JP2000350116A - Program selecting arrangement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a program selection receiver for digital broadcast to easily select a received program channel. SOLUTION: A table RAM 22 stores information obtained by receiving a program of a broadcast frequency channel in advance, and a program channel of the program designated by a program number selection means 30 can selectively be received on the basis of the program number information stored in the table RAM 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for receiving digitally modulated broadcast waves, and more particularly, to an apparatus for selecting a channel of a receiver by designating a channel number indicating a program supplier.

[0002]

2. Description of the Related Art Conventionally, a television broadcast receiver is operated as if a channel number is selected by selecting a number assigned to a program supplier. This is because when a broadcaster broadcasts in accordance with the frequency described in the license, the corresponding channel number is uniquely determined, and the receiver performs channel selection by integrating the program supplier and the channel number. In the Japanese analog television broadcasting, a channel number and a frequency band are defined for each frequency band of 6 MHz according to the NTSC system, and a broadcast wave is received based on the channel number and the frequency band.

In recent years, preparations for introducing a digital television system have been advanced, and digital terrestrial broadcasting is about to start. Here, a terrestrial digital television system using OFDM will be described. Figure 4 shows a typical OFD
3 shows a frequency spectrum of an M signal. OFDM is a modulation method of dividing, frequency-multiplexing, and transmitting an information signal to be transmitted to hundreds to thousands of digital carriers.
Are arranged at equal frequency intervals so as to maintain an orthogonal relationship with each other in order to prevent interference between adjacent carriers. The time given by the reciprocal of the frequency interval is a symbol period, and each carrier is modulated for each symbol period by, for example, well-known QPSK, and the information signal is transmitted. The OFDM signal shown in the figure is a signal spectrum when the amplitude and phase of each carrier constituting the OFDM signal do not change for each symbol period, and the carrier has a single frequency line spectrum. In FIG.
The signal spectrum when each carrier constituting the OFDM signal is QPSK-modulated in units of a symbol period is shown. This signal spectrum is "0" at the center positions c1 to c4 and c6 to c9 of the adjacent carriers. Has become. FIG. 6 shows a spectrum distribution of an OFDM signal composed of modulated majority carriers. The signal spectrum of each carrier is "0" at the center position of each adjacent carrier, indicating that the modulated signals do not interfere with each other and have an orthogonal relationship. As described above, since the carriers constituting the OFDM are modulated in the common symbol period, they are in an orthogonal relationship, and the carriers are configured not to interfere with each other. However, when an analog television signal is arranged adjacent to an OFDM signal, the OFDM signal and the analog television signal do not have an orthogonal relationship, and thus interfere with each other.
FIG. 7 shows an example in which an OFDM broadcast is performed using a vacant channel in the analog television broadcast wave band. In the current analog broadcast wave band, both types of broadcasting are performed by setting the frequency and power of the OFDM signal so as not to interfere with each other. However, OFDM broadcasting is intended to prevent interference with analog broadcasting. It is configured so that a predetermined service area is ensured despite low power transmission, for example, by transmitting with low power and correcting a data error caused by this using an error correction code. In a method as shown in this example, a method of shifting from the current analog television broadcasting to a new OFDM terrestrial digital television broadcasting can be considered.
The same program is broadcast by both methods at each frequency so that both broadcast receivers can receive the program respectively.

Meanwhile, terrestrial digital broadcasting currently being planned in Japan is a BST (Band Segmented Transmission).
-An OFDM scheme in which a broadcast wave is divided into a plurality of (13) segments to broadcast a program. The number of segments used for broadcasting is selected according to the amount of information required by the program. You. Also, the transmission parameters such as the multi-valued number of QAM modulation given to the carriers constituting the segment and the setting of the convolutional code for error correction are set in a manner that can be set for each segment. In this way, BST-
In the OFDM system, a plurality of programs can be transmitted within one band while setting transmission parameters, so that the receiver selects a broadcast channel number and also selects a segment number to receive a program of desired quality. become. Figure
FIG. 8 shows an example of the arrangement at the reception channel, the OFDM transmission wave, and the program level. In the figure, an OFDM signal is transmitted to reception channels Ch1 to Ch5 using Ch2 and Ch5 not used for analog broadcasting. The programs transmitted at the frequency of Ch2 are HDTV at ch1, the SDTV at ch2, the data at ch3, the radio at ch13 at the program level, and the programs transmitted at the frequency of Ch5 are SDTV at ch4 and HDTV at ch5.
V, ch9 and ch10 are data broadcasts.

[0005]

By the way, in the conventional analog broadcasting, a broadcasting channel, a broadcasting company, and a program to be broadcast are uniquely defined, and a viewer easily selects a program by a numeral. . However, newly introduced terrestrial digital broadcasting will use vacant channels of analog broadcasting, and a plurality of programs may be broadcast on one channel. It can be varied depending on the time. The selection of broadcasting the same program only on the SDTV or broadcasting it as an HDTV program is performed in a fluid manner such that the broadcaster can change the program while checking the degree of popularity of the program and the usage status of the segment. Therefore, it is difficult for the receiver to find a receiving channel with the optimum definition while considering them. Furthermore, in the case of in-vehicle reception, the manner in which the program is broadcast may be different for each region, and the receiver grasps, for example, the manner in which the program is broadcast and the manner in which the channel number is given, and selects an appropriate program. This is even more difficult, and it is necessary to further simplify the program selection operation. Therefore, an object of the present invention is to provide an inexpensive program selection means that can select a broadcast program with the same program number as in the past for digital terrestrial broadcast reception including a transition period from analog broadcast. In addition, even when the user moves to an area of a different broadcast channel during the mobile reception, the user can select and receive a program with a common program number in the destination area.

[0006]

The present invention comprises the following means 1) to 3) to solve the above-mentioned problems. That is,

[0007] 1) In a device for receiving a digitally modulated broadcast wave, a local oscillation means for obtaining an oscillation output corresponding to a selectively specifiable reception channel, and a demodulation for demodulating a digitally modulated signal of the received channel. Means,
Means for obtaining and storing program information from the demodulated demodulated output, and a program number specifying means for specifying a program number based on the program specifying information, at least comprising: a program specified by the program number specifying means; A program selecting apparatus, wherein an oscillation frequency of said local oscillation means is set based on program number information and broadcast frequency channel information stored in said storage means.

2) In a device for receiving a digitally modulated broadcast wave, a local oscillation means for obtaining an oscillation output corresponding to a selectively specifiable reception channel, and a demodulation for demodulating a digitally modulated signal of the received channel. Means,
Error detecting means for generating an output signal corresponding to the quality of the reception state, means for storing the detected output and program information obtained from the demodulated output of the demodulating means, and a program for designating a program number based on the program designation information Number designation means, and the local oscillation based on the program designated by the program number designation means, based on the program information, reception quality information, and broadcast frequency channel information stored in the storage means. A program selecting device configured to set an oscillation frequency of the means to an optimum receiving state.

[0009] 3) In the apparatus for receiving the digitally modulated broadcast wave, the means for obtaining and storing the program information from the demodulated demodulated output updates the contents of the storing means based on the output signal of the error detecting means. Program number information stored in the updated storing means,
The program selecting apparatus according to 1) or 2), wherein the oscillation frequency of the local oscillation means is set based on broadcast frequency channel information.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a program selecting apparatus according to the present invention. FIG.
Is a schematic configuration of a receiving apparatus employing the program selecting apparatus. The receiving apparatus receives a broadcast signal and outputs a video and audio signal, and a channel selecting unit which is a main component of the present embodiment. Unit 20 and program selection unit (remote control) 30
And is composed of Here, these detailed configurations will be described together with the operation. First, the reception of the broadcast program selected by the channel selection unit will be described. The terrestrial digital broadcast wave signal received by the antenna 1 is supplied to a high frequency amplifier (RFAMP) 11 to be amplified, and the amplified signal is The signal is supplied to a frequency conversion circuit (MIX) 12 together with an oscillation output signal of a local oscillation circuit (OSC) 13 for supplying a frequency of a difference between a frequency to be received and an intermediate frequency, and is subjected to frequency conversion. The signal is supplied to an intermediate frequency amplifier (IFAMP) 14 and the amplified signal is supplied to a demodulation circuit 15. The demodulation circuit 15 includes an FFT circuit (not shown), and demodulates an OFDM signal having a segment number specified by a microprocessor 21 described later. A part of the demodulated signal is supplied to an error detection circuit 16, which performs error detection on a digital signal obtained by demodulation, supplies the digital signal to a microprocessor 21 described later, and outputs a demodulated OFDM signal. Are supplied to an MPEG decoder to decode an MPEG bit stream signal, which is a demodulated signal, to obtain video and audio signals, and amplify and output the respective signals by amplifier circuits (AMP) 18 and 19. Next, the configuration of the channel selection unit 20, which is a main configuration unit of the present embodiment, and the table RAM 22 created in advance
The operation with the channel selection based on the above information will be described. The channel selection unit 20 includes the microprocessor 21, the table RAM 22, the timer 23, and the remote control receiver 24. The remote control receiver 24 receives the program number selection information transmitted by operating the program selection unit (remote control) 30 and supplies it to the microprocessor 21. The microprocessor 21 determines the program number stored in the table RAM 22, the broadcast frequency channel, the definition of the broadcasted video, and the frequency channel to be received based on the correspondence of the reception state grasped by the error detector 16. The segment number is determined, the oscillation frequency of the PLL incorporated in the local oscillation circuit 13 is controlled so that the frequency channel is received, and the demodulator 15 specifies the segment number to be demodulated. In this way, based on the program selection information supplied to the receiving unit 10 from the channel selecting unit 20, the receiving unit 10 operates as described above, and outputs the target video and audio signals.

The relationship between the frequency channel to be received and the program channel is stored in the table RAM 22, and the stored contents are updated as necessary. The update time interval differs depending on whether the receiving apparatus is a mobile type or a fixed type. In the case of fixed reception, a power switch (not shown) is operated, and when reception starts, program channel information is created and a table is created. The program channel information is stored in the RAM 22, and thereafter, the program channel information is updated at infrequent intervals.
In the case of mobile reception, it is necessary to update reception frequency channel information and program channel information according to the movement of the receiving device,
The storage contents of the table RAM 22 are updated as appropriate. The table RAM 22 is updated at a time interval generated by the timer 23, by a button operation on the remote controller 30 as necessary, and further, when the receiver moves out of the broadcast service area, an error detection unit is used. Inspection of the error output signal of No. 16 and detection of departure from the service area according to the increase of the error signal, and when a broadcast is received in a new broadcast area, the program channel information is obtained,
The table RAM 22 is updated. Here, referring to FIG.
The program channel information stored in the table RAM 22 will be briefly described. The program channel information searches for the channel on which the OFDM signal is received while scanning the OFDM broadcast channel in order of the oscillation frequency of the PLL incorporated in the local oscillation circuit 13 in accordance with a command from the microprocessor 21. When the OFDM signal is received, the program channel information is obtained from the received bit stream, and the frequency channel, the program channel, the segment number, and whether the video is SDTV or H
The information on the definition of whether or not the TV is a DTV and the information such as the reception state by the output of the error detection circuit are stored. In the example shown in the figure, program channels 1 and 3 are
This shows that the program channels 7 and 8 are received on the frequency channel 5, and further, not shown, program type information such as broadcast definition information, audio broadcast, data broadcast, and error detection indicating the reception state. The output information of the circuit 16 is also stored.

Next, referring to FIG.
Will be described in more detail. FIG. 5 is a flowchart showing these processing steps. Step 1 is to initialize a frequency channel, input a channel number to start scanning, and start receiving from the first frequency channel. Step 2 is a step of checking the output of the demodulator 15.
When an OFDM signal is received on the receiving frequency channel, information such as the program channel number and broadcast type is obtained. Step 3 is a step of checking the program channel. When the OFDM signal is received, the program channel number is detected. When the OFDM signal is not received, the program channel data cannot be read and the determination is "No". move on. In step 4, the number of reception frequency channels is increased by 1, and the operation from step 2 is repeated. O
When an FDM signal is received, program channel information is obtained from the demodulator 15, “Yes” in step 3, and the process proceeds to step 5. In step 5, the frequency channel information being received and all the program channel information, definition information, and reception quality information received on the channel are stored in the table RAM 22. In step 6, the frequency channel number is checked, and if it is not the last channel, the frequency channel is incremented by one in step 4, and the same operation is performed. The operation is continued until the frequency channel becomes the last channel. The data such as the OFDM frequency channel and the program channel information are stored, and the operation ends.

Thus, the OFDM is stored in the table RAM 22.
After the data of the frequency channel and the program channel information are stored, the program channel number designated by operating the remote controller 30 or the like refers to the frequency channel information of the table RAM 22 via the remote control receiver 24 and the microprocessor 21. , When multiple programs of the same type are being broadcast, the most suitable definition for the receiver,
The signal of the reception quality is selected, the local oscillation circuit 13 oscillates at the frequency for receiving the frequency channel, receives the frequency channel, and the demodulator 15 demodulates the program channel of the target segment number, and Reference numeral 17 decodes the demodulated bit stream and outputs a video signal and an audio signal of the designated program.

[0014] In this way, the viewer can receive the broadcast, for example, as if directly specifying the target program channel number, without being conscious of which frequency channel the program is being broadcast on. Works. Further, when the same program is being broadcast on SDTV and HDTV, a signal of a high definition which can be received by the receiving device is received in consideration of a receiving state, a more suitable channel is received, and a receiving output is obtained. In the case of fixed reception, when the receiving device is turned on and reception is started, transmission information of a new program channel is obtained and a reception channel is selected. The specified reception is performed.

In the case of mobile reception, the error detection circuit 16 detects whether or not the reception is within the broadcast service area. , A program channel can be received. Furthermore, in the BST-OFDM system, a dedicated segment for mobile reception is provided, and broadcasting is performed in which the definition and the quantization number of coding are small but the mobile performance is improved. When moving at high speed, receive by specifying the segment number for mobile reception,
When moving at a low speed, reception can be performed in the SDTV mode for fixed reception in a good reception environment in a good reception environment. I do. In the mobile reception in which the reception environment changes, the table RAM 22 is periodically updated. However, since the timer 23 updates the table RAM 22 with a signal output at predetermined time intervals, in a constantly updated program broadcast situation, Automatic selection of a channel is performed according to an instruction from the microprocessor 21 so that the program broadcast can be switched and received according to the optimum definition and the reception state.

As described above, according to the apparatus of the present embodiment, there is an effect that it is possible to specify the number of the program supplier and to receive a broadcast with the most preferable definition and reception state among the desired programs. In particular, in the mobile receiving apparatus, there is an effect that it is possible to automatically select and perform the reception of the best broadcast in the reception environment from a plurality of programs of the same content that are broadcast. In the above embodiment, the program number to be received is specified by the remote controller 30. However, the present invention is not limited to this. Any means may be used for inputting the program number. Similar effects can be obtained by a well-known configuration. In the above embodiment, the broadcasting method using OFDM has been described. However, the present invention is not limited to this, and 8 VSB (8 Vestigial Side Bands), which is adopted in US terrestrial broadcasting, expresses a binary digital signal as 3 bits. And other types of digital modulation to provide a plurality of programs in a single frequency band. The same effect is obtained as a receiving device. Furthermore, in a receiving apparatus having a function of receiving satellite broadcasting in a receiving unit,
By having both terrestrial and satellite broadcast program information,
Channel selection including satellite broadcasting can be performed, and the same effect can be obtained.

[0017]

According to the first aspect of the present invention, the program of the program number designated by the program designation information is received on the basis of the program broadcast information stored in the storage means. Even when the transmission channel is changed, such as a period, there is an effect that the program number can be directly specified to enable reception. According to the second aspect of the present invention, there is an effect that it is possible to automatically select the best program including the receiving state, especially when the same program is broadcast with different definition. Furthermore, according to the third aspect of the present invention, even when the mobile station moves to a different broadcast service area by mobile reception, the radio wave reception state is monitored by the error detector. In addition, there is an effect that another broadcast channel of the same program can be automatically selected and received.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a receiving device employing a program selection device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a table RAM data input method according to an embodiment of the present invention.

FIG. 3 is a diagram showing an operation flow of the microcomputer in the embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating a signal spectrum of an OFDM signal.

FIG. 5 is a diagram showing a spectrum of one carrier in a signal constituting OFDM.

FIG. 6 is a diagram illustrating a spectrum of a plurality of carriers in a signal constituting OFDM.

FIG. 7 is a diagram illustrating an example in which an OFDM wave is arranged in an empty channel of an existing broadcast.

FIG. 8 is a diagram illustrating a positional relationship between an OFDM transmission channel and a program channel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Antenna 10 Video and audio broadcast receiving part 11 High frequency amplification circuit 12 Frequency conversion circuit 13 Local oscillation circuit 14 Intermediate frequency amplification circuit 15 Demodulation circuit 16 Error detection circuit 17 MPEG decoder 18 Video signal amplification circuit 19 Audio signal amplification circuit 20 Channel selection part Reference Signs List 21 microprocessor 22 table RAM 23 timer 24 remote control receiving circuit 30 remote control transmitting unit c1, c2, c3, c4, c6, c7, c8, c9 center position of adjacent carrier

Claims (3)

[Claims] An apparatus for receiving a digitally modulated broadcast wave, comprising: a local oscillation means for obtaining an oscillation output corresponding to a selectively specifiable reception channel; and a demodulation for demodulating a digitally modulated signal of the received channel. Means for obtaining and storing program information from the demodulated demodulated output, and a program number specifying means for specifying a program number based on the program specifying information. A program selecting apparatus, wherein an oscillation frequency of said local oscillation means is set based on program number information and broadcast frequency channel information stored in said storage means. 2. An apparatus for receiving a digitally modulated broadcast wave, comprising: a local oscillator for obtaining an oscillation output corresponding to a selectively specifiable reception channel; and a demodulator for demodulating a digitally modulated signal of the received channel. Means, an error detection means for generating an output signal corresponding to the quality of the reception state, means for storing the detected output and program information obtained from the demodulated output of the demodulation means, and a program number based on the program designation information. Program number designation means for designating, at least, the program designated by the program number designation means, based on the program information, reception quality information, and broadcast frequency channel information stored in the storage means, A program selecting apparatus, wherein an oscillation frequency of said local oscillation means is set to an optimum reception state. 3. An apparatus for receiving a digitally modulated broadcast wave, wherein the means for obtaining and storing program information from a demodulated demodulated output updates the contents of the storing means based on an output signal of an error detecting means. Means for setting the oscillation frequency of said local oscillation means based on the updated program number information and broadcast frequency channel information stored in said storage means. Item 3. The program selection device according to item 1 or 2.