JP2001186493A - Receiver/transmitter for catv broadcast - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save power while in the stand-by for emergency broadcast. SOLUTION: This CATV broadcast transmitter/receiver is characterized in that it is tuned to a first broadcast frequency with which an emergency broadcast is transmitted to the receiver when it is in a stand-by state, an input bit stream is synchronized with an emergency synchronization code to pickup them (S22), a main power source is turned on (S22) when synchronization is established and the emergency broadcast is detected, the receiver is turned to a second broadcast frequency for transmitting emergency information data such as the start/end of the emergency broadcast (S24), an emergency is reported to a viewer when emergency information data indicates that the emergency broadcast is being performed by referring to emergency information data to be transmitted to the input bit stream (S27), the emergency report is ended when it is indicated that the emergency broadcast is ended (S28), the receiver is tuned to the first broadcasting frequency (S30) and also the main power source is turned off to obtain the stand-by state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a digital CATV.
The present invention relates to a receiving device for receiving an emergency broadcast in a system.

[0002]

2. Description of the Related Art FIG. 12 shows an example of the configuration of a conventional digital CATV broadcast receiving apparatus.

In FIG. 1, reference numeral 1 denotes, for example, 90 to 770.
This is a tuner that tunes the frequency from a high-frequency band of 1 MHz to one channel having a bandwidth of 6 MHz. In the future, all high-frequency bands will shift from current analog broadcasting to digital broadcasting or digital communication. A digital broadcast receiving tuner (hereinafter simply referred to as a tuner) is assumed. Numeral 2 denotes a digital demodulator corresponding to digital modulation. In the case of CATV, 64QAM is generally adopted. Reference numeral 30 denotes a synchronization processing unit for detecting the head of a block in an error correction unit using a block code at the subsequent stage.
The first synchronization byte of an MPEG2 transport packet (hereinafter, TS packet) specified by EC13818-1 is to be detected. Reference numeral 4 denotes an error correction unit for detecting and correcting an error when an error occurs in a TS packet. As shown in FIG. 13, an error correction code of 16 bytes is added for each 188 bytes of one TS packet. Is done. Hereinafter, the TS packet to which the error correction code is added is referred to as a frame. Generally, the ETS (Europen) in Europe is used as this error correction method.
Telecommunication Standa
rd) Standard ETS-300-429 is adopted,
Reed-Solomon codes are used as error correction codes. Reed-Solomon codes belong to block codes, and ETS
In −300-429, since one TS packet is treated as one block, a 1-byte synchronization code (usually a value of 47 hexadecimal and 8 T
Inversion is added for each S packet, and the synchronization is inverted with the demultiplexer 5 at the subsequent stage. Reference numeral 5 denotes a plurality of sub-channels multiplexed and transmitted in the channel selected by the tuner 1 and PSI (Progr) such as NIT, PAT, PMT, and the like.
am Specific Information (SI) or Service Information (SI)
n) is a demultiplexer that separates a video PES packet and an audio PES packet corresponding to a program desired by the user through a channel selection process of the controller 10. Since the demultiplexer 5 shares the same time with the broadcast station, the transmitted reference reference time PC
R (Program Clock Reference)
And phase locked loop circuit, 27MHz STC
(System Time Clock) is reproduced and synchronized with the broadcast station side. 6 is ISO / IEC138
This is a video decoder that decodes PES packets of MPEG2 video specified in 18-2. The built-in OSD (On Screen Display) function combines an EPG (Electronic Program Guide) with a broadcast screen and outputs it to a television. . 7 is ISO / IEC13818-
This is an audio decoder that decodes the MPEG2 audio PES packet specified in S.3. 8 and 9
Are video / audio D / A converters, each of which outputs a composite video signal and a stereo signal,
Display on V. Reference numeral 10 denotes a controller, which is used for remote control and PSI / SI processing, and whose operating frequency is generally several tens MHz to several hundred MHz.

Next, reception of an emergency broadcast in the digital CATV broadcast receiving apparatus during standby will be described.

[0005] Japan CATV Technical Association JCTEA STD
According to −003−1.1, the NI in the SI during an emergency broadcast
The CATV station is to transmit an emergency information descriptor as shown in FIG. 14 to T or PMT. Therefore, C
The ATV receiver always monitors the tuner 1, the digital demodulator 2, the synchronization processing unit 30, the error correction unit 4, the demultiplexer 5, and the controller 10 in order to monitor whether or not this descriptor has been sent. It is necessary to energize the receiving device even when it is in a standby state.

[0006] The operation flow when receiving an emergency broadcast will be described with reference to FIG.

First, in step 71, it is determined whether the NIT or PMT has been obtained from the input bit stream by the demultiplexer 5, and if so, in step 72, the controller 10 interprets these tables. And confirm that the emergency information descriptor is included. If the emergency information descriptor is not included,
In step 73, processing such as updating of the SI table is performed,
It returns to the polling state again. If the emergency information descriptor is included, the emergency broadcast start / end flag in the emergency information descriptor is being broadcast (start_end_end_
flag = 1) is identified. If the area is being broadcast, it is checked in steps 75 and 76 whether the area described in the area_code field matches the residence area stored in the nonvolatile memory 12 in advance. At step 77, it is determined whether or not the main power is on. At step 78, if the main power is on, the user is notified of an emergency using the OSD or the alarm buzzer 11 by using the OSD. If the main power supply is off (hereinafter, referred to as a standby state), in steps 79 and 78, the main power supply is turned on and the same notification is made. If it is determined in step 74 that the emergency broadcast is not being performed, it is determined in step 80 whether the main power has been turned on from the standby state. The end flag is in the end state (start_end_flag =
When it becomes 0), the main power supply is automatically turned off in step 81.

[0008] Conventionally, as an emergency broadcast system,
Although a system disclosed in Japanese Patent Application Laid-Open No. 7-336662 is known, this system does not particularly consider digital broadcasting.

[0009]

By the way, in recent years, the movement of global warming prevention has been increasing internationally, and at the same time, there is a demand for energy saving of electric products.

However, in the above-mentioned conventional emergency broadcast system, although the frequency of the emergency broadcast itself is rare,
In the ATV receiver, the emergency broadcast information (emergency_information_d) is included in the bit stream.
In order to monitor the transmission of the ESC (descriptor), in addition to the tuner and the digital demodulation in the standby state, it is necessary to keep the demultiplexer and the controller operated by the high-speed clock constantly energized. there were.

An object of the present invention is to provide a CATV broadcast receiving apparatus which saves power during standby for emergency broadcast.

[0012]

The present invention employs the following means in order to solve the above-mentioned problems.

The first means indicates that an emergency broadcast, which is digitally broadcast from a CATV station, is being transmitted,
The synchronization code indicating the beginning of the block of the block error correction code inserted in the data transmitted from the CATV station is a first broadcast frequency consisting of a normal synchronization code used during normal broadcasting and an emergency synchronization code used during emergency broadcasting. And a second broadcast frequency for transmitting emergency information data such as start / end of an emergency broadcast, the first broadcast frequency and the second broadcast frequency.
A broadcast frequency, storage means for storing the normal synchronization code and the emergency synchronization code, and means for tuning the CATV broadcast receiving apparatus to the first broadcast frequency in a standby state where the main power is off, In the tuning state of the first broadcast frequency, synchronization acquisition means for acquiring synchronization between a received input bit stream and the emergency synchronization code, and when synchronization is established in the synchronization acquisition means, emergency broadcast is performed. An emergency broadcast detecting means for determining that the broadcast is transmitted; and when an emergency broadcast is detected by the emergency broadcast detecting means, the main power supply is turned on and the CATV broadcast receiving apparatus is tuned to the second broadcast frequency. Means,
In the tuned state of the second broadcast frequency, reference is made to emergency information data transmitted in the input bit stream. Emergency notification means for notifying that there is, and when the emergency information data indicates that the emergency broadcast has ended, the emergency notification is terminated and the C
Means for tuning the ATV broadcast receiving apparatus to the first broadcast frequency and turning off the main power supply to put the apparatus in a standby state.

The second means indicates that an emergency broadcast, which is digitally broadcast from a CATV station, is being transmitted,
The synchronization code indicating the beginning of the block of the block error correction code inserted in the data transmitted from the CATV station is a first broadcast frequency consisting of a normal synchronization code used during normal broadcasting and an emergency synchronization code used during emergency broadcasting. And a second broadcast frequency for transmitting emergency information data such as start / end of an emergency broadcast,
A CATV broadcast receiving apparatus having the same broadcast frequency as the second broadcast frequency, a storage means for storing the first broadcast frequency and the second broadcast frequency, the normal synchronization code and the emergency synchronization code, Means for tuning the CATV broadcast receiving apparatus to the first broadcast frequency in a standby state in which the power is off; and receiving the input bit stream and the emergency synchronization code in the tuned state of the first broadcast frequency. Synchronization acquisition means for performing synchronization acquisition with, emergency broadcast detection means for determining that an emergency broadcast is transmitted when synchronization is established in the synchronization acquisition means, and emergency broadcast detection in the emergency broadcast detection means. Means for turning on the main power supply when detected, and when an emergency broadcast is detected by the emergency broadcast detection means, after error correction, A synchronization code changing means for returning a synchronization code to a normal synchronization code; and referring to emergency information data transmitted in the input bit stream in a tuned state of the first broadcast frequency; When indicating that there is an emergency notification means to notify the viewer of an emergency, and when the emergency information data indicates the end of the emergency broadcast, end the emergency notification, Means for turning off the main power supply to enter a standby state.

The third means is characterized in that in any one of the first means and the second means, an emergency broadcast target area code is assigned to the emergency synchronization code.

The fourth means is the third means, wherein when the emergency broadcast is detected by the emergency broadcast detection means, the emergency synchronization code of the received input bit stream is compared with the target area code, It is characterized by comprising means for judging whether it corresponds to the broadcast target area.

A fifth means is that in any one of the first means and the second means, the synchronization acquisition means is configured to output the synchronization code when the synchronization between the normal synchronization code and the input bit stream cannot be followed. Is changed to the emergency synchronization code, and the synchronization between the input bit stream and the emergency synchronization code is performed.

A sixth means is the temporary storage element according to any one of the first means and the second means, which is always energized with the normal synchronization code and the emergency synchronization code at the time of transition to the standby state. Means for transferring data to

The seventh means is the first means or the second means, wherein the emergency notification means is an alarm buzzer and / or an on-screen display built in the CATV broadcast receiving apparatus. , An emergency situation is displayed on the viewing screen.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 shows a digital CAT according to this embodiment.
It is a block diagram which shows the structure of the broadcast receiver for V.

In the figure, reference numeral 3 denotes a synchronization processing unit, 13 denotes a normal synchronization code register, 14 denotes an emergency synchronization code register, 15 denotes a selector, and the other components correspond to the components of the same reference numerals shown in FIG.

In the digital CATV broadcasting system according to the present invention, emergency broadcast information (emergency
y_information_descriptor)
(A second broadcast frequency: RFeme)
channel (first broadcast frequency: RFdefault) indicating that an emergency broadcast is occurring by changing the synchronization code from the time of normal broadcast.
It is assumed that the information is prepared in the station side, and these information is also stored in the nonvolatile memory 12 in advance on the CATV receiving apparatus side. In addition, the synchronization code (ETS) transmitted during normal broadcast
A synchronization code conforming to −300-429 (hereinafter referred to as a normal synchronization code) and a synchronization code (hereinafter referred to as an emergency synchronization code) that is exchanged and transmitted at the time of an emergency broadcast are also stored in the nonvolatile memory 12 in advance. It is assumed that the power is transferred to the respective registers 13 and 14 by plugging the power cord into the power plug when the receiver is installed. Hereinafter, the normal synchronization code and the emergency synchronization code are collectively referred to as a synchronization code.

FIG. 2 is a block diagram showing a detailed configuration of the synchronization processing unit 3 shown in FIG.
Compared with the synchronization processing unit 30 shown in FIG. 12, the synchronization code detected in the synchronization processing is improved so that the synchronization code can be selected from a normal synchronization code and an emergency synchronization code. A synchronization acquisition unit 31 that generates a period (hereinafter, referred to as a synchronization pulse) to check whether synchronization has been established between the synchronization pulse and the input frame;
It is composed of a synchronization follow-up unit 32 for monitoring whether the synchronization between the synchronization pulse and the input frame can be maintained, and a synchronization code control 33 for controlling the synchronization code input to the synchronization processing unit 3 for the selector 15. .

FIG. 3 is a block diagram showing a detailed configuration of the synchronization acquisition section 31.

In FIG. 3, reference numeral 311 compares an input frame with a synchronization code to generate a synchronization pulse, and upon receiving a recapture request instruction from the comparator 313, changes the position of the input frame to a clock synchronized with the frame (hereinafter referred to as a clock). ,
The comparator 312 has a built-in phase shift circuit for shifting by the frame clock). The comparator 312 performs a comparison by the comparator 311. When a coincidence occurs, a synchronization pulse width counter that counts until the next frame synchronization code comes with the frame clock. After the counting by the width counter 312 is completed, the comparator 314 reads the value of the frame and checks whether the value matches the synchronization code, and the synchronization pulse generated by the comparator 311 is synchronously captured with the input frame. In order to make a final determination, the synchronous capture judge counter checks whether the number of matches of the comparator 313 reaches a predetermined number.

FIG. 4 is a block diagram showing a detailed configuration of the synchronization follow-up unit 32.

In FIG. 3, reference numeral 321 denotes a latch circuit for temporarily storing a frame with a synchronization pulse generated by the synchronization acquisition unit 31; 322, a comparator for comparing whether the value of the latched frame matches a synchronization byte; Comparator 322
Out-of-synchronization counter that counts the number of mismatches at

Next, the operation of the synchronization processing unit 3 will be described with reference to FIGS.
This will be described with reference to the flowchart shown in FIG.

First, in the flowchart shown in FIG.
In step 11, the synchronization acquisition determination counter 314 of the synchronization acquisition unit 31 shown in FIG. 3 is reset, and in step 12, the acquisition failure counter of the synchronization acquisition unit 31 not shown is reset. Next, at step 13, the comparator 311 of the synchronization acquisition unit 31 shown in FIG. 3 compares whether the input frame and the synchronization code are the same. If they are not the same,
In step 14, the capture failure counter is incremented. In step 15, it is determined whether or not the capture failure counter has reached a predetermined number.
The input frame is shifted by the frame clock in step, and again in step 13, it is compared whether the input frame and the synchronization code are the same. If no match is found even after a predetermined number of retry operations, it is determined in step 17 that synchronization is impossible. On the other hand, if a match between the frame and the synchronization code is obtained, the synchronization pulse width counter 312 shown in FIG. 3 is started in step 18 and 204 bytes are counted in step 19. Step 20
At, the comparator 313 checks whether the value of the frame matches the value of the synchronization code at the beginning of the next frame, that is, at the 204th byte. Here, as shown in FIG. 5A, if the comparisons by the comparator 313 match, in step 21, the synchronization acquisition determination counter 314 is incremented, and the synchronization pulse generated at this time is used. Steps 18 to 2 until a predetermined number (K times) of determining that synchronization acquisition between the frame and the synchronization pulse has been established.
Step 2 is repeated. If they do not match in step 20, as shown in FIG. 5B, the same value as the synchronization code appears in the data area (area other than the synchronization code) in the frame, and the comparator 311 erroneously synchronizes this data. In this case, the comparator 311 shifts the position of the frame by the frame clock in the comparator 311 to attempt reacquisition. Re-acquisition should be obtained by repeating for a frame period (204 times). Finally, in step 22, when the synchronization acquisition determination counter 314 counts the number of acquisitions to K times, it is determined that synchronization acquisition of the frame has been established, and in step 23, the synchronization pulse is output from the buffer 315 to the subsequent synchronization follower. 32.

The synchronization pulse output from the synchronization acquisition unit 31 is input to the synchronization follow-up unit 32 shown in FIG. 4, and the input synchronization pulse is temporarily stored in the latch circuit 321 by the synchronization pulse, and further compared. The out-of-synchronization counter 323 monitors whether or not the out-of-synchronization has occurred due to the influence of transmission jitter or noise of the input frame. An instruction is given to the synchronization acquisition unit 31.

As shown in FIGS. 2 and 3, the result of the processing in the synchronization acquisition unit 31 is such that the synchronization code control 33 sends the synchronization code output to the synchronization processing unit 3 in a normal or in response to an instruction from the synchronization acquisition unit 31. The selector 15 is switched for emergency control. When the main power is turned on, the control is normally performed so as to output a synchronization code.

The synchronization processing unit 3 has been described above.
Actually, to make it easier to detect the synchronization code, ETS-
The synchronization code may be periodically inverted as in 300-429.

Next, the operation of the thus-configured CATV broadcast receiving apparatus when receiving an emergency broadcast in the standby state will be described with reference to the flowchart shown in FIG.

The circuit which is energized in the standby state is a tuner 1, a digital demodulation 2, a synchronization processing unit 3, a normal synchronization code register 13, an emergency synchronization code register 14 in the CATV broadcast receiving apparatus shown in FIG. ,
The selector 15.

In the standby state, the tuner 1 operates at RFde.
Synchronized to the fault, the normal synchronization code is loaded in the synchronization processing unit 3. At step 31, the synchronization processing unit 3 monitors whether the synchronization is normally followed by the synchronization code. Therefore, when the synchronization cannot be maintained by the synchronization processing unit 3 with the normal synchronization code, that is, the synchronization cannot be acquired by the synchronization acquisition unit 31 of the synchronization processing unit 3, or the synchronization is lost by the synchronization follow-up unit 32 and the synchronization acquisition unit 31 If synchronization is not obtained even if re-acquisition is attempted, the selector 15 is controlled by the synchronization code control unit 33 in step 32, and the selector 15 outputs an emergency synchronization code instead of the normal synchronization code. The synchronization processing unit 3 re-executes the synchronization acquisition processing using the emergency synchronization code. Here, the emergency synchronization code does not merely indicate that an emergency broadcast is being transmitted,
For example, an area code may be allocated within the business area of the CATV station as shown in FIG. 7, and the emergency notification may be performed only in a specific area. In step 33, it is determined whether the emergency synchronization code is synchronized. If synchronization cannot be established in the synchronization processing unit 3 with the loaded emergency synchronization code, it is determined in step 42 that a failure such as a line failure has occurred. Next, when the user turns on the main power supply next time, a process of notifying the user via the OSD is performed.

On the other hand, if the synchronization can be established by the emergency synchronization code in step 33, it is determined in step 34 that the emergency broadcasting code corresponds to the target area of the emergency broadcast being issued.
The main power supply is turned on, the RFemergency to which the emergency information descriptor is transmitted is read out from the nonvolatile memory 12, and the tuner 1 is set to the RFeme at step 35.
Synchronize with rgency. At the same time, in step 36, the synchronization code to be loaded into the synchronization processing unit 3 is instructed from the synchronization code control unit 33 to the selector 15, and the emergency synchronization code is changed to the normal synchronization code and output.
Here, the RFemergency is an emergency information descriptor (emergency_informatio) that the CATV station always conforms to JCTEA STD-003-1.1.
n_descriptor) to the PMT or NIT. In step 37, an emergency information descriptor is acquired, and an emergency broadcast is being broadcast (start_e
If nd_flag = 1), in step 38, the user is notified of the emergency by sounding the alarm buzzer 11 provided in the CATV broadcast receiver or by using the OSD. The emergency notification activated in this way continues until start_end_flag = 0. If the main power is turned on from the standby state in step 40 after the emergency notification is completed in step 39, the tuner 1 is changed to RFdefault in step 41, the main power is turned off, and the standby state is set again. Return.

When an emergency broadcast is transmitted while the user is watching (the main power is on), the synchronization processing unit 3 is loaded with a normal synchronization code, so that RFdef is used.
Including P.ult, according to the processing shown in FIG.
/ Emergency broadcast information is extracted from / SI and an emergency notification is made.

Next, a second embodiment of the present invention will be described with reference to FIGS.

In the CATV broadcast receiving apparatus according to the first embodiment, in the state of RFdefault during an emergency broadcast, the synchronization code is an emergency synchronization code, and RFd
There is a disadvantage that an emergency notification cannot be made with the default. The present embodiment is an improvement on this drawback.

FIG. 9 shows a digital CAT according to this embodiment.
It is a block diagram which shows the structure of the broadcast receiver for V.

In the figure, reference numeral 21 denotes a synchronous code replacement unit, and the other structure corresponds to the structure of the same code shown in FIG.

FIG. 10 is a circuit diagram showing a detailed configuration of the synchronous code changing unit 21.

In this circuit, the TS packet corrects an error existing in the frame by the error correction unit 4 at the preceding stage, and the synchronization code is changed to the normal synchronization code (as a value) for decoding by the demultiplexer 5 at the subsequent stage. Can be returned to 47 hex), so that the synchronization code output from the selector 15 is compared with the normal synchronization code, and if there is a difference, at the timing of the synchronization pulse, that is, at the beginning of the TS packet,
This is a circuit for rewriting the synchronization code into a normal synchronization code.

Next, an operation of receiving an emergency broadcast in the standby state of the thus configured CATV broadcast receiving apparatus will be described with reference to a flowchart shown in FIG.

Here, the circuit which is always energized in the standby state is the same as the CATV broadcast receiver shown in FIG.
Tuner 1, digital demodulation 2, synchronization processing unit 3, normal synchronization code register 13, emergency synchronization code register 1
4, selector 15;

In the standby state, the tuner 1 operates at RFde
Tuned to fault. That is, when transitioning from the viewing state to the standby state, the non-volatile memory 12 is read to make a transition from the viewing channel to RFdefault. In addition, the synchronization processing unit 3 is usually loaded with a synchronization code. At step 51, it is monitored whether or not the normal synchronization code is synchronized. However, when synchronization cannot be maintained by the synchronization processing unit 3 with the normal synchronization code, that is, the synchronization acquisition by the synchronization acquisition unit 31 of the synchronization processing unit 3 is also possible. If the synchronization is not achieved by the synchronization follow-up unit 32 and re-acquisition is attempted by the synchronization acquisition unit 31, synchronization is not obtained by the synchronization code control unit 33 in step 52. Output the emergency synchronization code instead of the normal synchronization code. The synchronization processing unit 3 re-executes the synchronization acquisition processing using the emergency synchronization code. Step 53
Then, it is determined whether or not the emergency synchronization code is synchronized. In step 60, if synchronization cannot be established with the emergency synchronization code, it is determined that a failure such as a line failure has occurred, and the next time the user turns on the main power supply, Processing such as notification is performed.

On the other hand, if the synchronization can be established by the emergency synchronization code in step 53, it is determined in step 54 that the area corresponds to the target area of the emergency broadcast being issued, and the main power supply is turned on. . Next, in step 55, RF
The synchronization code of the TS packet transmitted by default is replaced by the synchronization code replacement unit 21 with the normal synchronization code. In step 56, obtain the emergency information descriptor,
Emergency broadcast is broadcasting (start_end_flag =
If it is 1), in step 57, an alarm is given to the user by sounding the alarm buzzer 11 provided in the CATV broadcast receiver or by using the OSD. The emergency notification activated in this way is start_en
Continue until d_flag = 0. Step 58
Then, if the main power supply is turned on from the standby state in step 59 after the emergency notification ends, the main power supply is turned off and the processing returns to the standby state again.

As described above, according to the present embodiment, the tuner transition accompanying the main power on / off upon detection of an emergency broadcast required in the first embodiment (the processing of steps 36 and 42 shown in FIG. 8). Is convenient.

On the other hand, when an emergency broadcast is being transmitted while the user is watching (main power-on state), an emergency notification can be made by the processing shown in FIG. 15 as in the first embodiment.

[0051]

As described above, the first to seventh embodiments of the present invention are described.
According to the invention, the presence / absence of an emergency broadcast can be determined only by adding a means for detecting a synchronization code for an emergency broadcast to a CATV broadcast receiving apparatus. In addition, it is possible to receive an emergency broadcast without constantly energizing the error correction unit, thereby realizing power saving.

According to the second aspect of the present invention, the first aspect is provided.
As compared with the invention of the first aspect, it is possible to make an emergency notification using only the first broadcast frequency.

[Brief description of the drawings]

FIG. 1 is a digital CAT according to a first embodiment of the present invention.
It is a block diagram which shows the structure of the broadcast receiver for V.

FIG. 2 is a block diagram showing a detailed configuration of a synchronization processing unit 3 shown in FIG.

FIG. 3 is a block diagram showing a detailed configuration of a synchronization acquisition section 31 shown in FIG. 2;

FIG. 4 is a block diagram showing a detailed configuration of a synchronization follow-up unit 32 shown in FIG. 2;

FIG. 5 is a waveform diagram of a synchronization code and a frame clock for explaining the operation of the comparator 313 shown in FIG.

6 is a flowchart for explaining the operation of the synchronization acquisition section 31 shown in FIG.

FIG. 7 is a diagram showing an area code allocated in a business area of a CATV station.

FIG. 8 is a flowchart showing an operation of the CATV broadcast receiving apparatus according to the first embodiment when receiving an emergency broadcast in a standby state.

FIG. 9 is a block diagram illustrating a configuration of a digital CATV broadcast receiving apparatus according to a second embodiment.

FIG. 10 is a circuit diagram showing a detailed configuration of a synchronization code replacement unit shown in FIG. 9;

FIG. 11 is a flowchart showing an operation of the CATV broadcast receiving apparatus according to the second embodiment when receiving an emergency broadcast in a standby state.

FIG. 12 is a block diagram of a digital CATV broadcast receiving apparatus according to the related art.

FIG. 13 shows an MPEG2 transport packet (hereinafter, TS packet) defined by ISO / IEC13818-1.

FIG. 14 is an emergency information descriptor transmitted from a CATV station.

FIG. 15 is a diagram showing an operation flow when receiving an emergency broadcast in a digital CATV broadcast receiving apparatus according to the related art.

[Description of Code] 1 Tuner 2 Digital demodulator 3 Synchronization processing unit 31 Synchronization acquisition unit 312 Comparator 312 Synchronization pulse width counter 313 Comparator 314 Synchronization acquisition judgment counter 315 Buffer 32 Synchronization follow-up unit 321 Latch 322 Comparator 323 Out of synchronization counter 33 Synchronous code control unit 4 Error correction unit 5 Demultiplexer 6 Video decoder 7 Audio decoder 8, 9 D / A converter 10 Controller 11 Alarm buzzer 12 Non-volatile memory 13 Normal synchronous code register 14 Emergency synchronous code register 15 Selector

Claims (7)

[Claims] 1. A synchronization code indicating that an emergency broadcast, which is digitally broadcast from a CATV station, is being transmitted, and indicating the beginning of a block of a block error correction code inserted in data transmitted from the CATV station. , A first broadcast frequency including a normal synchronization code used during normal broadcasting and an emergency synchronization code used during emergency broadcasting, and a second broadcasting frequency for transmitting emergency information data such as start / end of emergency broadcasting can be received. A first CATV broadcast receiving device, wherein: the first broadcast frequency and the second broadcast frequency;
Storage means for storing the normal synchronization code and the emergency synchronization code, and in a standby state where the main power is off,
Means for tuning the CATV broadcast receiving apparatus to the first broadcast frequency; and synchronous acquisition means for performing synchronous acquisition of a received input bit stream and the emergency synchronization code in a state where the first broadcast frequency is tuned. When synchronization is obtained in the synchronization acquisition means, an emergency broadcast detection means for determining that an emergency broadcast is transmitted, and when an emergency broadcast is detected in the emergency broadcast detection means, the main power supply Means for turning on the CATV broadcast receiving apparatus to the second broadcast frequency, and referring to the emergency information data transmitted in the input bit stream in the tuned state of the second broadcast frequency, When the emergency information data indicates that an emergency broadcast is in progress, an emergency notification means for notifying the viewer of an emergency; When the transmission is completed, the emergency notification is terminated, the CATV broadcast receiver is tuned to the first broadcast frequency, and the main power is turned off to be in a standby state. And CATV broadcast receiving apparatus. 2. A synchronization code indicating that an emergency broadcast, which is digitally broadcast from a CATV station, is being transmitted, and indicating the beginning of a block of a block error correction code inserted in data transmitted from the CATV station. , A first broadcast frequency including a normal synchronization code used during normal broadcasting and an emergency synchronization code used during emergency broadcasting, and a second broadcasting frequency for transmitting emergency information data such as start / end of emergency broadcasting can be received. In the CATV broadcast receiving apparatus, wherein the first broadcast frequency and the second broadcast frequency are equal, the first broadcast frequency and the second broadcast frequency;
Storage means for storing the normal synchronization code and the emergency synchronization code, and in a standby state where the main power is off,
Means for tuning the CATV broadcast receiving apparatus to the first broadcast frequency; and synchronous acquisition means for performing synchronous acquisition of a received input bit stream and the emergency synchronization code in a state where the first broadcast frequency is tuned. When synchronization is obtained in the synchronization acquisition means, an emergency broadcast detection means for determining that an emergency broadcast is transmitted, and when an emergency broadcast is detected in the emergency broadcast detection means, the main power supply Means for turning on, when an emergency broadcast is detected by the emergency broadcast detection means, after error correction, a synchronization code replacement means for returning the emergency synchronization code to a normal synchronization code, and in a tuning state of the first broadcast frequency, Referring to the emergency information data transmitted in the input bit stream, when this emergency information data indicates that emergency broadcast is in progress, Emergency notification means for notifying the listener of an emergency, and when the emergency information data indicates that the emergency broadcast has ended, end the emergency notification, turn off the main power supply and enter a standby state. And a means for performing CATV broadcasting. 3. The CATV broadcast receiving apparatus according to claim 1, wherein an emergency broadcast target area code is assigned to the emergency synchronization code. 4. When an emergency broadcast is detected by the emergency broadcast detection means, an emergency synchronization code of a received input bit stream is compared with the target area code to determine whether the emergency bitstream corresponds to an emergency broadcast target area. 4. The CATV broadcast receiving apparatus according to claim 3, further comprising: 5. The synchronization acquisition means, when the synchronization between the normal synchronization code and the input bit stream cannot be followed,
The CAT according to claim 1 or 2, wherein a synchronization code is changed to an emergency synchronization code, and synchronization between the input bit stream and the emergency synchronization code is performed.
V broadcast receiver. 6. The apparatus according to claim 1, further comprising: means for transferring a normal synchronization code and an emergency synchronization code to a temporary storage element which is always energized when shifting to the standby state.
Or a CATV broadcast receiving apparatus according to claim 2. 7. The emergency notification means according to claim 1 or 2, wherein an emergency situation is displayed on a viewing screen by an alarm buzzer and / or an on-screen display built in the CATV broadcast receiving apparatus. The broadcast receiving device for CATV as described in the above.