JP2659470B2 - Facsimile broadcast receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile signal consisting of binary information subjected to four-phase differential phase modulation, and the modulated facsimile signal is newly provided in an audio frequency band of an existing television signal. The present invention relates to a facsimile broadcast receiving apparatus in a facsimile broadcast system transmitting using two subcarriers.

[0002]

2. Description of the Related Art In recent years, as described above, studies have been conducted for the practical use of digital facsimile broadcasting in which a facsimile signal is transmitted using a second subcarrier. The Council reported on "technical conditions for facsimile broadcasting." FIG. 2 shows a frame configuration of the facsimile signal of the report specification.

As shown in FIG. 1, one packet of data is composed of 16 bits of mode control code (MC), 14 bits of prefix (PFX), 176 bits of information part, and 82 bits of check code, for a total of 288 bits. Have been. One frame of data consists of 32 packets of data and 16 bits of frame synchronization signal (FC), totaling 9
It consists of 232 bits and has a data transmission rate of 16
kbps. The image information in the facsimile signal is stored in the 176-bit information section and transmitted. Therefore, the maximum amount of image information transmitted in one frame is 5
632 bits, and the actual transmission speed of image information in facsimile broadcasting is approximately 9.76 kbps. The minimum printing time for one line is 10 ms.

The transmission speed of image information is such that the printing time of one line does not become less than 10 ms even when the compression efficiency of the image information is good (for example, when the pixels of one line are all white or all black). Guaranteed to. As described above, in the report specification, there is a guarantee rule for the case where the compression efficiency of the image information is good (therefore, the transmission speed is high). There is no guarantee provision for the (late) case. Therefore,
Depending on the contents of the image to be transmitted, the required transmission time of the image information for one line may be extremely changed. In such a case, if printing is performed on the receiving side, print quality may be degraded due to uneven paper feeding of the recording apparatus or the heat storage effect of the thermal head for printing. Therefore, as means for dealing with the deterioration of print quality due to such uneven paper feeding, the timing of decoding of transmitted image information and the timing of starting recording of decoded pixel information are adjusted to mitigate the change in transmission time. The method is adopted.

[0005]

However, in the case of using a thermal recording apparatus for printing on thermal recording paper with a thermal head, if the printing cycle is short, the heat supplied when printing the previous one line cannot be reduced. Since a printing current for printing the next one line is applied to the printer, the temperature of the thermal head gradually increases. Thereafter, when a long printing cycle continues, the heat supplied to print the previous one line is sufficiently dissipated, so that even if a printing current for printing the next one line is applied, The temperature of the head does not rise. Thermal paper generally develops a deeper color as it is exposed to higher temperatures. Therefore, even if the timing of recording is adjusted by the above-described method to reduce paper feed unevenness,
The print density varies due to the change in the print cycle due to the change in the transmission time, and a stripe pattern may occur in the sub-scanning direction.

The present invention has been made in view of such a problem, and a facsimile capable of preventing deterioration of print quality caused by a change in transmission time of one line of image information due to a heat storage effect of a recording head. An object of the present invention is to provide a broadcast receiving device.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
A facsimile broadcast receiving apparatus for receiving a facsimile broadcast and forming a facsimile image by applying a print current to a thermal head for printing by applying a print current to each line, and receiving a facsimile from a received television signal. Reception processing means for extracting a signal, first storage means for storing the extracted facsimile signal in a frame unit composed of a plurality of packets, and packets which require decoding processing among packets constituting one frame Transfer control means for transferring the pixel information included in the facsimile signal at a timing corresponding to the number of the facsimile signals; decoding means for decoding the image information transferred by the transfer control means into pixel information; and A second storage unit for storing pixel information on a line-by-line basis, and a line stored in the second storage unit. Recording control means for instructing the thermal recording apparatus to start recording of the pixel information stored in the second storage means at a timing corresponding to the number of lines; A facsimile broadcast receiving apparatus comprising: a print density control unit for setting the application time of the print current applied to the thermal head for each line according to the number.

[0008]

When the data transmission speed is 16 kbps,
The time required to store all data of one frame in the first storage means is 577 ms. Therefore, the decoding means may process the facsimile signal composed of 32 packets per frame in a time of 577 ms. Assuming that all 32 packets in one frame are image information requiring decoding, the time allocated to the decoding of one packet is about 18 ms. Therefore, the transfer control means transfers the packet from the first storage means to the decoding means at a rate of one every 18 ms. The decoding means sequentially decodes the transferred packets and stores them as pixel information in the second storage means on a line-by-line basis. The recording control unit calculates the time until the second storage unit is completely filled with the pixel information by checking the number of lines stored in the second storage unit. The recording control means supplies a recording start command to the thermal recording apparatus at a timing corresponding to the calculated time, and further provides information indicating the number of lines stored in the second storage means to the print density setting means. The print density setting means sets the application time of the print current longer in consideration of heat radiation of the thermal head because the print cycle becomes longer when the number of lines is small, and conversely, when the number of lines is large, the print cycle becomes short. ,
The application time of the printing current is set shorter in consideration of the heat storage of the thermal head.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram schematically showing a configuration of one embodiment of the present invention. In the figure, 1 is a television broadcast receiving antenna, 2 is a facsimile signal reception processing unit for extracting a facsimile signal from the audio band of the television broadcast, 3 and 4 are frame buffer memories that store the facsimile signal in frame units, and 7 is A program selection unit for selecting and receiving a desired program, a reception control unit for extracting information of the selected program from the received facsimile signal and performing an error correction process, etc. After performing processing such as error correction on the facsimile signals stored in the buffer memories 3 and 4 by the reception control unit 8, a frame buffer memory for temporarily storing the facsimile signals is stored in the frame buffer memories 5 and 6 in frame units. A transfer processing unit 11 for reading out the stored image information in packet units is a transfer processing unit 11 which is transferred by the transfer processing unit 10. The decoding unit 12 decodes facsimile image information composed of original or two-dimensional compression codes and converts it into pixel information. Reference numeral 12 denotes a pixel information buffer memory for temporarily storing the decoded and converted pixel information. Has a capacity to store pixel information for eight lines.

Reference numeral 13 denotes a frame buffer memory 5 or 6
A timing control unit that controls the transfer timing when the transfer processing unit 10 transfers the image information stored in the pixel unit to the decoding unit 11 in packet units, and 15 reads out the pixel information stored in the pixel information buffer memory 12 A recording processing unit 9 for printing by a recording device 16 composed of a thermal printer, a control unit 9 for controlling the reception control unit 8, a transfer processing unit 10 and the like, and a control unit 9 for the recording processing unit 15 to start recording. This is a recording start timing control unit for controlling the timing at which a command is output.

The operation of extracting facsimile image information in the facsimile broadcast receiving apparatus having the above configuration will be described below. A television broadcast signal including a facsimile signal is received by the television broadcast receiving antenna 1,
It is provided to the facsimile signal reception processing unit 2. The facsimile signal reception processing unit 2 performs a television audio demodulation process on the received signal, extracts a facsimile broadcast signal from within the audio signal band, performs a series of processes such as descrambling and interleaving, and performs a frame buffer in frame units. The data is stored in the memories 3 and 4. Which of the frame buffer memories 3 and 4 stores the facsimile signal is managed by the reception control unit 8, and the facsimile signal reception processing unit 2 uses one frame buffer memory for storage processing. During this time, the reception control unit 8 can use the other frame buffer memory for error correction processing.

When the facsimile signal reception processing unit 2 completes the storage processing of the facsimile signal for one frame, it notifies the reception control unit 8 and prepares for the next frame processing. When the facsimile signal reception processing unit 2 is notified of the completion of the storage processing, the reception control unit 8 sets the frame buffer memory used by the facsimile signal reception processing unit 2 for storing and processing the next frame unit facsimile signal. Is switched from the frame buffer memory used for the immediately preceding storage process to the frame buffer memory not used for the immediately preceding storage process. The reception control unit 8 stores the facsimile signal in frame units after the error correction processing is completed in the frame buffer memory 5 or 6. The reception control unit 8 manages which of the frame buffer memories 5 and 6 stores the facsimile signal, and while the reception control unit 8 uses one of the frame buffer memories for storage processing, the transfer is performed. Processing unit 1
0 can be used to transfer facsimile image information in packet units to the decoding unit 11 using the other frame buffer memory. When the facsimile signal in frame units stored in the frame buffer memory 5 or 6 contains image information that needs to be decoded, the reception control unit 8 instructs the control unit 9 to start decoding. Request, and release the frame buffer memory 5 or 6 so that the transfer processing unit 10 can perform the transfer processing. After performing the next error correction processing, the frame buffer memory used for storing the facsimile signal in frame units is Is switched to a frame buffer memory different from the frame buffer memory opened to the transfer processing unit 10 and the facsimile signal reception processing unit 2 waits for the completion of the storage processing of the facsimile signal in the next frame unit.

As described above, the facsimile broadcast receiving apparatus according to the present embodiment is configured so that the information transferred from the transfer processing unit 10 to the decoding unit 11 is only facsimile image information in packet units.

Next, the operation of decoding and recording the extracted facsimile image information, which is the direct object of the present invention, will be described. As described above, when the image information is included in the facsimile signal in the unit of frame stored in the frame buffer memory 5 or 6, the reception control unit 8 sets the corresponding packet numbers and the decoding start The request is transmitted to the control unit 9. The control unit 9 receives the decoding start request and all the packet number information that requires the decoding process included in the facsimile signal in the frame unit, and determines how many packets need the decoding process in the facsimile signal. , And the time to be used for decoding one packet is calculated. The control unit 9 outputs the calculated time to the timing control unit 13 and sets the timing control unit 13 to output a facsimile image information transfer permission signal every time the calculated time elapses, A transfer start signal is output to the unit 10 so as to start the transfer process in accordance with the packet number that requires the decoding process in the facsimile signal in frame units received from the reception control unit 8. Transfer processing unit 1 that has received the transfer start signal
0 starts transfer processing of facsimile image information in packet units to the decoding unit 11 in accordance with a packet number requiring decoding processing in a facsimile signal in frame units. Thereafter, the control unit 9 repeats the above-described processing according to the facsimile image information transfer permission signal from the timing control unit 13 while confirming that the transfer processing unit 10 has completed the transfer of one packet of facsimile image information.

On the other hand, the decoding unit 11, which has received the facsimile image information in packet units, sequentially decodes this, converts it into pixel information, and records it in the pixel information buffer memory 12. When the decoding and recording processing for one line is completed, the decoding unit 11 notifies the control unit 9 of this. The control unit 9
Upon receiving the notification of the completion of the decoding and recording processing for the lines, a recording start command is output to the recording processing unit 15. At this time, it is checked how many lines of pixel information are recorded in the pixel information buffer memory 12. Thus, the time until the pixel information buffer memory 12 is filled with the pixel information is calculated. The control unit 9 outputs the calculated time to the timing control unit 15 and outputs a recording start command and information indicating the number of lines recorded in the pixel information buffer memory 12 to the recording processing unit 15. When the number of lines recorded in the pixel information buffer memory 12 is small, the recording processing unit 15 tends to lengthen the printing cycle. On the contrary, when the number of lines recorded in the pixel information buffer memory 12 is large, the printing cycle tends to be short. Therefore, the application time of the printing current is set short in consideration of the heat storage of the thermal head. I do. Thereafter, the control unit 9 reads one line of pixel information from the pixel information buffer memory 12 and records it by the recording device. When the calculated time elapses and the recording start timing control unit 14 outputs a recording start command, the control unit 9
Confirms again how many lines of pixel information are recorded in the pixel information buffer memory 12 at that time, and repeats the above processing.

[0016]

As described in detail above, the facsimile broadcast receiving apparatus of the present invention provides a decoding timing of image information contained in a received facsimile signal, a recording start timing of decoded pixel information, and a printing current. Since it has means for controlling the application time for each line,
Even if the transmission time of the image information for a line varies, the print density does not vary, and the print quality is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a facsimile broadcast receiving apparatus according to the present invention.

FIG. 2 is a frame configuration diagram of a facsimile signal in digital facsimile broadcasting.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 television broadcast receiving antenna 2 facsimile signal reception processing unit 3, 4, 5, 6, frame buffer memory 7 program selection unit 8 reception control unit 9 control unit 10 transfer processing unit 11 decoding unit 12 pixel information buffer memory 13 timing control Unit 14 recording start timing control unit 15 recording processing unit 16 recording device

Claims (1)

(57) [Claims] 1. A facsimile broadcast receiving apparatus for receiving a facsimile broadcast and forming a facsimile image by applying a print current to a thermal head for each line to perform printing. Reception processing means for extracting a facsimile signal from the extracted television signal, first storage means for storing the extracted facsimile signal in frame units composed of a plurality of packets, and decoding of packets constituting one frame A transfer control stage for transferring the image information contained in the facsimile signal in packet units at a timing corresponding to the number of packets requiring processing, and decoding the image information transferred by the transfer control means into pixel information Decoding means, a second storage means for storing the decoded pixel information on a line-by-line basis, Recording control means for instructing the thermal recording apparatus to start recording of pixel information stored in the second storage means at a timing corresponding to the number of lines stored in the storage means, and the second storage means A facsimile broadcast receiving apparatus comprising: a print density setting means for setting, for each line, an application time of a print current applied to the thermal head according to the number of lines stored in the means.