JP3712867B2 - Television receiver channel selection system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a channel selection method for a television receiver that automatically detects a broadcast wave that can be received by sweeping the frequency.
[0002]
[Prior art]
When a vehicle-mounted television receiver receives a program while the vehicle is running, the reception state of the currently received program changes greatly. For example, even if the broadcast wave of a certain broadcast station can be received well immediately after the power is turned on, if the vehicle moves outside the reception area of the broadcast station, it is natural that the program of the broadcast wave cannot be viewed. . When the reception state of the broadcast wave currently being received deteriorates, the user needs to perform an operation by himself to find a broadcast wave that can be received at that location. For example, it is conceivable that the reception channel is sequentially switched by manual operation and a broadcast wave program that can be satisfactorily viewed is visually confirmed, or a broadcast wave that can be received is searched using a search function. The search function automatically detects a receivable broadcast wave by sweeping a predetermined frequency range in one direction. By using this search function, the user can receive at that time. Since the broadcast wave can be searched, viewing of the program of the searched broadcast wave can be newly started.
[0003]
[Problems to be solved by the invention]
By the way, in the above-described conventional television receiver, when the reception state of a program currently being received becomes bad and viewing becomes impossible, the user performs a predetermined operation to receive a new broadcast wave that can be received. Therefore, there is a problem that the operation is complicated. In particular, when traveling in a remote place, it is not easy to find a receivable broadcast wave because it often does not know a receivable broadcast channel.
[0004]
Even if it is possible to search for a newly receivable broadcast wave, whether or not the broadcast wave is well received and whether there is a broadcast wave with a better reception state. I do not know until. For this reason, selecting a broadcast wave with a good reception state from among a plurality of broadcast waves that can be received at the location not only makes the operation more complicated, but also selects such a broadcast wave. It was impossible.
[0005]
The present invention was created in view of the above points, and an object of the present invention is to provide a television receiver that can select a receivable broadcast wave without performing a complicated operation when the reception state changes. It is to provide a channel selection method for the machine.
[0006]
Another object of the present invention is to provide a channel selection method for a television receiver that can select a broadcast wave with a good reception state without performing a complicated operation when the reception state changes. is there.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the television receiver channel selection system of the present invention detects a receivable broadcast wave by performing a frequency sweep operation when a reception incapable state of the broadcast wave being received is detected. Broadcast wave search means, selection candidate receiving means for receiving the detected broadcast waves in a predetermined order and outputting the contents thereof, and broadcast wave selection for selecting one of the broadcast waves in which the received contents are output in order Means. When the currently received broadcast wave becomes unreceivable, the broadcast wave that can be received at that time is automatically detected, so that the user can perform the detected broadcast without performing complicated operations. The desired one can be selected from the waves. In particular, since the searched broadcast waves are received in sequence and the contents are output, the user can select a desired broadcast wave after confirming the contents.
[0008]
Also, the reception field level of each broadcast wave is detected together with the presence or absence of the broadcast wave by the broadcast wave search means described above, and the reception content of the broadcast wave is detected in a state where the detected reception field level can be recognized by the selection candidate reception means. It is preferable to output. Since the user can select a desired broadcast wave while confirming the received electric field level, it is possible to select a broadcast wave with a good reception state.
[0009]
Moreover, it is preferable to output the reception contents of the broadcast wave in descending order of the reception electric field level by the selection candidate receiving means. Since the reception contents of the broadcast wave are output in descending order of the reception electric field level, the user can easily select a broadcast wave with a good reception state. In general, since it is considered that a broadcast wave with a good reception state is often selected, the time until the reception content of a desired broadcast wave is output is shortened, and the user can quickly Selection can be made.
[0010]
In particular, broadcast waves are grouped according to the magnitude of the received electric field level, and after the broadcast wave reception contents are output a plurality of times for a group with a high received electric field level, at least a group with a low received electric field level is included. Thus, it is preferable to output the reception content of the broadcast wave. By receiving a broadcast wave with a high reception electric field level that is likely to be selected first and displaying its contents multiple times, the user can quickly and reliably select a broadcast wave with a good reception state. it can. In addition, since each broadcast wave is received so that a broadcast wave with a small reception electric field level is included, the user can also select from broadcast waves with poor reception status, and the range of selection is wide. Can be spread.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a television receiver according to an embodiment to which the present invention is applied will be described with reference to the drawings.
[0012]
FIG. 1 is a diagram showing a configuration of an in-vehicle television receiver according to an embodiment to which the present invention is applied. The television receiver 100 according to the present embodiment shown in the figure includes a tuner unit 1 that extracts a desired tuning frequency component from a signal received via an antenna 40 and performs frequency conversion on the extracted signal. A PLL control unit 2 that performs PLL control on the tuning frequency of the tuner unit 1 and a tuning control unit 3 that sweeps the tuning frequency of the tuner unit 1 in one direction are configured.
[0013]
The tuner unit 1 described above includes an input circuit 10, a high frequency amplifier circuit 12, a mixing circuit 14, and a local oscillation circuit 16. The input circuit 10 is for matching the impedance of a connection line that draws a received signal from the antenna 40 and the input impedance of the high-frequency amplifier circuit 12. The high frequency amplifier circuit 12 performs a tuning operation to select and output a predetermined frequency component from a received signal input via the input circuit 10 while ensuring a predetermined bandwidth (6 MHz), and to perform the tuning operation. Perform high frequency amplification on the output. The mixing circuit 14 mixes the signal output from the local oscillation circuit 16 with the signal output from the high frequency amplifier circuit 12, and outputs an intermediate frequency signal having a frequency difference between these two signals. The frequency of the intermediate frequency signal is set to 58.75 MHz for the video carrier and 54.25 MHz for the audio carrier. The local oscillation circuit 16 is a voltage control type oscillation circuit in which an oscillation frequency can be set according to an applied control voltage, and this control voltage is applied from the PLL control unit 2.
[0014]
The PLL control unit 2 described above includes frequency dividers 20 and 24, a phase comparator 22, and a reference frequency oscillator (reference OSC) 26. These components are phase-shifted together with the local oscillation circuit 16 in the tuner unit 1 described above. A synchronous loop is formed, and the frequency of the local oscillation circuit 16 is set. The reference frequency oscillator 26 is a fixed frequency oscillator having a high frequency stability using a crystal oscillator or the like, and its oscillation output is divided by one of the frequency dividers 24 having a fixed frequency division ratio. Input to one input terminal. The other frequency divider 20 is a variable frequency divider that can arbitrarily set the frequency division ratio N, and a signal obtained by frequency dividing the output of the local oscillation circuit 16 by the frequency division ratio N is supplied to the phase comparator 22. It is input to the other input terminal. The phase comparator 22 compares the phases of the signals input from the two frequency dividers 20 and 24 and applies a control voltage to the local oscillation circuit 16 so as to reduce this phase difference. The 16 oscillation frequencies are controlled to a predetermined value determined by the variable frequency division ratio N described above.
[0015]
The channel selection control unit 3 described above includes a search control unit 30, a frequency sweep unit 32, a channel selection list memory 34, and a timer 36. The search control unit 30 instructs the frequency sweep unit 32 to start the sweep operation when the currently received broadcast wave is in an unreceivable state, and when the broadcast wave is detected by the frequency sweep operation. Create a channel selection list. Further, when the “determine” key of the operation unit 60 is pressed while the search control unit 30 cyclically outputs the broadcast wave program content that can be received based on the channel selection list, the search control unit 30 outputs the program at this time. The selected program is determined as the channel selection program. The operation unit 60 is used by the user to give various operation instructions, and includes various operation keys including the above-described “OK” key. Further, the frequency sweep unit 32 sweeps the tuning frequency of the tuner unit 1 in one direction by sequentially increasing or decreasing the variable frequency division ratio of the frequency divider 20 in the PLL control unit 2. The channel selection list memory 34 stores the channel selection list created by the search control unit 30. This channel selection list includes the reception electric field level of each broadcast wave detected in the frequency sweep operation in addition to the receivable broadcast wave reception channel. The timer 36 measures various times. For example, a time such as 3 seconds or 30 seconds is set, and the search control unit 30 is notified when the set time has elapsed.
[0016]
In addition to the above-described configuration, the television receiver 100 of the present embodiment includes a video intermediate frequency amplifier circuit 42, a video detector circuit 44, a video amplifier circuit 46, and a display device 48 in order to reproduce video from the received signal. In order to extract and reproduce an audio signal from the received signal, an audio intermediate frequency detection circuit 50, an FM detection circuit 52, and a low frequency amplification circuit 54 are included.
[0017]
The video intermediate frequency amplifying circuit 42 amplifies the intermediate frequency signal including the video signal and the audio signal output from the mixing circuit 14 of the tuner unit 1, and passes a predetermined frequency band component only. It has selectivity characteristics. Further, even if the level of the input signal varies due to automatic gain control, the level of the output signal does not change, and the amplified intermediate frequency signal is input to the video detection circuit 44 and the audio intermediate frequency detection circuit 50. . The video detection circuit 44 detects the video intermediate frequency signal amplified by the video intermediate frequency amplification circuit 42 and extracts a composite video signal. Generally, in order to faithfully reproduce the video signal, a diode detection or Low level video detection (LLD) is used. The video signal detected in this way is further divided into a luminance signal and a carrier color signal after passing through the video amplification circuit 46. Further, the carrier color signal is color-demodulated and again synthesized with the luminance signal, and then displayed on the display device. The video from 48 is displayed.
[0018]
The audio intermediate frequency detection circuit 50 extracts a 4.5 MHz SIF signal (beat signal) from the 54.25 MHz audio intermediate frequency signal included in the output of the video intermediate frequency amplification circuit 42. As a typical method for extracting the SIF signal, there are an intercarrier method and a separate carrier method. The FM detection circuit 52 performs FM detection on the 4.5 MHz SIF signal output from the audio intermediate frequency detection circuit 50. After the detected audio signal is amplified by the low frequency amplification circuit 54, the speaker 56. Is output from. The audio intermediate frequency signal output from the audio intermediate frequency detection circuit 50 is also input to the reception level detection circuit 58.
[0019]
The reception level detection circuit 58 detects the reception electric field level of the broadcast wave being received and outputs a reception electric field level signal, and outputs an SD (station detector) signal indicating the presence or absence of the broadcast wave. For example, the function of a signal meter that detects a received electric field level by direct current detection of an audio intermediate frequency signal and the frequency deviation Δf (bandwidth) of the received signal, and the received electric field level is a predetermined value or more. It sometimes has the function of a station detector that determines that a broadcast wave exists and creates a high-level SD signal.
[0020]
The search control unit 30, the frequency sweep unit 32, and the reception level detection circuit 58 described above are the broadcast wave search means, the tuner unit 1, the PLL control unit 2, the channel selection control unit 3, the video intermediate frequency amplification circuit 42, and the video detection circuit 44. , Video amplification circuit 46, display device 48, audio intermediate frequency detection circuit 50, FM detection circuit 52, low frequency amplification circuit 54, and speaker 56 are selection candidate reception means, search control unit 30 and operation unit 60 are broadcast wave selection means. Correspond to each.
[0021]
The television receiver 100 of this embodiment has such a configuration, and the operation thereof will be described next. 2 and 3 are flowcharts showing an operation procedure of the television receiver 100 of the present embodiment, and an operation procedure focusing on the channel selection operation mainly under the control of the channel selection control unit 3 is shown. In addition, it is assumed that any broadcast wave is currently received and the reception state changes as the vehicle moves.
[0022]
The search control unit 30 constantly monitors whether or not the currently received broadcast wave has become unreceivable (step 100). For example, the current reception electric field level output from the reception level detection circuit 58 and the past reception level of this broadcast wave stored in the channel selection list memory 34 are compared, and the difference is large, and the reception level detection circuit When the state in which the SD signal output from 58 is at a low level continues for a predetermined time (for example, 30 seconds), it is determined that this broadcast wave is in an incapable state.
[0023]
When the currently received broadcast wave is in an unreceivable state, the search control unit 30 next sends a frequency sweep instruction to the frequency sweep unit 32, and the frequency sweep unit 32 that has received this instruction receives, for example, the receivable frequency. The frequency sweep operation is started from the lower limit frequency of the band (step 101). For example, when the range from the VHF channel “1” to the UHF channel “62” is the receivable range, the frequency sweep operation is performed with the reception frequency corresponding to the channel “1” as the start frequency.
[0024]
Further, when the frequency sweep operation described above is started, the search control unit 30 determines whether there is a broadcast wave for each channel (step 102), and determines whether this frequency is the upper limit of the frequency sweep range. (Step 103). Whether or not a broadcast wave exists can be determined by examining whether or not the SD signal output from the reception level detection circuit 58 has become a high level. If there is a broadcast wave, the search control unit 30 sends an instruction to the frequency sweep unit 32 to interrupt the frequency sweep operation (step 104), and then receives the reception electric field level signal output from the reception level detection circuit 58. Then, the broadcast wave identification information (for example, any one of channel numbers 1 to 62) and the received electric field level corresponding thereto are added to the channel selection list stored in the channel selection list memory 34 (step 105). (Step 106). Thereafter, the search control unit 30 sends an instruction to the frequency sweep unit 32 to restart the frequency sweep operation (step 107), and then repeats the processing after step 102 (determining whether there is a broadcast wave).
[0025]
When the frequency sweep operation described above reaches the upper limit frequency, an affirmative determination is made in step 103, and then the search control unit 30 determines whether or not at least one broadcast wave has been detected (step 108). For example, when a vehicle enters a long tunnel, underground parking lot, etc., there may be cases where no broadcast wave is detected, and in this case, it is considered that only a temporary reception failure has occurred. The search control unit 30 sends an instruction to the frequency sweep unit 32 to reset the reception frequency to a frequency corresponding to the original broadcast wave (step 109), and then returns to step 100 and repeats the process. However, when traveling through a long tunnel, etc., even if the process immediately returns to step 100 and continues processing, it is determined that the reception is impossible again, and only the frequency sweep operation after step 101 is repeated. Therefore, it is preferable to reset the reception frequency to the frequency of the original broadcast wave after waiting for a predetermined time (for example, 5 minutes).
[0026]
When one or more broadcast waves are detected in the frequency sweep operation described above (when an affirmative determination is made in step 108), the search control unit 30 next selects the channel selection list stored in the channel selection list memory 34. All the broadcast waves in the station list are read out and divided into two groups in the order of the received electric field level (step 110). For example, eight broadcast waves are extracted in descending order of the received electric field level to form a higher group, and then eight broadcast waves are extracted in order from the highest received electric field level to form a lower group. Is stored in the tuning list memory 34. When a total of 16 or more broadcast waves are detected, broadcast waves having a received electric field level of 17th or later are excluded from grouping. If the number of detected broadcast waves is less than 16, if it is 8 or more, it is divided into an upper group including 8 broadcast waves and a lower group including other broadcast waves, and if it is 8 or less. Only the upper group is formed.
[0027]
Next, the search control unit 30 reads the channel number of the broadcast wave having the highest received electric field level in the upper group (step 111), sends an instruction to the frequency sweep unit 32, receives the broadcast wave, The program content of the broadcast wave is output from the display device 48 and the speaker 56 (step 112). After that, the search control unit 30 starts to output the program content whether or not the user who has seen the program content has pressed the “determine” key of the operation unit 60 and has selected the channel (step 113). It is then determined whether a predetermined time (for example, 3 seconds) has elapsed (step 114). When the “determine” key of the operation unit 60 is pressed by the user, it is assumed that the broadcast wave on which the program is displayed is selected, the subsequent channel selection operation is interrupted, and the output of the program content is continued. The Therefore, returning to step 100, the determination as to whether or not the selected broadcast wave has become unreceivable is repeated.
[0028]
In addition, when 3 seconds have passed since the output of the program content has been started (when an affirmative determination is made in step 114), the search control unit 30 then selects another program whose program content has not been output to the upper group. It is determined whether or not there is a broadcast wave (step 115). If there is another broadcast wave, after reading the channel number of the broadcast wave whose reception electric field level is one smaller (step 116), the program of step 112 The operation after the content output operation is repeated.
[0029]
When the output of the program contents of all broadcast waves included in the upper group is completed, a negative determination is made in step 115, and the search control unit 30 then determines whether the output of the program contents performed for the upper group has made two rounds. It is determined whether or not (step 117). If only one round has been completed, the process returns to step 111 described above, and another round, output of program contents (step 112), determination of presence / absence of channel selection (step 113), and the like are repeated. If the program contents are output twice, the program contents of the third round are output for broadcast waves included in both the upper group and the lower group (steps 118 to 123). When the user presses the “decision” key of the operation unit 60 while any program content is being output, the subsequent channel selection operation is interrupted assuming that the broadcast wave has been selected, The output of the program content is continued. In addition, if the user does not press the “decision” key of the operation unit 60 in the output of the program content of the third round, a negative determination is made in step 122 (determination of whether there is another broadcast wave). Next, the search control unit 30 reads the channel number of the broadcast wave having the highest received electric field level included in the upper group from the channel selection list memory 34 (step 124), and sends an instruction to the frequency sweep unit 32 to broadcast the broadcast. A wave program is received (step 125).
[0030]
As described above, the television receiver 100 according to the present embodiment automatically starts frequency sweeping and can receive a broadcast when the reception electric field level of the currently received broadcast wave is lowered and becomes unreceivable. Since the wave is detected, a complicated operation by the user is not necessary.
[0031]
In addition, when a receivable broadcast wave is detected, the received electric field level is also detected at the same time. The detected broadcast wave programs are received in order from the one with the best received electric field level, and the contents are output (video). Display and audio output). Therefore, since the user can know the magnitude of the received electric field level according to the output order of the programs, it is possible to preferentially select a broadcast wave program with a good received electric field level, and to quickly select a program with a good reception state. Can be watched reliably.
[0032]
Further, when the retrieved broadcast wave program contents that are receivable are output in order, the program is divided into an upper group and a lower group according to the received electric field level, and the program contents are output twice for the upper group. And the whole of the lower group is made one round. In this manner, by repeatedly showing the user a broadcast wave program with a high received electric field level, the user can easily select a program. Further, since a broadcast wave program with a low received electric field level can be selected in the third round, the selection range can be expanded.
[0033]
In particular, when receiving a program of a local station, since the transmission power is often low with UHF, the reception state of the currently received broadcast wave may change greatly during traveling. When the television receiver 100 of the form is used, even if the reception of the broadcast wave being received is frequently repeated, the user can receive it without performing complicated operations. Broadcast waves in good condition can always be received.
[0034]
In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the summary of this invention. For example, in the above-described embodiment, when a plurality of broadcast waves that can be received by sweeping the frequency are detected, they are divided into two groups according to the received electric field level. Two or more groupings may be made. Further, this grouping is simply divided into upper and lower levels according to the received electric field level, but other division methods may be used. For example, the reception state of the video includes a state where a colored video is obtained and a state where a color information is lost but a black and white video is obtained, and grouping may be performed in correspondence with each state. . In order to perform such grouping, as shown in FIG. 4, a color burst signal included in a video signal output from the video amplification circuit 46 is detected by a color signal detection unit 59, and the detection result is detected as a burst detection signal. To the search control unit 30.
[0035]
In the above-described embodiment, since the received electric field level is detected and the value is stored in the tuning list memory 34, when the program content of each broadcast wave is output, as shown in FIG. The detection level may be displayed on a part of the display screen. By displaying the received electric field level of the broadcast wave to be selected along with the program contents, the user can directly know not only the order of the received electric field level but also the level of reception. Can be a reference for selection.
[0036]
【The invention's effect】
As described above, according to the present invention, when a broadcast wave currently being received becomes unreceivable, a broadcast wave that can be received at that time is automatically detected. The desired one can be selected from the detected broadcast waves without performing the above. In particular, since the searched broadcast waves are received in sequence and the contents are output, the user can select a desired broadcast wave after confirming the contents. Also, by outputting the reception contents of broadcast waves in descending order of the received electric field level, the user can easily select a broadcast wave with a good reception state.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a television receiver according to an embodiment.
FIG. 2 is a flowchart showing an operation procedure of the television receiver of the present embodiment.
FIG. 3 is a flowchart showing an operation procedure of the television receiver of the present embodiment.
4 is a diagram showing a configuration in which the television receiver shown in FIG. 1 is partially modified.
FIG. 5 is a diagram showing an example of a screen displaying a received electric field level.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tuner part 2 PLL control part 3 Channel selection control part 30 Search control part 32 Frequency sweep part 34 Channel selection list memory 58 Reception level detection circuit 60 Operation part

Claims (4)

Broadcast wave search means for automatically detecting a presence or absence of one or a plurality of broadcast waves that can be received and the respective received electric field levels by automatically performing a frequency sweep operation when a reception impossible state of the broadcast wave being received is detected; ,
Selection candidate receiving means for receiving one or a plurality of broadcast waves detected by the broadcast wave search means in a predetermined order and outputting the contents;
The received content is selected from broadcast waves that are sequentially output by the selection candidate receiving means according to an operation instruction by the user, and is detected by the broadcast wave search means when there is no selection instruction by the user. Broadcast wave selection means for selecting the broadcast wave having the highest received electric field level from among the one or more broadcast waves generated,
A television receiver channel selection system characterized by comprising: In claim 1,
The selection candidate receiving unit outputs the reception content of the broadcast wave in a state where the received electric field level detected by the broadcast wave search unit is recognizable. . In claim 1 or 2 ,
The selection candidate receiving means outputs the received content of the broadcast wave in descending order of the received electric field level. In any one of Claims 1-3 ,
The selection candidate receiving unit performs grouping of the plurality of broadcast waves detected by the broadcast wave search unit according to the magnitude of the received electric field level, and the broadcast wave of the group having the high received electric field level is grouped. A television receiver channel selection system characterized in that after the reception content is output a plurality of times, the reception content of the broadcast wave is output so that at least the group having the low reception electric field level is included.

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