JP3060000U - Television receiver - Google Patents

Abstract

(57) [Summary] [Problem] To search a channel of a specific frequency band in advance and determine a receivable television broadcast form, and then execute a channel preset again, so that it may take time for the channel preset. Was. SOLUTION: The tuner 10 uses a television broadcast and a CAT.
If any one of the V broadcast signals can be received, the microcomputer 50 executes the channel preset so as to detect the broadcast signal of the television radio broadcast while presuming the CATV broadcast, It is determined whether a signal in a broadcast form can be received. If it is determined that a signal of a television radio broadcast can be received, the tuner 10 refers to a memory position, which is a preset content, to receive a channel with a station. Then, the target memory position is adapted to the channel of the television radio broadcast so as to be received.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a television receiver, and more particularly, to a television receiver capable of receiving a television broadcast signal corresponding to two different television broadcast modes.

[0002]

[Prior art]

 2. Description of the Related Art Conventionally, as an example of this type of television receiver, a television receiver capable of selectively receiving either a TV (television wave) broadcast or a CATV (cable television) broadcast has been known. Here, since the channel frequencies assigned to each are different, the channel frequency is not known unless it is previously known which TV broadcast to receive.Therefore, the user performs a predetermined switching according to the TV broadcast to be received. The switch had to be set. However, the setting of the changeover switch as described above was bothersome for the user, and the setting could not be received normally due to erroneous settings.Therefore, the television receiver determines which of the television broadcasts can be received. Accordingly, various configurations have been developed in which the setting is internally performed based on the determination result.

[0003] As an example, in the one disclosed in Japanese Patent Application Laid-Open No. Hei 6-326935, CATV broadcasting is focused on the fact that channels are allocated to a specific frequency band to which TV broadcasting channels are not allocated. By searching for a CATV broadcast channel in the specific frequency band in advance, it is determined whether CATV broadcast or TV broadcast can be received. Then, it is configured to execute a channel preset according to the result of the judgment, and to perform channel selection control based on the contents of the channel preset.

[0004]

[Problems to be solved by the invention]

 The conventional television receiver described above has the following problems. Certainly, since setting of the changeover switch is unnecessary, there is no trouble for the user, and it is unlikely that the reception cannot be performed normally due to an incorrect setting. However, after previously searching for the CATV broadcast channel in the specific frequency band, the channel preset is executed again, so that the channel preset may take a long time.

[0005] The present invention has been made in view of the above-described problems, and when it is possible to receive a television broadcast signal corresponding to two television broadcast forms, while determining a receivable television broadcast form, An object of the present invention is to provide a television receiver capable of reducing the time required for channel presetting.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the invention according to claim 1 includes a first television broadcast mode to which a predetermined channel frequency is allocated, and a channel which is the same as each channel frequency allocated to the first television broadcast mode. A signal of a desired frequency corresponding to a second television broadcasting mode in which a channel frequency is allocated to a specific frequency band in which a frequency or an adjacent channel frequency is allocated but not allocated in the first television broadcasting mode. Receiving means for receiving and outputting a signal, receiving instruction means for instructing the signal receiving means to receive a signal of each channel frequency corresponding to the second television broadcasting mode, and For each channel frequency specified in the above, the frequency including the channel frequency of the above-mentioned first television broadcasting format that is adjacent Station presence / absence judging means for judging the presence or absence of a station based on the output while changing the reception frequency of the signal reception means substantially continuously in a range, and a memory corresponding to the number of channels of the second television broadcast form A channel memory having a position and storing the data in a corresponding memory position in accordance with the determination result of the station presence / absence determining means; Either the signal of the first television broadcast form or the signal of the second television broadcast form can be received based on the determination result by the station presence / absence determination means for the channel in the specific frequency band assigned only to the form. Means for judging whether or not there is a broadcast, and based on the contents stored in the channel memory means. When the signal receiving means receives a channel with a station, if the television broadcast form determining means determines that the signal in the first television broadcast form can be received, the first television broadcast form is used. And receiving control means for receiving the signal in conformity with the channel of the mode.

[0007] In the invention according to claim 1 configured as described above, the first television broadcast mode to which a predetermined channel frequency is assigned, and each channel assigned to the first television broadcast mode. One of the second television broadcasting modes in which the same channel frequency as the frequency or a channel frequency close to the frequency is allocated, but the channel frequency is allocated to a specific frequency band not allocated in the first television broadcasting mode Can be received. Also, at the time of initial installation, etc., use the channel preset after executing it in advance. In this channel preset, when the reception instruction means instructs to receive a signal of each channel frequency corresponding to the second television broadcast mode, the signal reception means converts the signal of each channel frequency based on the instruction. Receive sequentially. At this time, the station presence / absence determining means outputs the output while changing the receiving frequency of the signal receiving means substantially continuously in a frequency band including the adjacent channel frequency of the first television broadcasting form for each channel frequency. Is determined based on the number of stations. On the other hand, the channel memory means has a memory position corresponding to the number of channels of the second television broadcast form, and stores the data in the corresponding memory position according to the judgment result of the station presence / absence judgment means.

[0008] When the channel memory means completes the storage processing for all the memory positions of the second television broadcast form, the television broadcast form judging means sets a unique frequency band assigned only to the second television broadcast form. It is determined which of the first television broadcast signal and the second television broadcast signal is receivable based on the result of the determination by the station presence / absence determination means for the channels within the above. Then, the reception control means causes the signal receiving means to receive the local channel based on the contents stored in the channel memory means. At this time, the television broadcast form determining means determines the first television broadcast form. If it is determined that the signal can be received, the signal is received in conformity with the channel of the first television broadcasting format.

[0009] That is, the station presence / absence determining means determines presence / absence of a station based on the channel frequency of the second television broadcast mode. The presence or absence of a station is determined in the frequency band including the channel frequency of the first television broadcast. Therefore, even if only the signal of the first television broadcast form can be received, the channel frequency with the station is detected. However, since the memory position in which the station-present channel is stored is based on the second television broadcast mode, the memory position may not be consistent with the first television broadcast mode. Therefore, the signal is received by the signal receiving means in accordance with the first television broadcasting form by the receiving control means.

[0010] Today, various television broadcast formats are adopted, and various types are applicable as a combination of the first and second broadcast formats, but the second television broadcast format is the first television broadcast format. Channel frequencies assigned to the same or adjacent channel frequencies as those assigned to the TV broadcast format of the first type, but to a specific frequency band not allocated in the first TV broadcast type. It is assumed that Therefore, as a more specific example of a television broadcast mode, the invention according to claim 2 is directed to the television receiver according to claim 1, wherein the first television broadcast mode is terrestrial broadcast, The second type of television broadcasting is cable television broadcasting. That is, either an U / V antenna for terrestrial broadcasting or a coaxial cable for cable television broadcasting is connected as an input source of the television broadcasting signal.

[0011] As described above, the station presence / absence judging means, for each channel frequency of the second television broadcast form, uses the signal receiving means in the frequency band including the adjacent channel frequency of the first television broadcast form. While changing the reception frequency almost continuously, the presence or absence of a station is determined based on the output. Of course, the configuration may be of various forms and is not particularly limited, but as an example of a more specific configuration, the invention according to claim 3 is described in either claim 1 or claim 2. In the television receiver, the synchronization detecting means for detecting the presence or absence of a synchronizing signal at the output of the signal receiving means and the reception frequency of the signal receiving means are changed substantially continuously in a predetermined frequency range, AFT pull-in means for pulling in to a normal tuning point based on an error voltage corresponding to the difference between the frequency of the video carrier and the reference frequency based on the output of the signal receiving means, and judges whether a station is present or not. In this case, when the synchronization signal can be detected by the synchronization detection means and the AFT pull-in means can be pulled into the normal tuning point, it is determined that there is a station. It is constituted.

In the invention according to claim 3 configured as described above, first, the presence / absence of a synchronization signal is detected by the synchronization detection unit based on the output of the signal reception unit. Here, when the presence of the synchronization signal is detected, the AFT pull-in means pulls in to the normal tuning point. In other words, the reception frequency of the signal receiving means can be changed to the normal tuning point based on the error voltage corresponding to the difference between the frequency of the video carrier and the reference frequency while changing the reception frequency substantially continuously in a predetermined frequency range. It is determined whether or not there is a station. If it can be pulled in, it is determined that there is a station. Otherwise, it is determined that there is no station.

When the receiving frequency is largely deviated from the normal tuning point, the error voltage has a voltage characteristic that saturates to a certain voltage value, so that the error voltage can be drawn to the normal tuning point over a wide frequency band. Instead, the frequency bands that can be pulled in are limited. Therefore, a device according to a fourth aspect of the present invention is the television receiver according to the third aspect, wherein the station presence / absence determining means includes a predetermined frequency band based on each channel frequency designated by the reception designating means. In the above, the receiving frequency of the signal receiving means is changed in a predetermined step unit, and the presence or absence of a station is determined at each receiving frequency by using the synchronization detecting means and the AFT pull-in means.

In the invention according to claim 4 configured as described above, in the predetermined frequency band based on each channel frequency indicated by the reception instruction means, the reception of the signal reception means in the predetermined step unit is performed. Change the frequency. Then, in order to determine the presence or absence of a station by using the synchronization detection means and the AFT pull-in means for each reception frequency, the station frequency over a relatively wide frequency band for each channel frequency specified by the reception instruction means is determined. The presence or absence of the station is determined.

[0015] The television broadcast form determining means determines which of the first television broadcast form signal and the second television broadcast form signal is receivable based on the determination result by the station presence / absence determining means. As an example of such a judging method, the invention according to claim 5 is characterized in that in the television receiver according to any one of claims 1 to 4, the television broadcast form judging means uses the first television broadcast form. In the specific frequency band not assigned, the station presence / absence determining means determines the receivable television broadcast form by comparing the number of channels determined to have a station with a predetermined constant.

[0016] In the invention according to claim 5 configured as described above, the television broadcast form judging means is arranged such that the station presence / absence judging means uses a specific frequency band not assigned in the first television broadcast form. The number of channels judged to be present is counted, and the number of channels is compared with a predetermined constant to determine a receivable television broadcast form. Of course, since the channel of the first television broadcast form is not allocated to the above specific frequency band, the signal of the second television broadcast form is originally transmitted if the number of counted channels is “1” or more. It may be determined that reception is possible. However, it may be judged that there is a station even though there is no station due to the influence of noise or the like. Therefore, the constant to be compared may be changed as appropriate to reduce erroneous judgment. Good.

[0017] The reception control means, upon causing the signal receiving means to receive a channel with a station based on the content stored in the channel memory means, causes the television broadcast form determination means to convert the signal in the first television broadcast form. If it is determined that the signal can be received, the signal is received while being adapted to the channel of the first television broadcast form, but the specific method is not particularly limited, and various forms can be applied. As described above, since the memory position where the channel with the station is stored is based on the second television broadcast form, if it is determined that the signal of the first television broadcast form can be received, However, the memory position may not be consistent with the first television broadcasting format. Therefore, the storage contents of the memory position may be rewritten so as to ensure the consistency.

[0018] As another example, the invention according to claim 6 is a television receiver according to any one of claims 1 to 5, wherein the reception control unit determines the television broadcast mode. When the means determines that the signal according to the first television broadcast form can be received, when the signal receiving means receives the channel with station, the channel to be received actually corresponds to the corresponding memory. The position is detected, and the reception is performed while judging whether or not there is a station based on the contents stored in the same memory position. In the invention according to claim 6 configured as described above, when the television broadcast form determining means determines that the signal according to the first television broadcast form is receivable, the reception control means sets the signal receiving means to a channel having a station. When receiving a channel, the memory position corresponding to the channel to be received is actually detected, and it is determined whether or not there is a station based on the contents stored in the memory position, and the channel is received.

[0019]

[Effect of the invention]

 As described above, the present invention presupposes the second television broadcast mode at the time of channel presetting, and after detecting the channel of the first television broadcast mode so that it can be detected, the signal of any television broadcast mode is detected. Is determined to be receivable, and if it is determined that the signal of the first television broadcast format is receivable, the first television broadcast format is used to receive the channel with station based on the preset contents. Since the reception is made in conformity with the channel of the present invention, it is possible to provide a television receiving apparatus in which only one channel search is required and the time required for channel presetting can be reduced. Further, according to the invention of claim 2, it is possible to provide an application example of a specific television broadcast form. According to the third aspect of the present invention, the presence or absence of a station is determined based on the presence / absence of a synchronization signal and the availability of AFT pull-in, so that a highly reliable determination can be made.

Further, according to the invention of claim 4, in a predetermined frequency band based on each channel frequency of the second television broadcast form, the reception frequency is changed in a predetermined step unit, and each reception frequency is changed. The presence / absence of a station is determined based on the presence / absence of a synchronization signal and the availability of AFT pull-in, so that highly reliable determination can be made and the presence / absence of a station over a relatively wide frequency band. Can be determined. Further, according to the invention of claim 5, a simple method of comparing the number of channels determined to have a station with a predetermined constant in a specific frequency band not allocated to the first television broadcast mode and comparing the magnitude with a predetermined constant. The receivable TV broadcast format can be determined by the method. Further, according to the invention of claim 6, when it is determined that the signal according to the first television broadcast form can be received, when the channel with station is to be received, the channel to be received is actually Since the corresponding memory position is detected and the reception is performed while judging whether or not there is a station based on the storage content in the same memory position, the storage content of the memory position does not need to be changed.

[0021]

[Embodiment of the invention]

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram showing a television to which a television receiver according to an embodiment of the present invention is applied. In FIG. 1, a tuner 10 can be connected to either a U / V antenna or a CATV (NORMAL) coaxial cable as an input source of a television broadcast signal, and has a desired frequency corresponding to both television broadcast bands. While receiving the signal, it selects only the required signal from the received signal, amplifies it at high frequency, converts it to an intermediate frequency signal, and outputs it. The tuner 10 according to the present embodiment employs a so-called PLL system tuning mechanism. By directly controlling the local oscillation frequency based on input of predetermined frequency data, the reception frequency can be controlled. ing.

The intermediate frequency signal output from the tuner 10 is amplified by the VIF circuit 20 at the video intermediate frequency and output to the video IC 30. The audio intermediate frequency signal is taken out as a second audio intermediate frequency signal in the process of video intermediate frequency amplification, is FM-detected by the audio IC 40, is appropriately amplified, and is supplied to the speaker 41. On the other hand, in the video IC 30, after the input video intermediate frequency amplified signal is video-detected, the horizontal and vertical synchronizing signals are separated based on the detected output and supplied to predetermined horizontal and vertical output stages, respectively. The VIF circuit 20 generates an AFT voltage corresponding to the difference between the actual frequency of the video carrier and the reference frequency. The AFT voltage and the synchronization signal separated by the video IC 30 are used as microcomputers. 50.

The microcomputer 50 can supply frequency data to the tuner 10, and the microcomputer 50 controls the reception frequency of the tuner 10. More specifically, when the remote controller 60 is operated to receive a desired channel, a corresponding infrared remote control signal is transmitted. Then, the microcomputer 50 receives the infrared remote control signal via an infrared remote control signal receiver (not shown), and sends frequency data to the tuner 10 so as to receive the corresponding channel. Of course, the TV broadcast and the CATV broadcast have different channel plans as shown in FIG. 2, so it is necessary to transmit frequency data corresponding to the type of television broadcast to be received. Therefore, in the present embodiment, the channel plan for TV broadcast and CATV broadcast as shown in FIG. 2 is stored in a predetermined storage medium, and the channel plan corresponding to the microcomputer 50 according to the type of television broadcast to be received. Is selected and used for tuning control.

By the way, regardless of whether the broadcast is a TV broadcast or a CATV broadcast, a TV broadcast signal does not always exist at each channel frequency. There is a so-called channel preset function that stores the existing channels with stations and selects a channel based on the stored contents. In this embodiment, the memory area corresponding to each channel number (CHNL IND) of “1” to “125” as shown in FIG. By the processing, the presence of the station is stored in the memory position of the channel with the station. Next, the channel preset processing will be described in detail.

When performing a channel preset, a channel preset is instructed by pressing down an operation button (not shown) of the remote controller 60 or the like. Then, similarly, an infrared remote control signal is transmitted from the remote controller 60, the microcomputer 50 detects the signal, and executes a channel preset process according to a flowchart shown in FIG. In the figure, first, in step S110, a channel plan for CATV broadcasting is selected, a predetermined flag (FLG) is set to indicate that it is CATV broadcasting, and stored in the EEPROM 70. Although not shown, in step S110, processing such as initializing all memory positions of the EEPROM 70 is executed. Thereafter, in step S120, a predetermined channel variable (CH) is set to "1", and in the next step S130, a station presence / absence determination process is executed.

FIG. 5 is a flowchart showing the station presence / absence determination processing. In the figure, in step S210, the channel frequency for the channel number set in the above channel variable is detected with reference to the channel plan of the CATV broadcast, and the corresponding frequency data (center frequency f0) is transmitted to the tuner 10. Send out. Then, since the tuner 10 tunes to the corresponding channel frequency, if a TV broadcast signal exists at the channel frequency, the video IC 30 can separate the synchronization signal and the synchronization signal is supplied to the microcomputer 50. become. Therefore, in the next step S220, it is determined whether or not the synchronization signal is supplied from the video IC 30, and if the synchronization signal is supplied, the AFT change point detection processing is executed in the next step S230, and the AFT change point is detected. Determine whether the point can be detected.

Here, before describing the AFT change point detection processing, the voltage characteristics of the AFT voltage will be described. As shown in FIG. 6, the AFT voltage has an inverted S-shaped voltage characteristic centered on the normal tuning point F, and the AFT voltage at the normal tuning point where the actual video carrier frequency and the reference frequency match. The voltage becomes the B voltage, and when both deviate slightly, they show a tendency of monotonic increase or monotonic decrease according to the direction of the deviation. When both deviate greatly, the upper and lower sides of the B voltage saturate and become constant. Become. Therefore, when the AFT voltage actually supplied from the video IC 30 is detected and compared with the B voltage, the direction of the above-mentioned shift can be determined.

In the AFT change point detection process in step S 230, the frequency data is set so that the reception frequency of the tuner 10 is sequentially shifted in small units so as to eliminate the above-described deviation, starting from the frequency at which the synchronization signal is detected. Send out. Then, even if the frequency at which the synchronization signal is detected deviates from the normal tuning point, the AFT voltage gradually becomes a value close to the B voltage, passes through the value closest to the B voltage, and then moves away from the B voltage again. . Therefore, at this point, the direction of the deviation from the normal tuning point has changed, and this point is called the AFT change point. That is, judging whether or not the AFT change point can be detected is nothing more than judging whether or not the normal tuning point can be detected. If the AFT change point can be detected in step S230, it is stored in step S240 that a station exists at the corresponding memory position of the EEPROM 70.

On the other hand, if it is determined in step S230 that the synchronization signal is not supplied from the video IC 30, or if the AFT change point cannot be detected in step S240, it is determined whether or not the AFT change point is the last detection point in step S250. Judge. That is, in the present embodiment, it is assumed that the detection of the synchronization signal in step S220 and the detection of the AFT change point in step S230 are performed at some detection points around the channel frequency. It is determined whether or not it is a detection point. If it is not the last, the frequency data of the next detection point is sent to the tuner 10 in step S260, and the process returns to step S220 to repeat the same processing.

Then, in the station presence / absence determination processing, the reception frequency of the tuner 10 transitions as shown in FIG. Referring to FIG. 3, ± 2... With respect to the channel frequency (f0). It can be seen that the AFT scanning range extends to a range of 44 [MHz]. Therefore, in this station presence / absence determination processing, the presence / absence of a television broadcast signal is detected in the range up to the channel frequency (f0) ± 2.44 [MHz], and if a television broadcast signal exists, the corresponding memory position of the EEPROM 70 is detected. The fact that there is a station is stored.

Returning to the description of the channel preset process, after performing the above-described station presence / absence determination process in step S130, it is determined in step S140 whether or not the value of the channel variable is equal to “125”. If not, the value of the channel variable is incremented by "1" in step S150, and the process returns to step S130 to repeat the same processing. Then, if it is determined in step S140 that the value of the channel variable is "125", it means that the preset processing for all the memory positions has been completed.

If it is determined in step S140 that the value of the channel variable is “125”, the memory position in the range of channel numbers “14” to “35” is referred to in step S160, and X) is calculated. Here, referring to the channel plan shown in FIG. 2, channel numbers “14” (121.25 [MHz]) to “35” (289.25 [MHz]) of the CATV broadcast are not allocated to the TV broadcast. It can be seen that this is a frequency band. Therefore, if an actual television broadcast signal is detected in this frequency band, it is known that the broadcast is CATV broadcast, and if it is not detected, it is a TV broadcast. Therefore, in the next step S170, the value of the number of channels (X) is compared with "2", and if the number of channels (X) is "2" or more, it is determined that the broadcast is CATV. On the other hand, if it is smaller than "2", it is determined that the broadcast is a TV broadcast, and in step S180, the flag (FLG) is set to indicate that the broadcast is a TV broadcast and stored in the EEPROM 70.

Note that since the channel frequency of the TV broadcast is not allocated to the above-mentioned frequency band, the number of channels (X) may be originally “1” as a comparison target. That is, if the number of channels (X) is "1" or more, it may be determined that the program is a CATV broadcast, and if it is smaller than "1", it may be determined that the program is a TV broadcast. However, although it is originally possible to receive only TV broadcast signals, there is a possibility that a channel with a station is detected in the above frequency band due to the influence of noise or the like. On the other hand, since there are usually at least two or more channels with CATV broadcasting stations in the above-mentioned frequency band, by comparing the number of channels (X) with “2”, erroneous determination of the television broadcasting form is reduced. As a result, the reliability is improved.

In the above-described channel preset processing, since the channel plan of the CATV broadcast is selected, if the TV broadcast receivable by the tuner 10 is the TV broadcast, the TV broadcast station-existing channel Does not seem to detect. However, as can be seen from the TV broadcast and CATV broadcast channel plans shown in FIG. 2, since the channel frequencies of the channel numbers “2” to “13” of the TV broadcast are the same as those of the CATV broadcast, The station-existing channel is surely detected.

On the other hand, the respective channel frequencies of the channel numbers “14” to “69” of the TV broadcast are higher than the respective channel frequencies of the channel numbers “65” to “94” and “100” to “125” of the CATV broadcast. The value is higher by 2 [MHz]. In the above-described station presence / absence determination processing, the presence / absence of a television broadcast signal can be detected within a range of ± 2.44 [MHz] with reference to each channel frequency of the CATV broadcast. It is also possible to surely detect the channels with station numbers up to "69". For example, as shown in FIG. 8, when the station presence / absence determination processing is performed for the channel number “65” (469.25 [MHz]) of the CATV broadcast, the channel number “14” (471.25 [MHz]) of the TV broadcast ) Can be sufficiently detected.

As described above, in the present embodiment, it is possible to detect a channel with a station of TV broadcasting while premising on CATV broadcasting, but it is stored as a premise that CATV broadcasting is used. The memory position corresponds to the channel number of CATV broadcasting. For example, in the example shown in FIG. 8 described above, even if the channel number “14” of the TV broadcast has a station, the memory position where the station is stored is “65”. In order to eliminate such a shift in the channel numbers, the contents of the memory positions of the channel numbers “65” to “94” and “100” to “125” are stored in the memory of the channel numbers “14” to “69”. Although a method of shifting to a position may be adopted, in the present embodiment, another method that does not involve such a shift is adopted, and this method will be described next.

The microcomputer 50 first refers to the contents of the flag (FLG) stored in the EEPROM 70 when a channel selection instruction such as channel up or channel down is issued from the remote controller 60 or the like. As a result, when it is detected that the broadcast is a CATV broadcast, the latest memory position in which the presence of the station is stored is detected by referring to the storage contents of the EEPROM 70. Then, referring to the channel plan of the CATV broadcast, the frequency data corresponding to the channel number of the detected memory position is transmitted to the tuner 10 and received. When the channel number is to be displayed on the OSD, the channel number of the detected memory position is displayed.

On the other hand, as a result of referring to the contents of the flag (FLG), if it is detected that the broadcast is a TV broadcast, the microcomputer 50 stores the channel numbers “65” to “94” and the memories of “100” to “125”. The positions are internally converted and interpreted as channel numbers "14" to "69", respectively. For example, as shown in FIG. 9, when the channel up is instructed from the state where the channel number “13” of the TV broadcast is selected, the channel number “65” corresponding to the channel number “14” of the TV broadcast is given. Search for the memory position after "." And detect the memory position that stores that there is a station. Here, the memory positions of channel numbers “1”, “14” to “64”, and “95” to “99” are excluded from the search targets.

Then, when a memory position in which the presence of a station is stored in the channel numbers “65” to “94” is detected, the difference from the channel number of the memory position is determined based on the TV broadcast channel plan. The frequency data of the TV broadcast corresponding to the channel number obtained by subtracting “51” from the above is transmitted to the tuner 10. When the channel number is displayed by OSD, the channel number after the subtraction is displayed by OSD. On the other hand, when a memory position where the presence of a station is stored is detected in the memory positions of “100” to “125”, the difference from the channel number of the memory position is determined based on the TV broadcast channel plan. The frequency data of the TV broadcast corresponding to the channel number obtained by subtracting “56” is transmitted to the tuner 10. When the channel number is displayed by OSD, the channel number after the subtraction is displayed by OSD.

In the case of TV broadcasting, channels should not be assigned to frequency bands corresponding to channel numbers “1”, “14” to “64” and “95” to “99” of CATV broadcasting. is there. Therefore, when it is detected by referring to the flag (FLG) that the broadcast is a TV broadcast, there is no memory position in which the presence of the station is stored when the memory position in the above range is searched. is there. Therefore, it is not necessary to exclude the memory positions in the above range from the search target at the time of tuning, and it seems that only the conversion of the channel number should be performed. However, in the frequency bands corresponding to the channel numbers “1”, “14” to “64”, and “95” to “99” of the CATV broadcast, the station is affected by noise and the like despite the fact that there is no station originally. It may be considered that there is a memory position in which the presence is stored. Therefore, when a TV broadcast is detected as in the present embodiment, the memory positions of channel numbers “1”, “14” to “64” and “95” to “99” are excluded from search targets. By doing so, the effects of noise and the like as described above can be eliminated, which is preferable.

Next, the operation of the present embodiment configured as described above will be described. When a channel preset is instructed by depressing an operation button (not shown) of the remote controller 60, a predetermined infrared remote control signal is transmitted from the remote controller 60, and the microcomputer 50 detects and executes a channel preset process. In this channel preset processing, it is assumed that CATV broadcasting can be received. First, a channel plan of CATV broadcasting is selected as an initial setting, and a predetermined flag (FLG) is set to indicate that the TV is CATV broadcasting. Then, it is stored in the EEPROM 70 (step S110).

Thereafter, based on the channel plan of the CATV broadcast, the channels of channel numbers “1” to “125” are sequentially selected by the tuner 10, and the presence or absence of the synchronization signal from the video IC 30 and the AFT from the VIF circuit 20 are selected. It is determined whether each channel has a station based on the voltage. If it is determined that there is a station, the fact that there is a station is stored in the corresponding memory position of the EEPROM 70 (steps S120 to S150). In determining whether or not each channel has a station, a television broadcast signal can be detected within a range of ± 2.44 [MHz] with respect to each channel frequency. If can be detected, it is determined that there is a station.

When the preset for all the channels of the CATV broadcast is completed, the memory positions of the channel numbers “14” to “35” are sequentially referred to, and the number of channels (X) of the channel with station is calculated (step S160). . Then, the value of the number of channels (X) is compared with “2” (step S170). If the number of channels (X) is “2” or more, the channel preset processing is terminated as it is. If so, the flag (FLG) is set to TV broadcasting and stored in the EEPROM 70, and then the channel preset processing is terminated (step S180).

When the channel up or channel down is instructed from the remote controller 60 after the completion of the channel preset in this way, a predetermined infrared remote controller signal is similarly transmitted from the remote controller 60 and the microcomputer 50 detects the signal. Then, the microcomputer 50 first refers to the contents of the flag (FLG) stored in the EEPROM 70, and detects whether the television broadcast signal of the CATV broadcast or the TV broadcast can be received. Here, when it is detected that the broadcast is a CATV broadcast, the nearest memory position where the presence of a station is stored is detected, and based on the channel plan of the CATV broadcast, a channel number corresponding to the memory position is detected. The frequency data is transmitted to the tuner 10, whereby the tuner 10 receives the television broadcast signal of the corresponding channel.

On the other hand, when detecting that the broadcast is a TV broadcast, the microcomputer 50 stores the memory positions of the channel numbers “65” to “94” and “100” to “125” to the channel numbers “14” and “14”, respectively. ６９69 internally converted and interpreted. For example, as shown in FIG. 9, when the channel up is instructed from the state in which the channel number “13” of the TV broadcast is selected, the channel number “65” corresponding to the channel number “14” of the TV broadcast is given. The subsequent memory positions are searched to detect the memory position where the presence of the station is stored.

When a memory position in which the presence of a station is stored in channel numbers “65” to “94” is detected, the difference from the channel number of the memory position is determined based on the TV broadcast channel plan. The frequency data corresponding to the channel number obtained by subtracting “51” from the above is transmitted to the tuner 10. On the other hand, when a memory position in which the presence of a station is stored in the channel numbers “100” to “125” is detected, the difference “from the memory position channel number” is determined based on the TV broadcast channel plan. The frequency data corresponding to the channel number obtained by subtracting “56” is transmitted to the tuner 10. Then, similarly, the tuner 10 results in receiving the television broadcast signal of the corresponding channel.

As described above, when the tuner 10 is capable of receiving a signal in one of the television broadcast format and the TV broadcast format, the microcomputer 50 controls the broadcast signal of the television broadcast while presuming the CATV broadcast. After executing the channel preset so that the signal can be detected, it is determined which type of TV broadcast signal can be received. If it is determined that the signal of the TV broadcast can be received, the preset contents are determined. When the tuner 10 receives the channel with the station by referring to the memory position, the target memory position is adapted to the channel of the television broadcast, so that the channel search can be performed only once. It is possible to provide a television receiver capable of reducing the time required for presetting. Wear.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram illustrating a configuration of a television receiver according to an embodiment of the present invention.

FIG. 2 is a diagram showing channel plans of TV broadcasting and CATV broadcasting in a table format.

FIG. 3 is a diagram for explaining a memory position.

FIG. 4 is a flowchart showing a processing procedure at the time of channel preset.

FIG. 5 is a flowchart illustrating a procedure of a station presence / absence determination process.

FIG. 6 is a waveform chart showing voltage characteristics of an AFT voltage.

FIG. 7 is a diagram showing frequency transition at the time of channel preset.

FIG. 8 is a diagram showing a detectable range of the presence or absence of a station.

FIG. 9 is a diagram showing a search operation of a memory position at the time of channel selection.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Tuner 20 ... VIF circuit 30 ... Video IC 40 ... Audio IC 50 ... Microcomputer 60 ... Remote control 70 ... EEPROM

Claims (6)

[Utility model registration claims] 1. A first television broadcast mode to which a predetermined channel frequency is allocated, and a channel frequency which is the same as or close to each of the channel frequencies allocated to the first television broadcast mode is allocated. Signal receiving means for receiving and outputting a signal of a desired frequency corresponding to a second television broadcast mode in which a channel frequency is allocated to a unique frequency band not allocated in the first television broadcast mode; Receiving instruction means for instructing the signal receiving means to receive a signal of each channel frequency corresponding to the second television broadcast form; and for each channel frequency instructed by the reception instruction means, The reception frequencies of the signal receiving means are substantially linked in a frequency band including a channel frequency of one television broadcast form. Presence / absence determination means for determining whether a station is present or absent based on the output of the second television broadcast, and a memory position corresponding to the number of channels of the second television broadcast form, and determining the presence / absence of the station. A channel memory means for storing in a corresponding memory position according to the result; and a channel in a specific frequency band assigned only to the second television broadcast form after the storage processing for all memory positions is completed in the channel memory means. A television broadcast form determining means for determining which of the first television broadcast form signal and the second television broadcast form signal is receivable based on a result of the determination by the station presence / absence determining means; The channel with station is received by the above signal receiving means based on the storage contents of the means In receiving, when it is determined that the signal of the first television broadcast form is receivable by the television broadcast form determination means, reception control means for receiving the signal adapted to the channel of the first television broadcast form. A television receiver, comprising: 2. The television receiving apparatus according to claim 1, wherein said first television broadcasting form is terrestrial broadcasting, and said second television broadcasting form is cable television broadcasting. Television receiver. 3. The television receiving apparatus according to claim 1, wherein: a synchronization detecting unit that detects presence or absence of a synchronization signal at an output of the signal receiving unit; While changing the receiving frequency substantially continuously in a predetermined frequency region, the pull-in to the normal tuning point is performed based on the error voltage corresponding to the difference between the frequency of the video carrier and the reference frequency based on the output of the signal receiving means. AFT to do
A pull-in means for detecting whether a station is present or absent, so that the synchronous signal can be detected by the synchronous detecting means, and
A television receiver characterized in that it is determined that there is a station when it is possible to pull in to a normal tuning point by FT pull-in means. 4. The television receiving apparatus according to claim 3, wherein the station presence / absence determining unit is configured to perform the step-by-step unit in a predetermined frequency band based on each channel frequency specified by the reception instruction unit. A television receiver, wherein the reception frequency of a signal reception means is changed, and the presence or absence of a station is determined at each reception frequency by using the synchronization detection means and the AFT pull-in means. 5. The television receiving apparatus according to claim 1, wherein the television broadcast mode determining unit determines a frequency band unique to the first television broadcast mode. A television receiving apparatus for determining a receivable television broadcast form by comparing the number of channels determined to have a station by the station presence / absence determining means with a predetermined constant. 6. The television receiver according to claim 1, wherein said reception control means includes means for receiving said signal relating to said first television broadcast form when said television broadcast form determination means receives the signal according to said first television broadcast form. If it is determined that it is possible, when the signal receiving means receives a channel with a station, the memory position corresponding to the channel to be received is actually detected, and the station is detected based on the stored contents in the memory position. A television receiving apparatus for receiving a signal while determining whether or not the signal is received.