JP4595698B2 - Television broadcast receiver - Google Patents

Description

  The present invention relates to a television broadcast receiver capable of receiving a television broadcast signal such as digital broadcast, and more particularly to a television broadcast receiver provided with an RF capture means capable of efficiently recording a television broadcast signal.

  Conventionally, a television broadcast receiving apparatus includes a tuner for receiving a television broadcast signal (RF signal), selectively receives a frequency signal corresponding to a desired channel from the television broadcast signal, and receives the received frequency signal. And the demodulated data is output to a display device and an audio output device. At this time, the tuner generally performs demodulation processing after converting the RF signal input from the antenna into an intermediate frequency signal (IF signal) having a low frequency. The following prior application techniques have been proposed as a technique related to a digital broadcast receiving apparatus having such a tuner.

  For example, Patent Literature 1 discloses that when a tuner is set to a predetermined channel selection frequency during channel selection, a frequency error of the IF signal is detected, and based on this, the channel selection frequency is determined as the broadcast signal reception frequency. After performing tuning control of the tuning frequency so that it becomes, the frequency error of the IF signal is detected from the demodulated data, and based on this, the tuning frequency is pulled so that the tuning frequency matches the reception frequency of the broadcast signal. A digital broadcast channel selecting apparatus that performs the above-described process is disclosed.

  Further, for example, Patent Literature 2 discloses a frequency setting method in a receiving apparatus including a redistribution frequency table that holds a redistribution frequency of a redistributed broadcast signal in a hearing system that redistributes broadcast signals from a plurality of networks. Is disclosed.

  Further, in Patent Document 3, when a digital broadcast wave is frequency offset to avoid an adjacent channel, this frequency offset is automatically detected at the time of channel selection, and shifted to a specified frequency band based on the result. A digital broadcast receiving apparatus that can be used is disclosed.

  Also, the transport stream of the digital broadcast signal includes a packet including a network information table (NIT) including various information necessary for receiving a program such as a program genre. Patent Document 4 discloses a digital reception apparatus that uses this NIT to acquire a service list from an area where the reception state of the receiver is advantageous and to set a reception environment.

By the way, in recent years, a so-called RF capture device has been provided in which received television broadcast signals are sequentially stored in a storage medium so that even a past program can be viewed. This RF capture device, for example, converts a signal of one TV channel bandwidth (for example, 6 MHz) from a television broadcast signal into an IF signal, and then samples it in an A / D converter and stores it in a storage medium. is there.
JP 2003-101388 A JP 2004-266365 A JP 2001-285032 A Japanese Patent Laying-Open No. 2005-064719

  As described above, the conventional RF capture device is usually designed to store only one TV channel, and cannot store a plurality of television broadcast signals. In addition, it is possible to store multiple TV broadcast signals that are broadcast simultaneously by providing multiple tuners, but since each TV channel's broadcast signal is stored separately, it is compatible with each tuner. Thus, it is necessary to provide a storage medium. Alternatively, when the broadcast signals extracted and output by a plurality of tuners are stored in one storage medium, it is necessary to associate the TV channel with the stored data, and the control becomes complicated.

  On the other hand, when the entire bandwidth (about 700 MHz) of all television broadcast waves is stored, it is difficult to record all channels for a long time because the storage capacity becomes enormous.

  An object of the present invention is to provide a television broadcast receiver capable of efficiently recording programs of a plurality of channels broadcast simultaneously.

  The present invention has been made to solve the above-described problems, and includes RF capture means capable of recording a television broadcast signal. The RF capture means is based on a television broadcast signal input via an antenna. Broadcast signal extraction means for extracting broadcast signals corresponding to a plurality of channels, broadcast signal synthesis means for synthesizing a plurality of broadcast signals extracted by the broadcast signal extraction means, and analog synthesis synthesized by the broadcast signal synthesis means A / D conversion means for converting a broadcast signal into digital data, broadcast signal storage means for storing the digital data converted by the A / D conversion means, and digital data stored in the broadcast signal storage means as an analog signal And a D / A conversion means for converting to a television broadcast receiver.

  Specifically, a plurality of the broadcast signal extraction means are provided, and each of the plurality of broadcast signal extraction means mixes the first local oscillation signal with the television broadcast signal to obtain the first intermediate frequency from the broadcast signal of an arbitrary channel. First frequency conversion means for generating a signal, filter means for extracting a first intermediate frequency signal in a specific frequency range from the output of the first frequency conversion means, and the first intermediate frequency signal obtained by the filter means Second frequency conversion means for generating a second intermediate frequency signal by mixing two local oscillation signals, and controlling the frequency of the first local oscillation signal based on the frequency information of the broadcast signal of each channel. The second local oscillation signal is controlled so that the bands of the second frequency signals output from the plurality of second frequency conversion means are continuous. At this time, broadcast signals of the same number of channels as the number of provided broadcast signal extraction means can be extracted.

  The frequency information of the broadcast signal of each channel is acquired from a network information table included in the broadcast signal of each channel. For example, a transport stream of a digital broadcast signal includes a packet including a network information table.

  Also, a broadcast signal processing unit is provided that can extract a broadcast signal of a desired channel from the analog signal output from the D / A conversion unit, generate a video signal and an audio signal from the broadcast signal, and output the video signal and the audio signal. .

  According to the present invention, in the television broadcast receiving apparatus provided with the RF capture means capable of recording the television broadcast signal, the RF capture means corresponds to a plurality of channels from the television broadcast signal input via the antenna. Broadcast signal extraction means for extracting broadcast signals to be transmitted, broadcast signal synthesis means for synthesizing a plurality of broadcast signals extracted by the broadcast signal extraction means, and conversion of analog synthesized broadcast signals synthesized by the broadcast signal synthesis means into digital data A / D conversion means, broadcast signal storage means for storing digital data converted by the A / D conversion means, and D / A conversion means for converting the digital data stored in the broadcast signal storage means into analog signals Therefore, it is possible to efficiently record broadcast signals of multiple channels broadcast simultaneously. Kill. That is, only the broadcast signal of the channel desired by the user is extracted and synthesized, and the synthesized broadcast signal is sampled and stored in the storage means. It is compressed efficiently. Accordingly, since the capacity required for recording a broadcast signal for a predetermined time is reduced, the broadcast signal can be recorded for a long time in a storage means having a predetermined capacity.

  In addition, a plurality of broadcast signal extraction means are provided, and each of the plurality of broadcast signal extraction means generates a first intermediate frequency signal from a broadcast signal of an arbitrary channel by mixing the first local oscillation signal with the television broadcast signal. A frequency conversion means, a filter means for extracting a first intermediate frequency signal in a specific frequency range from the output of the first frequency conversion means, and a second local oscillation signal mixed with the first intermediate frequency signal obtained by the filter means Since the second frequency conversion means for generating the second intermediate frequency signal is provided, broadcast signals of a plurality of channels can be easily extracted. In addition, the frequency of the first local oscillation signal is controlled based on the frequency information of the broadcast signal of each channel, and the second frequency signal output from each second frequency conversion means is continuous so that the band of the second frequency signal is continuous. Since the two local oscillation signals are controlled, a plurality of second frequency signals can be easily synthesized in the broadcast signal synthesis unit.

  Since the frequency information of the broadcast signal of each channel is obtained from the network information table included in the broadcast signal of each channel, the user can select the desired channel and the frequency of the first local oscillation signal can be obtained. It will be controlled automatically.

  Furthermore, a broadcast signal processing unit is provided that can extract a broadcast signal of a desired channel from the combined broadcast signal output from the D / A conversion unit, generate a video signal and an audio signal from the broadcast signal, and output the generated signal. Therefore, it is possible to output data that can be reproduced by a general display device (for example, a liquid crystal monitor or the like) or an audio output device (for example, a speaker or the like) without restoring the synthesized transmission signal to the original RF signal. it can.

  The best mode for carrying out a television broadcast receiver according to an embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a main configuration of a television broadcast receiving apparatus 100 according to the present invention.

  As shown in FIG. 1, the television broadcast receiving apparatus 100 of this embodiment includes an antenna 1, an RF capture unit 2, a signal selector 3, a reception processing unit (tuner) 4, a reproduction unit 5, a main control unit 6, and an input unit. 7 and so on. The television broadcast receiver 100 is connected to the display device 200 and the audio output device 300.

  The antenna 1 is a parabolic antenna, a UHF antenna or the like, receives a television broadcast signal, and outputs an RF (Radio Frequency) signal to the RF capture unit 2 or the signal selector 3. In addition, when receiving a television broadcast signal via a CATV line, a connection cable (not shown) or the like may be provided instead of the antenna 1.

  The RF capture unit 2 includes a plurality of broadcast signal extraction units 21, 22, 23,..., A broadcast signal synthesis unit 24, an A / D conversion unit 25, a storage unit (broadcast signal storage means) 26, a D / A And a conversion unit 27.

  Furthermore, the broadcast signal extraction units 21, 22, and 23 generate a first intermediate frequency signal from the broadcast signal of an arbitrary channel by mixing the first local oscillation signal with the television broadcast signal input via the antenna 1. Bandpass filters (filter means) 21b, 22b, 23b for extracting the first intermediate frequency signal in a specific frequency range from the outputs of the first frequency converters 21a, 22a, 23a and the first frequency converters 21a, 22a, 23a. And second frequency converters 21c, 22c, 23c for generating a second intermediate frequency signal by mixing the second local oscillation signal with the first intermediate frequency signal obtained by the bandpass filters 21b, 22b, 23b, It is configured with.

  The broadcast signal synthesis unit 24 synthesizes a plurality of broadcast signals (second intermediate frequency signals) extracted by the broadcast signal extraction units 21, 22, 23,. The A / D converter 25 samples the analog synthesized broadcast signal input from the broadcast signal synthesizer 24, converts it into digital data, and outputs it to the storage unit 26.

  The accumulation unit 26 is configured by, for example, a hard disk device or the like, and sequentially stores the digital data input from the A / D conversion unit 25. Further, when the digital data stored in the storage unit 26 is reproduced, the digital data is output to the D / A conversion unit 27. The D / A conversion unit 27 converts the digital data output from the storage unit 26 into an analog signal and outputs the analog signal to the signal selector 3.

  The signal selector 3 is connected to the tuner 4, selects either the RF signal from the antenna 1 or the analog signal from the RF capture unit 2 based on the operation signal from the input unit 7 by the user, and outputs it to the tuner 4. To do.

  The tuner 4 extracts a broadcast signal of a channel desired by the user from the broadcast signal selected by the signal selector 3 and outputs it to the reproduction unit 5. The reproduction unit 5 outputs a video signal and an audio signal obtained by performing demodulation processing, decoding processing, and the like on the broadcast signal input from the tuner 4 to the display device 200 and the audio output device 300, respectively. The broadcast signal processing means composed of the tuner 4 and the reproduction unit 5 extracts a broadcast signal of a desired channel from the analog signal output from the RF capture unit 2, and generates a video signal and an audio signal from the broadcast signal. It is desirable to be configured so that it can be output.

  The input unit 7 includes keys and the like for inputting input signals relating to various modifications to the television broadcast receiving apparatus 100, and input signals of various operations are input to the television broadcast receiving apparatus 100 by being operated by the user. Is done. The input unit 7 also includes a selection key (not shown) for the user to select a program stored in the memory unit 23.

  As shown in FIG. 2, the main control unit 6 includes a CPU 60, a RAM 61, a ROM 62, and the like, and each unit (RF capture unit 2, signal selector 3, tuner 4, reproduction unit 5, and so on) of the television broadcast receiver 100. The input unit 7 and the like are controlled.

  The CPU 60 reads the processing program stored in the ROM 62, develops it in the RAM 61, and executes it to control the entire television broadcast receiving apparatus 100.

  The RAM 61 expands the processing program executed by the CPU 60 in the program storage area in the RAM 61, and stores the input data and the processing result generated when the processing program is executed in the data storage area.

  The ROM 62 is composed of, for example, a semiconductor memory or the like, and stores various data, various processing programs, data processed by executing these programs, and the like for the CPU 60 to realize a function of controlling the entire television broadcast receiving apparatus 100. . More specifically, for example, as shown in FIG. 2, the ROM 62 stores a recording program 62a, a normal broadcast program 62b, a reproduction program 62c, and the like.

  The CPU 60 executes the RF capture process according to the present invention by executing the recording program 62a. This RF capture process will be described in detail later.

  Further, the CPU 60 executes the normal broadcast program 62b to control the signal selector 4 to output the RF signal input from the antenna 1 to the tuner 4 and control the tuner 4 to broadcast the channel desired by the user. A signal (intermediate frequency signal) is extracted and output to the reproduction unit 5, and the reproduction unit 5 is controlled to perform demodulation processing or the like on the intermediate frequency signal, and the obtained video signal and audio signal are respectively displayed on the display device 200. , Output to the audio output device 300.

  In addition, the CPU 60 executes the reproduction program 62c so that when the user presses a selection key (not shown) of the input unit 7, the CPU 60 designates the program included in the composite broadcast signal stored in the storage unit 26. The digital data of the broadcast program is output to the D / A converter 25, the D / A converter 27 is controlled to convert the digital data output from the storage unit 26 into an analog signal, and the signal selector 3 is controlled. The analog signal is output to the tuner 4. Then, the broadcast signal of the channel desired by the user is extracted by controlling the tuner 4 and output to the reproduction unit 5, and the reproduction unit 5 is controlled to perform demodulation processing or the like on the intermediate frequency signal. Video signals and audio signals are output to the display device 200 and the audio output device 300, respectively.

  Next, the RF capture processing of the television broadcast receiving apparatus 100 according to the embodiment of the present invention having the above-described configuration will be specifically described with reference to the flowchart shown in FIG. Note that the channel to be RF-captured can be set, for example, by the user operating the input unit 7.

First, the CPU 60 controls the first frequency converters 21a, 21b, and 21c by executing the recording program 62a, and mixes the first local oscillation frequency with the RF signal input via the antenna 1 to perform the first program. One intermediate frequency signal is generated (step S101). At this time, based on the frequency information of the broadcast signal of the channel that the user desires to record, the frequency of the first local oscillation signal at the time of frequency conversion in the first frequency converters 21a, 21b, 21c is controlled (frequency control means) ). For example, when the frequency of the broadcast signal of the channel that the user desires to record is f ₁ MHz, f ₂ MHz, and f ₃ MHz, the first frequency converter 21a sets the frequency of the first local oscillation signal as f ₁ +100 MHz. The first frequency converter 21b converts the frequency of the first local oscillation signal to f ₂ +100 MHz, and the first frequency converter 21c converts the frequency of the first local oscillation signal to f ₃ +100 MHz. The first frequency converters 21a, 21b, and 21c generate a first intermediate frequency signal of 100 MHz.

  Note that the frequency information of the broadcast signal of each channel may be acquired from a network information table (NIT) included in the broadcast signal of each channel, or may be acquired by channel scanning.

  Next, the bandpass filters 21b, 22b, and 23b are controlled to extract a frequency signal in a specific frequency range (for example, a bandwidth of 6 MHz) from the first intermediate frequency signal (step S102). Here, when the frequencies of the first intermediate frequency signals output from the first frequency converters 21a, 21b, and 21c are the same (for example, 100 MHz), the bandpass filters 21b, 22b, and 23b should have a common specification. Can do.

  Next, the second frequency converters 21c, 22c, and 23c are controlled so that the second local oscillation frequency is mixed with the first intermediate frequency signal output from the bandpass filters 21b, 22b, and 23b to obtain the second intermediate frequency. A signal is generated (step S103). At this time, the second local oscillation signal at the time of frequency conversion in the second frequency conversion units 23a, 23b, 23c so that the bands of the second frequency signals output from the second frequency conversion means 21c, 22c, 23c are continuous. Is controlled (frequency control means).

For example, the second frequency conversion unit 23a converts the frequency of the second local oscillation signal as f ₄ MHz, the second frequency conversion unit 23b converts the frequency of the second local oscillation signal as f ₄ +6 MHz, and the first frequency conversion. The frequency converter 23c converts the frequency of the second local oscillation signal to f ₄ +12 MHz so that the second intermediate frequency signal (bandwidth 6Mz) generated by the second frequency converters 23a, 23b, and 23c has a band. It will be continuous. At this time, it is desirable that the lower frequency limit of the second intermediate frequency signal having the lowest frequency be 0 MHz.

  Next, the broadcast signal synthesis unit 24 is controlled to synthesize the second intermediate frequency signal (step S104). Here, since the frequency bands of the respective second intermediate frequency signals are continuous without overlapping, they can be easily synthesized.

  Next, the A / D converter 25 is controlled to sample the analog synthesized broadcast signal input from the broadcast signal synthesizer 24 and convert it into digital data (step S105).

  Next, the digital data generated by the A / D conversion unit 25 is stored in the storage unit 26 (step S106).

  As described above, according to the television broadcast receiving apparatus according to the present embodiment, only the broadcast signal of the channel desired by the user is extracted and synthesized, and the synthesized broadcast signal is sampled and stored in the storage means. The frequency band that is an empty channel is eliminated, and the frequency band for sampling is efficiently compressed. For example, as shown in FIG. 4, even when RF capture is performed for broadcast signals of channels 1 to 5 with a bandwidth of several hundreds of MHz, the broadcast signals of each channel are extracted and frequency-converted so that they are continuous in sequence. Therefore, the frequency bandwidth to be sampled is compressed to 30 MHz (bandwidth of one broadcast signal: 6 MHz). Accordingly, since the capacity required for recording a broadcast signal for a predetermined time is reduced, the broadcast signal can be recorded for a long time in a storage means having a predetermined capacity.

  As mentioned above, although the invention made by this inventor was concretely demonstrated based on embodiment, this invention is not limited to the said embodiment, It can change in the range which does not deviate from the summary.

  The configuration of the RF capture unit 2 described in the above embodiment is an example, and any configuration that can realize the same function may be used. That is, there is no particular limitation as long as it can extract broadcast signals corresponding to a plurality of channels from a television broadcast signal input via an antenna and synthesize and store the extracted plurality of broadcast signals.

  Further, the number of broadcast signal extraction units constituting the RF capture unit 2 is not limited, and it is possible to capture broadcast signals of the same number of channels by increasing the number of broadcast signal extraction units.

It is a block diagram which shows the principal part structure of the television broadcast receiver which concerns on this invention. It is a block diagram explaining the structure of the main control part which concerns on this invention. It is a flowchart explaining the RF capture process of the television broadcast receiver which concerns on this invention. It is a conceptual diagram when carrying out RF capture of the broadcast signal of multiple channels.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna 2 RF capture part 3 Signal selector 4 Tuner 5 Playback part 6 Main control part 7 Input part 21,22,23 Broadcast signal extraction part 21a, 22a, 23a 1st frequency conversion part 21b, 22b, 23b Bandpass filter 21c 22c, 23c Second frequency converter 24 Broadcast signal synthesizer 25 A / D converter 26 Accumulator 27 D / A converter 100 Television broadcast receiver 200 Display device 300 Audio output device

Claims (1)

An RF capture means capable of recording a television broadcast signal, a broadcast capable of extracting a broadcast signal of a desired channel from the broadcast signal output from the capture means, and generating and outputting a video signal and an audio signal from the broadcast signal A television broadcast receiving device comprising signal processing means,
The RF capture means is
A plurality of broadcast signal extraction means for extracting broadcast signals corresponding to a plurality of channels from a television broadcast signal input via an antenna;
Broadcast signal combining means for combining a plurality of broadcast signals extracted by the broadcast signal extracting means;
A / D conversion means for converting the analog synthesized broadcast signal synthesized by the broadcast signal synthesis means into digital data;
Broadcast signal storage means for storing digital data converted by the A / D conversion means;
D / A conversion means for converting the digital data stored in the broadcast signal storage means into an analog signal;
Configured with
Each of the broadcast signal extraction means is
First frequency conversion means for generating a first intermediate frequency signal from a broadcast signal of an arbitrary channel by mixing the first local oscillation signal with the television broadcast signal;
Filter means for extracting a first intermediate frequency signal in a specific frequency range from the output of the first frequency conversion means;
Second frequency conversion means for generating a second intermediate frequency signal by mixing the second local oscillation signal with the first intermediate frequency signal obtained by the filter means,
Based on each frequency information acquired from the network information table included in the broadcast signal of each channel, the frequency of the first local oscillation signal is controlled to a frequency obtained by adding the same frequency to the frequency of each frequency information. And the second local oscillation signal is controlled so that the bands of the second frequency signals output from the plurality of second frequency conversion means are continuous.

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