the frequency f _A ″ ″ based on the reported one channel and the encoding level. Also,
In the receiving unit 1, the demodulator IB22 and the demodulator IC2
3. The demodulator ID 24 stops the demodulation operation, and k ₁₁ in the above equations (5), (6), (7) and (8),
The values of k ₂₁ and k ₂₂ are replaced with 0, and the moving image signal is output.

<When there is no empty channel> Next, when there is no empty channel, the reception control section I18 searches the channel use management table for one channel used at the coding level D. If there is no corresponding channel, the channels used in level C and level B are searched. If there is no corresponding channel also here, the terminal number is registered at the end of the queue of the level A waiting order management table, and all transmissions connected to the coaxial cable 9 using the baseband signal,
And, the transmission of the receiving terminal and the reception control unit are notified of the registration of the level A in the waiting order management table. Upon receiving this report,
The sending and receiving terminals modify the level A waiting order management table.

On the other hand, when the corresponding channel exists, the used terminal number and the coding level A used in the channel are recorded in the corresponding channel column of the channel use management table. Further, the use stoppage is reported to the terminal which has been used so far by using the baseband signal. Upon receipt of this notification, the corresponding terminal stops using the corresponding channel, changes the encoding compression rate according to the remaining number of used channels, and continues transmission of the moving image signal as described above. At the same time, the queue management table is registered at the end of the queue corresponding to the coding level of the channel whose use has been stopped.

When the relevant channel is released in this way, the receiving terminal receives the moving image signal using one channel as described above. When the end of the transmission of the moving image signal is input by the operator or the like through the MMI unit 19, the reception control unit I18 changes the column of the used channel in the channel use management table to unused and sets the level of each level. If there is registration in the queue of the waiting order management table, delete it. Then, the coding level A
From the head of the queue of the waiting order management table, the same number of terminal numbers as the number of released channels are extracted, and these terminals are notified of permission to use the corresponding channels using a broadband signal.

When no waiting queue exists in the waiting order management table of level A, levels B, C and D are searched sequentially. Further, the baseband signal is used to notify the control units of all the transmitting and receiving terminals connected to the coaxial cable 9 of the end of use of the corresponding channel, the newly used terminal number, and the like. Upon receiving this notification, all the transmitting and receiving terminals modify the channel use management table, the waiting order management table and the like. In addition, the terminal which newly obtains the right to use the channel transmits the moving image signal as described above in accordance with the number of channels combined with the number of channels used up to that point.

As described above, according to this embodiment,
After dividing the moving image signal to be transmitted into partial moving image signals, determine the coding level of the moving image signal to be transmitted according to the number of empty channels in the multi-channel transmission line, and then convert the signal modulated at the frequency corresponding to the coding level. By transmitting,
The use efficiency of the multi-channel transmission line is improved, the responsiveness can be improved by reducing the occurrence of the waiting state for the moving image signal transmission request, and the occurrence of the interruption of the moving image signal in the moving image network system is reduced. There is an effect that can be done.

The present invention is not limited to the above-described embodiments, but various modifications can be made without departing from the spirit of the invention. For example, as a modification of the configuration of the pixel unit of the moving image signal to be transmitted, the pixel unit may be divided as shown in FIG. By adopting this configuration, the value of k ₀₁ of the equation (1) in the above embodiment, which is obtained by the decomposition into the partial moving image signal, is transmitted using the 1-channel transmission path, and the combining processing of the receiving unit 1 is performed. In the unit 47, well-known 0 complementation, low-frequency cutoff processing, and re-sampling processing for image reduction are performed, so that good 1/2 × 1/2 is obtained.
A size-reduced moving image can be restored. Further, when the receiving terminal does not need to output a full-size moving image, it is possible to reduce the number of channels required for transmission.

In the above embodiment, all the transmission and reception terminals connected on the coaxial cable 9 have the channel use management table and the waiting order management table, and they are managed. It is possible to prevent troubles due to loss of coherency in the management table of each terminal by configuring only the channel use management table and the waiting order management table.

Further, an optical transmission system may be used as the multi-channel transmission line for transmitting the partial moving image signal. That is, in the moving image network system shown in FIG. 7, the semiconductor laser diodes 51 to 54, 64 are
It is a laser diode of a DFB type (Distributed Feedback) having a multi-electrode structure, and the amount of current injected into each electrode is controlled so that it is 1.50 μm to 1.56 μm.
Then, an electric signal from an encoder (not shown) is converted into an optical signal and transmitted.

The optical fiber 59 transmits the optical signals emitted from the semiconductor laser diodes 51 to 54 and 64, and the demultiplexers 57 and 58 take out the optical signals in the optical fiber 59 and respectively receive the receiving section 5a and the transmitting section. Lead to part 1a. Further, multi-electrode DFB semiconductor optical filters 60 to 6 based on the same configuration and principle as the above DFB laser diode.
Reference numerals 3, 56 are for selectively transmitting a desired wavelength between 1.5 μm and 1.56 μm by controlling the amount of current injected into each electrode. Further, the pin photodiodes 65 to 68, 55 convert the incident light signal into an electric signal.

The semiconductor laser diodes 51 to 54
Is equivalent to the modulator in the above embodiment,
Optical filters 60 to 63 and pin photodiodes 65 and 6
7 to 69 correspond to demodulators. The laser diode 64, the filter 56, and the photodiode 55 are related to the transmission of baseband signals for transmission / reception control. Portions (not shown) of the receiving unit 5a and the transmitting unit 1a have the same configurations as the receiving unit 5 and the transmitting unit 1 in the above-described embodiment.

As described above, by using the optical transmission system as the multi-channel transmission line, the transmission signal band can be widened and higher quality moving image transmission can be performed. The transmission channel in this embodiment is I
The SDN transmission line may be used, or another transmission line may be used. Further, in addition to the coding system in this embodiment, for example, an ADCT system, a vector quantization system, or a moving image coding system including motion compensation may be used. In this case, the compression rate may be controlled by controlling the quantization parameter for compression.

[0042]

As described above, according to the present invention,
This has the effects of improving the utilization efficiency of the multi-channel transmission path, reducing the occurrence of waiting states and improving the responsiveness to the transmission request for moving image information.

[Brief description of drawings]

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

FIG. 2 is a detailed configuration diagram of a moving image dividing unit included in the moving image network system according to the embodiment,

FIG. 3 is a detailed configuration diagram of a moving image restoration unit included in the moving image network system according to the embodiment.

FIG. 4 is a diagram showing a configuration of a pixel unit of a moving image signal transmitted in a moving image network system according to an embodiment,

FIG. 5 is a diagram showing a sampling signal generated by a system clock generator;

FIG. 6 is a diagram showing a modified example of a pixel unit division structure;

FIG. 7 is a diagram showing a configuration of a moving image network system using an optical transmission system.

[Explanation of symbols]

 1, 2, 3, 4 transmitter 5, 6, 7, 8 receiver 9 coaxial cable 10 moving image signal source 11 moving image dividers 12, 13, 14, 15 modulator 18 reception controller 21, 22, 23, 24 demodulator 25 moving image restoration unit 26 moving image output device

Claims (1)

[Claims] 1. A transmission system for transmitting a plurality of moving image information using a plurality of channels, wherein allocation of the plurality of channels is changed according to a transmission request of other moving image information. Transmission system.