JP4674049B2 - Terrestrial digital broadcast reception system - Google Patents

Description

  The present invention relates to terrestrial digital broadcasting technology.

  Patent Document 1 discloses a digital broadcast receiver that converts the level of a ghost wave and an adjacent disturbance wave of a terrestrial digital broadcast signal into image display data and outputs the image display data.

JP 2002-135808 A

  By the way, since the in-vehicle television broadcast receiver compatible with terrestrial digital broadcasting is mounted on a vehicle and used, the reception environment of the terrestrial digital broadcast signal changes according to the movement of the vehicle. For this reason, the reception environment of the terrestrial digital broadcast signal may deteriorate, and video data (broadcast content) may not be demodulated from the received terrestrial digital signal. When the video data cannot be demodulated, the video on the display device is suddenly cut. Such a situation may cause the user to misunderstand that the receiver has failed. In the technique described in Patent Document 1, the user can know these levels by displaying the image display data obtained by converting the levels of the ghost wave and the adjacent disturbance wave on the screen. However, if the video on the display device is interrupted unexpectedly, the user will still be surprised.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent a user from feeling that a video output from a terrestrial digital broadcast receiver has suddenly been cut off.

  In order to solve the above-described problem, a first aspect of the present invention is a video signal obtained by demodulating a received terrestrial digital broadcast signal when the electric field strength of the received terrestrial digital broadcast signal is lower than a predetermined threshold. Alternatively, or together with the video signal, predetermined display data is output to the display device.

For example, a first aspect of the present invention is a terrestrial digital broadcast receiving system that demodulates and outputs a video signal and an audio signal from a terrestrial digital broadcast signal. Video buffer means for buffering and sequentially outputting; display data storage means for storing predetermined display data; field strength of reception channel for terrestrial digital broadcast signal; and video signal buffered in the video buffer means A main control means for detecting the data amount, and when the electric field strength and the data amount are equal to or greater than a predetermined threshold, the video signal output from the video buffer means is output, and the electric field strength, And display control for outputting the predetermined display data when at least one of the data amounts is less than a predetermined threshold value. It has a stage, a.

According to a second aspect of the present invention, there is provided a terrestrial digital broadcast receiving system that demodulates and outputs a video signal and an audio signal from a terrestrial digital broadcast signal. Video buffer means for buffering and sequentially outputting; display data storage means for storing predetermined display data; field strength of reception channel for terrestrial digital broadcast signal; and video signal buffered in the video buffer means A main control means for detecting the data amount, and when the electric field strength and the data amount are equal to or greater than a predetermined threshold, the video signal output from the video buffer means is output, and the electric field strength, When at least one of the data amounts is less than a predetermined threshold value, the video signal output from the video buffer means is And a display control means for mixing and outputting the predetermined display data.

The third aspect of the present invention outputs an acoustic signal demodulated from a terrestrial digital broadcast signal when the electric field strength and the data amount are equal to or greater than a predetermined threshold value, and the electric field strength, When at least one of the data amounts is less than a predetermined threshold value, the apparatus further includes acoustic control means for mixing and outputting a predetermined noise to the acoustic signal demodulated from the terrestrial digital broadcast signal.

  Here, the predetermined display data is output to the display device when the reception state of the broadcast signal is poor in the analog broadcast receiver, for example, display data that suggests to the user that the terrestrial digital broadcast video may be interrupted. It may be data representing noise. In addition, when displaying predetermined display data together with video data of terrestrial digital broadcasting, for example, in the peripheral portion of the display screen of the display device, the predetermined display data is made translucent and superimposed with video data of terrestrial digital broadcasting. It is good to display.

  According to the present invention, when the possibility that the terrestrial digital broadcast video is interrupted increases due to the above configuration, the display device that displays the video has a predetermined indication that suggests that the video may be interrupted. Display data is displayed. Thereby, it can prevent that a user feels that the image | video of the terrestrial digital broadcasting receiver cut suddenly.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a schematic diagram of a terrestrial digital broadcast receiving system to which an embodiment of the present invention is applied. As shown in the figure, the terrestrial digital broadcast receiving system of the present embodiment includes an antenna 1, a terrestrial digital broadcast receiver 2, an AV controller 3, a speaker 4, and a display 5.

  The terrestrial digital broadcast receiver 2 restores a digital audio signal and a digital video signal from the terrestrial digital signal received by the antenna 1 and outputs them to the AV controller 3. As shown in the figure, the terrestrial digital broadcast receiver 2 includes a tuner 21, an OFDM demodulator 22, a DEMUX (separator) 23, an audio decoder 24, a video decoder 25, and an electric field strength detector 26. Have.

  The tuner 21 selects a channel designated by the user via an input device (not shown) from the terrestrial digital broadcast signal received by the antenna 1. An OFDM (Orthogonal Frequency Division Multiplexing) demodulator 22 demodulates the OFDM modulated signal of the channel selected by the tuner 21 and outputs a TS (Transport Stream). The DEMUX 23 separates the TS output from the OFDM demodulator 22 into encoded audio data and encoded video data of broadcast content. The audio decoder 24 decodes the encoded audio data output from the DEMUX 23 and outputs a digital audio signal to the AV controller 3. The video decoder 25 decodes the encoded video data output from the DEMUX 23 and outputs a digital video signal to the AV controller 5. The electric field strength detection unit 26 detects the electric field strength level of the channel (carrier wave) selected by the tuner 21 and outputs the detected value to the AV controller 3.

  The AV controller 3 mixes a digital video signal indicating a predetermined display content with the digital video signal output from the terrestrial digital broadcast receiver 3 according to the reception state and demodulation state of the terrestrial digital broadcast signal, and displays the display 5 Output to. Further, a predetermined noise signal is mixed with the digital acoustic signal output from the terrestrial digital broadcast receiver 3 according to the state, and is output to the speaker 4. As illustrated, the AV controller 3 includes a video buffer 31, a suggestion data storage unit 32, a drawing processing unit 33, an acoustic processing unit 34, and a main control unit 35.

  The video buffer 31 is configured by, for example, FIFO (First In First Out), buffers the digital video signal output from the terrestrial digital broadcast receiver 2, and sequentially outputs the digital video signal to the drawing processing unit 34. The suggestion data storage unit 32 stores predetermined display data (referred to as suggestion data) that suggests to the user that the video of the terrestrial digital broadcast content may be interrupted. In the present embodiment, suggestion data for displaying noise on the frame portion of the display screen of the display 5 is stored in the suggestion data storage unit 32.

  The drawing processing unit 33 mixes the digital video signal output from the video buffer 31 and the suggestion data stored in the suggestion data storage unit 32 using, for example, an α blending technique in accordance with an instruction from the main control unit 35. And output to the display 5. In response to this, the display 5 D / A converts the digital video signal and displays the video on the display screen. When the display 5 is not equipped with a D / A conversion function, the display controller 3 is provided with a D / A converter, and the digital video signal is D / A converted into an analog video signal before being output to the display 5. You may make it do.

  The acoustic processing unit 34 superimposes a predetermined noise signal on the digital acoustic signal output from the terrestrial digital broadcast receiver 2 in accordance with an instruction from the main control unit 35, and outputs it to the speaker 4. In response, the speaker 4 D / A converts the digital acoustic signal and outputs the sound. When the speaker 4 is not equipped with a D / A conversion function, a D / A converter is provided in the terrestrial digital broadcast receiver 2 and the digital sound signal is converted into an analog sound signal. You may make it output to the speaker 4. FIG.

  The main control unit 34 monitors the data amount (buffering data amount) of the digital video signal buffered in the video buffer 31 and the electric field intensity level output from the terrestrial digital broadcast receiver 2. Then, according to the monitoring result, it is determined whether the digital video signal output from the video buffer 31 is output to the display 5 without being mixed with the suggestion data, or is mixed and output to the display 5, and the drawing processing unit Instruct 33. Similarly, according to the monitoring result, it is determined whether or not a predetermined noise signal is superimposed on the digital acoustic signal output from the terrestrial digital broadcast receiver 2 and output to the speaker 4, and an instruction is given to the acoustic processing unit 34. put out.

  FIG. 2 is a diagram for explaining the operation of the main control unit 34.

  The main control unit 35 monitors the electric field intensity level output from the terrestrial digital broadcast receiver 2 and the buffering data amount of the video buffer 31. When the electric field intensity level is lower than the threshold T1 (YES in S101), or when the buffering data amount is smaller than the threshold T2 (YES in S102), the mixing instruction is output to the drawing processing unit 33 and the acoustic processing is performed. A noise superposition instruction is output to the unit 34. Also, the previous output instruction registered in a memory or the like (not shown) is updated to a mixing instruction / noise superposition instruction (S104). Here, the threshold value T1 indicates that the reception state of the terrestrial digital broadcast signal is poor, and therefore the electric field strength of the terrestrial digital broadcast signal, which is considered to increase the possibility that the broadcast content cannot be demodulated from the received terrestrial digital broadcast signal. Set to level. This electric field strength level can be estimated based on theoretical values or experimental values. The threshold value T2 is set to a buffering data amount (for example, half the capacity of the video buffer 31) that is likely to cause the digital video signal output to the display 5 to be interrupted due to the video buffer 31 becoming empty.

  When the drawing processing unit 33 receives the mixing instruction from the main control unit 35, the digital video signal output from the video buffer 31 at a predetermined ratio (ratio) and the suggestion data stored in the suggestion data storage unit 32 Are output to the display 5. In response to this, the display 5 displays an image of the digital terrestrial broadcast content mixed with noise at a predetermined ratio in the frame portion 502 of the display screen 501 as shown in FIG. This mixing process is continued until a mixing stop instruction is received from the main control unit 35. Similarly, upon receiving a noise superimposition instruction from the main control unit 35, the sound processing unit 34 superimposes a predetermined noise signal on the digital sound signal output from the terrestrial digital broadcast receiver 2 and outputs the signal to the speaker 4. In response to this, the speaker 4 outputs the sound of the terrestrial digital broadcast content mixed with noise. This superimposition process is also continued until a noise superposition stop instruction is received from the main control unit 35.

  Also, the main control unit 35, when the electric field strength level output from the terrestrial digital broadcast receiver 2 is equal to or higher than the threshold T1, and the buffering data amount of the video buffer 31 is equal to or higher than the threshold T2 (S101, NO in 102) checks whether or not the previous output instruction registered in a memory or the like (not shown) is a mixing instruction / noise superposition instruction (S103). If the previous output instruction is a mixing instruction / noise superposition instruction (YES in S103), a mixing stop instruction is output to the drawing processing unit 33, and a noise superposition stop instruction is output to the acoustic processing unit 34. Also, the previous output instruction registered in a memory or the like not shown is updated to a mixing stop instruction / noise superposition stop instruction (S105). On the other hand, when the previous output instruction is not the mixing instruction / noise superposition instruction, that is, when the previous output instruction is the mixing stop instruction / noise superposition stop instruction (NO in S103), the main control unit 35 performs the rendering processing unit 33 and the sound. The process returns to S101 without outputting an instruction to the processing unit 34.

  When the drawing processing unit 33 receives the mixing stop instruction from the main control unit 35, the drawing processing unit 33 does not mix the digital video signal output from the video buffer 31 with the suggestion data stored in the suggestion data storage unit 32. Output to the display 5. In response to this, the display 5 displays an image of the digital terrestrial broadcast content in which noise is not intentionally mixed on the display screen 501 as shown in FIG. Similarly, when the sound processing unit 34 receives a noise superposition stop instruction from the main control unit 35, the sound processing unit 34 does not superimpose a predetermined sound signal on the digital sound signal output from the terrestrial digital broadcast receiver 2. Output to. In response to this, the speaker 4 outputs the sound of the terrestrial digital broadcast content that is not intentionally mixed with noise.

  The embodiment of the present invention has been described above.

  When the possibility that the video of the terrestrial digital broadcast content is interrupted increases, the AV controller 3 superimposes suggestion data indicating that the video may be interrupted on the video. Also, noise is superimposed on the acoustic data of the terrestrial digital broadcast content. This can prevent the user from feeling that the video of the terrestrial digital broadcast content has been suddenly cut.

  In addition, this invention is not limited to said embodiment, Many deformation | transformation are possible within the range of the summary.

  For example, in the above embodiment, the suggestion data stored in the suggestion data storage unit 32 is display data for displaying noise on the frame portion of the display screen of the display 5 as shown in FIG. However, the present invention is not limited to this. For example, as shown in FIG. 5, display data for displaying noise on the entire display screen of the display 5 may be used as suggestion data.

  In the above embodiment, the mixing instruction output from the main control unit 35 to the drawing processing unit 33 includes the digital video signal output from the video buffer 31 and the suggestion data stored in the suggestion data storage unit 32. The designation of the mixing ratio (ratio) is included, and the digital video signal output from the video buffer 31 and the suggestion data storage unit 32 at the ratio specified by the mixing instruction received from the main control unit 35 are displayed in the drawing processing unit 33. The suggestion data stored in the display 5 may be mixed and output to the display 5. Here, the mixing ratio is reduced as the electric field strength level output from the terrestrial digital broadcast receiver 2 decreases (in the case of YES in S101) or as the buffering data amount of the video buffer 31 decreases (YES in S102). ), Increase the proportion of suggestion data.

  Similarly, the noise superimposition instruction output from the main control unit 35 to the sound processing unit 34 includes the specification of the noise level, and is designated by the noise superimposition instruction received from the main control unit 35 to the drawing processing unit 33. It is also possible to superimpose the noise at the noise level being superimposed on the digital acoustic signal output from the terrestrial digital broadcast receiver 2 and output it to the speaker 4. Here, the noise level is lower as the electric field strength level output from the terrestrial digital broadcast receiver 2 is lower (in the case of YES in S101) or as the buffering data amount of the video buffer 31 is smaller (YES in S102). ), Make it bigger.

  In the above embodiment, the main control unit 35 generates display data indicating the electric field strength level output from the terrestrial digital broadcast receiver 2 or display data indicating the buffering data amount of the video buffer 31. The electric field strength level or the buffering data amount indicated by the display data is superimposed and displayed on a part (for example, one corner) of the display screen of the display 5. Alternatively, it may be superimposed on the digital video signal. FIG. 6 is an example in which a meter 503 representing the electric field strength level is superimposed on the video of the terrestrial digital broadcast content at the lower right of the display screen 501 of the display 5.

  In the embodiment described above, the main control unit 35 may output a suggestion data output instruction to the drawing processing unit 33 instead of the mixing instruction. When the drawing processing unit 33 receives an instruction data output instruction from the main control unit 35, the drawing processing unit 33 replaces the digital video signal stored in the video buffer 31 with the suggestion data stored in the suggestion data storage unit 32. The output may be switched so as to continue outputting. In this case, as the electric field strength level output from the terrestrial digital broadcast receiver 2 decreases in the drawing processing unit 33 (YES in S101) or as the buffering data amount of the video buffer 31 decreases (S102). In the case of YES), the brightness value of the suggestion data may be lowered. Further, the main control unit 35 may copy the digital video signal buffered in the video buffer 31 to the suggestion data storage unit 32 and use it as suggestion data. In this case, the digital video signal used as suggestion data may be subjected to predetermined effect processing such as changing the color signal so that the video becomes monotone.

  In the above embodiment, the main control unit 35 monitors both the electric field intensity level output from the terrestrial digital broadcast receiver 2 and the buffering data amount of the video buffer 31. However, the present invention only needs to be able to monitor at least one of the electric field intensity level and the buffering data amount.

  In the above embodiment, the terrestrial digital broadcast receiver 2 and the AV controller 3 may be housed in a single casing. When the above-described embodiment is mounted on a vehicle, the AV controller 3 may be incorporated in, for example, a navigation device.

FIG. 1 is a schematic diagram of a terrestrial digital broadcast receiving system to which an embodiment of the present invention is applied. FIG. 2 is a diagram for explaining the operation of the main control unit 34. FIG. 3 is a diagram showing a display example on the display 5. FIG. 4 is a diagram showing a display example of the display 5. FIG. 5 is a diagram showing a display example of the display 5. FIG. 6 is a diagram showing a display example of the display 5.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Antenna, 2 ... Terrestrial digital broadcasting transmitter, 3 ... AV controller, 4 ... Speaker, 5 ... Display, 21 ... Tuner, 22 ... ODFM demodulation part, 23 ... DEMUX, 24 ... Audio decoder, 25 ... Video decoder, 26 ... Electric field intensity detection unit, 31 ... Video buffer, 32 ... Display data storage unit, 33 ... Drawing processing unit, 34 ... Sound processing unit

Claims (7)

A terrestrial digital broadcast receiving system that demodulates and outputs a video signal and an audio signal from a terrestrial digital broadcast signal,
Video buffer means for buffering a video signal demodulated from a terrestrial digital broadcast signal and sequentially outputting it;
And the display data storage means for storing the Jo Tokoro of the display data,
Main control means for detecting the electric field strength of the reception channel of the terrestrial digital broadcast signal and the data amount of the video signal buffered in the video buffer means;
When the electric field strength and the data amount are equal to or greater than a predetermined threshold value, the video signal output from the video buffer means is output, and at least one of the electric field strength and the data amount is a predetermined threshold value. A terrestrial digital broadcast receiving system , comprising: display control means for outputting the predetermined display data when the number is less than A terrestrial digital broadcast receiving system according to claim 1,
Wherein the display control unit, if the previous SL electric field strength is less than the predetermined threshold value, a terrestrial digital broadcast receiving system and outputs the predetermined display data in luminance value corresponding to the electric field strength. A terrestrial digital broadcast receiving system according to claim 1,
Wherein the display control unit, before the case Kide over data amount is less than the predetermined threshold value, a terrestrial digital broadcast receiving system and outputs the predetermined display data in luminance value corresponding to the amount of data. A terrestrial digital broadcast receiving system that demodulates and outputs a video signal and an audio signal from a terrestrial digital broadcast signal,
Video buffer means for buffering a video signal demodulated from a terrestrial digital broadcast signal and sequentially outputting it;
And the display data storage means for storing the Jo Tokoro of the display data,
Main control means for detecting the electric field strength of the reception channel of the terrestrial digital broadcast signal and the data amount of the video signal buffered in the video buffer means;
When the electric field strength and the data amount are equal to or greater than a predetermined threshold value, the video signal output from the video buffer means is output, and at least one of the electric field strength and the data amount is a predetermined threshold value. A terrestrial digital broadcast receiving system , comprising: display control means for mixing the predetermined display data with the video signal output from the video buffer means . A terrestrial digital broadcast receiving system according to claim 4 ,
Wherein the display control unit, before Symbol electric field intensity of less than a predetermined threshold value, said predetermined display data to the video signal output from said image buffer means, and outputs the mixed at a ratio in accordance with the electric field intensity This is a terrestrial digital broadcast reception system. A terrestrial digital broadcast receiving system according to claim 4 ,
Wherein the display control unit, before when the data amount of Kiutsu image signal is smaller than the predetermined threshold value, said predetermined display data to the output video signal from said image buffer means, and mixed at a ratio in accordance with the data amount A terrestrial digital broadcast receiving system characterized by output. A terrestrial digital broadcast receiving system according to any one of claims 1 to 6,
When the electric field strength and the data amount are equal to or greater than a predetermined threshold, an acoustic signal demodulated from a terrestrial digital broadcast signal is output , and at least one of the electric field strength and the data amount is a predetermined threshold. A terrestrial broadcast receiving system, further comprising: acoustic control means for outputting a predetermined noise mixed with an acoustic signal demodulated from the terrestrial digital broadcast signal.

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