JP5453891B2 - Demodulator - Google Patents

Description

  The present invention relates to a demodulation device.

  In terrestrial digital broadcasting for portable terminals, it is important to enable reception with low power consumption in order to increase the reception time of a battery-powered terminal. For this reason, the method of transmitting broadcast programs by frequency division used in ISDB-T and ISDB-Tmm in Japan, and DVB-H adopted mainly in Europe and MediaFLO adopted mainly in the United States. There is a method for transmitting a broadcast program in a time-division manner.

  DVB-H and MediaFLO are terrestrial digital broadcast standards for portable terminals, and are broadcast standards for receiving broadcast programs by time division multiplexing (TDM).

  International Publication No. WO2005 / 060113 Pamphlet has a receiving method for receiving a signal corresponding to one selected service with respect to a plurality of input signals each including information on a plurality of data corresponding to each of a plurality of services. It is disclosed.

  Japanese Patent Laid-Open No. 2006-261785 discloses a power consumption control device for controlling power consumption in a playback device that plays back input content data and outputs video and audio.

  Japanese Patent Laid-Open No. 2007-174013 discloses a receiving unit that receives a channel selection signal and selects a TV signal of a designated channel, and a demodulation that demodulates the TV signal of the selected channel and outputs a digital signal stream. Means, a demultiplexing means for outputting an audio signal stream, a video signal stream and a data signal stream from the digital signal stream, a data decoding means for decoding the data signal stream and outputting a data broadcast document, and the data broadcast document And a digital broadcast receiver comprising a data broadcast browser for forming a data broadcast screen and a control means for controlling the above means.

  Japanese Unexamined Patent Application Publication No. 2008-10931 discloses a portable terminal device for receiving broadcasts having a function of receiving a broadcast wave of a radio signal and performing at least one of reproduction and recording of program content included in the broadcast wave. ing.

  Japanese Patent Application Laid-Open No. 2007-19695 discloses a playback apparatus for playing a program, and detecting means for detecting the start of zapping and the start channel when it is detected that zapping has started. There is disclosed a playback apparatus comprising display control means for displaying a menu marked with a button on the screen.

International Publication No. WO2005 / 060113 Pamphlet JP 2006-261785 A JP 2007-174013 A JP 2008-10931 A JP 2007-19695 A

  An object of the present invention is to provide a demodulator capable of reducing power consumption and responding at high speed to a viewing program switching instruction.

According to one aspect of the present invention, a program switching operation unit for operating a viewing program switching instruction, a program switching interval detecting unit for detecting an interval between viewing program switching instructions by the program switching operation unit, A demodulator that performs demodulation by inputting a plurality of viewing programs received by division multiplexing and a switching mode operation detected by the program switching interval detector is longer than a first interval threshold as a first mode. A control unit that controls the demodulation unit, and controls the demodulation unit as a second mode when the interval of the switching instruction operation detected by the program switching interval detection unit is shorter than the first interval threshold, control unit, wherein in the first mode, receiving division multiplexing when switching instruction by the program switcher view Program turns on the power of the demodulator when entered, turns off the power of the demodulator when the other of the viewing program is entered, and in the second mode, the previous switched by at least said program switcher When a viewing program received by time division multiplexing that is instructed and is not instructed to be switched this time is input, and when a viewing program that is received by time division multiplexing that is instructed to be switched this time by the program switching operation unit is input In the first mode, the demodulator inputs and demodulates the viewing program received by time division multiplexing instructed to be switched by the program switching operation unit, and the other viewing programs are Without demodulating, in the second mode, at least the program switching operation unit Switching indicated and watch programs received by time division multiplexing is not currently switching instruction, and enter the viewing program to be received by time division multiplexing is currently switching instruction by the program switching unit, wherein the demodulating A demodulator is provided.

  By controlling the power supply of the demodulator according to the interval of the viewing program switching instruction operation, it is possible to reduce power consumption and respond quickly to the viewing program switching instruction.

It is a block diagram which shows the structural example of the terrestrial digital broadcast demodulator for portable terminals by time division multiplexing (TDM). It is a time chart which shows the processing method of the demodulation apparatus of FIG. It is a flowchart which shows the processing method of the demodulation apparatus of FIG. It is a time chart which shows the reception process of a demodulation part. It is a flowchart which shows the reception process of the method of buffering in an off time period. It is a time chart which shows the outline | summary of the process of the flowchart of FIG. It is a block diagram which shows the structural example of the terrestrial digital broadcast demodulation apparatus for portable terminals of TDM by the 1st Embodiment of this invention. It is a flowchart which shows the processing method of the demodulation apparatus of FIG. It is a flowchart which shows the processing method of the demodulation apparatus of FIG. It is a time chart which shows the reception operation | movement outline | summary of the continuous reception mode which receives all the programs continuously. It is a time chart which shows the reception operation | movement outline | summary in the multiple program reception mode which receives a specific some program.

(Reference technology)
FIG. 1 is a block diagram showing a configuration example of a terrestrial digital broadcast demodulator for mobile terminals using time division multiplexing (TDM). To the bus 100, a MAC unit 102, a video decoder 103, an audio decoder 105, a CPU 107, a ROM 108, a RAM 109, and a program switching detection unit 111 are connected.

  The demodulation unit 101 is a block that receives broadcast waves and performs demodulation processing on digital data. A MAC unit (Media Access Controller) 102 is a control unit that controls on / off of an operation power supply when the demodulation unit 101 receives TDM by a control signal 120. The demodulation unit 101 and the MAC unit 102 are the blocks that form the basis of the TDM reception process.

  The video decoder 103 is a block that acquires a video stream from the data demodulated by the demodulation unit 101 and the MAC unit 102 and performs decoding processing. The video display device 104 is a block that displays the video data decoded by the video decoder 103, and corresponds to a liquid crystal display or the like.

  The audio decoder 105 is a block that acquires an audio stream from the data demodulated by the demodulation unit 101 and the MAC unit 102 and performs decoding processing. The audio output device 106 is a block that outputs the audio data decoded by the audio decoder 105, and corresponds to a speaker.

  The CPU 107 is a block that drives the firmware of the demodulation device and controls the entire demodulation device. The ROM 108 is a block for storing the firmware driven by the CPU 107 and the binary code of the control software for the entire demodulator. The RAM 109 is used as a buffer for buffering data demodulated by the demodulation unit 101 and the MAC unit 102, or as a work area for firmware.

  The program switching button 110 corresponds to a button for the user to instruct switching of the viewing program. The program switching detection unit 111 is a block that detects a user input operation to the program switching button 110 and notifies the CPU 107 of the information.

  FIG. 2 is a time chart showing a processing method of the demodulating device of FIG. The program broadcast by TDM is performed on one broadcast channel (frequency) 200 on program A (201), program B (202), program C (203), program D (204), program E (205), program F ( A plurality of programs are divided by time and broadcasted such as 206). One cycle of the programs A to F is, for example, 1 to 2 seconds.

  In broadcasting by TDM, the demodulator turns on the power of the demodulator 101 only during a period when a program to be received is broadcast, and turns off the power of the demodulator 101 during a period when other programs are broadcast. Driving with low power consumption is possible.

  An operation 207 of the demodulator 101 in FIG. 2 shows how the demodulator receives the TDM broadcast. When receiving the program A (201) on the broadcast channel 200, the demodulator turns on the power to the demodulator 101 during the period 208 during which the program 201 to be received is broadcast, and receives the program. During the broadcast period 209, the demodulator 101 is powered off.

  FIG. 3 is a flowchart showing a processing method of the demodulator of FIG. By starting the demodulator, in step 301, the program switching button 110 is instructed to operate the program to be viewed by the user.

  Next, in step 302, the MAC unit 102 turns on the power of the demodulation unit 101 to receive all programs on the TDM channel.

  Next, in step 303, the CPU 107 detects reception of TDM data of the program to be viewed from all TDM programs being received. During a period when the TDM data of the program to be viewed is not detected, in step 310, the CPU 107 displays on the video display device 104 that the program is being searched.

  When reception of TDM data to be viewed in step 303 is detected, in step 304, the demodulation unit 101 performs demodulation processing of the viewing program.

  Next, in step 305, the CPU 107 checks whether there is a program switching instruction from the user using the program switching button 110. If there is no program switching instruction, the demodulator 101 completes the demodulation of the viewing program and proceeds to step 306. If there is a program switching instruction, the process proceeds to step 311.

  In step 306, the MAC unit 102 turns off the power of the demodulation unit 101 during an off-time period in which another program is received.

  Next, in step 307, the CPU 107 checks whether there is a program switching instruction from the user using the program switching button 110. If there is no program switching instruction, the process proceeds to step 308, and if there is a program switching instruction, the process proceeds to step 311.

  In step 308, the CPU 107 detects whether the off-time period in which another program is received has expired. If the off-time period has not ended and it is not yet time for the viewing program to be received, the process returns to step 307 to continue the off-time detection process.

  When the CPU 107 detects the end of the off-time period and the period for receiving the viewing program is reached, in step 309, the MAC unit 102 turns on the power of the demodulation unit 101, returns to step 304, and the demodulation unit 101 stores the viewing program. The reception and demodulation processing of TDM data is started.

  The loop of steps 304 to 309 represents the TDM reception process. During this loop period, the CPU 107 displays the image data of the program demodulated in step 304 on the video display device 104.

  If the CPU 107 detects a viewing program switching instruction in step 305 or 307, the MAC unit 102 turns on the power of the demodulation unit 101 in step 311, returns to step 303, and the CPU 107 receives a new viewing program. Perform detection.

  The use of the terrestrial digital broadcast demodulator for portable terminals is mainly for viewing programs on the go. At this time, it is considered that the user often watches the broadcast for a time-crushing use such as a gap between movements in the place where the user is away from home.

  In such viewing, the user may switch between several programs in a short time in order to search for a program of interest. During such operations, the user expects a fast program switching display.

  FIG. 4 is a time chart showing reception processing of the demodulator 101 when the user switches programs under the TDM reception flow shown in FIG. It is assumed that when the TDM data of the programs A to F is being broadcast on the TDM broadcast channel 401, the program A is first received as shown in the reception period 402. At this time, the demodulation unit 101 receives and demodulates only the TDM data 405 of the program A.

  Here, when a program B reception request is generated at the time 403 by the program switching button 110, the demodulator detects the switching at step 305 or 307 in FIG. The program B reception detection process starts. In FIG. 4, in a period 406 until the reception of TDM data of the next program B is detected, the demodulator displays on the screen that the program shown in step 310 of FIG. 3 is being searched. Depending on the design of the demodulator, the program A data received immediately before may continue to be displayed. In any case, in the period 406 from the time 403 of the user's viewing program switching request until the program that the user actually wants to view is displayed, a delay time associated with the TDM reception time occurs, and the program is shortened for a short time. When performing the process of switching one after another, the high-speed viewing program switching process expected by the user cannot be satisfied.

  As a method for solving this problem, the power of the demodulator 101 is turned on during an off-time period when a program that is not viewed at a certain period is broadcast, and a program that is not viewed is received in advance and held in a buffer. You can think of a way to keep it.

  FIG. 5 is a flowchart showing the reception process of the method of buffering during the off-time period. By starting the demodulator, in step 501, the program switching button 110 is operated to switch the program to be viewed by the user.

  In step 502, the MAC unit 102 turns on the power of the demodulating unit 101 so as to receive all programs on the TDM channel.

  Next, in step 503, the CPU 107 detects reception of TDM data of the program to be viewed from all TDM programs being received. If not, in step 514, the CPU 107 checks whether there is received data of the program to be viewed in the buffer. Immediately after the start of reception, there is no received data in the buffer. Therefore, during a period when the TDM data of the program to be viewed is not detected, the CPU 107 displays a display on the video display device 104 indicating that the program is being searched. Do.

  When reception of TDM data to be viewed is detected in step 503, in step 504, the demodulation unit 101 performs demodulation processing of the viewing program.

  Next, in step 505, the CPU 107 checks whether there is a program switching instruction from the user using the program switching button 110. If there is no program switching instruction from the user, the process proceeds to step 506. If there is a program switching instruction from the user, in step 513, the MAC unit 102 turns on the power of the demodulation unit 101, and proceeds to step 514.

  In step 506, the CPU 107 checks whether or not the current time is the background reception time. The background reception time is set so as to occur periodically at a certain cycle. For example, the background reception time is set once every 10 program cycles. If it is not the background reception time, the demodulation of the viewing program is completed, and the MAC unit 102 turns off the power of the demodulation unit 101 in step 507 during a period in which another program is received.

  Next, in step 508, the CPU 107 checks whether there is a program switching instruction from the user using the program switching button 110. If there is no program switching instruction from the user, the process proceeds to step 509. If there is a program switching instruction from the user, in step 513, the MAC unit 102 turns on the power of the demodulation unit 101, and proceeds to step 514.

  In step 509, the CPU 107 detects whether the off-time period in which another program is received has expired. If the off-time period has not ended, it is not yet the time for the viewing program to be received, so the process returns to step 508 to continue the off-time detection process.

  When the end of the off-time period is detected and the viewing program is received, in step 510, the MAC unit 102 turns on the power of the demodulation unit 101 and starts receiving TDM data of the viewing program. Thereafter, the process returns to step 504.

  The loop of steps 504 to 510 represents the TDM reception process. The CPU 107 displays the image data of the program demodulated in step 504 on the video display device 104 during this loop period.

  If the background reception time is detected in step 506 during the TDM reception period of steps 504 to 510, the MAC unit 102 does not turn off the power of the demodulator 101, and the demodulation unit 101 Demodulate TDM data other than programs. The CPU 107 stores the demodulated data in a buffer. The background reception in step 506 is set to occur periodically at a certain period.

  Next, in step 512, it is checked whether or not there is a program switching instruction from the user by the program switching button 110. If there is no program switching instruction from the user, the process returns to step 504. If there is a program switching instruction from the user, in step 513, the MAC unit 102 turns on the power of the demodulation unit 101, and proceeds to step 514.

  When the instruction to switch the viewing program is detected in step 505, 508, or 512, the MAC unit 102 turns on the power of the demodulation unit 101 in step 513. Next, in step 514, the CPU 107 checks whether the data acquired by the background reception in step 511 exists in the buffer. When the data acquired by the background reception in step 511 exists in the buffer, in step 516, the CPU 107 acquires the data of the program for which a new reception instruction has been issued from the buffer and causes the video display device 104 to display the data. While this data is being displayed, the process returns to step 503, and the CPU 107 detects reception of TDM data to be viewed.

  If the data acquired by the background reception in step 511 does not exist in the buffer, the CPU 107 displays on the video display device 104 that the program is being searched in step 515. Thereafter, the process returns to step 503.

  FIG. 6 is a time chart showing an outline of the processing of the flowchart of FIG. It is assumed that program A is first received in period 602 when TDM data of program A to program F is being broadcast on TDM broadcast channel 601. At this time, the demodulation unit 101 receives and demodulates only the TDM data of the program A (607).

  In this reception, the background reception process in the period 609 is performed in the reception period 602 of the program A, the demodulator 101 demodulates the programs B to F in the period 609, and the CPU 107 stores them in the buffer.

  Here, when a reception request for program B occurs at time 603, the image cannot be displayed until the TDM data of program B is received in the flowchart of FIG. 3, but program B is received in the flowchart of FIG. 5. Until the time 608, the image of the program B acquired by background reception in the period 609 can be immediately displayed in the period 610. Similarly, when a reception request for program C occurs at time 605, the program C data acquired by background reception in period 609 can be displayed immediately in period 611 until TDM data for program C is received. Is possible.

  In the flowchart of FIG. 5, an image of the corresponding program can be displayed immediately in response to the occurrence of a user program switching request, and the user's expectation for high-speed program switching display can be satisfied.

  However, in order to acquire data to be displayed at high speed, it is necessary to periodically perform background reception processing regardless of whether or not there is a user program switching request. For this reason, power consumption increases by the amount of periodic background reception.

  Hereinafter, an embodiment of a demodulator that can reduce power consumption and can respond to a viewing program switching instruction at high speed will be described.

(First embodiment)
FIG. 7 is a block diagram showing a configuration example of a terrestrial digital broadcast demodulator for TDM portable terminals according to the first embodiment of the present invention. The bus 700 includes a MAC unit 702, a video decoder 703, an audio decoder 705, a CPU 707, a ROM 708, a RAM 709, a program switching detection unit 711, a program switching time interval measurement unit 712, a viewing program information holding unit 715, and a program switching processing detection unit. 716 is connected.

  The demodulator 701 is a block that receives broadcast waves and performs demodulation processing on digital data. A MAC unit (Media Access Controller) 702 is a control unit that controls on / off of an operation power supply when the demodulation unit 701 receives TDM by a control signal 720. The demodulation unit 701 and the MAC unit 702 are blocks that form the basis of the TDM reception process.

  The video decoder 703 is a block that acquires a video stream from the data demodulated by the demodulation unit 701 and the MAC unit 702, and performs a decoding process. The video display device 704 is a block that displays the video data decoded by the video decoder 703, and corresponds to a liquid crystal display or the like.

  The audio decoder 705 is a block that acquires an audio stream from the data demodulated by the demodulation unit 701 and the MAC unit 702 and performs decoding processing. The audio output device 706 is a block that outputs the audio data decoded by the audio decoder 705, and corresponds to a speaker.

  The CPU 707 is a block that drives the firmware of the demodulation device and controls the entire demodulation device. The ROM 708 is a block for storing the firmware driven by the CPU 707 and the binary code of the control software for the entire demodulator. The RAM 709 is used as a buffer for buffering data demodulated by the demodulation unit 701 and the MAC unit 702, or as a work area for firmware.

  The program switching button 710 corresponds to a button for the user to instruct switching of the viewing program. The program switching detection unit 711 is a block that detects a user input operation to the program switching button 710 and notifies the CPU 707 of the information.

  The program switching time interval measurement unit 712 receives a switching instruction for a currently input viewing program and a switching instruction for a viewing program input immediately before it, in order to detect whether there is a frequent request for switching the viewing program of the user. Measure the time interval. In addition, in response to the currently inputted viewing program switching instruction, the timeout until the next viewing program switching instruction is also measured.

  The timer 713 is a timer used in the program switching time interval measuring unit 712. The timer 713 includes a timer for measuring the time interval between the currently input viewing program switching instruction and the immediately preceding viewing program switching instruction, and program switching when all the programs are continuously received. It has a timer for detecting a timeout and a timer for detecting a timeout of program switching when receiving a plurality of specific programs.

  The timeout threshold storage unit 714 stores a threshold for a timer value for detecting a timeout of the timer 713. The stored threshold values are a threshold value for determining a timeout for a process for continuously receiving all programs and a threshold value for determining a timeout for a process for receiving a plurality of specific programs. The timeout threshold for the process of continuously receiving all the programs is desirably a threshold of the order of several tens of seconds in order to cope with the viewing program switching in a short time. In addition, it is desirable that the timeout threshold for the process of receiving a plurality of specific programs is on the order of ten or more in order to correspond to the process of switching by viewing for a certain period.

  The viewing program information holding unit 715 holds information on a program that has been instructed to switch (information corresponding to a viewing channel such as a program ID). The program information held in the viewing program information holding unit 715 gives information for determining which program is demodulated when receiving a plurality of specific programs. The holding of the program information in the viewing program information holding unit 715 is held when the viewing program is switched from the user. When the timer 713 detects a time-out or when it is determined that the normal program switching does not correspond to an operation of continuously receiving all programs or an operation of receiving a plurality of specific programs, the timer 713 holds this. The information on the viewing program is cleared.

  The program switching process detection unit 716 continuously receives all programs or receives only a plurality of specific programs from the viewing program switching instruction time interval measured by the program switching time interval measurement unit 712. Whether or not normal viewing program switching which is neither of them is determined. This determination is performed by comparing the time interval measured by the program switching time interval measuring unit 712 with the program switching threshold set in the program switching threshold storage unit 717.

  The program switching threshold storage unit 717 stores a threshold used for determination by the program switching process detection unit 716. The stored threshold values are a threshold value for determining whether to perform a process of continuously receiving all programs and a threshold value for determining whether to receive a plurality of specific programs. The threshold value for determining whether to perform the process of continuously receiving all the programs is preferably a threshold value on the order of several seconds in order to cope with the switching of the viewing program in a short time. Further, it is desirable that the threshold for determining whether or not to receive a plurality of specific programs be on the order of several minutes in order to correspond to a process of switching by viewing for a certain period.

  When the program switching process detection unit 716 detects a program switching process, the information is notified to the MAC unit 702. The MAC unit 702 performs a process of continuously receiving all the programs notified from the program switching process detection unit 716, receives a plurality of specific programs, or demodulates according to an instruction of normal program switching. Power on / off control of the unit 701 is performed.

  The functions indicated by blocks 712 to 717 may be implemented as hardware or software operating on the CPU 707.

  8 and 9 are flowcharts showing a processing method of the demodulating device of FIG. First, the TDM reception flow in the normal reception mode in which the viewing program is not switched will be described. It is assumed that the program switching button 710 is instructed to switch the program to be viewed by the user's operation in step 801 by activating the demodulator.

  Next, in step 802, the MAC unit 702 turns on the power of the demodulating unit 701 so as to receive all programs on the TDM broadcast channel.

  Next, in step 803, the CPU 707 detects reception of TDM data of the program to be viewed from all TDM programs being received. If not, in step 810, the CPU 707 checks whether there is data to be viewed in the buffer (RAM) 709. Immediately after startup, since there is no program data to be viewed in the buffer 709, the CPU 707 is searching for a program in the video display device 704 during a period when TDM data of the program to be viewed is not detected. Is displayed. Thereafter, the process returns to step 803.

  When reception of TDM data to be viewed in step 803 is detected, in step 804, the demodulator 701 performs a viewing program demodulation process.

  Next, in step 805, the CPU 707 checks whether there is a program switching instruction from the user using the program switching button 710. If there is no program switching instruction from the user, the demodulator 701 completes the demodulation of the viewing program, and proceeds to step 806 during a period in which another program is received. If there is a program switching instruction from the user, the process proceeds to step 814. In step 806, the MAC unit 702 turns off the power of the demodulation unit 701.

  Next, in step 807, the CPU 707 checks whether there is a program switching instruction from the user using the program switching button 710. If there is no program switching instruction from the user, the process proceeds to step 808. If there is a program switching instruction from the user, the process proceeds to step 814.

  In step 808, the CPU 707 detects whether the off-time period during which another program is received has expired. If it is not the off-time period in which the viewing program is still received, the process returns to step 807 to continue the off-time detection process.

  When the end of the off-time period is detected and the viewing program is received, the MAC unit 702 turns on the power of the demodulating unit 701 in step 809 and returns to step 804 to start receiving TDM data of the viewing program. To do.

  The loop of steps 804 to 809 represents the TDM reception process. During this loop period, the CPU 707 displays the image data of the program demodulated in step 804 on the video display device 704.

  Next, a description will be given of the reception flow in the continuous reception mode in which switching of viewing programs occurs one after another in a short time in order to search for a program to be viewed among the switching of viewing programs in FIG.

  When normal TDM reception processing is performed in the loop of steps 804 to 809, if the CPU 707 detects a viewing program switching instruction in step 805 or 807, in order to receive a new viewing program, in step 814 The MAC unit 702 turns on the power of the demodulation unit 701.

  Next, when a viewing program switching request is generated, in step 815, the CPU 707 retains and stores in the viewing program information retaining unit 715 information on a program for which a viewing request is newly made (program ID corresponding to a general channel number or the like). To do.

  Next, in step 816, the program switching time interval measuring unit 712 measures the time from the last viewing program switching request to the current viewing program switching request. This uses the value of the timer started in step 817 in the viewing program switching request made immediately before.

  In step 817, the CPU 707 starts a switching time measurement timer 713 for detecting the time for switching the next viewing program.

  Next, in step 818, the CPU 707 checks whether or not the switching instruction time interval measured in step 816 is less than or equal to the short-time switching threshold value. The switching instruction time interval measured in step 816 indicates the time interval between the switching instruction by the previous program switching button 710 and the switching instruction by the current program switching button 710. Here, the short-time switching threshold value is a threshold value for detecting whether or not a program switching instruction is issued in a short time in order to search for a program that the user wants to view and is stored in the program switching threshold storage unit 717. Yes.

  If it is detected that the switching instruction time interval measured in step 816 is less than or equal to the short-time switching threshold, it is determined that a program switching instruction is issued in a short time in order to search for a program to be viewed, and all programs are continuously executed. In order to enter the continuous reception mode process for receiving automatically, the process proceeds to step 819.

  In step 819, the demodulation unit 701 stops the TDM reception in the normal reception mode, and enters a process of continuously demodulating all the programs.

  Next, in step 820, the CPU 707 checks whether there is a program switching instruction from the user using the program switching button 710. If there is no program switching instruction from the user, the process proceeds to step 821. If there is a program switching instruction from the user, the process returns to step 814.

  Next, in step 821, the CPU 707 checks whether or not the value of the switching time measurement timer 713 exceeds the continuous reception timeout threshold. If exceeded, the process proceeds to step 842, and if not, the process proceeds to step 822. The continuous reception timeout threshold value is stored in the timeout threshold storage unit 714.

  In step 822, the CPU 707 checks whether a viewing program is being received. If it is being received, the process proceeds to step 823, and if it is not being received, the process proceeds to step 824.

  For example, if the TDM data to be viewed has not been received and demodulated immediately after switching of the viewing program, the process proceeds to step 824.

  In step 824, the CPU 707 checks whether there is program data to be viewed in the buffer 709. In step 824, if there is viewing program data in the buffer 709, in step 825, the CPU 707 displays the data in the buffer 709 on the video display device 704 for a while, and the process proceeds to step 819. Receiving and demodulating TDM data of the program.

  If there is no viewing program data in the buffer 709 in step 824, the CPU 707 displays on the video display device 704 that the program search is being performed in step 826, and the process proceeds to step 819. The TDM data is received and demodulated.

  If the TDM data of the viewing program has already been received and demodulated in step 822, in step 823, the CPU 707 displays the received and demodulated received video on the video display device 704, proceeds to step 819, and demodulator 701. Receives and demodulates the TDM data of the viewing program. Then, the processing of steps 819 to 823 is repeated. The processes in steps 819 to 823 are processes for continuously receiving and demodulating all the programs.

  If a viewing program switching instruction is received in step 820 during the processing of steps 819 to 823, the processing returns to step 814 again, and processing for switching the viewing program in steps 814 to 818 is performed in the same manner as described above. I do.

  If it is determined in step 818 that the switching instruction time interval is equal to or shorter than the short-time switching threshold, it can be determined that the program switching instruction in a short time is continued by the user, and the processing in steps 814 to 820 is performed again. repeat.

  If a timeout occurs in response to a program switching instruction for the process of continuously demodulating all the programs in step 821 during the processes in steps 819 to 823, the viewing program stored in step 815 by the CPU 707 in step 842. And the process returns to the TDM reception process in the normal reception mode in step 804. This process represents a process in which a user who has been looking for a viewing program finds a program that the user wants to view and enters the viewing of the program.

  FIG. 10 is a time chart showing an outline of the reception operation in the continuous reception mode in which all the programs shown above are continuously received. It is assumed that programs A to F are broadcast on TDM broadcast channel 901 by TDM.

  In this broadcast, it is assumed that the program A is being received in the period 902. This period 902 is a processing period of only the TDM data 908 of the program A, and performs reception and demodulation processing.

  If a program C reception request occurs at time 903, the program switching instruction time interval is determined in step 818 of FIG. At this time, only the program A is received before the program C reception request at the time 903, and the program switching instruction time interval is larger than the short-time switching threshold value. When the TDM data 909 of the program C is received without entering, the demodulated image of the program C is displayed.

  Next, when a reception request for the program F at time 904 occurs, in step 816 in FIG. 9, the switching instruction time interval from the program C reception request at time 903 to the program F reception request at time 904 is measured. If it is determined in step 818 in FIG. 9 that this switching instruction time interval is equal to or shorter than the short-time switching threshold, processing in the continuous reception mode for all programs is started from time 913.

  As for the reception example in the continuous reception processing period 914 for all programs, for the program F reception request at time 904, the TDM data of program F at time 910 immediately after that is received and demodulated, and the program D reception request at time 905 is received. For the above, the TDM data of the program D at the time 911 immediately after that is received and demodulated.

  Here, when the program B reception request at time 906 occurs, the program B data already received by continuous reception is acquired from the buffer 709 and displayed for a period until the TDM data 912 of the program B is received. It becomes possible to obtain a fast screen switching display in response to a program switching request.

  When there is no program switching request for a while from the program B reception request at time 906, a continuous reception timeout at time 915 is detected, and the processing returns to the normal reception mode processing at period 907.

  Next, the reception flow in the multiple program reception mode in which the viewing program switching such that the viewing is performed while alternately switching the plurality of programs among the viewing program switching in FIGS. 8 and 9 will be described.

  When TDM reception processing in the normal reception mode is performed in the loop of steps 804 to 809, if a viewing program switching instruction is detected in step 805 or 807, in order to receive a new viewing program, in step 814, The MAC unit 702 turns on the power of the demodulation unit 701.

  When a viewing program switching request is generated, in step 815, the CPU 707 holds and stores information on a program for which a viewing request is newly made (generally, a program ID corresponding to a channel number, etc.).

  In step 816, the program switching time interval measuring unit 712 measures the time from the most recent viewing program switching request to the current viewing program switching request. This uses the value of the timer started in step 817 in the viewing program switching request made immediately before.

  In step 817, the CPU 707 starts a switching time measurement timer 713 for detecting the time for switching to the next viewing program.

  In step 818, the CPU 707 checks whether or not the switching instruction time interval measured in step 816 is equal to or shorter than the short-time switching threshold. Here, the short-time switching threshold value is a threshold value for detecting whether or not a program switching instruction is given in a short time in order to search for a program that the user wants to view. When viewing a program while alternately switching a plurality of programs, the time interval of the program switching request becomes longer than the time interval of the program switching request when searching for the program to be viewed. Therefore, it is detected that the switching instruction time interval measured in step 816 is larger than the short-time switching threshold.

  In step 827, it is checked whether or not the switching instruction time interval measured in step 816 is less than or equal to the long-time switching threshold. Here, the long-time switching threshold value is a threshold value for detecting whether or not a program switching instruction is given in a long time for alternately viewing a plurality of programs, and is stored in the program switching threshold value storage unit 717. ing. If it is detected that the switching instruction time interval measured in step 816 is less than or equal to the long-time switching threshold, it is determined that the program switching instruction is given in a long time in order to view a plurality of programs alternately. The multi-program receiving mode process for receiving a plurality of programs is started.

  In step 828, the CPU 707 checks whether the data of the currently requested program is in the buffer 709. If there is already program data requested to be received in the buffer 709, the CPU 707 displays the program data in the buffer 709 on the video display device 704 in step 829, thereby realizing high-speed screen switching. To do. If the data of the program requested to be received does not exist in the buffer 709, in step 830, the CPU 707 displays on the video display device 704 that the received program is being searched.

  Next, in step 831, the CPU 707 checks whether there is a program switching instruction from the user using the program switching button 710. If there is no program switching instruction from the user, the process proceeds to step 832. If there is a program switching instruction from the user, the process returns to step 814.

  In step 832, the CPU 707 checks whether or not the value of the switching time measurement timer 713 exceeds the multiple program reception timeout threshold. If exceeded, the process proceeds to step 842, and if not exceeded, the process proceeds to step 833. The multiple program reception timeout threshold is stored in the timeout threshold storage unit 714.

  In step 833, the demodulation unit 701 performs reception and demodulation processing of TDM data of a program that is currently requested for viewing.

  Next, in step 834, the CPU 707 checks whether there is a program switching instruction from the user using the program switching button 710. If there is no program switching instruction from the user, the process proceeds to step 835. If there is a program switching instruction from the user, the process returns to step 814.

  Next, in step 835, the CPU 707 checks whether or not the value of the switching time measurement timer 713 has exceeded the multiple program reception timeout threshold. If exceeded, the process proceeds to step 842, and if not exceeded, the process proceeds to step 836. During the off-time period when the demodulator 701 completes the demodulation of the viewing program and receives other programs, the MAC unit 702 turns off the power of the demodulator 701 in step 836.

  Next, in step 837, the CPU 707 checks whether or not it is a period for receiving a program of another ID held in step 815. If it is the reception period, the process proceeds to step 838, and if it is not the reception period, the process proceeds to step 840.

  If there is an ID of another program held in step 815, the MAC unit 702 turns on the power of the demodulator 701 in step 838 during the off-time period in which TDM data of this other program is received.

  Next, in step 839, the demodulator 701 performs demodulation processing of TDM data of the other ID program held in step 815. If the demodulation processing of another program is completed, the process returns to step 834, and the MAC unit 702 turns off the power of the demodulation unit 701 again in step 836. The processing of step 837 is performed until all of the TDM data of other programs held in step 815 are completely demodulated during the off-time period of the program that is currently requested to view.

  In step 840, the CPU 707 detects the end of the off-time period of the program that is currently requested for viewing. If it is detected that the off-time period has ended, the MAC unit 702 turns on the power of the demodulator 701 in step 841, returns to step 833, and the demodulator 701 again performs the demodulating process of the program that is currently requested to view. Do. Then, the reception and demodulation processes from step 833 to step 841 are repeated. If the off-time period has not ended, the process returns to step 834.

  When a viewing program switching instruction is generated in step 831 or when a viewing program switching instruction is generated in step 834 during the reception and demodulation processing of step 833 to step 841, the process returns to step 814 again. In the same manner as in the case of the above, the process of instructing switching of the viewing program in steps 814 to 827 is performed.

  If it is determined in step 827 that the switching instruction time interval is equal to or shorter than the long-time switching threshold, it can be determined that the process of alternately viewing a plurality of programs by the user is continued, and again from step 828 to step 828. After the process 832, the processes of steps 833 to 841 are repeated.

  If a time-out occurs in step 832 or in step 837 in the processing of steps 834 to 841, a process for receiving a plurality of specific programs alternately occurs, in step 842, the viewing program held in step 815 is stored. The ID information is deleted, and the process returns to the normal TDM reception process in step 804. This process represents a process in which a user who has alternately viewed a plurality of programs has started viewing only one specific program.

  FIG. 11 is a time chart showing an outline of the reception operation in the multiple program reception mode for receiving the specific multiple programs shown above. It is assumed that programs A to F are broadcast on TDM broadcast channel 1001 by TDM.

  In this broadcast, it is assumed that the program A is being received in the period 1002. This period 1002 is a processing period for only the TDM data 1007 of the program A, and performs reception and demodulation processing.

  If a reception request for the program E at time 1003 is generated, the program switching instruction time interval is determined in step 827 of FIG. At this time, only the program A is received before the program E reception request at time 1003, and the program switching instruction time interval is larger than the long-time switching threshold value. First, when the TDM data 1008 of the program E is received, the demodulated image of the program E is displayed. However, the ID of the program E is held in step 815 of FIG.

  Next, when a reception request for program A at time 1004 occurs, in step 816 in FIG. 9, the switching instruction time interval from the program E reception request at time 1003 to the program A reception request at time 1004 is measured. If it is determined in step 827 of FIG. 8 that this switching instruction time interval is equal to or shorter than the long-time switching threshold, processing in a reception mode for a specific plurality of programs is started from time 1011.

  Further, in step 815 of FIG. 9, the ID of the program A is held when the reception request of the program A at time 1004 is requested. As a result, the TDM reception process for the programs A and E is executed in the period 1012 for receiving a plurality of specific programs.

  In response to the program A reception request at time 1004, if there is an image of program A in the buffer 709 during step 828 in FIG. 9 until the TDM data 1009 of program A is demodulated, that image is displayed, and the buffer 709 is displayed. If there is no image of program A, a message indicating that the program search is in progress is displayed.

  In a period in which a plurality of specific programs in period 1012 are received, TDM data of programs A and E is demodulated. Therefore, when a reception request for the program E at time 1005 is generated, the TDM data 1013 of the program E that has already been received is displayed in step 1014 until the TDM data 1010 of the program E is received. On the other hand, high-speed image display is possible.

  Similarly, in response to the program A reception request at time 1006, the TDM data 1015 of the program A that has already been received is displayed in step 1016 until the TDM data of the program A is received. On the other hand, high-speed image display is possible.

  The reception flow in the normal reception mode in which the switching of the normal single viewing program, which is not the continuous program switching request, occurs when the viewing program switching in FIGS. 8 and 9 occurs.

  When a viewing program switching request is generated, the MAC unit 702 turns on the power of the demodulating unit 701 in step 814 to receive another program. When switching to another program during normal viewing in steps 804 to 808, the switching instruction time interval becomes larger than the threshold values in steps 818 and 827. Therefore, in step 843, the viewing request viewing program ID held in step 815 is deleted, and then step 810 is reached.

  In step 810, if there is data of a program for requesting switching in the buffer 709, the CPU 707 displays an image of the data on the video display device 704 in step 811, and enters the viewing program reception detection process in step 803.

  In step 810, if there is no switching request program data in the buffer 709, the CPU 707 displays on the video display device 704 that the search is being performed in step 812, and enters the viewing program reception detection processing in step 803.

  In the present embodiment, a high-speed program switching response is made when a user makes a frequent program switching request while maintaining the operation with low power consumption, which is a feature of the digital broadcast demodulating device based on TDM, throughout the reception processing. Can be realized.

  This embodiment is a control method having the following features. The operation in the normal reception mode for receiving only the viewing program shown in FIG. 2 is performed in a period in which the user continues to watch a certain program without performing a program switching operation. Whether the user requests to switch between programs one after another in a short time such as searching for a program to watch or zapping by detecting the interval of the program switching operation when the user performs the program switching operation It has a function to detect. This detection measures the interval between button presses when a user switches programs, and determines that a plurality of programs are switched in a short time when it is determined that the period is shorter than a preset threshold. Can do.

  When the demodulator determines that the user is switching between multiple programs in a short period of time, it stops normal reception mode operation and continues all programs, including programs with viewing instructions and other programs. Switch to receiving operation automatically. All programs received and demodulated continuously are stored in the buffer 709 of the demodulator. Data other than the program that is currently instructed to be viewed is updated in the buffer 709 every time new TDM data is demodulated by continuous reception.

  A TDM demodulator that performs continuous reception processing during a period in which it is detected that a user is switching between a plurality of programs in a short period of time until receiving and demodulating TDM data of a program instructed to be viewed by the user In the meantime, the reception and demodulation are already completed by the continuous reception process, and the data held in the buffer 709 is displayed, thereby realizing high-speed screen switching.

  A TDM demodulator that performs continuous reception watches a specific program when it detects that the interval between user program switching operations exceeds a predetermined time. And transition from the continuous reception state to the TDM reception state.

  The continuous reception process during the period in which it is detected that the user is switching between a plurality of programs in a short time has two operation modes: a continuous reception mode and a multiple program reception mode.

  The continuous reception mode is a reception mode in which program switching processing is performed one after another in a very short time of about several seconds in order to search for a program to be viewed. At this time, the TDM demodulator continuously receives all programs regardless of the viewing channel designated by the user.

  The multiple program reception mode is a mode for receiving a specific plurality of programs. This is control for realizing high-speed program switching when, for example, two programs are viewed alternately. Unlike the case of searching for a program to be viewed in the continuous reception mode, this viewing is performed by switching from one program to another while viewing one program for a relatively long time.

  In the control operation in the multiple program reception mode, in addition to the program information currently being viewed, program information instructed to be viewed immediately before is retained, TDM reception is performed for these two programs, and the data is stored in the buffer 709. Hold. This reception makes it possible to realize high-speed screen switching even when switching from the currently viewed program to the program that was viewed immediately before.

  Also, the multiple program reception mode can be adapted to high-speed switching of three or more programs by increasing the number of viewing program information to be held.

  Switching between the continuous reception mode and the multiple program reception mode is determined according to the interval of the user's program switching instruction. About the threshold of the interval of the program switching operation of the user who detects that continuous reception is being performed, a short threshold for detecting the case where the program switching processing is performed one after another in a very short time of about several seconds described above, Detection is possible by preparing a long threshold value for detecting a case where two programs are viewed alternately. When neither of these threshold values is satisfied, it is determined that the user program switching process has been completed, and the process proceeds to the normal reception mode process.

  According to the present embodiment, by introducing a program switching instruction detection function of the user, the normal reception mode is operated when only a certain program is viewed, and the user switches the program at a short interval. By continuously receiving only a certain period, it is possible to suppress power consumption when viewed as a whole viewing period, and to enable a high-speed screen switching response to a user's program switching request.

  The demodulating device according to the present embodiment can be applied to a portable receiving terminal that performs data transmission using DVB-H standard or MediaFLO standard TDM, or a receiving terminal of a wireless device that employs the TDM transmission method.

  As described above, the demodulating device according to the present embodiment detects the interval between the program switching operation unit (button) 710 for operating the viewing program switching instruction and the viewing program switching instruction operation by the program switching operation unit 710. A program switching interval detection unit (program switching time interval measurement unit) 712 and a demodulation unit 701 that inputs and demodulates a plurality of viewing programs received by time division multiplexing (TDM). The control unit (MAC unit) 702 controls the demodulation unit 701 as the first mode (normal reception mode) when the switching instruction operation interval detected by the program switching interval detection unit 712 is longer than the first interval threshold. When the interval of the switching instruction operation detected by the program switching interval detector 712 is shorter than the first interval threshold, the demodulator 701 is controlled as the second mode (continuous reception mode or multiple program reception mode).

  In the first mode (normal reception mode), the control unit 702 turns on the power of the demodulation unit 701 when a viewing program instructed to be switched by the program switching operation unit 710 is input, and other viewing programs are input. When the power is lost, the power of the demodulator 701 is turned off. In addition, in the second mode (continuous reception mode or multiple program reception mode), the control unit 702 at least the viewing program instructed to be switched last by the program switching operation unit 710 and the viewing instructed to be switched this time by the program switching operation unit 710. When the program is input, the demodulator 701 is turned on.

  Further, in the second mode (multiple program reception mode), the control unit demodulates when a plurality of viewing programs instructed to be switched by the program switching operation unit 710 are input during the period of the continuous second mode. The power source of the demodulator 701 is turned off when the power source of the video source 701 is turned on and other viewing programs are input.

  In the second mode (continuous reception mode), the control unit 702 turns on the power of the demodulation unit 701 when all viewing programs received by time division multiplexing are input.

  Further, the control unit 702 controls the demodulating unit 701 as the first mode (normal reception mode) when the interval of the switching instruction operation detected by the program switching interval detecting unit 712 is longer than the first interval threshold, and the program switching When the interval of the switching instruction operation detected by the interval detection unit 712 is shorter than the first interval threshold (long-time switching threshold) and longer than the second interval threshold (short-time switching threshold), the second mode (multiple programs) The demodulator 701 is controlled as a reception mode), and the demodulator 701 is controlled as a third mode (continuous reception mode) when the switching instruction operation interval detected by the program switching interval detector 712 is shorter than the second interval threshold. To do. In the second mode (multiple program reception mode), the control unit 702 demodulates when a plurality of viewing programs instructed to be switched by the program switching operation unit 710 are input during the continuous second mode. The power of the unit 701 is turned on, and when the other viewing program is input, the power of the demodulator 701 is turned off. In the third mode (continuous reception mode), the control unit 702 turns on the power of the demodulation unit 701 when all viewing programs received by time division multiplexing are input.

  A buffer (RAM) 709 buffers the viewing program demodulated by the demodulator 701 in the second mode (multiple program reception mode or continuous reception mode). The display unit (video display device) 704 reads the viewing program instructed by the program switching operation unit 710 from the buffer 709 and displays it.

  According to the present embodiment, by controlling the power supply of the demodulator 701 according to the interval of the viewing program switching instruction operation, the power consumption can be reduced and the viewing program switching instruction can be responded at high speed. Can do.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

700 Bus 701 Demodulator 702 MAC 703 Video decoder 704 Video display device 705 Audio decoder 706 Audio output device 707 CPU
708 ROM
709 RAM
710 Program switching button 711 Program switching detection unit 712 Program switching time interval measurement unit 713 Timer 714 Timeout threshold storage unit 715 Viewing program information holding unit 716 Program switching processing detection unit 717 Program switching threshold storage unit

Claims (5)

A program switching operation unit for operating a viewing program switching instruction;
A program switching interval detection unit that detects an interval of a viewing program switching instruction operation by the program switching operation unit;
A demodulator that performs demodulation by inputting a plurality of viewing programs received by time division multiplexing;
When the interval of the switching instruction operation detected by the program switching interval detector is longer than a first interval threshold, the demodulator is controlled as a first mode, and the switching instruction operation detected by the program switching interval detector is A control unit that controls the demodulation unit as a second mode when the interval is shorter than the first interval threshold;
The controller is
In the first mode, the power of the demodulator is turned on when a viewing program received by time division multiplexing instructed by the program switching operation unit is input, and when a viewing program other than that is input, Turn off the power to the demodulator,
In the second mode, at least when a viewing program received in time division multiplex that has been instructed to be switched at the previous time by the program switching operation unit and is not instructed to be switched this time is input, and this switching instruction is performed by the program switching operation unit. When a viewing program received by time division multiplexing is input, the demodulator is turned on,
The demodulator
In the first mode, a viewing program received by time division multiplexing instructed to be switched by the program switching operation unit is input and demodulated, and other viewing programs are not demodulated,
In the second mode, at least the viewing program received in the time division multiplex that has been instructed to be switched last time by the program switching operation unit and has not been instructed to switch this time, and the time division multiplex that has been instructed to switch this time by the program switching operation unit. A demodulating device for receiving and demodulating a viewing program to be received . In the second mode, the control unit receives a viewing program received by time division multiplexing that has been instructed to be switched last time by the program switching operation unit and is not instructed to switch this time, and by the program switching operation unit. Turn on the power of the demodulator when a viewing program received in time division multiplex instructed to switch this time is input, turn off the power of the demodulator when a viewing program other than that is input ,
In the second mode, the demodulating unit is instructed to switch by the program switching operation unit last time and is not instructed to switch this time by the time division multiplex viewing program, and the program switching operation unit is instructed to switch this time. 2. The demodulator according to claim 1, wherein a viewing program received by time division multiplexing is input and demodulated, and other viewing programs are not demodulated. In the second mode, the control unit turns on the power of the demodulation unit when all viewing programs received by the time division multiplexing are input ,
2. The demodulator according to claim 1 , wherein in the second mode, the demodulator inputs and demodulates all viewing programs received by the time division multiplexing . The controller is
When the interval of the switching instruction operation detected by the program switching interval detector is longer than a first interval threshold, the demodulator is controlled as a first mode, and the switching instruction operation detected by the program switching interval detector is When the interval is shorter than the first interval threshold and longer than the second interval threshold, the demodulator is controlled as a multiple program reception mode, and the interval of the switching instruction operation detected by the program switching interval detector is the first When it is shorter than the interval threshold of 2, the demodulator is controlled as a continuous reception mode,
In the multiple program reception mode, when a viewing program received by time-division multiplexing that was previously instructed to be switched by the program switching operation unit and not instructed to be switched this time is input, and this program switching operation unit is instructed to switch this time When a viewing program received by time division multiplexing is input, the demodulator is turned on.When other viewing program is input, the demodulator is turned off.
In the continuous reception mode, when all viewing programs received by the time division multiplexing are input, the power of the demodulator is turned on,
The demodulator
In the multiple program reception mode, a viewing program received by time division multiplexing that was previously instructed by the program switching operation unit and not currently instructed to be switched, and received by time division multiplexing that has been instructed by the program switching operation unit this time. Enter the viewing program to be demodulated, do not demodulate the other viewing program,
The demodulator according to claim 1, wherein in the continuous reception mode, all viewing programs received by the time division multiplexing are input and demodulated. Furthermore, in the second mode, a buffer for buffering the viewing program demodulated by the demodulator,
5. The demodulator according to claim 1, further comprising: a display unit that reads out the viewing program instructed to be switched by the program switching operation unit from the buffer and displays the program.

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