JP2002271707A - Digital broadcasting receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital broadcasting receiver the display mode of which can be selected by a user when a modulation system of a displayed video image is switched from a high hierarchical modulation system into a low hierarchical modulation system. SOLUTION: The digital broadcasting receiver is provided with a station frequency selection means that extracts a desired station selection channel from a received signal of a digital broadcasting program where two or more hierarchical services exist in the same channel, a layer demodulation means that demodulates two or more layers in a channel selected by the station frequency selection means by each layer, and a display layer changeover means that selects a displayed layer based on reception quality of each layer, and also with a display mode changeover means that can allow the user to select a display mode to display a low hierarchical video image when the modulation system of the displayed video image is switched from the high hierarchical modulation system into the low hierarchical modulation system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcast receiving apparatus for receiving a digital broadcast having two or more hierarchical services in the same channel.

[0002]

2. Description of the Related Art In recent years, in addition to television broadcasting using terrestrial waves, digital broadcasting services have been started in satellite broadcasting using geostationary satellites and CATV (cable television), and are becoming widespread.

[0003] In this digital broadcasting, for example, MPEG2 (Moving Picture Image codin) is used as a video encoding system.
The moving image compression encoding technique of g Experts Group phase 2) is adopted, and a plurality of pieces of information such as image data and audio data are multiplexed and transmitted. Since the MPEG2 standard and the like are known, detailed description thereof will be omitted.
2 means that the upper limit of the transfer rate is 60 Mbit / sec and HD
This is a standard that can be applied to high definition image quality of TV (High Definition Television).

[0004] The digital satellite broadcasting system is MPE.
A signal of a plurality of television broadcast programs data-compressed by a compression technology such as G2 is multiplexed and provided on one carrier (carrier), and is provided in a form different from a conventional television broadcast using terrestrial waves. It can be performed.

Currently, satellite digital broadcasting formats adopted in Japan include, for example, 480i, 480p,
720p and 1080i. Among them, for the high-layer image, “1080i” which is an interlace system with 1125 scanning lines (the number of effective scanning lines is 1080) and “720p” which is a blog regressive system with 720 lines are used. The video has an interlaced format of 525 scanning lines (480 effective scanning lines) with the same standard image quality as the current BS analog broadcasting.
80i "and the blog progressive system" 480p ".

Here, "interlacing (interlaced scanning)"
The "method" is a method in which one scanning line is operated every other scanning line to display one screen with odd and even fields.
The “blogless (sequential scanning) method” is a method in which all scanning lines are sequentially scanned from the top and displayed. As described above, the amount of information in the blog regressive method is twice as large as that in the interlace method, so that a higher image quality without flicker can be obtained than in the interlace method. In other words, the sharpness of the video in each format is 720p, 1080
i, 480p, and 480i.

[0007] However, even if the video format is the same, the receiving condition differs depending on the environment in which satellite digital broadcasting is received.
For example, the receiving state differs depending on the direction in which the receiving antenna is installed. In other words, when installing a receiving antenna for satellite digital broadcasting, aim at the direction of the satellite using the pointer of the compass as a guide, and further check the strength of the received signal with a level meter or the like of the satellite broadcasting receiver. Need to adjust. For example, the satellite broadcast signal strength meter disclosed in Japanese Patent Application Laid-Open No. 10-206473 has a function of identifying reception of radio waves from satellite digital broadcasts, so that the direction of the antenna can be easily adjusted.

It is known that the receiving condition of satellite digital broadcasting greatly depends on the weather and atmospheric conditions. For example, during a thunderstorm or snowfall, the intensity of the received radio wave becomes weak, and noise is mixed in the image. , Or video / audio is interrupted (video freezes, audio mutes)
As a result, the broadcast quality is reduced. Therefore, usually, in addition to the high-layer image, the low-layer image resistant to rainfall or the like is transmitted in parallel to the same program, and when the rainfall occurs, the modulation method is switched so that the low-layer image is displayed. For example, in a digital broadcast receiving apparatus disclosed in Japanese Patent Application Laid-Open No. 2000-165766, disturbance of output video and audio is reduced by automatically switching to a layer that always provides the best reception state and receiving. Like that.

[0009]

As described above, in the digital broadcast receiving apparatus, various measures have been taken to receive high quality video information from a digital satellite broadcast and obtain a clear video. It has been done.

[0010] In a commercially available digital broadcasting receiver corresponding to a high-layer image, the high-layer image is normally displayed, and when the reception state of the high-layer image is deteriorated due to rainfall or the like, it is automatically set. The display is switched to a lower hierarchy image.

[0011] However, although the low-layer video is resistant to the deterioration of the weather such as rainfall, the amount of information that can be transmitted is considerably smaller than that of the high-layer video, so that the resolution is low. When displayed on a large screen area, the image becomes more coarse. In particular,
There is a problem in that the most suitable television for high-layer images has a large screen, so that the roughness of the images becomes noticeable.

[0012] On the other hand, there is a demand for enjoying a large-screen image even if it is a low-hierarchy image because it is a large-screen television because it is a large-screen television.

According to the present invention, when a modulation method of a video to be displayed is switched from a high-layer modulation method to a low-layer modulation method,
It is an object of the present invention to provide a digital broadcast receiving apparatus in which a display mode can be selected by a user.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned object, and extracts a desired channel from a received signal of a digital broadcast in which two or more hierarchical services exist in the same channel. Frequency selecting means for performing demodulation, hierarchical demodulating means for demodulating two or more layers in the channel selected by the frequency selecting means for each layer, and displaying based on the reception quality for each layer. A display hierarchy switching unit capable of switching between layers, wherein in the digital broadcast receiving apparatus capable of switching between layers to be displayed, when the display layer switching unit switches the hierarchy from a high layer to a low layer, A display mode switching unit capable of selecting a display mode for displaying a hierarchical image is provided.

This allows the user to determine whether to emphasize the size of the display area or to emphasize the sharpness of the image quality at his or her own will in displaying the low hierarchical image.

Specifically, the display mode switching means comprises:
The display mode is switched between a first display mode in which the entire screen of the digital broadcast receiving apparatus is displayed as a display area and a second display mode in which the display is performed in a display area reduced in accordance with the displayed hierarchy. I do. That is, when the user places importance on the size of the display area, the mode is switched to the first display mode, and when the user places importance on the sharpness of the image quality, the mode is switched to the second display mode.

Here, the second display mode is, for example,
In a digital broadcast receiving apparatus compatible with 1080i format high-layer video, a display mode in which a 480i format low-layer video is displayed in a display area (about の of the entire screen) of 480 scanning lines can be set. . The image is displayed with the aspect ratio maintained.

[0018] The display mode switching means may be configured to switch the display mode based on input information from an input device. Thereby, the user can freely select a desired display mode.

For example, there is provided display mode switching support means for displaying a display mode switching screen for switching the display mode, and the display mode switching means is provided on the basis of information selected and input by the user on the display mode switching screen. The display mode can be switched.

Alternatively, the display mode can be sequentially switched each time the display mode switching button provided on the digital broadcast receiving apparatus main body or the remote controller is pressed without displaying the display mode switching screen.

Further, the display mode switching support means includes:
The display mode switching screen may be displayed based on switching from a higher layer to a lower layer by the display layer switching means or based on an input of an execution command from an input device. For example, a display mode switching button is provided on a remote controller or the like of the digital broadcast receiving apparatus, and when the user wants to change the display mode, the display mode switching support unit is executed by pressing the button to display the display mode switching screen. Can be.

Alternatively, a display mode selected when the hierarchical modulation method is switched may be set in advance, and the display mode may be automatically selected when the hierarchical modulation method is switched. .

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram schematically showing the configuration and signal flow of a digital broadcast receiving apparatus for high-layer video according to the present embodiment.

In FIG. 1, first, for example, a signal received by a BS antenna 20 such as a parabolic antenna is received.
The satellite broadcasting radio wave of the GHz band is converted into a transport stream output signal TS which is frequency-converted into a 1 GHz band intermediate frequency signal by an LNB (Low Noise Block downconverter) provided in the BS antenna 20.
It is input to the tuner pack 1 of the digital broadcast receiving device.

The tuner pack 1 selects a frequency to be received from the transport stream output signal TS, performs quadrature detection, and outputs the result to the demodulation / decoding unit 2. In the demodulation / decoding unit 2, TC8PSK (Trellis Coded
8 Phase Shift Keying) demodulation processing, QPSK (Quadratur
e Phase Shift Keying: demodulation processing and BPSK (Binary Phase Shift Keying: binary PS)
K) After performing the processing, output to the deinterleave unit 4.

Here, TC8PSK is a digital modulation system used for BS digital broadcasting, and has higher frequency utilization efficiency and better noise immunity than the QPSK system used for CS digital broadcasting. QPSK is a digital modulation method used for CS digital broadcasting currently being broadcast. Note that PSK is a phase modulation method for transmitting information using the phase of a carrier (a high-frequency signal for transmitting information), and TC8PSK indicates that the number of phases used is eight. I have. Also, TC8PSK can transmit 3 bits, QPSK can transmit 2 bits, and BPSK can transmit 1 bit. Normally, TC8PSK is used as a high-level modulation scheme, and QPSK or BPSK is used as a low-level modulation scheme.

A part of the signal selected and quadrature-detected by the tuner pack 1 is transmitted by a TMCC (Transmission & Multipl.
exing Configuration Control: transmission multiplex control signal) The TMCC is inserted to specify a carrier modulation method, error correction, and the like for each layer.

Here, the deinterleaving process is a process of restoring the interleaved symbols to the original time series. Note that interleaving is a technique for improving the robustness against burst errors used in the transmission path coding technique. By rearranging symbols transmitted in time series, the burst errors are converted into pseudo random errors. Some improve the error correction capability. Also,
The descrambling process is a process for decoding the scrambled (encrypted) transport stream output signal TS.

Next, the transport stream output signal TS is input to the Reed-Solomon decoding unit 5. Here, the Reed-Solomon code is a type of error correction code, and is one type of block code that corrects errors in byte units. In satellite broadcasting, a strong error correction function is added using this Reed-Solomon code or the like in order to maintain stable reception quality even when the reception state deteriorates due to rainfall or the like. Then, the Reed-Solomon decoding unit 5 performs an error correction process using the Reed-Solomon code. In this error correction processing, an error correction rate can be calculated.

Subsequently, the transport stream output signal TS is input to the CA descrambler 6 and the CA module 7. The CA module 7 is a module having a high-speed digital interface for receiving data enabling conditional access (CA: conditional access) such as a pay broadcast, and is connected to a telephone line or a dedicated line via the modem 14. It is configured to be able to communicate with a host computer or the like of a billing center of a broadcasting company. Then, the CA descrambler 6 performs a process of descrambling the limited reception scramble based on the received data.

Next, the descrambled transport stream output signal TS is input to the MPEG2 demultiplex unit 8, and the multiplexing of the broadcast contents compressed by MPEG2 is released. Then, the demultiplexed signal is input to the EPC & basic data decoder 9, the high-layer video decoder 10, the lower-layer video decoder 11, and the audio decoder 12.

In the EPG & basic data decoder 9, the MP
From a signal compressed by EG2, an electronic program guide (EPG: El
ectronic Program Guide) data and basic data related to program selection and conditional access are separated and extracted.

The high-layer video decoding section 10 separates and extracts high-resolution video data from the signal compressed by MPEG2, and the low-layer video decoding section 11 converts the low-resolution low-resolution video from the signal compressed by MPEG2. Data separation / extraction is performed. The audio decoder 12 separates and extracts audio data from the signal compressed by MPEG2 and outputs the audio.

The electronic program guide data, high-resolution video data, and low-resolution video data separated and extracted as described above are combined with the video synthesizing display processor 13.
And output as a synthesized video signal to a display such as a CRT or a liquid crystal display device. The screen display by switching the display mode, which will be described later, is realized by enlarging / reducing a low-resolution image of a low hierarchy by the image synthesizing display processor 13.

Reference numeral 30 denotes a control device composed of a microcomputer or the like for controlling the above components in an integrated manner. Reference numeral 40 denotes an input key provided on the main body of the digital broadcast receiving apparatus, or a remote controller provided with a cursor key, a number key, and the like, and is used when a display mode is selected in the present embodiment. Note that the configuration of the existing input device can be applied to the input device 40, and thus the description is omitted.

FIG. 2 is an explanatory diagram showing a display example of the digital broadcast receiving apparatus according to the present embodiment. In the system according to the present embodiment, the image is normally displayed as a high-layer image (see FIG. 2A), and when the error correction rate exceeds a specified value (for example, 50%) due to deterioration of weather or the like, the display is changed to a low-layer image. Switching is performed. The hierarchy switching may be automatically performed by the digital broadcast receiving apparatus, or the user may determine whether to perform the hierarchy switching.

In the present embodiment, as the display mode for the low-layer video, for example, a normal mode (see FIG. 2B) in which the entire TV screen is a display area, and a part of the entire TV screen based on the low-layer video. (See FIG. 2 (c)). In the normal mode, the lower layer video of the 480i format is displayed on the digital broadcast receiving apparatus corresponding to the higher layer video of the 1080i format.
Since the video information of the resolution of the book is displayed in the display area of the large screen having 1080 scanning lines, the roughness of the video is displayed conspicuously as shown in FIG. On the other hand, in the reduction mode, as shown in FIG.
Since the display area is reduced to a display area for 0 lines, that is, less than half of the entire screen, the image is clearly seen as compared with the normal mode. For example, in the present embodiment, the reduced screen is arranged at the center of the screen.

Next, a procedure for setting and switching the display mode of the low hierarchical video in the digital broadcast receiving apparatus according to the present embodiment will be described with reference to the flowchart shown in FIG.

When the display is switched from the high-layer image display to the low-layer image display, the control according to the flowchart of FIG. 3 is started.
Is displayed on the entire screen, and the display mode can be selected using the input device provided in the digital broadcast receiving device. The display mode switching screen shown in FIG. 4 is an example, and the display mode switching screen may be displayed on a part of the screen while displaying an image on the background.

After the display mode switching screen is displayed in step S11, it is determined in step S12 whether the display mode has been specified by the user. If the display mode has been specified, the process proceeds to step S15, and if there is no input from the user. Is shifted to step S13.

For example, on the display mode switching screen shown in FIG. 4, the user uses the cursor keys of the remote control or presses the number key of the number attached to the top of the display mode to display the cursor on the right side of FIG. The display mode can be selected by moving C.

In step S12, when the display mode is selected by the user's remote control operation and the display mode is determined by the determination button or the like, the process proceeds to step S15, where the display mode determined in step S12 is set as the display mode. You.

On the other hand, if there is no input by the user's remote control operation in step S12, the flow shifts to step S13 to determine whether a predetermined time has elapsed. If it is determined in step S13 that there is no input by the user for a fixed time (for example, 10 seconds), the process proceeds to step S14, and the display mode (for example, the normal mode) set by default is set.

Then, step S14 or step S14
When the normal mode is set at 15 in FIG.
As shown in FIG. 2B, the image is switched to a low-quality image, and when the reduction mode is set, a relatively clear image is displayed on the reduced screen as shown in FIG. 2C (step S).
16).

As described above, according to the present embodiment, the user can select the display mode of the low hierarchical video, so that
The user can determine which one of the size of the display screen and the sharpness of the image quality should be displayed.

Although the invention made by the inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments. For example, the change of the display mode is not limited to the time of the hierarchy switching, and by pressing the display mode switching screen button provided on the digital broadcast receiving apparatus main body or the remote controller or the like, the screen in which the display mode can be selected is displayed. , May be configured to be changed by the user at any time. Further, the display mode is switched, for example, between a normal mode and a reduced mode each time a display mode switching button provided on a digital broadcast receiving apparatus main body or a remote controller is pressed without displaying the display mode switching screen. You can also.

Alternatively, by setting a display mode to be used when hierarchical switching is performed in advance, it is possible to prevent a screen on which a display mode can be selected from being displayed every time hierarchical switching is performed.

In the reduction mode of the present embodiment, the reduced display screen is arranged at the center of the screen. However, the reduced display screen can be displayed near the edge of the screen, and the display position can be arbitrarily set by the user. Can also be set.

[0050]

According to the present invention, according to the present invention, two
Frequency selecting means for extracting and outputting a desired channel selected from a received signal of digital broadcasting in which the above-described hierarchical service exists, and demodulating two or more layers in the channel selected by the frequency selecting means. In a digital broadcast receiving apparatus including a layer demodulation unit that performs each layer and a display layer switching unit that can switch a layer to be displayed based on the reception quality of each layer, a display mode displayed on a screen can be selected. Since the display mode switching means is provided, the user can determine whether to give priority to the size of the display area or to emphasize the sharpness of the image quality by himself / herself when displaying the low hierarchical video. It works.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically illustrating a configuration and a signal flow of a digital broadcast receiving apparatus according to an embodiment.

FIG. 2 is an explanatory diagram showing a display state for each display mode in the digital broadcast receiving device according to the embodiment.

FIG. 3 is a flowchart showing a processing procedure in a control device of the digital broadcast receiving device according to the embodiment.

FIG. 4 is an explanatory diagram showing an example of a display mode switching screen in the digital broadcast receiving device according to the embodiment.

[Explanation of symbols]

 Reference Signs List 1 Tuner pack 2 Demodulation / decoding unit 3 TMCC decoding unit 4 Deinterleave unit 5 Reed-Solomon decoding unit 6 CA descramble unit 7 CA module 8 MPEG2 demultiplex unit 9 EPG, basic data decoder 10 High-layer video decoder 11 Lower layer Video decoding unit 12 Audio decoding unit 13 Video synthesis display processor 14 Modem 20 BS antenna 30 Control device (microcomputer) 40 Input device TS Transport stream output signal

Claims (6)

[Claims] 1. A frequency tuning means for extracting and outputting a desired tuning channel from a received signal of a digital broadcast in which two or more hierarchical services exist in the same channel, and a channel selected by the frequency tuning means. 2 in
A digital broadcast receiving apparatus comprising: a layer demodulation unit that performs demodulation of the above layers for each layer; and a display layer switching unit that can switch a layer to be displayed based on the reception quality of each layer. A first display mode for displaying a low-layer image when the layer switching from the high layer to the low layer is performed by the display layer switching unit, a first display mode for displaying the entire screen of the digital broadcast receiving apparatus as a display area, A display mode switching unit configured to switch to a display mode of any one of a second display mode in which a display area is reduced and displayed according to a hierarchy to be displayed, wherein the display mode switching unit is configured to switch an input from an input device. A digital broadcast receiving apparatus that switches a display mode based on the display mode. 2. A frequency selecting means for extracting and outputting a desired channel selected from a received signal of a digital broadcast in which two or more hierarchical services exist in the same channel, and a channel selected by said frequency selecting means. A digital demodulation means for demodulating two or more of the layers for each layer, and display layer switching means for switching a layer to be displayed based on the reception quality of each layer. A display mode switching unit that can select a display mode for displaying a low-layer image when the layer switching from the high layer to the low layer is performed by the display layer switching unit. Broadcast receiver. 3. The display mode switching means includes: a first display mode for displaying the entire screen of the digital broadcast receiving apparatus as a display area; and a second display mode for displaying in a display area reduced corresponding to a hierarchy to be displayed. The digital broadcast receiving apparatus according to claim 2, wherein the display mode is switched to one of the display modes. 4. The digital broadcast receiving apparatus according to claim 2, wherein the display mode switching means switches the display mode based on input information from an input device. 5. A display mode switching support means for displaying a display mode switching screen for switching the display mode, wherein the display mode switching means is based on information selected and input by a user on the display mode switching screen. The digital broadcast receiving device according to claim 4, wherein switching of a display mode is performed. 6. The display mode switching support means displays the display mode switching screen based on a hierarchy switching from a higher hierarchy to a lower hierarchy by the display hierarchy switching means or based on an execution command input from an input device. The digital broadcast receiving apparatus according to claim 5, wherein the digital broadcast receiving apparatus displays the digital broadcast.