JP4134099B2 - Television broadcast receiver - Google Patents

Description

  The present invention relates to a television broadcast receiving apparatus.

  Conventionally, a television broadcast receiver includes a plurality of tuners for receiving a plurality of channels, and allows each tuner to selectively receive a television broadcast wave having a frequency of each channel from the television broadcast waves. The television broadcast wave data is demodulated, and the demodulated data is output to a display device or an audio output device or stored in a memory unit (for example, Patent Documents 1 and 2).

  Further, not only video data and audio data but also program schedule data called EPG (Electronic Program Guide) are transmitted simultaneously as television broadcast waves. A television broadcast receiver that displays a program schedule on a display device using the EPG data is also known (for example, Patent Document 3).

  Further, in a television broadcast receiving apparatus that performs a channel search for searching for a television broadcast wave that is broadcasting a program from among the television broadcast waves, based on the reception level and noise level of the received television broadcast wave data It is also known that a television broadcast wave that broadcasts a program is determined and only a television broadcast wave that broadcasts a program is reliably searched (for example, Patent Documents 4 and 5). ).

By the way, in the television broadcast receiving apparatus, the received television broadcast wave data is subjected to demodulation processing and the like and sequentially stored in the memory unit so that even past programs can be viewed. When storing programs of a plurality of channels broadcast simultaneously, a tuner is required for each channel. That is, for example, about 50 channels of television broadcast waves are included in the digital television broadcast waves, so that the tuners for 50 channels are used to store the data of the television broadcast waves of all channels in the memory unit. Is required.
JP 2004-336518 A JP 2003-163852 A JP 2005-39487 A JP 2004-266658 A JP 2005-5894 A

  However, if a tuner is provided for each channel, the cost increases, and the television broadcast receiving apparatus becomes very expensive.

  An object of the present invention is to provide a television broadcast receiver capable of storing programs of a plurality of channels that are broadcast simultaneously without requiring a tuner for each channel.

The invention according to claim 1 is a baseband signal generating means for generating a predetermined baseband signal from an RF signal of a television broadcast wave;
A / D conversion means for converting the baseband signal generated by the baseband signal generation means into digital data by analog-digital conversion;
A memory unit for storing digital data converted by the A / D conversion unit;
D / A conversion means for converting the digital data stored in the memory section into a baseband signal by digital-analog conversion;
IF signal generation means for generating an IF signal of a channel desired by the user from the baseband signal converted by the D / A conversion means;
Storage control means for adding to the digital data time information when the television broadcast wave of the digital data is received and storing it in the memory unit;
It is characterized by having.

According to a second aspect of the present invention, there is provided baseband signal generation means for generating a predetermined baseband signal from an RF signal of a television broadcast wave;
A / D conversion means for converting the baseband signal generated by the baseband signal generation means into digital data by analog-digital conversion;
A memory unit for storing digital data converted by the A / D conversion unit;
D / A conversion means for converting the digital data stored in the memory section into a baseband signal by digital-analog conversion;
IF signal generation means for generating an IF signal of a channel desired by the user from the baseband signal converted by the D / A conversion means;
It is characterized by having.

  According to a third aspect of the present invention, in the television broadcast receiving apparatus according to the second aspect, the A / D conversion means performs sampling at a frequency that is at least twice the frequency of the target band. .

  According to a fourth aspect of the present invention, in the television broadcast receiving apparatus according to the second or third aspect, time information when a digital broadcast wave of the digital data is received is added to the digital data, and the memory unit It is characterized by having a storage control means for storing the data.

  According to the first aspect of the present invention, the baseband signal generation means generates a predetermined baseband signal from the RF signal input from the receiving unit that receives the television broadcast wave, and the A / D conversion means The baseband signal generated by the baseband signal generation means is converted into digital data by analog-digital conversion, and the digital data converted by the A / D conversion means is stored in the memory unit. The data is converted into an IF signal by the tuner and stored in the memory unit without being demodulated or the like, so that a program of a plurality of channels broadcast simultaneously can be stored in the memory unit without providing a tuner for each channel. Can be remembered.

  Further, the digital data stored in the memory unit is converted into a baseband signal by the D / A conversion means, and converted into a baseband signal. From the baseband signal converted by the D / A conversion means by the IF signal generation means, the user Since the IF signal of the desired channel is generated, the user can directly generate the IF signal of the desired channel without reproducing the RF signal from the digital data stored in the memory unit. Digital data stored in the memory unit can be reproduced.

  Further, the storage control means adds the time information when the digital broadcast of the digital data is received to the digital data and stores it in the memory unit. Therefore, when reproducing the digital data stored in the memory unit, The digital data to be reproduced can be selected based on the time information.

According to the second aspect of the present invention, the baseband signal generation means generates a predetermined baseband signal from the RF signal input from the receiving unit that receives the television broadcast wave, and the A / D conversion means The baseband signal generated by the baseband signal generation means is converted into digital data by analog-digital conversion, and the digital data converted by the A / D conversion means is stored in the memory unit. The data is converted into an IF signal by the tuner and stored in the memory unit without being demodulated or the like, so that a program of a plurality of channels broadcast simultaneously can be stored in the memory unit without providing a tuner for each channel. Can be remembered.

  Further, the digital data stored in the memory unit is converted into a baseband signal by the D / A conversion means, and converted into a baseband signal. From the baseband signal converted by the D / A conversion means by the IF signal generation means, the user Since the IF signal of the desired channel is generated, the IF signal of the desired channel is directly generated by the user without reproducing the RF signal from the digital data stored in the memory unit 23, which is more efficient. The digital data stored in the memory unit can be reproduced.

  According to the invention described in claim 3, the same effect as that of the invention described in claim 2 can be obtained. In particular, the A / D conversion means has a frequency more than twice the frequency of the target band. Since sampling is performed at the frequency, it is possible to prevent deterioration when the RF signal is reproduced.

  According to the invention described in claim 4, the same effect as that of the invention described in claim 2 or 3 can be obtained, and in particular, the digital data is converted into the television of the digital data by the storage control means. Since the time information when the broadcast wave is received is added and stored in the memory unit, the digital data to be reproduced can be selected based on the time information when the digital data stored in the memory unit is reproduced. .

  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.

  First, the configuration of the television broadcast receiving apparatus 100 according to the embodiment of the present invention will be described. As shown in FIG. 1, a television broadcast receiving apparatus 100 according to the present invention includes an antenna 1, a broadcast wave storage unit 2, a tuner 3, a signal selector 4, a reproduction unit 5, a main control unit 6, an input unit 7, and the like. Configured.

  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 wave, and outputs an RF (Radio Frequency) signal to the broadcast wave storage unit 2 or the tuner 3. In the case of receiving a television broadcast wave via a CATV line, a connection cable (not shown) or the like may be provided instead of the antenna 1.

The broadcast wave storage unit 2 includes a first mixer 20, a first LPF (Low Pass Filter) 21,
The A / D conversion unit 22, the memory unit 23, the control unit 24, the D / A conversion unit 25, the second LPF 26, the second mixer 27, and the like are configured, and the antenna is set according to the control signal from the main control unit 6. 1 stores the digital data generated by performing the digital-analog conversion processing or the like on the television broadcast wave received by 1 in the memory unit 23, and the IF signal of the channel desired by the user from the digital data stored in the memory unit 23 Is generated.

  The first mixer 20 includes a crystal oscillator or the like, and reduces the frequency of the RF signal by mixing the local oscillation frequency with the RF signal input from the antenna 1 so that the lower frequency limit of the target band is zero. A converted signal is generated and output to the first LPF 21. The first LPF 21 passes only a signal having a frequency equal to or lower than the cutoff frequency among the signals input from the first mixer 20, generates a baseband signal, and outputs the baseband signal to the A / D converter 22. Thereby, the first mixer 20 and the first LPF 21 function as baseband signal generation means.

  The A / D conversion unit 22 samples the baseband signal input from the first LPF 21, performs analog-digital conversion to generate digital data, and outputs the digital data to the memory unit 23. Thereby, the A / D converter 22 functions as an A / D converter. Here, the sampling in the A / D converter 22 may be performed at a frequency that is twice or more the frequency of the baseband signal in consideration of the Nyquist frequency in order to prevent deterioration when the baseband signal is reproduced. desirable.

  The memory unit 23 is configured by, for example, an HDD device, and sequentially stores digital data input from the A / D conversion unit 22. More specifically, digital data input from the A / D converter 22 and time information when the television broadcast wave of the digital data is received are stored. The time information is the time when the television broadcast wave of the digital data is received every predetermined unit time (for example, several tens of units, etc.), and may be added as header information to the digital data. It may be added as a table. Here, the time information may be, for example, time data based on a signal output from a clock circuit (not shown) provided in the broadcast wave storage unit 2, or the time information is included in the television broadcast wave. In such a case, the time information may be used.

  Further, when the digital data stored in the memory unit 23 is reproduced, the digital data is output to the D / A conversion unit 25.

  In accordance with a control signal from the main control unit 6, the control unit 24 adds time information when the television broadcast wave of the digital data is received to the digital data output from the A / D conversion unit 22 to the memory unit 23. Control of storing and control of output of digital data output from the memory unit 23 to the D / A conversion unit 25 are performed. Thereby, the control unit 24 functions as a storage control unit.

  The D / A converter 25 converts the digital data output from the memory unit 23 from digital to analog, generates a baseband signal, and outputs the baseband signal to the second LPF 26. Thereby, the D / A converter 25 functions as a D / A converter.

  The second LPF 26 passes only a signal having a frequency equal to or lower than the cutoff frequency among the baseband signals input from the D / A conversion unit 25 and outputs the signal to the second mixer 27. The second mixer 27 is composed of a crystal oscillator or the like, and generates the IF signal of the channel desired by the user by mixing the local oscillation frequency of the channel desired by the user with the signal input from the second LPF 26. Output to the signal selector 4. Thereby, the second LPF 26 and the second mixer 27 function as IF signal generation means.

The tuner 3 is an analog tuner or a digital tuner, and an IF (Intermediate Frequency) of a channel desired by the user from an RF signal input from the antenna 1.
Generate a signal. More specifically, the tuner 3 mixes the local oscillation frequency of the channel desired by the user with the input RF signal to generate an IF signal. The IF signal converted by the tuner 3 is output to the signal selector 4.

  The signal selector 4 is connected to the tuner 3, the second mixer 27, and the like, and an IF input from the tuner 3 or the second mixer 27 based on a signal input by operating the input unit 7 by the user. One of the signals is selected and output 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 IF signal input from the signal selector 4 to the display device 200 and the audio output device 300, respectively.

As shown in FIG. 2, the main control unit 6 includes a CPU (Central Processing Unit) 60,
A RAM (Random Access Memory) 61, a storage unit 62, and the like are provided. The main control unit 6 includes a first mixer 20, a first LPF 21, an A / D conversion unit 22, a memory unit 23, a control unit 24, a D / A conversion unit 25, a second LPF 26, a second mixer 27, The tuner 3, the signal selector 4, the reproduction unit 5, the input unit 7, and the like are connected to control each unit of the television broadcast receiving apparatus 100.

  The CPU 60 controls the entire television broadcast receiving apparatus 100 by reading out the processing program stored in the storage unit 62 and developing the processing program in the RAM 61 for execution.

  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 storage unit 62 includes, for example, a recording medium (not shown) in which programs, data, and the like are stored in advance, and this recording medium is configured by, for example, a semiconductor memory. In addition, the storage unit 62 stores various data, various processing programs, data processed by executing these programs, and the like for realizing a function for the CPU 60 to control the entire television broadcast receiving apparatus 100. More specifically, the storage unit 62 stores, for example, a recording program 62A, a normal broadcast program 62B, a reproduction program 62C, etc., as shown in FIG.

  The recording program 62A, for example, causes the CPU 60 to control the first mixer 20 and the first LPF 21 to generate a predetermined baseband signal from the RF signal input from the antenna 1, and to cause the A / D converter 22 to A function to control the baseband signal to be converted into digital data, and to control the control unit 24 to add the time information when the television broadcast wave of the digital data is received to the digital data and store it in the memory unit 23. This is a program to be realized. The CPU 60 functions as a storage control unit by executing the recording program 62A.

  The normal broadcast program 62B, for example, causes the CPU 60 to control the tuner 3 to generate an IF signal of a channel desired by the user from the RF signal input from the antenna 1, and controls the signal selector 4 to Video signals and audio signals obtained by causing the reproduction unit 5 to output and controlling the reproduction unit 5 to perform demodulation processing on the IF signal input from the signal selector 4 respectively. This is a program for realizing a function of outputting to the display device 200 and the audio output device 300.

  The reproduction program 62C, for example, controls the CPU 60 to control the control unit 24 so that the user depresses a selection key (not shown) of the input unit 7 (to be described later) digital data of the broadcast time of the designated program. Output to the A conversion unit 25, control the D / A conversion unit 25, digital-analog convert the digital data output from the memory unit 23 to generate a baseband signal, control the second LPF 26, Of the baseband signals input from the D / A converter 25, only the signal below the cut-off frequency is output to the second mixer 27, and the second mixer 27 is controlled by adjusting the local oscillation frequency. The IF signal of the channel desired by the user is generated from the signal input from the second LPF 26, and the signal selector 4 is controlled to input from the second mixer 27. The output unit 5 outputs the IF signal to the playback unit 5, and controls the playback unit 5 to perform demodulation processing on the IF signal input from the signal selector 4 and output it to the display device 200 and the audio output device 300. It is a program to let you.

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

  Next, the operation of the television broadcast receiving apparatus 100 according to the embodiment of the present invention configured as described above will be described with reference to the flowcharts shown in FIGS.

  First, operations from the reception of the television broadcast wave of the television broadcast receiving apparatus 100 to the storage of digital data in the memory unit 23 will be described with reference to the flowchart shown in FIG.

  First, the CPU 60 executes the recording program 62A to control the first mixer 20 and mix the local oscillation frequency with the RF signal input from the antenna 1, thereby down-converting the frequency of the RF signal. The generated signal is generated (step S1).

  Next, the CPU 60 controls the first LPF 21 to pass only a signal having a frequency equal to or lower than the cutoff frequency among the signals input from the first mixer 20 to generate a baseband signal (step S2). .

  Next, the CPU 60 controls the A / D converter 22 to sample the entire band of the baseband signal input from the first LPF 21 at a frequency that is twice or more the frequency of the band of the baseband signal, Analog-digital conversion is performed to generate digital data (step S3).

  Next, the CPU 60 controls the control unit 24 to store the digital data input from the A / D conversion unit 22 and time information when the television broadcast wave of the digital data is received in the memory unit 23 ( Step S4).

  Next, the operation of outputting the currently received broadcast of the television broadcast receiving apparatus 100 and the operation of outputting the digital data stored in the memory unit 23 will be described with reference to the flowchart shown in FIG.

  First, the CPU 60 executes the normal broadcast program 62B, controls the tuner 3, mixes the local oscillation frequency of the channel desired by the user with the RF signal input from the antenna 1, and generates an IF signal, The signal selector 4 is controlled to output the IF signal input from the tuner 3 to the reproduction unit 5, and the reproduction unit 5 is controlled to perform demodulation processing or the like on the IF signal input from the signal selector 4. The video signal and audio signal thus obtained are output to the display device 200 and the audio output device 300, respectively (step S101).

  Next, the CPU 60 determines whether or not the user has selected a program stored in the memory unit based on a selection signal input when the user presses a selection key (not shown) of the input unit 7. (Step S102).

  In step S102, when the CPU 60 determines that the selection signal from the input unit 7 is not input (step S102; Yes), the process returns to step S101.

On the other hand, when the CPU 60 determines in step S102 that the selection signal is input from the input unit 7 (step S102; No), the CPU 60 controls the control unit 24 by executing the reproduction program 62C. Thus, the digital data of the broadcast time of the program selected by the user from the memory unit 23 is output to the D / A conversion unit 25, and the D / A conversion unit 25 is controlled to output the digital data output from the memory unit 23. Digital-analog conversion is performed to generate a baseband signal (step S103).

  Next, the CPU 60 controls the second LPF 26 to pass only a signal having a frequency equal to or lower than the cutoff frequency among the baseband signals generated by the D / A converter 25 and outputs the signal to the second mixer 27. (Step S104).

  Next, the CPU 60 controls the second mixer 27 to mix the input baseband signal with the local oscillation frequency for generating the IF signal of the channel of the program that the user wants to reproduce, so that the user desires. The IF signal of the channel to be generated is generated (step S105).

  Next, the CPU 60 controls the signal selector 4 to output the IF signal input from the second mixer 27 to the reproduction unit 5 (step S106).

  Next, the CPU 60 controls the playback unit 5 so that a video signal and an audio signal obtained by performing demodulation processing and the like on the IF signal input from the signal selector 4 are displayed on the display device 200 and the audio, respectively. The output is made to the output device 300 (step S107).

  According to the television broadcast receiver 100 according to the present embodiment described above, the first mixer 20 and the first LPF 21 are used to generate a predetermined signal from an RF signal input from the antenna 1 that receives a television broadcast wave. A baseband signal is generated, and the baseband signal generated by the first mixer 20 and the first LPF 21 is converted into digital data by the A / D converter 22 and converted into digital data. Since the digital data converted by the D conversion unit 22 is stored, the television broadcast wave data is converted into an IF signal by the tuner and stored in the memory unit 23 without being demodulated. 3 is stored for each channel in the memory unit 23 even if a plurality of channels are broadcast simultaneously. It is possible.

  Also, the digital data stored in the memory unit 23 is converted from digital to analog by the D / A conversion unit 25 into a baseband signal, and the second mixer 27 and the second LPF 26 are used by the D / A conversion unit 25. Since the IF signal of the channel desired by the user is generated from the converted baseband signal, the IF signal of the channel desired by the user is generated directly from the digital data stored in the memory unit 23 without reproducing the RF signal. As a result, the digital data stored in the memory unit 23 can be reproduced more efficiently.

  Further, since the A / D converter 22 performs sampling at a frequency that is at least twice the frequency of the target band, it is possible to prevent deterioration when the RF signal is reproduced.

  Further, when the CPU 60 executes the recording program 62A, the digital data is added to the time information when the television broadcast wave of the digital data is received, and is stored in the memory unit 23. Therefore, the digital data is stored in the memory unit 23. When reproducing the digital data, the digital data to be reproduced can be selected based on the time information.

  In this embodiment, the IF signal of the channel desired by the user is generated from the baseband signal input from the second LPF 26 by the second mixer 27. However, the second mixer 27 An RF signal may be reproduced from the baseband signal. In this case, the RF signal reproduced by the second mixer 27 is output to the tuner 3, and the tuner 3 generates an IF signal desired by the user from the RF signal.

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 operation | movement of the television broadcast receiver which concerns on this invention. It is a flowchart explaining operation | movement of the television broadcast receiver which concerns on this invention.

Explanation of symbols

20 First mixer (baseband signal generating means)
21 First LPF (baseband signal generating means)
22 A / D converter (A / D converter)
23 memory unit 24 control unit (storage control means)
25 D / A converter (D / A converter)
26 Second LPF (IF signal generating means)
27 Second mixer (IF signal generating means)
60 CPU (storage control means)
62A Recording program (storage control means)
100 Television broadcast receiver

Claims (4)

Baseband signal generating means for generating a predetermined baseband signal from an RF signal of a television broadcast wave;
A / D conversion means for converting the baseband signal generated by the baseband signal generation means into digital data by analog-digital conversion;
A memory unit for storing digital data converted by the A / D conversion unit;
D / A conversion means for converting the digital data stored in the memory section into a baseband signal by digital-analog conversion;
IF signal generation means for generating an IF signal of a channel desired by the user from the baseband signal converted by the D / A conversion means;
Storage control means for adding to the digital data time information when the television broadcast wave of the digital data is received and storing it in the memory unit;
A television broadcast receiving apparatus comprising: Baseband signal generating means for generating a predetermined baseband signal from an RF signal of a television broadcast wave;
A / D conversion means for converting the baseband signal generated by the baseband signal generation means into digital data by analog-digital conversion;
A memory unit for storing digital data converted by the A / D conversion unit;
D / A conversion means for converting the digital data stored in the memory section into a baseband signal by digital-analog conversion;
IF signal generation means for generating an IF signal of a channel desired by the user from the baseband signal converted by the D / A conversion means;
A television broadcast receiving apparatus comprising:   The television broadcast receiving apparatus according to claim 2, wherein the A / D conversion means performs sampling at a frequency that is twice or more the frequency of a target band.   4. The television broadcast according to claim 2, further comprising storage control means for adding time information when a television broadcast wave of the digital data is received to the digital data and storing the information in the memory unit. 5. Receiver device.

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