JP2000059706A - Channel selection system for television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the channel selection system for a television receiver that selects a receptible broadcast wave without troublesome operations when reception state is changed. SOLUTION: When a search control section 30 detects that a broadcast wave received at present is not receptible, the control section 30 gives an instruction to a frequency sweep section 32, which starts a frequency sweep operation and searches a receptible broadcast wave at that time, based on an SD signal from a reception level detection circuit 58 to generate a channel selection list, including receptible electric field levels and channel numbers of receptible broadcast waves. After the end of search, the search control section 30 reads a channel number of the broadcast wave in the order of higher reception electric field levels, sequentially receives the contents of the program and displays the contents and sounds the output. When an enter key of an operation section 60 is depressed on the way of channel selection, the control section 30 confirms the reception state of the broadcast wave at that time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a channel selection system for a television receiver which automatically detects a receivable broadcast wave by sweeping a frequency.

[0002]

2. Description of the Related Art When a vehicle receives a program while the vehicle is running, the receiving condition of the program currently being received greatly changes. For example, immediately after power on,
Even if the broadcast wave of a certain broadcast station can be received well, if the vehicle moves out of the reception area of the broadcast station, the program of the broadcast wave cannot be naturally viewed. When the reception state of the currently received broadcast wave deteriorates, the user needs to perform some operation by himself to search for a receivable broadcast wave at that location. For example, there may be a case where the reception channels are sequentially switched by a manual operation to visually confirm a broadcast wave program that can be viewed well, or a case where a search function is used to search for a receivable broadcast wave. The search function is to automatically detect a receivable broadcast wave by sweeping the frequency in a predetermined frequency range in one direction, and the user can use the search function to
Since a broadcast wave receivable at that time can be searched, viewing of a program of the searched broadcast wave can be newly started.

[0003]

By the way, in the above-mentioned conventional television receiver, when the reception state of the program currently being received becomes poor and viewing becomes impossible, the user performs a predetermined operation. Thus, there is a problem that the operation is complicated because a new receivable broadcast wave must be searched. In particular, when traveling in a remote place, it is often difficult to find a receivable broadcast wave because a receivable broadcast channel is often not known.

[0004] Further, even if a new receivable broadcast wave can be found, it is determined whether the broadcast wave is in a good reception state, and whether there is another broadcast wave with a better reception state. I don't know. For this reason,
If you try to select a broadcast wave with a good reception condition from a plurality of broadcast waves that can be received at that location, the operation becomes more complicated, and it is almost impossible to select such a broadcast wave. there were.

[0005] The present invention has been made in view of the above points, and an object thereof is to select a receivable broadcast wave without performing a complicated operation when the reception state changes. An object of the present invention is to provide a method of selecting a television receiver.

Another object of the present invention is to provide a television receiver channel selection system capable of selecting a broadcast wave having a good reception state without performing a complicated operation when the reception state changes. Is to do.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a channel selection method for a television receiver according to the present invention performs a frequency sweep operation when a reception failure state of a broadcast wave being received is detected. Broadcast wave search means for detecting broadcast waves receivable and received, selection candidate receiving means for receiving the detected broadcast waves in a predetermined order and outputting the contents thereof, and Broadcast wave selecting means for selecting any one of the following. When the broadcast wave currently being received becomes unreceivable, the broadcast wave that can be received at that time is automatically detected, so that the user does not need to perform any complicated operation and the detected broadcast wave can be detected. A desired one can be selected from the waves. In particular, since the searched broadcast waves are sequentially received and the contents are output, the user can select the desired broadcast wave after confirming the contents.

The broadcast wave search means detects the presence or absence of a broadcast wave and the reception electric field level of each broadcast wave. The selection candidate receiving means detects the reception electric field level of the broadcast wave in a recognizable state. It is preferable to output received contents. Since the user can select a desired broadcast wave while checking the received electric field level, it is possible to select a broadcast wave having a good reception state.

[0009] It is preferable that the selection candidate receiving means outputs the reception contents of the broadcast wave in descending order of the reception electric field level. Since the received contents of the broadcast wave are output in order of the received electric field level, the user can easily select the broadcast wave having a good reception state. In addition, since it is generally considered that a broadcast wave having a good reception condition is generally selected, the time required for outputting the reception content of a desired broadcast wave is shortened, and the user can quickly receive the broadcast wave. You can make a selection.

In particular, after grouping broadcast waves in accordance with the magnitude of the reception electric field level and outputting the reception content of the broadcast waves a plurality of times for a group having a high reception electric field level, at least a group having a small reception electric field level is output. It is preferable to output the received content of the broadcast wave so that The user can quickly and reliably select a broadcast wave with a good reception condition by first receiving a broadcast wave having a large reception electric field level and displaying the contents thereof several times. it can. After that, since each broadcast wave is received so that a broadcast wave with a small reception electric field level is also included, the user can select from broadcast waves with poor reception conditions. Can be spread.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a television receiver according to an embodiment to which the present invention is applied will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an on-vehicle television receiver according to an embodiment to which the present invention is applied. The television receiver 100 of the present embodiment shown in FIG. 1 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.

The above-described tuner 1 includes an input circuit 10,
A high-frequency amplifier circuit 12, a mixing circuit 14, and a local oscillation circuit 16 are provided. The input circuit 10 is for matching the impedance of a connection line for drawing a received signal from the antenna 40 with the input impedance of the high frequency amplifier circuit 12. The high-frequency amplifier circuit 12 has a predetermined bandwidth (6 M
Hz), a tuning operation for selecting and outputting a predetermined frequency component from a received signal input via the input circuit 10 is performed, and high-frequency amplification is performed on the tuned output. The mixing circuit 14 mixes the signal output from the high-frequency amplification circuit 12 with the signal output from the local oscillation circuit 16 and outputs an intermediate frequency signal having a frequency equal to the 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-controlled oscillation circuit whose oscillation frequency can be set according to an applied control voltage, and this control voltage is applied from the PLL control unit 2.

The above-described PLL control unit 2 includes a frequency divider 20,
24, phase comparator 22 and reference frequency oscillator (reference O
SC) 26, and each of these components forms a phase locked loop together with the local oscillation circuit 16 in the tuner unit 1 described above, and sets the frequency of the local oscillation circuit 16. 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 frequency-divided by one frequency divider 24 having a fixed frequency division ratio. It is input to one input terminal. The other frequency divider 20 is a variable frequency divider whose frequency division ratio N can be arbitrarily set, and a signal obtained by dividing the output of the local oscillation circuit 16 by the frequency division ratio N is output from the phase comparator 22. It is input to the other input terminal. The phase comparator 22 includes two frequency dividers 20, 24
And a control voltage for reducing the phase difference is applied to the local oscillation circuit 16, and the oscillation frequency of the local oscillation circuit 16 is set at the above-mentioned variable frequency division ratio N. It is controlled to a predetermined value determined.

The above-mentioned tuning control unit 3 includes a search control unit 3
0, a frequency sweep unit 32, a tuning list memory 34, and a timer 36. The search control unit 30 instructs the frequency sweeping unit 32 to start the sweep operation when the broadcast wave that is currently being received becomes unreceivable, and when the broadcast wave is detected by the frequency sweep operation. Create a channel selection list. The search control unit 30
Is displayed when the program content of the receivable broadcast wave is output cyclically based on the tuning list.
When the key is pressed, the program output at this time is determined as a selected program. The operation unit 60 is used by a user to issue various operation instructions, and includes various operation keys such as the above-described “enter” key. 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 tuning list memory 34 stores a tuning list created by the search control unit 30. The tuning list includes the reception electric field level of each broadcast wave detected in the frequency sweep operation in addition to the reception channels of the receivable broadcast waves. The timer 36 measures various times. For example, 3
A time such as seconds or 30 seconds is set, and when the set time has elapsed, the search control unit 30 is notified of that.

Also, the television receiver 1 of the present embodiment
00, in addition to the above-described configuration, the video intermediate frequency amplification circuit 42, the video detection circuit 44, the video amplification circuit 46, and the display device 48 for reproducing a video from a reception signal, and extract an audio signal from the reception signal. The audio intermediate frequency detection circuit 50, the FM detection circuit 52, and the low frequency amplification circuit 54 are configured to include the audio intermediate frequency detection circuit 50 and the low frequency amplification circuit 54, respectively, for reproduction.

The video intermediate frequency amplifying circuit 42 amplifies an intermediate frequency signal including a video signal and an audio signal output from the mixing circuit 14 of the tuner unit 1, and passes only components in a necessary frequency band. Have a predetermined selectivity characteristic. Further, even if the level of the input signal fluctuates due to automatic gain control, the level of the output signal does not change.
4 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. In general, the video detection circuit 44 performs diode detection with little distortion to reproduce the video signal faithfully. Low-level video detection (LL
D) is used. The video signal detected in this way further passes through a video amplification circuit 46, is divided into a luminance signal and a carrier chrominance signal, and the carrier chrominance signal is color-demodulated and synthesized again with the luminance signal. Video display from 48 is performed.

The audio intermediate frequency detection circuit 50 extracts a 4.5 MHz SIF signal (beat signal) from a 54.25 MHz audio intermediate frequency signal included in the output of the video intermediate frequency amplification circuit 42. Representative methods for extracting the SIF signal include an intercarrier method and a separate carrier method. The FM detection circuit 52 is connected to the 4.5 MHz SIF output from the audio intermediate frequency detection circuit 50.
The signal is subjected to FM detection, and the detected audio signal is amplified by the low frequency amplifier circuit 54 and then output from the speaker 56. The audio intermediate frequency signal output from the audio intermediate frequency detection circuit 50 is
Is also entered.

The reception level detection circuit 58 detects the reception electric field level of the broadcast wave being received, 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 for detecting a received electric field level by DC detection of an audio intermediate frequency signal and the frequency deviation Δf (bandwidth) of the received signal
, And a function of a station detector that determines that a broadcast wave is present when the received electric field level is equal to or higher than a predetermined value and creates a high-level SD signal.

The above-described search control unit 30, frequency sweep unit 32, and reception level detection circuit 58 serve as broadcast wave search means.
Tuner unit 1, PLL control unit 2, tuning control unit 3, video intermediate frequency amplification circuit 42, video detection circuit 44, video amplification circuit 46, display device 48, audio intermediate frequency detection circuit 50, FM
The detection circuit 52, the low-frequency amplification circuit 54, and the speaker 56 correspond to a selection candidate receiving unit, and the search control unit 30 and the operation unit 60 correspond to a broadcast wave selection unit.

The television receiver 100 of this embodiment has such a configuration, and its operation will be described next. 2 and 3 are flowcharts showing the operation procedure of the television receiver 100 of the present embodiment, and mainly show the operation procedure focusing on the channel selection operation under the control of the channel selection control unit 3. It is also assumed that any broadcast wave is currently being received, and the reception state changes with the movement of the vehicle.

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 channel selection list memory 3
4, the difference between the broadcast wave and the past reception level of the broadcast wave is large, and the reception level detection circuit 5
When the state in which the SD signal output from 8 is at a low level continues for a predetermined time (for example, 30 seconds), it is determined that this broadcast wave is in a reception disabled state.

When the broadcast wave currently being received becomes unreceivable, the search control unit 30 sends a frequency sweeping instruction to the frequency sweeping unit 32. The frequency sweep operation is started from the lower limit frequency of the receivable frequency band (step 101).
For example, assuming that the range from VHF channel “1” to UHF channel “62” is the receivable range, the frequency sweep operation is performed with the reception frequency corresponding to channel “1” as the start frequency.

When the above-described frequency sweeping operation is started, the search control unit 30 determines whether or not a broadcast wave exists for each channel (step 102) and whether or not this frequency is the upper limit of the frequency sweeping range. (Step 10
3). Whether or not a broadcast wave exists can be determined by checking whether or not the SD signal output from the reception level detection circuit 58 has become high level. If a broadcast wave is present, the search control unit 30 sends an instruction to the frequency sweeping unit 32 to interrupt the frequency sweeping operation (step 104), and then outputs the reception electric field level signal output from the reception level detection circuit 58. Capture (step 105)
The identification information of this broadcast wave (for example, any one of channel numbers 1 to 62) and the reception electric field level corresponding thereto are added to the tuning list stored in the tuning list memory 34 (step 106). After that, the search control unit 30 sends an instruction to the frequency sweeping unit 32 to restart the frequency sweeping operation (Step 107), and thereafter repeats the processing from Step 102 (determination of the presence or absence of a broadcast wave).

When the frequency sweep operation reaches the upper limit frequency, an affirmative decision is made in step 103,
Next, the search control unit 30 determines whether at least one broadcast wave has been detected (Step 108). For example, when a vehicle enters a long tunnel, an underground parking lot, or the like, no broadcast wave may be detected,
In addition, in this case, it is considered that only the reception has been temporarily disabled, so the search control unit 30 sends an instruction to the frequency sweeping unit 32 to reset the reception frequency to the frequency corresponding to the original broadcast wave. After the setting (Step 109), the process returns to Step 100 to repeat the processing. However,
In the case where the vehicle is traveling through a long tunnel, for example, even if the process immediately returns to step 100 and continues the process, it is determined that the reception is not possible again, and the frequency sweeping operation after step 101 is simply repeated. After waiting a predetermined time (for example, 5 minutes), it is preferable to reset the reception frequency to the frequency of the original broadcast wave.

In the above-described frequency sweep operation, 1
When one or more broadcast waves are detected (when a positive determination is made in step 108), the search control unit 30
Reads out all the broadcast waves in the tuning list stored in the tuning list memory 34 and divides them into two groups in 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 an upper group, and then, eight broadcast waves are extracted in descending order of the received electric field level to form a lower group. Is stored in the channel selection list memory 34. When a total of 16 or more broadcast waves are detected, the broadcast waves having the received electric field level of 17th or later are excluded from the grouping. Also, if the detected broadcast wave is 1
If it is less than 6, if it is 8 or more, it is divided into an upper group containing eight broadcast waves and a lower group containing other broadcast waves, and if it is less than 8, only the upper group is formed.

Next, the search control unit 30 reads out the channel number of the broadcast wave having the highest received electric field level in the upper group (step 111), and the frequency sweeping unit 3
2 to receive the broadcast wave and output the program contents of the broadcast wave from the display device 48 and the speaker 56 (step 112). After that, the search control unit 30
It is determined whether the user has selected the channel by pressing the "OK" key of the operation unit 60 by viewing the program contents (step 113), and starts outputting the program contents for a predetermined time (for example, 3 seconds). ) Has elapsed (step 11)
4) is determined. "Determination" of the operation unit 60 by the user
When the key is pressed, the subsequent tuning operation is interrupted assuming that the broadcast wave displaying the program is selected,
The output of the program contents is continued. Therefore, returning to step 100, the determination as to whether or not the selected broadcast wave has become unreceivable is repeated.

If three seconds have elapsed since the start of the output of the program contents (when a positive determination is made in step 114), the search control unit 30 then outputs the program contents to the upper group. It is determined whether or not there is another broadcast wave that does not exist (step 115). If there is another broadcast wave, the channel number of the broadcast wave whose reception electric field level is smaller by one is read (step 116). 112
The operation after the output operation of the program contents is repeated.

When the output of the program contents of all the broadcast waves included in the upper group is completed, a negative determination is made in step 115, and then the search control unit 30 determines that the output of the program contents performed for the upper group is 2 It is determined whether or not the tour has been completed (step 117). If only one round has been completed, the process returns to step 111, and another round, the output of program contents (step 112), the presence / absence of channel selection (step 113), and the like are repeated. When the program contents are output twice, the output of the third program contents is performed for broadcast waves included in both the upper group and the lower group (steps 118 to 12).
3). When the user presses the “OK” key of the operation unit 60 while any of the program contents is being output, the subsequent channel selection operation is interrupted assuming that the broadcast wave is selected, The output of the program contents is continued. Also, if the user does not press the “Enter” key of the operation unit 60 even in the output of the program contents of the third round, a negative determination is made in step 122 (determination of whether or not there is another broadcast wave). Next, the search control unit 30 reads out the channel number of the broadcast wave having the highest received electric field level included in the higher order group from the tuning list memory 34 (step 124), and sends an instruction to the frequency sweeping unit 32 to broadcast the broadcast. A wave program is received (step 125).

As described above, the television receiver 100 of the present embodiment automatically starts frequency sweeping and performs reception when the reception electric field level of the currently receiving broadcast wave is lowered and reception becomes impossible. Since a possible broadcast wave is detected, a complicated operation by the user is not required.

When detecting receivable broadcast waves,
At the same time, the reception electric field level is also detected, and the programs of the detected broadcast waves are received in order from the reception electric field level having a good reception electric field level, and the contents are output (video display and audio output).
Therefore, since the user can know the level of the received electric field level according to the output order of the programs, the user can preferentially select a broadcast wave program having a good received electric field level, and can quickly select a program having a good reception state. , And can be surely viewed.

When the searched program contents of the receivable broadcast wave are sequentially output, the program contents are divided into an upper group and a lower group according to the received electric field level. , The entire upper group and lower group together make one round. As described above, the user can easily select a program by repeatedly showing a broadcast wave program having a large received electric field level to the user. Also, a broadcast wave program with a low received electric field level can be selected in the third round, so that the range of selection can be expanded.

In particular, in the case of receiving a program of a local station, since the transmission power is often UHF and the transmission power is small, the reception state of the currently received broadcast wave may change greatly during traveling. In the case where the television receiver 100 of the present embodiment is used, the user can perform complicated operations even if the reception of the broadcast wave being received becomes unreceivable frequently. Therefore, a broadcast wave having a good reception state can be always received.

The present invention is not limited to the above embodiment, and various modifications can be made within the gist of the present invention. For example, in the above-described embodiment, when a plurality of receivable broadcast waves are detected by sweeping the frequency, they are divided into two groups according to the received electric field level. More than one grouping may be performed. In addition, although this grouping is simply divided into higher order and lower order according to the reception electric field level, another method may be adopted. For example, the video receiving state includes a state in which a colored image is obtained and a state in which color information is lost but a black-and-white image is obtained. . To perform such grouping, as shown in FIG. 4, a color burst signal included in the video signal output from the video amplification circuit 46 is detected by the color signal detection unit 59, and the detection result is used as a burst detection signal. May be sent to the search control unit 30.

In the above-described embodiment, the received electric field level is detected and the value is stored in the channel selection list memory 34. Therefore, when the program content of each broadcast wave is output, FIG.
As shown in (1), the electric field detection level may be displayed on a part of the display screen. By displaying the reception electric field level of the broadcast wave to be tuned together with the program contents, the user can directly know not only the order of the reception electric field levels but also the degree of reception status, and the program Can be a reference for selection.

[0036]

As described above, according to the present invention, when a broadcast wave currently being received becomes unreceivable, a broadcast wave receivable at that time is automatically detected. The user can select a desired one from the detected broadcast waves without performing a complicated operation. In particular, since the searched broadcast waves are sequentially received and the contents are output, the user can select the desired broadcast wave after confirming the contents. Also, by outputting the received content of the broadcast wave in descending order of the received electric field level, the user can easily select a broadcast wave having 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 embodiment.

FIG. 3 is a flowchart showing an operation procedure of the television receiver of the 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 Tuning control part 30 Search control part 32 Frequency sweeping part 34 Tuning list memory 58 Reception level detection circuit 60 Operation part

Claims (4)

[Claims] 1. A broadcast wave search means for performing a frequency sweep operation to detect one or a plurality of receivable broadcast waves when an unreceivable state of a broadcast wave being received is detected, and said broadcast wave search means A selection candidate receiving means for receiving one or a plurality of broadcast waves detected by the predetermined order and outputting the contents thereof, and selecting one of the broadcast waves whose received contents are sequentially output by the selection candidate reception means. And a broadcast wave selecting means for selecting a broadcast wave. 2. The broadcast wave search means according to claim 1, wherein the broadcast wave search means detects the presence / absence of a broadcast wave and a reception electric field level of each broadcast wave, and the selection candidate receiving means is detected by the broadcast wave search means. With the received electric field level being recognizable,
A channel selection method for a television receiver, wherein the reception content of the broadcast wave is output. 3. The method according to claim 2, wherein the selection candidate receiving means outputs the reception content of the broadcast wave in descending order of the reception electric field level. 4. The method according to claim 2, wherein the selection candidate receiving unit performs grouping of the plurality of broadcast waves detected by the broadcast wave search unit in accordance with the magnitude of the received electric field level. After outputting the received content of the broadcast wave a plurality of times for the group having the higher received electric field level, outputting the received content of the broadcast wave so as to include at least the group having the lower received electric field level. TV receiver selection system.