JP2005333592A - Broadcast receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a broadcast receiver capable of surely extracting superimposed data from a broadcasting wave. <P>SOLUTION: In automatic superimposed data receiving and updating processing at the time of non-use (while a television is turned off at midnight or the like), a microcomputer 5 generates a local frequency (for example, 235.15+α MHz) shifted higher than specified value just by α. In automatic superimposed data receiving and updating processing, AFT is not operated. In the SAW output waveform of an IF step at such a time, high video frequency characteristics (f-characteristics) are shifted up to provide a nearly shooting waveform. Therefore, a frequency portion containing a superimposed data signal can be shifted to a position where a high output level can be obtained, in an intermediate frequency signal. Thus, superimposed data can be accurately extracted by a decode circuit 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a broadcast receiving apparatus capable of extracting superimposed data superimposed on a video blanking period of a received TV broadcast signal.

  A system (PDC, VPS, EDS, TELETEXT, text broadcasting, EPG, etc.) that superimposes data (time, text, program data, etc.) at a high bit rate during the video blanking period of a TV (television) broadcast signal is adopted in each country. Has been. In a receiving apparatus that receives such a TV broadcast signal, the data separated from the received TV broadcast signal is used for automatic time correction (see Patent Document 1), program recording reservation (see Patent Document 2), and the like. doing. Normally, when the TV is turned off at midnight or the like, the receiving device is automatically turned on (video display is not performed: the pseudo power supply is turned on), the TV broadcast signal is automatically received, and the stored data is updated based on newly acquired data. .

  For example, the bit rate of the superimposed data in the PDC is 6.9375 Mbit / s, and in the VPS is 5 Mbit / s. In order to receive data accurately, a broadcast receiving apparatus having good characteristics up to a high frequency is required.

  A conventional broadcast receiving apparatus will be described with reference to FIGS. 1 and 2 used in the first embodiment. The microcomputer generates a local frequency (for example, 235.15 MHz) in the PLL channel selection circuit based on the channel selection data stored in the EEPROM. The TV broadcast signal (E8ch: video carrier 196.25 MHz, audio carrier wave 201.75 MHz) input from the antenna is subjected to an IF frequency (PIF: 235.15 MHz-196.25 MHz = 38.9 MHz SIF: 235.15 MHz− by a tuner circuit). 201.75 MHz = 33.4 MHz) and input to the IF circuit. An AFT output signal is output from the AFT (auto fine tuning) circuit to the microcomputer, and the frequency is automatically finely adjusted (AFT = ON operation) so that the reception frequency becomes the center.

A detailed configuration diagram of the IF circuit is as shown in FIG. The IF signal output from the tuner circuit is input to a video / audio SAW (surface acoustic wave) filter. Thereafter, the video IF signal passes through the IF amplification circuit and IF detection circuit, and further passes through an audio trap to become a video signal including a data information signal. The audio IF signal becomes an audio output by passing through the audio BPF, FM detection circuit, and limiter circuit.
JP-A-9-44933 Patent No. 3026686

  FIG. 7A shows a waveform (IF stage SAW output characteristic waveform) output from a conventional IF circuit, and FIG. 7B shows a waveform of data superimposed in the vertical blanking period. . FIG. 8 is an explanatory diagram showing the frequency position relationship of the PDC with respect to the video / audio frequency. In the video output of the broadcast receiving apparatus, the frequency characteristics are lowered on the higher frequency side due to the characteristics of the SAW filter, audio traps, adjacent CH traps, and the phase distortion is further deteriorated. In addition, since the broadcast receiving apparatus has a basic function of outputting video and audio, the superimposition data is extracted by turning on the AFT. For this reason, the output waveform of the received data signal varies greatly depending on the characteristics of the receiving device, which originally has a large variation, and the data waveform becomes small and dull. Therefore, it took a very long time to confirm the content match by taking the same data several times.

  An object of this invention is to provide the broadcast receiver which can extract superimposition data from a TV broadcast signal reliably in view of said situation.

  In order to solve the above-described problem, the broadcast receiving apparatus of the present invention can extract the superimposed data superimposed on the video blanking period of the received TV broadcast signal. For the purpose of receiving a TV broadcast signal of a predetermined channel, the control means for controlling to shift the local frequency for generating the intermediate frequency signal of the predetermined channel (hereinafter referred to in this section) This is referred to as the first configuration).

  With the above configuration, when receiving a TV broadcast signal of a predetermined channel for the purpose of extracting the superimposed data, for example, the local frequency of the predetermined reception channel is intentionally shifted higher. Thereby, the high frequency characteristic of the intermediate frequency signal (IF) is raised. That is, the frequency portion in which the superimposed data signal is included can be shifted to a position where a high output level is obtained in the intermediate frequency signal, and the superimposed data can be extracted accurately. When the local frequency is deliberately shifted, a video with an audio beat is output, but the process of receiving a TV broadcast signal of a predetermined channel for the purpose of extracting superimposed data is automatically performed at midnight when the user is not using it. This is not a problem at all because it does not require video and audio output.

  The broadcast receiving apparatus of the first configuration includes an auto fine tuning processing means, and the control means turns off the auto fine tuning function when receiving a TV broadcast signal of a predetermined channel for the purpose of extracting the superimposed data. It is good to do. In addition, in the first configuration or a subordinate configuration, the shift frequency of the local frequency is set to the superimposed bit so that a plurality of TV broadcast signals in which data is superimposed at different bit rates are mixed in the same region. It may be configured to change according to the rate.

  Also, the broadcast receiving apparatus of the present invention provides an intermediate frequency obtained by receiving a TV broadcast signal in the broadcast receiving apparatus capable of extracting superimposed data superimposed on the video blanking period of the received TV broadcast signal. In addition to the video / audio generation system, the signal is guided to a generation system dedicated to superimposition data (hereinafter referred to as a second configuration in this section).

  In the second configuration, a filter having a filter characteristic suitable for extraction of superimposed data may be provided in the input stage of the generation system dedicated to the superimposed data. In addition, a video and / or audio filter and a filter dedicated to superimposition data may be accommodated in the same casing. In addition, the characteristic of the filter dedicated to the superimposed data may be switched so as to cope with a mixture of a plurality of TV broadcast signals on which data is superimposed at different bit rates in the same region.

  If the configuration is such that the local frequency is shifted when receiving broadcasts for the purpose of extracting superimposed data signals, the data superimposed in the vertical blanking period can be received by changing the channel selection software without changing the existing configuration at all. Accurate acquisition is possible without depending on the characteristics of the apparatus. In addition, if the terminal is dedicated to data acquisition, the data superimposed in the vertical blanking period can be changed to the characteristics of the receiver by changing the IF circuit configuration without changing the existing channel selection software. Accurate acquisition is possible without depending on the video output and without causing any trouble in video output.

(Embodiment 1)
Hereinafter, an analog broadcast receiving apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the tuner circuit 1 includes a PLL channel selection circuit 1a and the like. The PLL channel selection circuit 1a generates an intermediate frequency signal (IF) by mixing a signal (broadcast wave) of a desired channel and a local oscillation signal, and is configured as an IC circuit. The local oscillation signal is output from, for example, a PLL synthesizer. The PLL synthesizer generates a local oscillation signal that is changed according to a signal of a desired channel so that a predetermined intermediate frequency signal is generated from a mixer (mixer). The channel selection information (SDA) and clock (SCL) of the desired channel are given from the microcomputer (microcomputer) 5.

  The IF (intermediate frequency) circuit 2 includes a signal amplification circuit, an AGC circuit, an AFT (auto fine tuning) circuit 2a, and the like. The AFT circuit 2a gives a local oscillation frequency adjustment signal (AFT up request signal / AFT down request signal) to the PLL channel selection circuit 1a so that the video intermediate frequency maintains a predetermined frequency.

  The video processing circuit 3 generates a video signal (color difference signal or the like) or a superimposed data signal by demodulation. The superimposed data signal is decoded by the decoding circuit 4 to become various data, and the various data is given to the microcomputer 5. The microcomputer 5 updates the stored data in the non-volatile memory (for example, EEPROM) 6 using various newly acquired data or sends correction information to the data information display unit 7.

  As shown in FIG. 2, the IF signal output from the tuner circuit 1 is input to the video / audio SAW filter 11. Thereafter, the video IF signal passes through the IF amplifier circuit 12 and the IF detection circuit 13 and further passes through the audio trap 14 to become a video signal including superimposed data. The audio IF signal becomes an audio output by passing through the audio BPF (band pass filter) 15 and the FM detection circuit (limiter circuit) 16.

  The analog broadcast receiving apparatus of this embodiment is characterized in that the following processing is performed at the time of broadcast reception for the purpose of extracting a superimposed data signal. In the following, processing examples corresponding to both VPS and PDC will be shown.

  In the superimposition data automatic reception update process when not in use (when the television is turned off at midnight or the like), the microcomputer 5 generates a local frequency shifted higher than specified (for example, 235.15 + α MHz for E8ch). In this case, the received signal of E8ch (video carrier 196.25 MHz audio carrier 201.75 MHz) is converted to an intermediate frequency (PIF: 38.9 + α MHz, SIF: 33.4 + α MHz) by the tuner circuit 1 and input to the IF circuit 2. Will be. In the superimposed data automatic reception update process, the AFT is not operated. For example, the microcomputer 5 gives an OFF command to the ATF circuit 2a using the IIC bus or the like when executing the superimposed data automatic reception update process.

  The IF stage SAW output waveform at this time is shown in FIG. 4A, and the waveform of the vertical blanking superimposed data is shown in FIG. 4B. As can be seen from this figure, the high frequency video frequency characteristic (f characteristic) is raised, resulting in a shoot-like waveform. Therefore, it is possible to shift the frequency portion in which the superimposed data signal is included at a position where a high output level is obtained in the intermediate frequency signal. As a result, the decoding circuit 4 can accurately extract the superimposed data.

  FIG. 3 is a flowchart showing an example of superposition data automatic reception update processing. When the automatic update time is reached (for example, at AM0) (YES in step S1), it is confirmed whether or not the power is off (the user is not using the receiving device) (step S2). When the power is on, the process is terminated. When the power is off, the automatic update state is entered and the pseudo power source is turned on (step S3). Then, a channel where superimposition data exists is selected, and AFT is turned OFF (step S4).

  In order to cope with a mixture of a plurality of TV broadcast signals in which data is superposed at different bit rates in the same region as in Europe (for example, VPS and PDC coexist), the local frequency according to the superposed bit rate The shift width may be changed. For example, in the case of VPS, the channel is selected by shifting by α MHz (0 <α ≦ 2.5 MHz) so that the f characteristic of the video frequency of 2.5 MHz is increased (step S6). On the other hand, in the case of PDC, the channel is selected by shifting by β MHz (0 <β ≦ 3.5 MHz) so that the f characteristic of 3.5 MHz is increased (step S7), and data acquisition is performed (step S8). It should be noted that which method is used as the data superimposition method may be stored in advance or can be known from the received superimposed data. Next, it is confirmed whether the data update has been completed (step S9). If the update has not been completed, the process returns to step S5. If the data has been updated, the local frequency is returned to the basic frequency, and the AFT is turned ON. (Step S10), automatic data acquisition ends.

(Embodiment 2)
Hereinafter, an analog broadcast receiving apparatus according to Embodiment 2 of the present invention will be described with reference to FIGS.

  As shown in FIG. 5, the analog broadcast receiving apparatus of this embodiment is provided with a data-dedicated output terminal 20 at the output (IF circuit output) of the tuner circuit 1 separately from the video output and the audio output. The output terminal 20 is provided with a dedicated SAW filter 21 specialized for extracting data superimposed in the video blanking period. The IF signal output from the tuner circuit 1 is input to the video / audio SAW filter 11 and the data SAW filter 21. The IF signal that has passed through the data SAW filter 21 is output through the data amplification circuit 22 and the data detection circuit 23 sequentially.

  The output characteristic waveform of the data output dedicated SAW filter 21 is shown in FIG. Since it is provided separately from the video / audio output SAW filter 11, the SAW output characteristics can be determined so that the decoding circuit 4 can accurately extract the superimposed data. The waveform of the vertical blanking superimposed data is shown in FIG. What is necessary is just to determine SAW output characteristics so that it may have a high passage characteristic with respect to the frequency part in which the superimposition data signal in the intermediate frequency signal is included. Note that the SAW output characteristics shown here are set so that the horizontal synchronization signal and the like can be left. However, when the configuration is such that the horizontal synchronization signal and the like can be obtained from the video / audio output system, other SAW characteristics are used. Output characteristics can be selected.

  Thus, by providing the data dedicated output terminal 20, the intermediate frequency signal dedicated to superimposing data extraction (data dedicated SAW output) is not affected by the voice trap or the adjacent CH trap. In addition, the data-only SAW output can extend the frequency characteristics to a high frequency and can also improve the phase distortion. Further, since it is separate from video and audio output, it is not necessary to turn off the AFT operation as in the first embodiment, and data can be acquired while maintaining good video output.

  Instead of the configuration in which the audio / video SAW filter 11 is provided (intercarrier method), a configuration in which the video dedicated SAW filter and the audio dedicated SAW filter are respectively provided (split carrier method) may be employed. Further, a configuration is known in which the video-only SAW filter and the audio-only SAW filter are accommodated in the same housing. Similarly, the data output-only SAW filter 21 is housed in the same housing as the other SAW filters. You may employ | adopt the structure to accommodate.

  Further, instead of the data output dedicated SAW filter 21, a band pass filter dedicated to data output may be used. In addition, as described in the first embodiment, when data information superimposed at different bit rates is mixed, a configuration for switching data-dedicated filter characteristics according to the superimposed bit rate (connection / disconnection of a coil or a capacitor) A mechanism or the like) may be employed.

It is the block diagram which showed the broadcast receiver of embodiment of this invention. It is a detailed block diagram of the IF circuit of FIG. It is the flowchart which showed the processing content of embodiment of this invention. 1A shows the IF stage SAW output waveform in the configuration of FIG. 1, and FIG. 2B is an explanatory diagram showing the waveform of the vertical blanking superimposed data. It is the block diagram which showed the broadcast receiving apparatus of the structure which has a filter only for data of embodiment of this invention. 5A shows an IF stage SAW output waveform in the configuration of FIG. 5, and FIG. 5B is an explanatory diagram showing a waveform of vertical blanking superimposed data. FIG. 6A shows an IF stage SAW output waveform in the conventional configuration, and FIG. 6B is an explanatory diagram showing a waveform of vertical blanking superimposed data. It is explanatory drawing which showed the frequency positional relationship of PDC with respect to an audiovisual frequency.

Explanation of symbols

1 Tuner Circuit 1a PLL Tuning Circuit 2 Intermediate Frequency Circuit 2a AFT Circuit 5 Microcomputer 21 Data Dedicated SAW Filter

Claims (7)

In a broadcast receiving apparatus capable of extracting superimposed data superimposed in a video blanking period of a received TV broadcast signal, the predetermined channel is received when a TV broadcast signal of a predetermined channel is received for the purpose of extracting the superimposed data. A broadcast receiving apparatus comprising control means for controlling to shift a local frequency for generating the intermediate frequency signal. 2. The broadcast receiving apparatus according to claim 1, further comprising an auto fine tuning processing means, and the control means turns off the auto fine tuning function when receiving a TV broadcast signal of a predetermined channel for the purpose of extracting the superimposed data. A broadcast receiving apparatus characterized by comprising: 3. The broadcast receiving apparatus according to claim 1 or 2, wherein a local frequency shift width is superimposed so that a plurality of TV broadcast signals on which data is superimposed at different bit rates are mixed in the same region. The broadcast receiving apparatus is configured to change according to the bit rate. In a broadcast receiving apparatus capable of extracting superimposed data superimposed on a video blanking period of a received TV broadcast signal, an intermediate frequency signal obtained by receiving the TV broadcast signal is superimposed on the video / audio generation system. A broadcast receiving apparatus configured to be guided to a data-only generation system. 5. The broadcast receiving apparatus according to claim 4, wherein a filter having a filter characteristic suitable for extraction of superimposed data is provided in an input stage of the generation system dedicated to the superimposed data. 6. The broadcast receiving apparatus according to claim 4, wherein a video and / or audio filter and a filter dedicated to superimposed data are accommodated in the same housing. apparatus. 7. The broadcast receiving apparatus according to claim 4, wherein a filter dedicated to superimposition data is used to cope with a mixture of a plurality of TV broadcast signals on which data is superimposed at different bit rates in the same region. A broadcast receiver characterized in that the characteristics can be switched.

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