JP2986852B2 - Facsimile broadcast receiver - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile broadcast receiving apparatus for receiving digital multiplexed facsimile broadcasts by a digital system.

[Summary of the Invention]

The present invention relates to a digital television multiplex facsimile broadcast receiving apparatus, and when a frame memory for receiving and processing a facsimile signal is configured, a mode control unit and a memory for storing a data packet unit are independently configured and operated. The mode control unit performs error correction and service identification determination at the stage when the transmission is completed, and determines the number of facsimile broadcast packets transmitted in the frame and the transmission position in the frame without waiting for the transmission of all frame data to be completed. When the detection and the result and the transmission format of the facsimile signal are specified to be continuously transmitted in the frame, the mode control unit detects an error or determines that the broadcast is a non-facsimile broadcast by erroneous correction. But that mode control If the mode control assigned to the facsimile broadcast is transmitted after the control section, the data packet corresponding to the mode control section in which an error is detected or determined to be a non-facsimile broadcast is regarded as a data packet of the facsimile broadcast. The receiving process is performed thereafter.

[Conventional technology]

In a receiver for receiving a digital television multiplex facsimile broadcast, in order to process a facsimile signal transmitted by interleaving for each frame, two frame memories are prepared, and a writing side for each frame is provided.
And, while switching the reading side and writing data to be transmitted in a frame to one frame memory, the other frame memory in which the data of the previous frame has already been written is read out and read out, In general, a method of repeating the error correction of the mode control unit, the service identification determination, and the error correction of the data packet unit in the order of the transmission packet is used.

In addition, in such a processing mode, a transmission error occurs in the mode control unit that specifies the service identification for each packet, and an uncorrectable error is detected. For error processing when the mode control is not facsimile broadcasting, an error processing method of discarding the data packet is generally used.

[Problems to be solved by the invention]

In the digital television multiplex facsimile broadcasting, a packet in which a different mode control unit is designated is not transmitted in a frame during a transmission period of program data.

Therefore, when an error occurs in the mode control unit due to a transmission error and an uncorrectable error is detected, and even when the result of determining the mode control unit is determined not to be assigned to facsimile broadcasting, If a mode control packet assigned to facsimile broadcasting is transmitted after the packet in the frame, it may be determined that the mode control unit in which the error has occurred was originally assigned to facsimile broadcasting. Will be.

However, as described above, in the processing method in which the frame data transmitted in the frame is de-interleaved and read, and the error correction of the mode control unit, the service identification determination, and the error correction of the data packet unit are repeated in the order of the transmission packet, the error is corrected. A packet memory for temporarily saving the generated packet is prepared separately from the frame memory, and it is determined whether to actually discard the saved packet based on the result of processing the subsequent packets in the same manner. Requires a large amount of packet memory.

Accordingly, it is an object of the present invention to provide a facsimile broadcast receiving apparatus capable of processing the above-described error without requiring a new memory.

[Means for solving the problem]

In order to achieve the above object, a facsimile broadcast receiving apparatus according to the present invention is a facsimile broadcast receiving apparatus having a mode control unit memory independent of a data packet unit memory, wherein the mode control unit memory has a frame. When the storage of the mode control unit is completed, first processing means for performing error correction and service identification of the mode control unit, and an uncorrectable error occurs in the mode control unit by the first processing means. If it is determined that
Even when it is determined that the service identification is not assigned to facsimile broadcasting, when the mode control unit after the determination is made is determined to be assigned to facsimile broadcasting, the determination is made. And a second processing means for processing the data packet as a data packet allocated to the facsimile broadcast without discarding the data packet to the mode control unit in the case where the processing is performed.

(Operation)

The present invention focuses on the fact that a transmission signal in a digital television multiplex facsimile broadcast is transmitted in order of a mode control section data and a data packet section data following a framing code, and a mode control for a memory for writing one frame data. By independently configuring the data control section and the data packet section, the mode control section memory is read when transmission and writing of the mode control section data is completed, and the mode control section memory is read while the data packet section is being transmitted. After completing the error correction and service identification determination processing, by determining the number of transmission packets for each service and the transmission position within the frame for the data packet transmitted within the frame, the above-described processing can be performed without requiring a new memory. I And it makes it possible to process for errors, such as.

〔Example〕

Before describing the embodiments of the present invention, first, a transmission signal of digital television multiplex facsimile broadcasting will be briefly described.

FIG. 2 is a diagram showing a frame configuration for transmitting a facsimile channel signal defined in digital television multiplex facsimile broadcasting. One frame is
It is composed of 32 rows x 288 bits, and a framing code of 16 bits is provided at the head of the frame. Each row of 288 bits has a packet configuration. FIG. 3 shows the packet configuration. The packet length is 288 bits, and is composed of a 16-bit mode control section and a 272-bit data packet section.

The service control of the packet is performed by the mode control unit. The mode control unit can perform error protection using a BCH (16,5) code. A total of three service identifications are assigned to codes of the mode control unit for general programs, for pay programs, and for dummy data transmission.

Facsimile broadcast program data is transmitted by the data packet section. The data packet portion is protected from errors by a (272,190) code.

Since the order of writing packet data and the order of reading data are determined as shown in FIG. 2 for the frame having the above configuration, the framing code, the mode control unit data and the data packet unit as shown in FIG. Data is transmitted sequentially for each frame. However, the mode control part data and data packet part data of each packet have an interleave length of 32.
Data is transmitted by bit interleaving with bits.

Since the transmission speed of the facsimile signal is 16 kbps and the number of bits in one frame is 9232, the transmission time of one frame data is 577 msec. Of these, the framing code section is 1 msec, the mode control section is 32 msec, and the packet data section is 544 msec.

The above is the description of the transmission signal of the digital television multiplex facsimile broadcast.

 Next, an embodiment of the present invention will be described.

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, a signal A is a bit stream signal obtained by demodulating a facsimile channel signal. Signal A has the configuration shown in FIG.

The framing code detector 10 detects the framing code from the signal A. When the framing code is detected, a detection pulse signal B is output.

When receiving the framing code detection signal B, the MC memory write address controller 11 transmits the mode control data transmitted immediately after the framing code.
A write address for writing 512 bits to the MC memory 12 is controlled. In accordance with the address signal C from the MC memory write address controller 11, 512-bit data immediately after the framing code of the signal A is written to the MC memory 12.

The MC unit memory write address control unit 11 outputs a mode control unit data write end pulse signal D when the 512-bit write address control ends.

Upon receiving the mode control section data write end signal D, the DPAC section memory write address control section 14 writes 8704 bits of data packet section data transmitted following the mode control section data to the DPAC section memory 15. Control the write address. According to the address signal E from the DPAC unit memory write address control unit 14, 8704 bits of data after the mode control unit data of the signal A are written to the DPAC unit memory 15.

The DPAC memory 15 is composed of two memories having a capacity capable of storing 8704 bits of data. This is to process the data packet part data transmitted by interleaving every frame,
While switching the reading side, while writing the data packet part data transmitted in the frame to one DPAC part memory, the other DPAC part in which the data packet part data transmitted in the previous frame has already been written This is because the memory is deinterleaved and read, and error correction is performed using the (272,190) code in the order of transmission data packets.

The DPAC unit memory select unit 13 receives the framing code detection signal B from the framing code detection unit and
A DPAC section memory switching signal F for controlling switching between the writing side and the reading side to the system DPAC section memory is output. The signal F switches between the writing side and the reading side of the two DPAC unit memories for each frame. Data packet part data transmitted in the frame is written in the memory on the writing side.

On the other hand, the MC section memory read address control section 16
Receiving the mode control section data write end pulse signal D from the section memory write end address control section 11 and
Control of a read address for reading the mode control unit data written in the unit memory 12 is started.

Since the mode control section data is written in the MC section memory 12 in the transmission order, the MC section memory read address control section performs address control for de-interleaving, reads the mode control section data block by block, and outputs the signal G Output as

The MC error correction unit 17 corrects the mode control unit of 32 blocks by the signal G using the BCH (16,5) code, and outputs the correction result as a signal H.

The MC determination unit 18 determines whether the signal H is a service identification indicating a general program or a pay program, a service identification indicating a dummy, or none of the above (for convenience, the non-facsimile broadcasting Service identification), and 4
And a flag signal I indicating the determination result is output.

The signal I needs to be a flag of at least 2 bits for each mode control unit in order to indicate four determination results for one mode control unit.

By repeating the above operation 32 times, the error correction and identification determination operation for the 32 mode control unit data transmitted in one frame is completed.

The signal I is a flag signal indicating whether or not the service identification is assigned to facsimile broadcasting for each mode control unit, and is output in 64 bits for each frame.

Here, as a result of correcting and determining the mode control unit, even if an error that cannot be corrected is detected or if a non-facsimile broadcast is determined, the mode control unit may be treated as a facsimile broadcast. Explain the possibilities.

In digital television multiplex facsimile broadcasting, during a transmission period of program data, a packet in which a different mode control unit is designated is not interrupted and transmitted in a frame. Therefore, within one frame, the program data is continuously transmitted with a maximum value of 32 packets. The meaning of the maximum value of 32 is that a method of guaranteeing the minimum scanning line time of the receiver in units of one frame transmission time is allowed as a method of transmitting an image signal. In this case, for example, 20 packets are transmitted from the beginning of the frame. This is because transmission of image data may be interrupted at a stage. When the transmission of the image data is interrupted, dummy data is transmitted in the frame.

However, transmission of auxiliary information for facsimile broadcasting using this suspension period is currently being studied. If mode control is assigned to auxiliary information,
Although auxiliary information may be transmitted by the assigned mode control, it is assumed here that dummy data is generally transmitted.

On the other hand, the BCH (16,5) code used for error protection of the mode control unit can correct all errors within 3 bits, and can detect all 4-bit errors. . Therefore, when there is an error of 5 bits or more, there is a possibility that the error is erroneously corrected.

However, in facsimile broadcasting, only three codewords are valid for general, pay, and dummy among 32 codewords of BCH (16,5) code. Since the probability of coincidence with any one of the three programs assigned to the program, the pay program, and the dummy is extremely low, the probability that the result determined as general, pay, or dummy is erroneous is extremely low.

In consideration of the above two points, even when a transmission error occurs in the mode control unit and an uncorrectable error is detected, and when it is determined that the broadcast is a non-facsimile broadcast due to erroneous correction, the mode control unit of the frame is not used. If it is determined that the subsequent mode control is the mode control assigned to the facsimile broadcast, it can be determined that the uncorrectable or erroneously corrected mode control has also been transmitted as the facsimile broadcast. As a judgment condition, not only the mode control immediately after, but also the mode control after that is referred to, and if all of them are the mode control assigned to the facsimile broadcast, the mode control unit in which the transmission error has occurred is determined. Probability of facsimile broadcasting is even higher.

In order to perform these processes, the MC complement unit 19 takes in a flag signal I of a total of 64 bits every two bits into a memory, and sets a flag indicating that an uncorrectable error has been detected,
And if there is a flag indicating non-facsimile broadcasting, if the subsequent flags are flags indicating facsimile broadcasting,
The flag is replaced with a facsimile broadcast flag.
Similarly, when a subsequent flag is set as a dummy signal, the flag is replaced with a dummy signal flag. However, when the flag of the last packet in the frame indicates a non-facsimile broadcast, it is impossible to determine the flag, so that the flag is not replaced.

After complementing by the MC complementing unit 19, the number of packets for each service transmitted in one frame can be calculated by counting the flags for each state.

Also, as is apparent from the above description, the MC memory 12
, The arrangement order of the flags in the memory corresponds to the transmission position of each packet of the facsimile broadcast transmitted in one frame.

The above operation needs to be performed simultaneously with the operation of writing the data packet part data to the DPAC part memory 15, but the transmission time of the data packet part data part is 544 ms
c and can be processed sufficiently.

When the transmission of the data packet part data is completed and the operation of writing to the DPAC part memory 15 is completed, the framing code is transmitted again, so that the operation described above is repeated. As for the mode control section, all processing has been completed and information is stored as flags,
The MC section memory 12 may be one system.

When the framing code is detected, the DPAC unit memory select unit 13 reverses the control on the write side and the read side so far.

At this stage, the DPAC unit memory which has been operating as the writing side during the previous frame period is switched to the reading side, so that the DPAC unit memory read address control unit 20 reads the data packet unit data written in the DPAC unit memory 15. The address control is started, and a signal N is output.

Since the data packet portion data is written in the DPAC portion memory 15 in the order of transmission, the DPAC portion memory read address control portion 20 performs read address control for de-interleaving, and reads out the data packet portion data by a signal N. , And a signal J.

The DPAC error correction unit 21 corrects the error of the signal J by the (272,190) code for each data packet part data, but refers to the flag information for each packet in the MC complement unit 19 as the signal K, and performs the facsimile broadcast. The error correction is performed on the data packet portion at the packet position corresponding to the flag for which the service identification has been determined and the flag replaced as the facsimile broadcast, and the 190 bit corrected data packet portion data is output as a signal L.

The MC complement unit 19 outputs the signal M when the reference from the DPAC error correction unit ends, and outputs the mode control unit determination flag information I in a new frame that has already been processed.
The data is loaded from the MC determination unit 18 and a mode control unit complementing operation is performed to prepare for a data packet part error correction operation of a new frame.

〔The invention's effect〕

According to the present invention, if a transmission error occurs in the mode control unit and an uncorrectable error is detected, and if the mode control unit is determined and identified as a non-facsimile broadcast, the subsequent mode control unit performs facsimile transmission. If the broadcast can be identified and identified, it should be originally transmitted as a facsimile broadcast,
The data packet is processed as a facsimile broadcast data packet without being discarded, and discarding is performed only when the data packet cannot be corrected by the (272, 190) code, thereby preventing packet loss and reducing image quality deterioration.

In addition, the memory for writing data in the mode control section is one system enough to handle the reception of facsimile signals, and the memory for storing flag information can be as small as 64 bits, reducing the memory load on the receiver. can do.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of the configuration of a facsimile receiver according to the present invention, FIG. 2 is a diagram showing a frame configuration of facsimile broadcasting by a digital system, FIG. 3 is a diagram showing a packet configuration, FIG. 4 is a facsimile signal FIG. 3 is a diagram showing a transmission order of the data. FC: framing code, MC: mode control section data, DPAC: data packet section data, 10: framing code detection section, 11: mode control section memory write address control section, 12: mode control section memory, 13: Data packet section memory select section, 14: Data data packet section memory write address control section, 15: Data packet section memory (1), (2), 16: Mode control section memory read address control section, 17: Mode control section error correction section, 18: Mode control section determination section, 19: Mode control section complement section, 20: Data packet section memory read address control section, 21: Data packet section error correction section.

Claims (1)

(57) [Claims] 1. A facsimile broadcast receiving apparatus having a mode control unit memory independent of a data packet unit memory, wherein the mode control unit in a frame is stored in the mode control unit memory when the storage of the mode control unit in a frame is completed. First processing means for performing error correction and service identification of a mode control unit; and when the first processing means determines that an uncorrectable error has occurred in the mode control unit, or when service identification is performed by facsimile. Even when it is determined that the mode control unit is not allocated to a broadcast, when it is determined that the mode control unit after the determination is allocated to facsimile broadcast, the case where the determination is made Data packet breakage for the mode control unit The without, facsimile broadcasting receiver of the data packet, characterized by comprising a second processing means for processing as there against The data packets to the facsimile broadcast.