JP3722719B2 - Digital broadcast receiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital broadcast receiving apparatus and relates to a digital broadcast receiving apparatus capable of displaying the contents of a reception state. More specifically, the present invention relates to a receiving apparatus including means for quickly displaying a reception state after starting a channel selection operation and before decoding video / audio.
[0002]
[Prior art]
In the conventional digital broadcast receiving apparatus, the reception state of the selected channel is such that after the channel selection operation is started, the video / audio decoding is completed and the video / audio is displayed. It was confirmed by.
[0003]
Or, when a video / audio disturbance occurs, the viewer operates the receiver with a remote controller or the like to display a reception level display screen such as an antenna level.
[0004]
In this way, the viewer discriminates the reception state, and after judging that the reception state is bad, selects a channel with another good reception state.
[0005]
In Japanese Patent Laid-Open No. 3-214324, the receiver calculates the error rate of the received signal after channel selection, and displays the quality of the reception state based on this error rate rate.
[0006]
[Problems to be solved by the invention]
In the case of digital broadcasting, after tuning operation starts, it takes time to tune, demodulate, decode video, and to display a picture, so after tuning operation, no image is displayed for a certain period of time. A period arises.
[0007]
Conventionally, since the reception state is confirmed due to the disturbance of video / audio, the viewer cannot know the reception state of the selected channel during that time. Therefore, when selecting a receivable channel, it was necessary to select a channel and wait for a picture to appear before selecting the next channel.
[0008]
In Japanese Patent Laid-Open No. 3-214324, an error rate is calculated after channel selection so that the reception state can be displayed. However, in this method, the error rate must be set after tuning and demodulating operations. Could not be calculated, and the reception status could not be confirmed during that time.
[0009]
In addition, when performing mobile reception received outdoors or mobile reception received by a mobile object such as an automobile, the reception status varies depending on the location of reception and the direction of the antenna. It is not always possible to receive the received channel this time, and it is necessary to quickly determine whether or not the channel can be received.
[0010]
An object of the present invention, Ri near to to know the reception state of the selected channel during a pending the picture after the tuning, especially, the other receiving a plurality of channels after channel selection of one channel state immediately had a row the list, this time, the display of the receiving state, rather than a display by the channel, it is to display a service number unit.
[0011]
[Means for Solving the Problems]
A tuner unit that selects a signal having a desired frequency from a digital broadcast signal input from an antenna, and a demodulation and correction unit that performs demodulation and error correction on the received signal and detects the reception state of the received signal. A digital broadcast receiver,
Each of the tuner unit and the demodulation / correction unit has a plurality,
Displaying the reception state detected by the one demodulation and correction unit from the start of the channel selection operation of one frequency channel to the end of video decoding by one tuner and one demodulation and correction unit;
Channel selection operation of each frequency channel in a frequency range that can be received by another tuner unit and another demodulation and correction unit to detect the reception state of each frequency channel, together with the display of the reception state by the one tuner unit, Displays the reception status of each frequency channel in a list,
The display of the reception status of the one frequency channel and each frequency channel is based on the information related to the frequency channel and the service number recorded in the memory, and when the service number is selected, the service number is displayed. A digital broadcast receiving apparatus that displays a reception state of a corresponding frequency channel in units of the selected service number.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
A digital broadcast receiving apparatus according to an embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing an internal configuration of a demodulation and correction unit in the present embodiment, and FIG. 3 is a CPU at the time of channel selection It is a flowchart which shows the example of operation | movement.
[0015]
The embodiment of the present invention shows a configuration example when receiving an OFDM (Orthogonal Frequency Division Multiplexing) system that is a broadcasting system of terrestrial digital TV.
[0016]
In the digital broadcast receiver shown in FIG. 1, 1 is an antenna for receiving broadcast radio waves, 2 and 12 are tuners that select a desired channel and convert an RF (Radio Frequency) signal into an internal processing IF (Intermediate Frequency). Reference numerals 3 and 13 denote demodulation / correction sections that perform demodulation and error correction in accordance with a modulation method obtained by modulating the signal converted into IF on the broadcast side, and 8 denotes a transport that divides transport stream data into video and audio. Each represents a decoder.
[0017]
4 is a CPU (central processing unit) that controls the entire system, 5 is a RAM (random access memory) for storing data such as tuner status, and 6 is a reception for displaying the reception status on the CRT 11. A status display generation unit, 7 is a display for displaying the reception status, 14 is a switch for switching inputs when there are a plurality of tuners, 16 is a program for controlling the CPU, or reception read from the demodulation and correction unit It is a ROM (Read Only Memory) that stores programs and data for converting status information into information for display as a reception state.
[0018]
As shown in FIG. 2, the internal blocks of the above-described demodulation and correction units 3 and 13 are roughly divided into 18 demodulation units, 20 error correction units, and 23 CPU I / F units. The demodulator 18 includes an AGC 19 that adjusts the level of an input signal from the tuner, an orthogonal demodulator, FFT (Fast Fourier Transform), equalization, and TMCC decoding. The error correction unit 20 includes a deinterleave, Viterbi decoding, RS (Reed Solomon) decoding, a reception C / N measurement unit 21, and a BER measurement unit 22.
[0019]
As described above, the digital broadcast receiving apparatus according to the present invention includes an antenna that receives broadcast radio waves, a tuner that selects a desired channel and converts an RF signal into an IF for internal processing, and a signal converted into an IF. A demodulating and correcting unit that demodulates, decodes, and corrects errors according to a modulation method and a coding method that are modulated on the broadcast side, a video processor unit that decodes demodulated video and audio, an audio processor unit, and a demodulation and correcting unit A CPU that creates display contents based on the reception status information from the computer, a ROM section that records a conversion formula program or data for converting the reception status information into contents for display on the CRT as reception information, and A reception status display generating unit for outputting the display contents as a video, a display indicating the reception status, and a system bus for the CPU to control each device It is those with a.
[0020]
Next, as an example of the reception state at the time of channel selection, the operation when displaying the intensity of the input signal will be described based on the flowchart of FIG. The CPU 4 sets the frequency to be received by the tuner (step S1), and starts the tuning operation by causing the demodulation and correction unit to start the tuning operation (step S2). The demodulation / correction unit operates an AGC (Automatic Gain Control) circuit, controls the amplifier in the tuner, and adjusts the output signal level of the tuner so that the input signal from the tuner becomes an optimum signal. When the optimum level is reached, the demodulation and correction unit sets a status indicating that the AGC adjustment is completed in the register.
[0021]
Meanwhile, the CPU reads a status indicating whether or not the AGC adjustment is completed from the CPU I / F 23 of the demodulation and correction unit (step S3), and performs a polling process for confirming the completion (step S4). When the adjustment is completed, the AGC register of the demodulation and correction unit is read from the CPU I / F (step S5), and information on the signal strength of the currently received signal is acquired.
[0022]
Next, based on the read AGC register value, the value is converted into an actual signal level, and the information can be output to the display through the reception state generating unit and the video processor.
[0023]
Here, the AGC register value can be converted into a numerical value representing another reception state by the CPU. For example, regarding the display on the display device 7, the display color can be divided according to the signal intensity. For example, when displaying on the LED, blue (steps S6 and S7) is displayed when the signal can be received without any problem, yellow (step S10) when the reception state is near the level where an error occurs, and red when reception is not possible. (Steps S8 and S9). It is also possible to display similar information by the color of the channel number number on the CRT.
[0024]
Since the above operation ends in a period in which the AGC level adjustment ends after the channel selection starts, the subsequent operations such as tuning operation, decoding, error correction, TS decoding, etc. are completed and a picture is not displayed. In addition, it is possible to immediately display the reception strength of the signal.
[0025]
As the display contents, in addition to the AGC value, the reception C / N level and the BER value may be displayed in the same manner as described above by the reception C / N measurement unit and the BER measurement unit in the error correction unit of FIG. Is possible.
[0026]
As a BER calculation method, there is a calculation method by performing re-encoding of a signal that has been error-corrected by an error correction unit and comparing it with data before correction.
[0027]
As a method for calculating the reception C / N level, the reception state can be detected by dispersion of reception coordinates of pilot signals (SP) whose coordinates of the constellation are known in advance in the reception signals of the constellation after equalization.
In addition, the displayed contents at the time of tuning include information on the set frequency (frequency of the current channel), information on whether it is in a synchronized state, during a synchronization operation, or in a synchronization failure state, and a modulation method Information, frequency offset value information indicating how much the frequency of the received radio wave is deviated from the set frequency can be displayed. These pieces of information can also be displayed in an easy-to-read format as a graphical display such as a numerical value or a bar graph.
[0028]
In addition, by providing a plurality of tuners and demodulation / correction units, for example, one tuner / demodulation / correction unit selects a frequency and displays the video, while the other tuner / demodulation / correction unit receives it. Search for each frequency in the possible frequency range, record the reception status of each frequency continuously, and repeat the operation to obtain the latest reception status. When performing the channel selection operation, it is also possible to display the reception state information recorded in advance for the reception state information of the frequency.
[0029]
Further, when displaying the reception state, not only the frequency set for tuning but also the display of the reception state in each channel of other frequencies can be displayed simultaneously with the selected channel. For example, when 15 channels are selected, not only the display of 15 channels but also the reception statuses of 13 to 25 channels are displayed in a list on the screen.
[0030]
When the reception state is displayed, display by service is possible instead of display by channel. It is possible to record information associating the frequency channel with the service number in the RAM unit, and display the reception status in units of service numbers based on this information. For example, if the service number “001” is a service existing on the frequency 15 channel, the reception state of the frequency 15 channel is displayed when the “001” number is selected.
[0031]
In the receiver including the two tuners and the demodulation / correction unit, it is possible to display a channel list that can be selected at the time of channel selection failure. When searching for each frequency, information on whether or not the reception state of the channel is receivable is recorded in the RAM section, so that if channel selection fails, the current channel selection is possible. The channel list or service list can be displayed immediately after tuning.
[0032]
【The invention's effect】
As described above, according to the present invention, it is possible to display the reception state such as the input signal level of the frequency after the tuning operation is started and until the tuning is completed. After that, it is possible to know the reception status of the channel before the picture appears.
[0033]
When the reception state varies depending on the position of the receiver as in mobile reception or mobile reception, the reception state differs for each channel selection. In the present invention, since the reception state is displayed immediately after channel selection, it is possible to change the channel immediately when reception is impossible. In addition, since the level of the reception state of the channel can be immediately grasped, it is possible to save the trouble of displaying the reception state according to the antenna level later.
[0034]
In addition, according to the present invention, the list of reception states of each frequency is created using the other tuner other than the one tuner that is selected and displaying the video, and the demodulation correction unit. The reception status of that channel can be displayed immediately.
[0035]
Even if the reception state of the channel is bad and reception is not possible, it is possible to immediately display a list of currently receivable channels. The viewer does not have to wait until a picture appears, and when the list is displayed, the user can tune to another channel.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an internal configuration of a demodulation and correction unit in the present embodiment.
FIG. 3 is a flowchart illustrating an operation example of a CPU at the time of channel selection.
[Explanation of symbols]
1 Antenna 2, 12 Tuner 3, 13 Demodulation Correction Unit 4 CPU
5 RAM
6 Reception Status Display Generation Unit 7 Display 8 Transport Decoder 9 Video Processor 10 Audio Processor 11 CRT
14 Switch 15 System bus 16 ROM
17 Demodulation Correction Unit 18 Demodulation Unit 19 AGC Circuit 20 Error Correction Unit 21 Reception C / N Measurement Unit 22 BER Measurement Unit 23 CPU I / F

Claims (1)

A tuner unit that selects a signal having a desired frequency from a digital broadcast signal input from an antenna, and a demodulation and correction unit that performs demodulation and error correction on the received signal and detects the reception state of the received signal. A digital broadcast receiver,
Each of the tuner unit and the demodulation / correction unit has a plurality,
Displaying the reception state detected by the one demodulation and correction unit between the start of the channel selection operation of one frequency channel and the end of video decoding by one tuner and one demodulation and correction unit,
Channel selection operation of each frequency channel in a frequency range receivable by another tuner unit and another demodulation correction unit to detect the reception state of each frequency channel , together with the display of the reception state by the one tuner unit, shows the reception status of each frequency channel in the list,
The display of the reception status of the one frequency channel and each frequency channel is based on the information related to the frequency channel and service number recorded in the memory, and when the service number is selected, the service number is displayed. A digital broadcast receiving apparatus which displays a reception state of a corresponding frequency channel in units of the selected service number .

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