Patent Publication Number: US-2005118984-A1

Title: Receiving, displaying, and recording apparatus

Description:
BACKGROUND OF THE INVENTION  
      The present invention relates to a receiving apparatus for receiving a digital broadcast radio signal or a high-priority signal and to a video displaying apparatus and a recording apparatus using the receiving apparatus. More particularly, it relates to a receiving apparatus for receiving an emergency broadcast transmitted from a broadcasting station.  
      A digital broadcast receiving apparatus for receiving digital broadcasts using transmission media such as terrestrial wave, cable, and satellite selects an optional broadcast wave from a plurality of broadcast waves with a tuner, selects an optional channel from a plurality of channels included in the selected broadcast wave by demultiplexing, takes out a digital signal of the selected channel, and outputs video and audio signals by decoding the digital signal.  
      In digital broadcasting, it is possible, in an emergency, to transmit a displayable character message stream and a displayable video and audio stream with such a stream multiplexed on the transport stream. On the side of a receiving apparatus, it is possible to detect that an emergency message included in the digital broadcast is being broadcast and, by extracting the data for the emergency broadcast, to have the data displayed superimposed on the received video, or to switch the channel for decoding and displaying over to the stream for the emergency broadcast.  
      There are established regulations for emergency broadcast in18 2001: Emergency Alert Message for Cable as a US standard for digital cable broadcasting. When it is detected that an emergency broadcast is being made, receiving apparatus conforming to this standard must perform the procedure to tune in to the emergency broadcast channel without fail.  
      In receiving apparatus, it is generally practiced to output a received digital signal or an analog signal obtained by decoding to a recorder for recording the signal. Further, there is devised a method causing, when an emergency broadcast is started, an apparatus while recording a signal to preferentially display the emergency broadcast. (Refer, for example, to Japanese Laid-open Patent Publication No. 2003-244600.)  
      Also, there is disclosed a system in which an apparatus is provided with two tuning sections and the apparatus is allowed to automatically display an emergency alarm by making use of teletext. (Refer, for example, to Japanese Laid-open Patent Publication No. H10-145751.)  
     SUMMARY OF THE INVENTION  
      In prior art, when the received channel has to be forcedly switched to an emergency broadcast at the time of an emergency broadcast as specified in the above mentioned US digital cable broadcast standard, the displayed screen is switched to an emergency broadcast channel and, at the same time, a received signal output to a recorder is forcedly switched to the emergency channel following detection of an emergency broadcast and subsequent switching of the tuned channel to the emergency broadcast channel. Therefore, video recorded in a recorder is switched to the emergency broadcast channel upon detection of the emergency broadcast. The emergency broadcast channel is transmitted for the purpose of being received and watched while it is transmitted, and hence its being recorded in a recorder is meaningless. It is, however, desired by the user of the receiver and recorder that originally intended recording of the channel be continued, while the emergency broadcast is received and displayed.  
      In view of the abovementioned situations, it is an object of the present invention to provide a digital broadcast receiving apparatus capable of ceaselessly recording a channel originally intended by the user to record, while an emergency broadcast channel is received and displayed.  
      An apparatus comprises a first and a second receiver for receiving different physical channels, a first and a second output unit for outputting one of the signals received by the first receiver and the second receiver, and a detector for detecting presence of an emergency broadcast. When an emergency broadcast is detected by the detector, the first receiver and the first output unit are controlled such that the physical channel over which the emergency broadcast is broadcast is received by the first receiver and output from the first output unit, while the second receiver and the second output unit are controlled such that one of the first physical channel having been received by the first receiver and the second physical channel having been received by the second receiver before the emergency broadcast was detected is received by the second receiver and output from the second output unit.  
      Further, the second receiver and the second output unit are controlled, when an emergency broadcast is detected by the detector, such that the physical channel signal having been output from the second output unit before the emergency broadcast was detected is received by the second receiver and put out by the output unit.  
      The present invention provides improved operability for the user. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and other features, objects and advantages of the present invention will becomes more apparent from the following description when taken in conjunction with the accompanying drawings wherein:  
       FIG. 1  is a drawing explanatory of a method of practicing a receiving apparatus according to the present invention. (First embodiment.)  
       FIG. 2  is a drawing explanatory of a method of practicing a receiving apparatus according to the present invention. (Second embodiment.)  
       FIG. 3  is a drawing explanatory of a method of practicing a receiving apparatus according to the present invention. (Third embodiment.) 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
      While we have shown and described several embodiments in accordance with our invention, it should be understood that disclosed embodiments are susceptible of changes and modifications without departing from the scope of the invention. Therefore, we do not intend to be bound by the details shown and described herein but intend to cover all such changes and modifications a fall(?) within the amabit (?) of the appended claims.  
      Embodiments of the present invention will be described below with reference to the accompanying drawings.  
      First Embodiment  
       FIG. 1  shows an embodiment of the present invention and is a block diagram including a receiving apparatus of the present invention. Referring to  FIG. 1 , reference numeral  10  denotes a controller,  13  denotes a selector,  12  denotes a video display,  14  denotes a video-audio output terminal, and  15  denotes a recorder. Selector  13  has first input  131 , second input  132 , first output  133 , and second output  134 . First receiving system is made up of first input terminal  110 , first tuner  111 , first demodulator  112 , first demultiplexer  113 , and first decoder  114 . Second receiving system is made up of second input terminal  120 , second tuner  121 , second demodulator  122 , second demultiplexer  123 , and second decoder  124 . Further, third receiving system is made up of third tuner  171 , third demodulator  172 , and data separator  173 .  
      On the transmission side, the logic channel composed of video, audio, and subsidiary data is encoded with use of such an encoding system as MPEG (Moving Picture Experts Group) and one or a plurality of encoded logic channels are multiplexed by using the MPEG system. Thus, a multiplexed encoded signal to be transmitted over one physical channel is obtained. The multiplexed encoded signal is modulated with use of a digital modulation system to become physical channel modulated signals to be transmitted over a physical channel employing different frequencies and the signals are input to input terminals  110  and  120  in  FIG. 1 .  
      Information about an emergency broadcast is transmitted with use of a channel called OOB (Out Of Band) as specified in SCTE 18 2001: Emergency Alert Message for Cable. In the OOB, there is included scramble information for the encoded signal and there are employed a modulation system and a physical channel different from those for the encoded signal. In the standards SCTE 18 2001, it is specified that, when it is detected that an emergency broadcast is being made, the related emergency broadcast channel must be displayed. Accordingly, if the physical channel of the emergency broadcast channel is different from the logic channel that has so far been watched, it is a matter of course that the tuned physical channel should also be changed.  
      We now return to the explanation of the receiving apparatus shown in  FIG. 1 . First, in the first receiving system, a received signal is tuned, demodulated, demultiplexed, and decoded. More specifically, tuner  111  tunes a signal of an arbitrary physical channel out of a modulated signal input to input terminal  110 . The tuned modulated signal is demodulated by demodulator  112  and the demodulated signal is input to demultiplexer  113 . Demultiplexer  113  separates a desired logic channel and inputs it to decoder  114 . The decoder decodes the video and audio signals and the thus decoded video and audio signals are input to input terminal  131  of the selector. Such receiving operations are controlled by controller  10 .  
      In the second receiving system, i.e., in second tuner  121 , second demodulator  122 , second demultiplexer  123 , and second decoder  124 , an input signal to input terminal  120  is tuned, demodulated, demultiplexed, and decoded the same as in the above described first receiving system. The demodulated video and audio signals are input to input terminal  132  of the selector.  
      The third receiving system is made up of third tuner  171 , third demodulator  172 , and data separator  173 . A modulated signal from input terminal  120  is fed to tuner  171  and an OOB channel is tuned by tuner  171 , the obtained signal is demodulated by demodulator  172 , emergency broadcast information is separated from the obtained signal by data separator  173  and, thereby, it is detected whether an emergency broadcast is present or not. Incidentally, the third receiving system is such that only extracts information about an emergency broadcast and detects whether or not it is present. The emergency broadcast itself is received by the first or second receiving system.  
                                   TABLE 1                           Displayed and   131   132   133   134       No.   Recorded Conditions   1st Input   2nd Input   1st Output   2nd Output                  1-1   One normal ch. received.   ch. A   —   ch. A   —       1-2   Not displayed, but recorded outside.   ch. A   —   —   ch. A       1-3   Channel displayed and also recorded.   ch. A   —   ch. A   ch. A       1-4   One ch. displayed; the other oh. recorded   ch. A   ch. B   ch. A   ch. B       2-1   When emergency broadc. received (1)   ch. C   —   ch. C   —           (while one normal ch. is being received)   ch. A   ch. C   ch. C   ch. A       2-2   When emergenoy broadc. is received (2)           (while recording is being made)       2-3   When emergenoy broadc. is received (3)   ch. C   ch. B   ch. C   ch. B           (while the other ch. is being recorded)                  
 
      Operation of selector  13  will be described with reference to Table 1. Table 1 shows displayed and recorded conditions of received channels and input to and output from selector  13 . Here, it is assumed that channels A and B are channels arbitrarily selected by the user and channel C is an emergency broadcast channel to be forcedly displayed.  
      First, conditions in a normal state where there is present no emergency broadcast will be described. In a case where only channel  1  is received and it is not recorded by recorder  15 , channel A is received by the first receiving system and the received signal is displayed by display  12 . Accordingly, as shown in No. 1-1 of Table 1, the signal of input channel A from the first receiving system is fed to output  133 . The second receiving system is not required to make any signal reception and output  134  for output terminal  14  is stopped.  
      Then, a case where only recording is performed in recorder  15  and no display is required will be considered. In such a case, as shown in No. 1-2 of Table 1, output  133  for display  12  is stopped and the signal of channel A received by the first receiving system is fed to output  134  for output terminal  14 .  
      Then, when display and recording of the same channel are performed simultaneously, as shown in No. 1-3 of Table 1, signals of channel A received by the first receiving system are fed to output  133  for display  12  and to output  134  for output terminal  14 .  
      Finally, when a displayed channel and a recorded channel are different, as shown in No. 1-4 of Table 1, the signal of input channel A from the first receiving system is fed to output  133  and the signal of channel B received by the second receiving system is fed to output  134  for output terminal  14 .  
      There has so far been described the control executed in a normal state in which any emergency broadcast is made. If it is detected in data separator  173  that an emergency broadcast is being made, emergency broadcast channel C must be displayed on display  12 . Further, when the emergency broadcast is started, information of the emergency broadcast channel that must be forcedly displayed is also extracted by data separator  173 .  
      When an emergency broadcast is detected in the state of No.1-1 of Table 1, the first receiving system tunes in to channel C as shown in No. 2-1, and accordingly, input  131  and output  133  of selector  13  are turned into signals of channel C.  
      Then, when an emergency broadcast is detected in the state of No. 1-2 of Table 1, if channel C is received by the first receiving system, output  134  is also switched to the signal of channel C. Hence, recorder  15  becomes unable to record the signal of channel A, the signal originally intended to record. To prevent this, controller  10  in the present invention performs control such that channel A is continuously received by the first receiving unit, whereas emergency broadcast channel C is received by the second receiving system. At this time, as shown in No. 2-2 of Table 1, the signal of emergency broadcast channel C started to be received by the second receiving system is fed to input  132 , while selector  13  feeds the signal of channel C to output  133  for display  12 . In other words, it is surveyed or detected whether or not recording is being made by the recorder, and if the recording is being made by the recorder, the operation of receiving the emergency broadcast by the second receiving system and the switching operation by selector  13  are performed accordingly.  
      Also when an emergency broadcast is detected in the state shown in No. 1-3 of Table 1, while channel A is continuously received by the first receiving system, the emergency broadcast channel C is received by the second receiving system as shown in No. 2-2 of Table 1.  
      Finally, when an emergency broadcast is detected in the state of No. 1-4 of Table 1, the second receiving system which has so far been functioning for the recording is allowed to continue its signal reception and the first receiving system which has so far been functioning for the displaying is switched to receive the emergency broadcast channel. More particularly, as shown in No. 2-3 of Table 1, the first receiving system is switched from channel A to channel C and its signal is fed to input  131 , whereupon selector  13  feeds the signal of channel C to output  133  for display  12 . The signal of channel B is fed from output  134  to output terminal  14  the same as before the start of the emergency broadcast.  
      According to the present invention, as described above, when recording is being performed by recorder  15 , the reception of the channel which has so far been recorded can be continued even after the emergency broadcast is started and, thus, recording of the channel intended to record by the user can be recorded without being interrupted.  
      Further, although not included in Table 1, if the channel having been displayed by display  12  is arranged to be recorded by recorder  15 , instead of the channel having been recorded by recorder  15 , before the emergency broadcast was started, the channel having been watched can be recorded completely.  
      The above description has been made on the precondition that the system is such that transmits emergency broadcast information with OOB. Another system is also conceivable in which emergency broadcast information is transmitted not with OOB but with an ordinary coded signal channel. In such a case, the third receiving system becomes unnecessary and presence or absence of an emergency broadcast can be detected by having the related table or flag extracted in demultiplexing unit  113  or  114  and having it monitored by controller  10 .  
      Second Embodiment  
      In the first embodiment, a signal decoded by decoder  114  or  124  is fed to recorder  15 . However, when recorder  15  is of a type performing digital recording, such a configuration can also be made in which a demultiplexed signal, before being decoded, is fed to recorder  15 .  FIG. 2  shows a second embodiment of the present invention in which a demultiplexed signal is recorded. Selector  13  has only one output  133  to be fed only to display  12 . Second selector  16  has inputs  161 ,  162  and output  163  and is adapted such that a demultiplexed signal by first demultiplexer  113  is fed to input  161 , while a demultiplexed signal by second demultiplexer  123  is fed to input  162 , and one of those signals is fed to output  163 . Reference numerals corresponding to those in  FIG. 1  denote corresponding elements.  
      Functions of selectors  13 ,  16  are basically the same as given in Table 1. However, inputs  161 ,  162  of selector  16  correspond to inputs  131 ,  132  of selector  13  and the signals at input  161 ,  162  are the signals obtained in each of the channels before being decoded. Output  163  corresponds to output  134  in Table 1.  
      First, conditions in a normal state where there is present no emergency broadcast will be explained. In the conditions corresponding to No. 1-1 of Table 1, a decoded signal of input channel A from the first receiving system is fed to output  133 , while the second receiving system does not function. In the conditions corresponding to No. 1-2 of Table 1, output  133  for display  12  is stopped and a demultiplexed signal of channel A is fed to output  163  for output terminal  14 . In the conditions corresponding to No. 1-3 of Table 1, a decoded signal of channel A received by the first receiving system is fed to output  133  and a demultiplexed signal of the same channel is fed to output  163 . In the conditions corresponding to No. 1-4 of Table 1, a decoded signal of input channel A is fed to output  133  and a demultiplexed signal of channel B received by the second receiving system is fed to output  163 .  
      If an emergency broadcast is detected, channel C must be displayed on display  12  the same as in the case of  FIG. 1 . When an emergency broadcast has been detected in the conditions corresponding to No. 1-1 of Table 1, the first receiving system tunes in to channel C the same as in No. 2-1 of Table 1, and accordingly input  131  and output  133  of selector  13  are turned into the signal of channel C.  
      Then, when an emergency broadcast has been detected in the conditions corresponding to No. 1-2 of Table 1, controller  10  controls such that, while channel A is continuously received by the first receiving system, emergency broadcast channel C is received by the second receiving system. At this time, as in No. 2-2 of Table 1, a demultiplexed signal of channel A being received by the first receiving system is fed to input  161  and delivered from output  163 . At the same time, the decoded signal of channel C started to be received by the second receiving system is fed to input  132  and delivered from output  133 . Further, also when an emergency broadcast has been detected in the state given in No. 1-3 of Table 1, channel A is continuously received by the first receiving system, while emergency broadcast channel C is received by the second receiving system.  
      Finally, when an emergency broadcast has been detected in the state given in No. 1-4 of Table 1, the second receiving system functioning so far for recording continues its reception the same as before and the first receiving system functioning so far for displaying is switched to receive the emergency broadcast channel. More specifically, the same as in No. 2-3 of Table 1, the received channel in the first receiving system is switched from channel A to channel C and a decoded signal of channel C is fed to input  131  and delivered from output  133 . The demultiplexed signal of channel B is delivered from output  163  to output terminal  14  the same as before the start of the emergency broadcast.  
      According to the present invention, as described above, when recording is being performed in recorder  15 , the reception of the recorded channel can be continued even after the emergency broadcast is started and, thus, recording of the channel intended to record by the user can be recorded without being interrupted.  
      There are provided two decoders in the embodiment shown in  FIG. 2 . In the case where digital recording is performed, however, it is only one channel for displaying that is to be decoded. Therefore, such a system may be made in which the number of decoders is reduced to one and the demultiplexed signal fed to the recorder is suitably switch-selected.  
      In the description made above, there are provided input terminals  110  and  120  for the first receiving system and the second receiving system, respectively. However, such a receiving apparatus may be made in which only one input terminal is provided with the input configured to branch off within the receiving apparatus.  
      Third Embodiment  
      In the foregoing description, it is premised that the input signals to input terminals  110 ,  120  are identical. However, by providing a second selector in the preceding stage of input terminals  110 ,  120 , the same effect can be obtained even if input signals are different. An embodiment in such a case will be shown in  FIG. 3 .  
      Referring to  FIG. 3 , reference numeral  18  denotes a second selector,  181  denotes a first input terminal,  182  denotes a second input terminal,  183  denotes a first output terminal, and  184  denotes a second output terminal. It is assumed that different signals are input to input terminals  181 ,  182 .  
      For example, a signal from a terrestrial wave antenna is input to terminal  181  and a signal from a cable television network is input to terminal  182 . One of the signals at terminals  181 ,  182  selected by controller  10  is fed to output terminal  183  and  184 .  
      When the signals fed to output terminals  183 ,  184  are identical with each other, selector  18  does not need to be particularly controlled and, hence, the same operation as in the above described  FIG. 1  may be made. In the case where the signals fed to output terminals  183  and  184  are input signals to terminals  181  and  182 , respectively, and different from each other, selector  18  is controlled when an emergency broadcast is detected while recorder  15  is being operated.  
      Control of selector  18  will be described with reference to Table 1. In Table 1, we assume that channel A is a terrestrial wave signal and both channel B and channel C are cable signals. Hence, in the cases of conditions given in Nos. 1-1, 1-2, 1-3, and 1-4 of Table 1, selector  18  is controlled such that the terrestrial wave signal input to terminal  181  is fed to output terminal  183  and the cable signal input to terminal  182  is fed to output terminal  184 .  
      In the case of conditions No.2-1, namely in the case where an emergency broadcast is detected while a normal channel is being received, the display must be switched to emergency broadcast channel C. Then, by controlling selector  18  such that the cable signal input to input terminal  182  is fed not only to output terminal  184  but also to output terminal  183 , channel C becomes receivable by the first receiving system.  
      It is also possible to receive channel C by the second receiving system for displaying without controlling selector  18 . In this case, the receiving system for displaying is switched from the first to the second receiving system.  
      In the case of conditions No.2-2, i.e., when the displayed channel is recorded, selector  18  does not need to be controlled because channel C is received by the second receiving system. Finally, in the case of conditions No. 2-3, i.e., when the other channel than the displayed channel is being recorded, channel C becomes receivable by the first receiving system by controlling selector  18  such that the cable signal input to terminal  182  is fed not only to terminal  184  but also to terminal  183 , the same as in the case of conditions 2-1.  
      According to the present invention, as described above, even when different signals such as terrestrial wave signal and cable signal are input, the reception of the channel being recorded can be continued whether an emergency broadcast is started or not. Thus, recording of the channel intended to record by the user can be recorded without being interrupted.  
      In any of the embodiments described above, the receiving apparatus of the present invention, while continuing the reception of a channel being recorded, can newly receive and display an emergency broadcast channel with use of another receiving system. The receiving apparatus, while receiving and displaying an emergency broadcast channel, is capable of continuously recording the channel intended to record by the user without interruption. Thus, a receiving apparatus providing improved operability to the user can be realized.