JP2579412Y2 - CATV terminal device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CATV terminal device of a bidirectional CATV system, and more particularly to a descrambling unit in a video scramble synchronous compression system.

[0002]

2. Description of the Related Art Broadcasting in a two-way CATV system is a television broadcasting (hereinafter referred to as a pay broadcasting) which is supplied to a specific viewer who is permitted to view (for example, pay television contract).
And a television broadcast that does not require viewing permission (hereinafter referred to as a general broadcast), and a data channel that is repeatedly transmitted on one independent specific frequency channel.
Data channel, or a broadcast channel of each currently sending Do Broadcast of the Yuka broadcast of the, and the pay program information indicating whether not whether they perform the broadcasting viewing permit prohibited for each channel to perform the pay broadcast These data signals are repeatedly transmitted. The pay television signals, the scrambled video signal compressed amplitude in the horizontal blanking period and the vertical blanking period for theft viewing prevention, images in descrambling stage timing of the compression processing in CATV terminal unit A scrambled television signal is obtained by frequency-multiplexing a sound FM signal subjected to AM modulation processing with a timing pulse whose transmission time difference from a system signal is substantially corrected.
Here, the timing pulse in the vertical retrace period is wider than the timing pulse in the horizontal retrace period.

[0003] The conventional CATV terminal device 90 is
As shown in the block diagram shown in FIG. 4, a duplexer 1, a tuner unit 13, a synchronizing extension unit 2, a VIF detection unit 3, a video output unit 4, and a video output terminal are connected in series from a CATV input terminal. From the tuner unit 13 to the SIF detection unit 7, the audio output unit 1
2. The audio output terminals are connected in series. Demultiplexer 1,
It is connected to a pay program information table 52 and a viewing permission prohibition information table 53 via a data demodulation unit 11 and a data analysis unit 51. Pay program information table 52 and the viewing permit prohibition information table 53 is connected to the timing adjusting unit 9 via the operation control unit 54. Data analysis unit 51 is connected via a data modulation unit 10 in the demultiplexer 1. Control unit 5
Comprises a data analysis unit 51, a pay program information table 52, a viewing permission prohibition information table 53, and an operation control unit 54. The descrambling unit 30 includes an AM detection unit 8, a timing adjustment unit 9, and a synchronization extension unit 2, which are connected in series. The SIF detector 7 and the AM detector 8 are connected.

FIG. 5 shows a first timing chart of waveforms of respective parts, and the operation will be described with reference to FIG. This waveform shows a case where the current reception channel is in the viewing permitted state and switches from general broadcast (A side) to pay broadcast (B side) at the time of the broken line. Then, the CATV terminal unit is a case where incidentally viewing permission has been made on that channel. A television signal of a plurality of channels and a data signal are frequency-multiplexed and input to the CATV input terminal. Demultiplexer 1 demultiplexes these signals into the television signal and a data signal of a plurality of channels. A desired channel is selected from the plurality of channels of the television signal by the tuner unit 13, separated into a video intermediate frequency signal 71 and an audio intermediate frequency signal 72 and output. The SIF detector 7 receives the audio intermediate frequency signal from the tuner 13 and performs FM demodulation to obtain an audio signal. This signal is output to the audio output unit 12
Through to the audio output terminal.

On the other hand, the data signal is demodulated by the data demodulator 11 and input to the data analyzer 51. Therefore, the data is analyzed. That is, the pay program information is sent first, and the contents are rewritten in the pay program information table 52. Thereafter, the viewing permission prohibition information of the pay program with the ID number set for each CATV terminal device 90 is sent, the viewing permission prohibition information matching the ID number of the pay program is received , and the data of the viewing permission prohibition information table 53 is read. Rewrite. Further, in the case when a correctly received information of his ID number, the acknowledgment information via a data modulation unit 10 demultiplexer 1 center sends, which Paritera etc. could not be received correctly generated modulates the frequency of the uplink signal at the data modulator 10, and Sentahe sends error information via the demultiplexer 1, and requests a retransmission to the center. While Yuka program is being broadcast, the amplitude compression processing in the repeating repetition and the horizontal blanking period and vertical blanking period of the transmission data indicating that the pay broadcast pay program information being transmitted in the transmission device Is being performed at the same time.

[0006] Regarding the receiving channel, (1)
When the tangible program information is tangible broadcast, the viewing permission prohibition information is viewing permission, and the tuner unit 13 is receiving a scrambled television signal, it corresponds to the right side B portion of the broken line in FIG. . (2) There is a case where the pay program information is a tangible broadcast, the viewing permission prohibition information is a viewing prohibition, and the tuner unit 13 is receiving a scrambled television signal. (3) This corresponds to a case where the pay program information is not a pay broadcast and the tuner unit 13 is receiving a non-scrambled television signal (the left A portion of the broken line in FIG. 5 ) .
Hereinafter, the citation of the waveform diagram of FIG.

By the way, the operation control unit 54, with respect to viewing permit prohibition information receiving channel and pay program information of the received channel, these data are sent to pay program information table 52 and the viewing permit prohibition information table 53 to the data analysis unit come time reference, if the channel is (1) issues an operation signal 76B to the timing adjusting section 9, and outputs a control signal 76A to be stopped if the (2) and (3).

The AM detector 8 receives the intermediate voice frequency signal 72 from the SIF detector 7 and performs AM detection (waveform 73). Here, in the cases (1) and (2), the timing pulse and the noise 73B substantially synchronized with the timing of the compression processing of the video intermediate frequency signal 71 output from the tuner unit 13
Is output. In the case of the above (3), only the noise of the AM component 73A is output. In the case of the above (1), the timing adjustment unit 9 synchronizes the timing pulse of the AM detection unit 8 with the timing of the compression processing of the video intermediate frequency signal by using the timing pulse 73B and the operation control signal 76B from the operation control unit 54. and waveform shaping on the width of the compression period, particularly for wide timing pulse 77, and outputs a control timing pulse 77 that waveform shaping to the width of the vertical blanking interval compression period. In the above cases (2) and (3), nothing is output by the stop control signal from the operation control unit 54.

The video intermediate frequency signal output from the tuner section 13 is expanded in the synchronizing / expanding section 2 by the control timing pulse from the timing adjusting section 9 in the case of the above (1) to expand the amplitude of the compression processing portion of the video intermediate frequency signal. To restore the amplitude and output it to the VIF detector 3. For the (2), not applied to control the timing pulses from the timing adjusting unit 9, and outputs the left VIF detection section 3 the amplitude of the extension of the compression portion of the video intermediate frequency signal is not performed. In the case of the above (3) , the control timing pulse is not added and the video intermediate frequency signal is output to the VIF detection unit 3 without being expanded. The video signal is reproduced by the VIF detector 3 and output to the video output terminal through the video output 4. The above (1)
In the case of (3) and (3), a normal video signal is obtained. In the case of (2), a video signal whose amplitude is compressed in the horizontal retrace period and the vertical retrace period is obtained, and a normal screen is obtained. Cannot be played.

[0010]

When you are sending a general broadcast amplitude has not been compression processing in the horizontal blanking period and vertical blanking period from the center [devised is to solve the above, erroneous pay program information is permitted viewing in pay television If the prohibition information had sent the specified data signals allowed composed view, showing a conventional waveform of each part CATV terminal unit 90 when the tuning of the program by the tuner 13 in FIG. 6. Before the timing of starting the compression processing of the amplitude of the video intermediate frequency signal 81 during the horizontal retrace period and the vertical retrace period, a high-level signal that is the operation control signal 86 from the operation control unit 54 to the timing adjustment unit 9 Out. In this period, the audio intermediate frequency signal 82
The AM detector 8 performs AM detection, and the output (waveform 83) operates the timing adjustment unit 9 (waveform 87). And <br/> Te, synchronous decompression unit 2 picks up noise of the AM component of the audio signal
Operates, and the video signal is disturbed. In particular, when the synchronizing signal portion is expanded, the synchronizing signal level becomes excessive and the synchronization is disturbed (waveform 89). Therefore, the present invention enables a normal image to be obtained even if a general broadcast signal is broadcast on a channel for which pay program information is designated as a pay broadcast from the center due to an erroneous operation or the like, so that the center can be notified of the abnormal state. By doing so , a highly reliable two-way CATV system is provided.

[0011]

SUMMARY OF THE INVENTION Therefore, in order to achieve the above-mentioned object, the first invention of the present invention is to provide the tangible program information and the viewing permission prohibition information of the data channel transmitted from the center of the bidirectional CATV system. And a viewing permission prohibition information table, an AM detector for obtaining an envelope of an audio intermediate frequency signal, and a pulse having a predetermined pulse width cycle for a predetermined period from the output waveform of the AM detector. a scrambling television signal determination unit for detecting that, when the current reception channel from the pay program information table and viewing permission prohibition information table is scrambled detected and viewing permitted and scrambled television signal determination unit in the pay program, the operation an operation control section for outputting a control signal, and operates in response to operation control signals, and the trigger output of the AM detection section It is characterized by comprising a timing adjustment unit for generating a control timing pulse having a predetermined pulse width, and a synchronization extension unit for extending the amplitude of the video intermediate frequency signal at the timing of the control timing pulse. Further, in the second invention, in addition to the first invention, when the current reception channel is a tangible program and viewing is permitted from the tangible program information table and the viewing permission prohibition information table, the output of the AM detector is It is characterized by including an abnormality detection unit for detecting that the pulse is not continuous for a predetermined period at a predetermined period from the waveform.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a first embodiment of the descrambling unit of the CATV terminal device of the present invention. The conventional CATV shown in FIG.
The description of the parts common to the terminal device 90 is omitted. A comparator 40, a retriggerable monomultivibrator 41, and a scramble detector 55 are connected in series between a connection point between the AM detector 8 and the timing adjuster 9 and the second operation controller 57. The scramble determination unit 20 includes a comparator 40 and a retriggerable monomultivibrator 41. The operation control unit 54 is configured by connecting a first operation control unit 56 and a second operation control unit 57 in series. The first operation control unit 56 is connected to the viewing permission prohibition information table 53 and the pay program information table 52. The second operation control unit 57 is connected to the scramble detection unit 55 and the timing adjustment unit 9. The control unit 5 includes a data analysis unit 51, a pay program information table 52, a viewing permission prohibition information table 53, an operation control unit 54, and a scramble detection unit 55.

FIG. 2 shows a second embodiment of the CATV terminal device according to the present invention.
It is a block diagram showing an example. CATV shown in the figure
The terminal device 200 is provided with an abnormality detection unit 58 in addition to the first embodiment of the present invention shown in FIG . Abnormality detector 58
Are the connection point between the retriggerable monomultivibrator 41 and the scramble detection unit 55, the connection point between the second operation control unit 57 and the timing adjustment unit 9, and the connection point between the first operation control unit and the second operation control unit. The connection point is connected to the data modulation unit 10.

[0014] Figure 3, the CATV terminal unit 100, 2
4 shows a timing chart of the waveforms of the respective parts of FIG. Waveform 15
Numerals 1 , 152 , 153 , 154 , and 155 show waveforms of respective sections when the tuner section 13 selects a television signal changed from general broadcast to pay broadcast. Waveform 15
Reference numeral 1 denotes an envelope waveform of the video intermediate frequency signal transmitted from the tuner unit 13 to the synchronizing / expanding unit 2. Waveform 152,
7 is a waveform of an envelope of an audio intermediate frequency signal transmitted from the tuner unit 13 to the SIF detection unit 7. A waveform 153 is a control timing pulse waveform transmitted from the timing adjustment unit 9 to the synchronization decompression unit 2. The waveform 154 is a signal waveform transmitted from the scramble television signal discriminating unit 20 to the scramble detecting unit 55. Waveform 155 is the first
7 is a signal waveform transmitted from the operation control unit 56 to the second operation control unit 57. The waveform 156 indicates that the second operation control unit 5
7 is a signal waveform transmitted to the timing adjustment unit 9 from FIG. A waveform 157 is a control timing pulse waveform. Waveform 158 is the alarm signal waveform in the second embodiment of the present invention. The waveform 159 indicates that V
7 is a waveform of an envelope of a video intermediate frequency signal that is synchronously expanded and transmitted to the IF detection unit 3.

Next, in FIGS. 1 and 2 with reference to FIG. 3
The operation of the embodiment shown will be described. Waveform 151 represents the envelope of the image in question frequency signal, horizontal blanking interval and the vertical blanking period on the way in the first general broadcast is if changes in pay broadcast which is amplitude compression. Waveform 152 represents the envelope of the audio intermediate frequency signal indicates a state in which the timing pulses in the audio intermediate frequency signal in synchronization with the change of the pay broadcast wave 151 is AM modulated, this waveform, Ya transmission path A noise component induced inside the CATV terminal device 100 or the like is present. A waveform 153 is an output of the AM detector 8. The waveform is shaped from this waveform by the comparator 40, and the vertical blanking period 2
While the timing pulse is input is the period of the following pulse width by retriggerable monostable multivibrator 41 of a long, for example, 20 number pulse width of H than 0H is retriggered (retrigger) in the set state is continued. A waveform 154 is an output of the retriggerable multivibrator 41, and a pulse is generated also by a noise component. This signal,
In order to avoid erroneous detection due to noise, when a pulse is input to the scramble detection unit 55 and, for example, the set state continues for one field period, it is assumed that the video intermediate frequency signal and the audio intermediate frequency signal have been scrambled. I have. The waveform 155 represents a signal in which the tangible program information of the receiving channel is a tangible program and the viewing permission prohibition information is the viewing permission, and is transmitted earlier than the compression processing of the video intermediate frequency signal shown in the waveform 151. Seen when When the scramble processing of the waveform 154 is not detected , as shown in the waveform 156 , the first operation control unit 56
The operation control of the timing adjustment unit 9 is stopped (low level) by the second operation control unit 57 with respect to the waveform 155 that is the waveform output of (2). Therefore, such as when the Yuka program information of the received channel waveform 155 is left just earlier than the compression processing of the video intermediate frequency signal by mistake signal is permitted viewing prohibiting information is permitted viewing a fee program, timing adjustment The operation of the section 9 is stopped, and the malfunction of the synchronization extending section 2 erroneously extending the synchronization signal portion is eliminated. Further, in FIG. 2, when the signal whose tangible program information of the reception channel of waveform 155 is a tangible program and the viewing permission prohibition information indicates that viewing is permitted is active (high level) in FIG.
Once the output signal of the retriggerable multivibrator 54 goes low, the alarm signal is activated (high level). When the output signal of the waveform 156 for controlling the operation of the timing adjustment unit 9 rises to active (high level), the alarm signal is set to non-active (low level). This waveform is referred to as waveform 15
8 shows the alarm signal. The active (high-level) output of the alarm signal reports an abnormal state to the center through the data modulator 10 and the duplexer 1.

[0016]

[Effects of the Invention] As described above, CA according to the present invention
TV terminal equipment, to Yuka program information of the received channel by mistake at the center side view permitted in pay program prohibition information is sent the signal is permitted viewing, scrambling of the video intermediate frequency signal and the audio intermediate frequency signal When the processing is not being performed, the operation of the timing adjustment unit is stopped , the extension of the video intermediate frequency signal by the synchronous extension unit is prohibited, and a normal image can be obtained. Further , by adding an abnormality determination unit for the scrambled television signal, the center is notified of alarm information when an abnormal state occurs , and the CATV
Fixed abnormality in the terminal device, furthermore, by resulting in the ability to detect in the center, it is possible to provide a more reliable system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the CATV terminal device of the present invention.

FIG. 2 is a block diagram showing a second embodiment of the CATV terminal device according to the present invention;

FIG. 3 is a timing chart of waveforms of respective parts of the CATV terminal device shown in the first and second embodiments .

FIG. 4 is a block diagram of a conventional CATV terminal device.

FIG. 5 shows a first timing chart of waveforms at various points in a conventional CATV terminal device.

FIG. 6 shows a second timing chart of waveforms of respective parts of the conventional CATV terminal device.

[Explanation of symbols]

 2 Synchronous decompression unit 8 AM detection unit 9 Timing adjustment unit 20 Scramble television signal discrimination unit 52 Pay program information table 53 Viewing permission prohibition information table 54 Operation control unit 58 Abnormality detection unit

Claims (2)

(57) [Scope of request for utility model registration] 1. A tangible program information table for storing tangible program information and viewing permission prohibition information of a data channel transmitted from a center of a two-way CATV system, a viewing permission prohibition information table, and an envelope of an audio intermediate frequency signal. AM detector for obtaining a line, a scrambled television signal discriminator for detecting that a pulse has been continued for a predetermined period at a predetermined pulse width cycle from an output waveform of the AM detector, a tangible program information table and viewing permission prohibition information when the current reception channel from the table is scrambled detected and the viewing permission and scrambled television signal determination unit in Yuka program, an operation control section for outputting an operation control signal, and operates in response to operation control signals, AM a timing adjustment unit to trigger the output of the detection unit generates a control timing pulse having a predetermined pulse width CATV terminal apparatus characterized by comprising a synchronization extension unit for extending the amplitude of the video intermediate frequency signal at a timing of the control timing pulse. From wherein pay program information table and viewing permission prohibition information table when the current reception channel is and permitted viewing by Yuka program for a predetermined period pulse from the output waveform of the AM detection section at a predetermined cycle 2. The CATV terminal device according to claim 1, further comprising an abnormality detection unit that detects that the terminal is not continuous.