Automatic tuning apparatus

Abstract: An automatic tuning apparatus capable of automatically switching the tuning mode of a tuner circuit, automatically arranging various signal data in or after completion of tuning and arbitrarily and automatically arranging various signal data by the user comprises a SYNC discrimination circuit (11) discriminating whether a video signal system is the NTSC system or another system, a tuning mode switching circuit (12) for switching the tuning mode, and a color discrimination circuit (13) receiving a color bust signal (identic signal) for discriminating whether the video signal system is the PAL system or the SECAM system. As to the NTSC system, the PAL system, the SECAM system and the SECAM-L system, the user may not set the tuning mode of tuning means, whereby an automatic tuning apparatus imposing no burden on the user can be obtained.

Description: The present invention relates to an automatic tuning apparatus, according to the preamble of claim 1 and more particularly, it relates to an automatic tuning apparatus for a VTR, which is adapted to discriminate the signal system and process stored signal information in automatic tuning. A conventional automatic tuning apparatus for a VTR (video tape recorder) is now described with reference to Figs. 21 to 23. Fig. 21 is a block diagram showing a principal part in the conventional automatic tuning apparatus for a VTR, and Fig. 22 is a flow chart as to its operation. Fig. 23 shows the relations between station numbers (expedient broadcasting station numbers) and position numbers (expedient numbers on the VTR unit for selecting the broadcasting stations) after completion of tuning. Referring to Fig. 21, numeral 2 denotes a tuner circuit which can be switched in correspondence to a video signal system by an external control signal, numeral 3 denotes a video signal processing circuit (referred to as Y/C in the figure) including a synchronizing signal (abbreviated as SYNC) separation circuit which receives a composite video signal S1 from the tuner circuit 2 and carries out signal processing, numeral 4 denotes an AFT detection circuit which detects presence/absence of a broadcasting station by a signal received from the tuner circuit 2, numeral 5 denotes a tuning control circuit, and numeral 6 denotes a memory circuit, and a system controller 7 is formed by the tuning control circuit 5 and the memory circuit 6. Numeral 8 denotes an input signal system switch for switching the operation of the tuning control circuit 5 in response to the carrier system of the input signal. The operation is now described with reference to Figs. 22 and 23. First, the operation of automatic tuning (hereinafter referred to as auto tuning) is described with reference to the flow chart of Fig. 22. When a command for automatic tuning (hereinafter referred to as auto tuning) is received from the user, the system controller 7 sets the tuning mode of the tuner circuit 2 at the PAL system and sets a memory address of the memory 6 at a station number "0", as initialization (step ST1). Then, a tuning control signal S3 is transmitted to the tuner circuit 2, to control the same in a direction for increasing its tuning frequency by a constant amount (step ST2). At this time, an AFT (automatic fine tuning) signal S4 which is outputted from the AFT detection circuit 4 and a SYNC signal S2 indicating presence/absence of a signal separated by the video signal processing circuit 3 are inputted in the tuning control 5 for making a discrimination, in order to detect presence/absence of a broadcasting station transmitting a signal of the frequency (step ST3). When both of the AFT signal S4 and the SYNC signal S3 are supplied at this point of time, the tuning control circuit 5 determines that it has been possible to receive the signal from the broadcasting station, and stores current tuning data in the address of the station number "0" in the memory 6 (step ST4). The tuning data indicates data related to the frequency. Then, the address of the memory 6 is incremented by one to a station number "1" to enter a next tuning operation, in order to store next tuning data (step ST5). When both of the AFT signal S4 and the SYNC signal S2 are not supplied, on the other hand, a discrimination is made as to whether or not the current frequency reaches the upper limit of the tuning frequency, i.e., whether or not the tuning is ended (step ST6). The tuning is ended if the current frequency reaches the upper limit of the tuning frequency, otherwise the operation at the step ST2 is carried out again. The operations at the steps ST2 to ST6 are repeated, so that the tuning is ended when the frequency reaches the upper limit of the tuning frequency. The tuning data obtained by the tuning is supplied to a channel selection system from the address in the memory 6, so that a position number for channel selection is allotted and the tuning mode is ended. Results obtained by the aforementioned auto tuning are expressed as shown in Fig. 23. Fig. 23 shows station numbers of the addresses of the memory 6 and the tuning data stored therein, and the relations between the station numbers and the position numbers for channel selection. Fig. 23 indicates that frequency data corresponding to transmission frequencies of "B station", "D station", "C station" and "A station" are stored in the station numbers "0" to "3" as the tuning data respectively. On the other hand, it indicates that no data to be stored are present, i.e., no broadcasting stations are present in the station numbers "4" to "99". In the channel selection system, the frequency data corresponding to the transmission frequencies of "B station", "D station", "C station" and "A station" are stored in the position numbers "0" to "3" respectively, while the position numbers "4" to "99" are skipped since no data reading is necessary. The user can use the channel selection system of the VTR from the point of time when the auto tuning is completed, and obtain a tuned signal by selecting a switch corresponding to the position number. In the auto tuning, the tuning operation is carried out only as to a signal which is transmitted in the PAL system, and hence no signal transmitted in a transmission system other than the PAL system can be obtained. In order to tune a signal of a transmission system other than the PAL system, the input signal system switch 8 which is connected to the tuning control circuit 5 is so switched that the tuning control circuit 5 supplies a control signal SCON for switching the input signal system to the tuner circuit 2. The conventional automatic tuning apparatus is structured in the aforementioned manner, and hence the transmission system of the input signal is set at the PAL system in initialization. In order to tune a signal of a transmission system other than the PAL system, the user must manually switch the input signal system switch 8 after completion of auto tuning, to carry out re-tuning. In the auto tuning, further, only the data related to the frequency is stored and hence there are no data as to the type of the tuned broadcasting station, strongness/weakness of the signal, and the sound and video signal systems which are varied with countries. Thus, the user is disadvantageously forced to select the position in relation to these differences after completion of the auto tuning. An automatic tuning apparatus according to the preamble of claim 1 is known from EP-A-624979 and EP-A-263555. It is an object to provide an automatic tuning apparatus by means of which a broadcasting station information can be recognized at need. This object is solved by the subject matter of claim 1. Further advantageous modifications of the present invention are subject matter of the dependent claims In the automatic tuning apparatus according to claim 1, the broadcasting station information specifying the broadcasting station is separated from the decoded text data in the tuning control means and stored in the memory means along with the data related to the tuning frequency, whereby the broadcasting station information can be recognized at need during and after completion of automatic tuning. In the automatic tuning apparatus according to claim 2, the broadcasting station information can be displayed on a receiver screen due to provision of the character generator means for superposing the broadcasting station information stored in the memory means on the video signal. In the automatic tuning apparatus according to claim 3, the broadcasting station information specifying the broadcasting station is separated from the decoded text data in the tuning control means and stored in the memory means along with the data related to the tuning frequency while the broadcasting station information and the data related to the corresponding tuning frequency are automatically sorted in previously set order, whereby the user may not set a call number in correspondence to the broadcasting station information. The automatic tuning apparatus according to claim 4 further comprises the sorting order set means which is connected with the memory means for arbitrarily setting the sorting order for the storage contents, whereby an automatic tuning apparatus having a large degree of freedom for the user can be obtained. The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. Fig. 1 illustrates the structure of an automatic tuning apparatus according to a first embodiment of the present invention; Fig. 2 illustrates a partial structure of the automatic tuning apparatus according to the first embodiment of the present invention; Fig. 3 is a flow chart for illustrating the operation of the automatic tuning apparatus according to the first embodiment of the present invention; Fig. 4 illustrates the structure of an automatic tuning apparatus according to a second embodiment of the present invention; Fig. 5 illustrates an exemplary operation of the automatic tuning apparatus according to the second embodiment of the present invention; Fig. 6 illustrates the structure of an automatic tuning apparatus for elucidating the subject matter of the present invention; Fig. 7 illustrates a partial structure of the automatic tuning apparatus of Fig. 6; Fig. 8 is a flow chart for illustrating the operation of the automatic tuning apparatus of Fig 6; Fig. 9 is a flow chart for illustrating the operation of the automatic tuning apparatus of Fig. 6; Fig. 10 illustrates the structure of an automatic tuning apparatus for elucidating the subject matter of the present invention; Fig. 11 is a flow chart for illustrating the operation of the automatic tuning apparatus of Fig. 10; Fig. 12 illustrates the structure of an automatic tuning apparatus for elucidating the subject matter of the present invention; Fig. 13 is a flow chart for illustrating the operation of the automatic tuning apparatus of Fig. 12; Fig. 14 illustrates the structure of an automatic tuning apparatus according to a third embodiment of the present invention; Fig. 15 illustrates a partial structure of the automatic tuning apparatus according to the third embodiment of the present invention; Fig. 16 is a flow chart for illustrating the operation of the automatic tuning apparatus according to the third embodiment of the present invention; Fig. 17 is a flow chart for illustrating the operation of the automatic tuning apparatus according to the third embodiment of the present invention; Fig. 18 illustrates the structure of an automatic tuning apparatus according to an fourth embodiment of the present invention; Fig. 19 illustrates a partial structure of the automatic tuning apparatus according to the fourth embodiment of the present invention; Fig. 20 is a flow chart for illustrating the operation of the automatic tuning apparatus according to the fourth embodiment of the present invention; Fig. 21 illustrates the structure of a conventional automatic tuning apparatus; Fig. 22 is a flow chart for illustrating the operation of the conventional automatic tuning apparatus; and Fig. 23 illustrates the operation of the conventional automatic tuning apparatus. Fig. 1 shows the structure of an automatic tuning apparatus A1 for a VTR according to a first embodiment of the present invention. Referring to Fig. 1, numeral 2A denotes a tuner circuit which is connected to an antenna 1, numeral 3 denotes a video signal processing circuit including a SYNC separation circuit receiving a composite video signal S1 from the tuner circuit 2A and carrying out signal processing, numeral 4 denotes an AFT detection circuit receiving a signal from the tuner circuit 2A and detecting presence/absence of a broadcasting station, numeral 5 denotes a tuning control circuit for controlling the tuning operation of the tuner circuit 2A, and numeral 6 denotes a memory circuit which is connected with the tuning control circuit 5, and a system controller 7 is formed by the tuning control circuit 5 and the memory circuit 6. Numeral 10 denotes a text data decoder circuit receiving the video signal S1 and extracting a teletext signal S5, which is information from the broadcasting station, from the video signal S1 for supplying the same to the tuning control circuit 5. With reference to Fig. 2, the structure of the text data decoder circuit 10 is now described. Referring to Fig. 2, the text data decoder circuit 10 is formed by a blanking detection circuit 101 and a blanking gate circuit 102 which are supplied with the video signal S1, and a text data detection circuit 103 which is connected to the blanking gate circuit 102 and outputs the teletext signal S5. The operation is now described. The blanking detection circuit 101 detects a part (vertical blanking period) of the video signal S1 having no actual signal su ch as a picture in the vicinity of a synchronizing signal, and supplies a blanking signal S101 to the blanking gate circuit 102. In the video signal S1 which is supplied to the blanking gate circuit 102, only the part having no actual signal such as the picture in the vicinity of the synchronizing signal is extracted in response to the blanking signal S101 and supplied to the text data detection circuit 103, so that text data included in this part is read in the text data detection circuit 103 and outputted as the teletext signal S5. The operation of the automatic tuning apparatus A1 is now described with reference to a flow chart shown in Fig. 3. When a command for auto tuning is received from the user, the system controller 7 sets the tuning mode of the tuner circuit 2A at the PAL system while setting the memory address of the memory 6 at a station number "0" as initialization (step ST1). Then, a tuning control signal S3 is transmitted to the tuner circuit 2A, to control the same in a direction for increasing the tuning frequency by a constant amount (step ST2). In order to detect presence/absence of a broadcasting station transmitting a signal of the frequency at this time, an AFT (automatic fine tuning) signal S4 outputted from the AFT detection circuit 4 and a SYNC signal S2 indicating presence/absence of a signal separated by the video signal processing circuit 3 are inputted in the tuning control circuit 5, for making a discrimination (step ST3). If both of the AFT signal S4 and the SYNC signal S2 are supplied at this point of time, the tuning control circuit 5 determines that the signal from the broadcasting station can be received, and stores the current tuning data (data related to the frequency) in the address of the station number "0" in the memory 6 (step ST4). At the same time, the text data decoder circuit 10 decodes text information which is superposed on a blanking period of the signal from the composite video signal S1, so that the decoded teletext signal S5 is inputted in the tuning control circuit 5 (step ST5). The tuning control circuit 5 extracts broadcasting station information from the teletext signal S5, and stores the same in the address of the station number "0" in the memory 6, similarly to the data related to the frequency (step ST6). Then, the address of the memory 6 is incremented by one to a station number "1" in order to store next tuning data, and the process advances to a next tuning operation (step ST7). If both of the AFT signal S4 and the SYNC signal S2 are not supplied at the step ST3, on the other hand, a discrimination is made as to whether or not the current frequency reaches the upper limit of the tuning frequency, i.e., whether or not the tuning is ended (step ST8). The tuning is ended if the current frequency reaches the upper limit of the tuning frequency, otherwise the operation at the step ST2 is carried out again so that the operations through the steps ST2 to ST7 are repeated, and the tuning is ended when the frequency reaches the upper limit of the tuning frequency. The tuning data obtained by the tuning is supplied to a system for channel selection from the address of the memory 6, so that a position number for channel selection is allotted thereto and the tuning mode is ended. The automatic tuning apparatus A1 for a VTR according to the present invention comprises the text data decoder circuit 10 and the memory 6 of the system controller 7 stores the broadcasting station information along with data related to the frequency, whereby the broadcasting station can be discriminated through the teletext signal S5 serving as broadcasting station information during and after completion of the auto tuning operation. While the broadcasting station information is extracted from the teletext signal S5 in the tuning control circuit 5 in the aforementioned automatic tuning apparatus A1, the broadcasting station information may be replaced by another information, or all of the teletext signal may be extracted and stored. For example, an error rate of text data may be calculated to discriminate the state of a received electric field. While the data related to the frequency and the teletext signal are stored only in the auto tuning operation in the aforementioned automatic tuning apparatus A1, a teletext signal of a currently received video signal may be stored in the system controller 7 after completion of auto tuning, so that the same is compared with that in the auto tuning or the data is updated. Thus, it is possible to cope with such case that the received electric field or the broadcasting station is changed after the auto tuning. While the aforementioned automatic tuning apparatus A1 determines presence/absence of the broadcasting station in the auto tuning operation by inputting both of the AFT signal S4 and the SYNC signal S2 in the system controller 7, the same may alternatively be determined only through presence/absence of the teletext signal S5, the AFT signal S4 or the SYNC signal S2, for example. If any broadcasting station has no teletext signal S5, this fact can be stored in the system controller 7. While the frequency is increased from the lower side to the higher side in the auto tuning operation of the aforementioned automatic tuning apparatus A1, the frequency may alternatively be reduced from the higher side to the lower side. When there are various frequency bands for VHF, UHF and the like, the tuning may be carried out from any frequency band or only in a specific frequency band. Further, the tuning direction may be varied with the frequency band. The tuning control signal S3 which is outputted from the tuning control circuit 5 is a dc voltage, a PWM pulse, or serial data. Fig. 4 illustrates the structure of an automatic tuning apparatus A4 for a VTR according to a second embodiment of the present invention. Referring to Fig. 4, a character generator circuit (hereinafter referred to as a CG circuit) 40 for superposing data on a video signal S1 for displaying characters etc. on a screen is connected to a video signal processing circuit 3, so that an output of the CG circuit 40 is supplied to a video signal output terminal 9. The other structural parts of this embodiment are identical to those of the automatic tuning apparatus A1 shown in Fig. 1, and hence the same are denoted by the same reference numerals, to omit redundant description. The operation of the automatic tuning apparatus A4 is now described. When a command for auto tuning is received from the user, a tuning operation similar to that of the automatic tuning apparatus A1 is carried out along the flow chart shown in Fig. 3, while a teletext signal S5 is extracted from a received broadcasting station signal through a text data decoder circuit 10, so that broadcasting station information is stored in a memory 6 of a system controller 7 with data related to the frequency. When the broadcasting information is read from the memory 6 with the data related to the frequency again after completion of the auto tuning, the broadcasting information is superposed on a video signal through the CG circuit 40 and displayed on a receiver screen. The CG circuit 40, which is formed by a ROM, stores characters, symbols etc. consisting of matrices of prescribed dots. This structure is generally well known in the art, and hence redundant description is omitted. Fig. 5 illustrates exemplary display of broadcasting information on a receiver screen SC. Referring to Fig. 5, the name of the currently received broadcasting station is displayed as "BBC1" on the receiver screen SC. Thus, the user can recognize the received broadcasting station information. While the broadcasting station information is outputted on the receiver screen after completion of the auto tuning according to this embodiment, the same may alternatively be displayed in the auto tuning. Further, the same may not be outputted on the receiver screen, but a fluorescent display tube, a light emitting diode or a liquid crystal display may be provided on a portion out of the receiver screen, to display the broadcasting station information. Fig. 6 illustrates the structure of an automatic tuning apparatus A5 for a VTR for elucidating the subject matter of the present invention, which is, however, as such not part of the present invention. Referring to Fig. 6, numeral 2 denotes a tuner circuit which is connected to an antenna 1 for allowing switching in correspondence to an input signal system by an external control signal, numeral 3 denotes a video signal processing circuit including a SYNC separation circuit which receives a composite video signal S1 from the tuner circuit 2 for carrying out signal processing, numeral 4 denotes an AFT detection circuit which receives a signal from the tuner circuit 2 for detecting presence/absence of a broadcasting station, numeral 5 denotes a tuning control circuit which controls a tuning operation of the tuner circuit 2, numeral 6 denotes a memory which is connected to the tuning control circuit, numeral 11 denotes a SYNC discrimination circuit which receives a SYNC signal S2 outputted from the video signal processing circuit 3 for discriminating whether the video signal system is the NTSC system or another system through the number of the SYNC signal, and numeral 12 denotes a tuning mode switching circuit which receives a mode switching circuit first control signal S9 outputted from the SYNC discrimination circuit 11 and outputs a mode switching signal S11 to the tuner circuit 2 for switching the tuning mode. A system controller 7A is formed by the tuning control circuit 5, the memory 6, the SYNC discrimination circuit 11 and the tuning mode switching circuit 12. Further, a color discrimination circuit 13 is provided for receiving a color burst signal (identic signal) S8, which is one of outputs of the video signal processing circuit 3, discriminating whether the video signal system is the PAL system or the SECAM system, and supplying the result to the tuning mode switching circuit 12 as a mode switching circuit second control signal S10. The SYNC discrimination circuit 11 has a structure of counting the number (pulse number) of SYNC per second by a microcomputer or the like, and makes a discrimination on the NTSC system when 60 SYNCs are counted in one second (60 Hz), or the SECAM system or the PAL system when 50 SYNCs are counted in one second. The color discrimination circuit 13 is now described. Fig. 7 is a block diagram showing the structure of the color discrimination circuit 13. Referring to Fig. 7, the color discrimination circuit 13 comprises a burst gate circuit 131 which passes the color bust signal S8 every 1H, a frequency filter 132 which is connected to the burst gate circuit 131 for extracting only a color burst signal (identic signal) S8 having a frequency of 4.43 MHz, a DC conversion circuit 133 which DC-converts the signal passed through the frequency filter 132, and a comparator 135 which compares a DC signal outputted from the DC conversion circuit 133 with another DC signal obtained by delaying the output of the DC conversion circuit 133 by 1H through a delay circuit 134. The operation is now described. The color burst signal (identic signal in the SECAM system) S8 is present behind the SYNC signal S2 in general in either one of the SECAM system and the PAL system as shown in Fig. 7 and its frequency is entirely 4.43 MHz in the case of the PAL system, while signals of 4.25 MHz and 4.41 MHz alternately appear every 1H in the case of the SECAM system. Therefore, the burst gate circuit 131 and the frequency filter 132 are employed to extract the frequency of the color bust signal S8 per 1H by the filter, convert the same to a DC value by the DC conversion circuit 132 and compare the DC level per 1H by the comparator 135, thereby making a discrimination on the PAL system if the DC level per 1H is identical or on the SECAM system if the DC level per 1H is different. With reference to flow charts shown in Figs. 8 and 9, the operation of the automatic tuning apparatus A5 is now described. When a command for auto tuning is received from the user, a system controller 7 sets the tuning mode of the tuner circuit 2 at a PAL system, and sets the memory address of a memory 6 at a station number "0" as initialization (step ST1). Then, a tuning control signal S3 is transmitted to the tuner circuit 2, to control the same in a direction for increasing the tuning frequency by a constant amount (step ST2). At this time, a discrimination is made as to whether or not the current frequency reaches the upper limit of the tuning frequency, i.e., whether or not the tuning is ended (step ST3), so that the tuning is ended if the current frequency reaches the upper limit of the tuning frequency, otherwise an AFT signal S4 which is outputted from an AFT detection circuit 4 and a SYNC signal S2 indicating presence/absence of a signal separated by a video signal processing circuit 3 are inputted in the tuning control circuit 5, in order to detect presence/absence of a broadcasting station transmitting a signal of the frequency (step ST4). If both of the AFT signal S4 and the SYNC signal S2 are supplied at this time, the tuning control circuit 5 determines that the signal from the broadcasting station can be received and executes a next step S5. If both of the AFT signal S4 and the SYNC signal S2 are not supplied, on the other hand, the tuning frequency is increased by a constant amount at the step ST2. At a step ST5, the SYNC signal S2 from the video signal processing circuit 3 is transmitted to the SYNC discrimination circuit 11 in the system controller 7A, so that the SYNC discrimination circuit 11 outputs the mode switching circuit first control signal S9 and supplies the same to the tuning mode switching circuit 12 when the SYNC signal S2 is supplied at 60 Hz, to change the tuner circuit 2 to the NTSC mode by the mode switching signal S11 (step ST6). If the SYNC signal is supplied at 50 Hz, on the other hand, it is discriminated as being other than the NTSC system. When the tuner circuit 2 is set at the NTSC mode, the current tuning data (data related to the frequency) is stored in the address of the station number "0" of the memory 6 while information that the current video signal system is the NTSC system is also stored, and the address of the memory 6 is incremented by one to a station number "1" in order to store next tuning data (step ST7). Then, the tuning mode of the tuner circuit 2 is set at the PAL mode at a step ST8, the tuning frequency is increased by a constant amount at the step ST2 to enter a next tuning operation, the operations through the steps ST2 to ST8 are repeated, and the tuning is ended upon reaching the upper limit of the tuning frequency. The tuning data obtained by the tuning is supplied to a system for channel selection from the address of the memory 6, so that a position number for channel selection is allotted thereto and the tuning mode is ended. When a discrimination is made on a system other than the NTSC system at the step ST5, the color discrimination circuit 13 receiving the color burst signal S8 from the video signal processing circuit 3 makes a color discrimination, to discriminate the system to the SECAM system and another system (step ST9). In the case of the SECAM-L system, the video signal S1 is hunting since the same is tuned in the PAL mode and frequency change of the color burst signal S8 cannot be correctly discriminated, and hence a system other than the SECAM system is assumed. When a discrimination on the SECAM system is made at the step ST9, the current tuning data (data related to the frequency) is stored in the address of the station number "0" of the memory 6 in a state maintaining the tuning mode at the PAL mode, while information that the current video signal system is the SECAM system is also stored, and the address of the memory 6 is incremented by one to a station number "1", for storing next tuning data (step ST7). In the case of the SECAM system, tuning is possible in the PAL mode. The tuning mode of the tuner circuit 2, which is the PAL mode, may not be re-set at the step ST8, and the tuning frequency is then increased at the step ST2 by a constant amount to enter a next tuning operation, so that the operations through the steps ST2 to ST5, ST9 and ST7 are repeated and the tuning is ended upon reaching the upper limit of the tuning frequency. When a determination on a system other than the SECAM system is made at the step ST9, on the other hand, the color discrimination circuit 13 receiving the color burst signal S8 from the video signal processing circuit 3 again makes a color discrimination, to discriminate the system to the SECAM system and other system (step ST10). The discrimination at the step ST10 is made on the assumption of the PAL system when the color burst signal S8 is 4.43 MHz, otherwise on a system other than the PAL system. When a discrimination on the PAL system is made at the step ST10, the tuner circuit 2 stores the current tuning data (data related to the frequency) in the address of the station number "0" of the memory 6 while also storing information that the current video signal system is the PAL system in a state maintaining the PAL mode, and increments the address of the memory 6 by one to a station number "1" for storing next tuning data (step ST7). The tuning mode of the tuner circuit 2, which is the PAL mode, may not be re-set at the step ST8, and the tuning frequency is then increased at the step ST2 by a constant amount to enter a next tuning operation, so that the operations through the steps ST2 to ST5, ST9 and ST7 are repeated and the tuning is ended upon reaching the upper limit of the tuning frequency. When the discrimination at the step ST10 is on a system other than the PAL system, on the other hand, the color discrimination circuit 13 outputs the mode switching circuit second control signal S10 and supplies the same to the tuning mode switching circuit 12, to change the tuner circuit 2 to the SECAM-L mode by the mode switching signal S11 (step ST11). Then, the color discrimination circuit 13 receiving the color burst signal S8 from the video signal processing circuit 3 makes a color discrimination at a step ST12, to again discriminate the system to the SECAM system and other mode. When a discrimination on the SECAM system is made at the step ST12, the current tuning data (data related to the frequency) is stored in the address of the station number "0" of the memory 6 in a state maintaining the tuning mode in the SECAM-L mode, while information that the current video signal system is the SECAM system is also stored, and the address of the memory 6 is incremented by one to a station number "1", for storing next tuning data (step ST7). Then, the tuning mode of the tuner circuit 2 is set at the PAL mode at a step ST8, the tuning frequency is increased by a constant amount at the step ST2 to enter a next tuning operation, the operations through the steps ST2 to ST5, ST9, ST10, ST11, ST12, ST8 and ST8 are repeated, and the tuning is ended upon reaching the upper limit of the tuning frequency. The tuning data obtained by the tuning is supplied to a system for channel selection from the address of the memory 6, so that a position number for channel selection is allotted thereto and the tuning mode is ended. When the discrimination at the step ST12 is on a system other than the SECAM system, on the other hand, the tuning mode is maintained at the SECAM-L mode (step ST13), so that the current tuning data (data related to the frequency) is stored in the address of the station number "0" of the memory 6 and information that the current video signal system is an undiscriminable other system is also stored, and the address of the memory 6 is incremented by one to the station number "1", for storing next tuning data (step ST7). Then, the tuning mode of the tuner circuit 2 is set at the PAL mode at the step ST8, the tuning frequency is increased by a constant amount at the step ST2 to enter a next tuning operation, the operations through the steps ST2 to ST5, ST9, ST10, ST11, ST12, ST7 and ST8 are repeated, and the tuning is ended upon reaching the upper limit of the tuning frequency. The tuning data obtained by the tuning is supplied to the system for channel selection from the address of the memory 6, so that a position number for channel selection is allotted thereto and the tuning mode is ended. The operation following the step ST12 is a system for not stopping the tuning operation also when an undiscriminable signal such as a ghost signal is received, and the user can arbitrarily designate the video signal system after the tuning by storing the undiscriminable signal. This is also effective in the case where the signal field is so weak that the color discrimination circuit 13 cannot discriminate the video signal system. As hereinabove described, the automatic tuning apparatus A5 shown in Fig. 6 comprises the SYNC discrimination circuit 11 and the color discrimination circuit 13 to discriminate to which one of the PAL system, the SECAM system, the SECAM-L system and the NTSC system the receiving signal belongs so that the tuning mode of the tuner circuit 2 can be automatically switched, whereby the user may not carry out a switching operation in response to the video signal system by himself. Further, it is possible to obtain an automatic tuning apparatus whose tuning operation is not stopped also when an undiscriminable signal such as a ghost signal is received or the signal field is so weak that the color discrimination circuit 13 cannot discriminate the video signal system. The data of the video signal system stored in the memory 6 may be read from the memory 6 at need during and after completion of the auto tuning to be used for switching of a chromatic circuit or a tuner circuit or sorting of channel positions, for example. While the frequency is increased from the lower side to the higher side in the auto tuning operation of the aforementioned automatic tuning apparatus A5, the frequency may alternatively be reduced from the higher side to the lower side. When there are various frequency bands for VHF, UHF and the like, tuning may be carried out from any frequency band or only in a specific frequency band. Further, the tuning direction may be varied with the frequency band. Fig. 10 illustrates the structure of an automatic tuning apparatus A6 for a VTR for elucidating the subject matter of the present invention, which is, however, as such not part of the present invention. Referring to Fig. 10, structural parts which are identical to those of the automatic tuning apparatus A5 described with reference to Fig. 6 are denoted by the same reference numerals, to omit redundant description. As understood from Fig. 10, the automatic tuning apparatus A6 has such a structure that the color discrimination circuit 13 is removed from the automatic tuning apparatus A5. Thus, the automatic tuning apparatus A6 is an apparatus having a function of discriminating whether the video signal system of a received signal is the PAL system or the NTSC system. With reference to a flow chart shown in Fig. 11, the operation of the automatic tuning apparatus A6 is now described. When a command for auto tuning is received from the user, a system controller 7A sets the tuning mode of a tuner circuit 2 at the PAL system, and sets the memory address of a memory 6 at a station number "0" as initialization (step ST1). Then, a tuning control signal S3 is transmitted to the tuner circuit 2, to control the same in a direction for increasing the tuning frequency by a constant amount (step ST2). At this time, a discrimination is made as to whether or not the current frequency reaches the upper limit of the tuning frequency, i.e., whether or not the tuning is ended (step ST3), so that the tuning is ended if the current frequency reaches the upper limit of the tuning frequency, otherwise an AFT signal S4 which is outputted from an AFT detection circuit 4 and a SYNC signal S2 indicating presence/absence of a signal separated by a video signal processing circuit 3 are inputted in the tuning control circuit 5, in order to detect presence/absence of a broadcasting station transmitting the signal of the frequency (step ST4). If both of the AFT signal S4 and the SYNC signal S2 are supplied at this time, the tuning control circuit 5 determines that the signal from the broadcasting station can be received and executes a next step ST5. If both of the AFT signal S4 and the SYNC signal S2 are not supplied, on the other hand, the tuning frequency is increased by a constant amount at the step ST2. At a step ST5, the SYNC signal S2 from the video signal processing circuit 3 is transmitted to a SYNC discrimination circuit 11 in the system controller 7A, so that the SYNC discrimination circuit 11 outputs a mode switching circuit first control signal S9 and supplies the same to a tuning mode switching circuit 12 when the SYNC signal S2 is supplied at 60 Hz, to change the tuner circuit 2 to the NTSC mode by a mode switching signal S11 (step ST6). If the SYNC signal is supplied at 50 Hz, on the other hand, a discrimination is made on a system other than the NTSC system. When the tuner circuit 2 is set at the NTSC mode, current tuning data (data related to the frequency) is stored in the address of the station number "0" of the memory 6 while information that the current video signal system is the NTSC system is also stored, and the address of the memory 6 is incremented by one to a station number "1" in order to store next tuning data (step ST7). Then, the tuning frequency is increased by a constant amount at the step ST2 to enter a next tuning operation, the operations through the steps ST2 to ST7 are repeated, and the tuning is ended upon reaching the upper limit of the tuning frequency. The tuning data obtained by the tuning is supplied to a system for channel selection from the address of the memory 6, so that a position number for channel selection is allotted thereto and the tuning mode is ended. When a discrimination on a system other than the NTSC system is made at the step ST5, the mode switching circuit first control signal S9 is outputted and supplied to the tuning mode switching circuit 12, to change the tuner circuit 2 to the PAL mode by the mode switching signal S11 (step ST6). Since the tuning mode of the tuner circuit 2 is set at the PAL mode as initialization, this step ST6 is unnecessary if the tuning mode is not changed to the NTSC mode. When the tuner circuit 2 is set at the PAL mode, the current tuning data (data related to the frequency) is stored in the address of the station number "0" of the memory 6 while information that the current video signal system is the PAL system is also stored, and the address of the memory 6 is incremented by one to a station number "1" in order to store next tuning data (step ST7). Then, the tuning frequency is increased by a constant amount at the step ST2 to enter a next tuning operation, the operations through the steps ST2 to ST7 are repeated, and the tuning is ended upon reaching the upper limit of the tuning frequency. The tuning data obtained by the tuning is supplied to the system for channel selection from the address of the memory 6, so that a position number for channel selection is allotted thereto and the tuning mode is ended. As hereinabove described, the automatic tuning apparatus A6 shown in Fig. 10 comprises the SYNC discrimination circuit 11 to discriminate whether the video signal system of the received signal is the PAL system or the NTSC system so that the tuning mode of the tuner circuit 2 can be automatically switched, whereby the user may not carry out a switching operation in response to the video signal system by himself. The remaining functions are similar to those of the automatic tuning apparatus A5, and hence redundant description is omitted. Fig. 12 illustrates the structure of an automatic tuning apparatus A7 for a VTR for elucidating the subject matter of the present invention, which is, however, as such not part of the present invention.Referring to Fig. 12, a system controller 7B comprising a tuning control circuit 5, a memory circuit 6 and a tuning mode switching circuit 12 is provided in place of the system controller 7A of the automatic tuning apparatus A5 described with reference to Fig. 6. The remaining structural parts which are identical to those of the automatic tuning apparatus A5 are denoted by the same reference numerals, to omit redundant description. As understood from Fig. 12, the automatic tuning apparatus A7 has such a structure that the SYNC discrimination circuit 11 is removed from the automatic tuning apparatus A5. Thus, the automatic tuning apparatus A7 is an apparatus having a function of discriminating to which one of the PAL system, the SECAM system and the SECAM-L system the video signal system of a received signal belongs. With reference to a flow chart shown in Fig. 13, the operation of the automatic tuning apparatus A7 is now described. When a command for auto tuning is received from the user, the system controller 7B sets the tuning mode of a tuner circuit 2 at the PAL system, and sets the memory address of the memory 6 at a station number "0" as initialization (step ST1). Then, a tuning control signal S3 is transmitted to the tuner circuit 2, to control the same in a direction for increasing the tuning frequency by a constant amount (step ST2). At this time, a discrimination is made as to whether or not the current frequency reaches the upper limit of the tuning frequency, i.e., whether or not the tuning is ended (step ST3), so that the tuning is ended if the current frequency reaches the upper limit of the tuning frequency, otherwise an AFT signal S4 which is outputted from an AFT detection circuit 4 and a SYNC signal S2 indicating presence/absence of a signal separated by a video signal processing circuit 3 are inputted in the tuning control circuit 5, in order to detect presence/absence of a broadcasting station transmitting a signal of the frequency (step ST4). If both of the AFT signal S4 and the SYNC signal S2 are supplied at this time, the tuning control circuit 5 determines that the signal from the broadcasting station can be received and executes a next step S5. If both of the AFT signal S4 and the SYNC signal S2 are not supplied, on the other hand, the tuning frequency is increased by a constant amount at the step ST2. At a step ST5, a color discrimination circuit 13 receiving a color burst signal S8 from the video signal processing circuit 3 carries out a color discrimination, to discriminate the system to the SECAM system and another system. In the case of the SECAM-L system, a video signal S1 is hunting since the same is tuned in the PAL mode and frequency change of the color burst signal S8 cannot be correctly discriminated, and hence the system is assumed to be that other than the SECAM system. When a discrimination on the SECAM system is made at the step ST5, on the other hand, current tuning data (data related to the frequency) is stored in the address of the station number "0" of the memory 6 while information that the current video signal system is the SECAM system is also stored, and the address of the memory 6 is incremented by one to a station number "1" in order to store next tuning data (step ST6). In the case of the SECAM system, tuning is possible in the PAL mode. No re-setting at the step ST7 is required at a step ST7 since the tuning mode of the tuner circuit 2 is the PAL mode, and the tuning frequency is then increased by a constant amount at the step ST2 to enter a next tuning operation, the operations through the steps ST2 to ST7 are repeated and the tuning is ended upon reaching the upper limit of the tuning frequency. When a determination on a system other than the SECAM system is made at the step ST5, on the other hand, the color discrimination circuit 13 receiving the color burst signal S8 from the video signal processing circuit 3 again makes a color discrimination, to discriminate the system to the PAL system and another system (step ST8). The discrimination at the step ST8 is made on the assumption of the PAL system when the color burst signal S8 is 4.43 MHz, otherwise on a system other than the PAL system. When the PAL system is discriminated at the step ST8, the tuner circuit 2 stores the current tuning data (data related to the frequency) in the address of the station number "0" of the memory 6 while also storing information that the current video signal system is the PAL system in a state maintaining the PAL mode, and increments the address of the memory 6 by one to a station number "1" for storing next tuning data (step ST6). No re-setting at the step ST7 is required since the tuning mode of the tuner circuit 2 is the PAL mode, and the tuning frequency is then increased by a constant amount at the step ST2 to enter a next tuning operation, the operations through the steps ST2 to ST5, ST8, ST6 and ST7 are repeated and the tuning is ended upon reaching the upper limit of the tuning frequency. When a discrimination on a system other than the PAL system is made at the step ST8, on the other hand, the color discrimination circuit 13 outputs a mode switching circuit second control signal S10 and supplies the same to the tuning mode switching circuit 12, to change the tuner circuit 2 to the SECAM-L mode by a mode switching signal S11 (step ST9). Then, the color discrimination circuit 13 receiving the color bust signal S8 from the video signal processing circuit 3 carries out a color discrimination to again discriminate the system to the SECAM system and another system at a step ST10. When the SECAM system is discriminated at the step ST10, the current tuning data (data related to the frequency) is stored in the address of the station number "0" of the memory 6 while information that the current video signal system is the SECAM system is also stored in a state maintaining the tuning mode in the SECAM-L mode, and the address of the memory 6 is incremented by one to a station number "1" for storing next tuning data (step ST6). Then, the tuning mode of the tuner circuit 2 is set at the PAL mode at the step ST7, the tuning frequency is increased by a constant amount at the step ST2 to enter a next tuning operation, the operations through the steps ST2 to ST5, ST8, ST9, St10, ST6 and ST7 are repeated, and the tuning is ended upon reaching the upper limit of the tuning frequency. The tuning data obtained by the tuning is supplied to a system for channel selection from the address of the memory 6, so that a position number for channel selection is allotted thereto and the tuning mode is ended. When a discrimination on a system other than the SECAM system is made at the step ST10, on the other hand, the tuning mode is maintained at the SECAM-L mode (step ST11) and the current tuning data (data related to the frequency) is stored in the address of the station number "0" of the memory 6 and information that the current video signal system is an undiscriminable other system is also stored, and the address of the memory 6 is incremented by one to the station number "1" for storing next tuning data (step ST6). Then, the tuning mode of the tuner circuit 2 is set at the PAL mode at the step ST7, the tuning frequency is increased by a constant amount at the step ST2 to enter a next tuning operation, the operations through the steps ST2 to ST5, ST8, ST9, St10, ST6 and ST7 are repeated, and the tuning is ended upon reaching the upper limit of the tuning frequency. The tuning data obtained by the tuning is supplied to the system for channel selection from the address of the memory 6, so that a position number for channel selection is allotted thereto and the tuning mode is ended. The operation following the step ST10 is a system for not stopping the tuning operation also when an undiscriminable signal such as a ghost signal is received, and the user can arbitrarily designate the video signal system after the tuning by storing the undiscriminable signal. This is also effective in the case where the signal field is so weak that the color discrimination circuit 13 cannot discriminate the video signal system. As hereinabove described, the automatic tuning apparatus A7 shown in Fig. 12 comprises the color discrimination circuit 13 to discriminate to which one of the PAL system, the SECAM system and the SECAM-L system the video signal system of the received signal belongs so that the tuning mode of the tuner circuit 2 can be automatically switched, whereby the user may not carry out a switching operation in response to the video signal system by himself. Further, it is possible to obtain an automatic tuning apparatus whose tuning operation is not stopped also when an undiscriminable signal such as a ghost signal is received or the signal field is so weak that the color discrimination circuit 13 cannot discriminate the picture signal system. The remaining functions are similar to those of the automatic tuning apparatus A5, and hence redundant description is omitted. The structures of the automatic tuning apparatus A1 and A4 according to the first and second embodiments may be added to the aforementioned automatic tuning apparatus A5 to A7 for storing broadcasting station information and displaying the same on the receiver screens. In a structure therefore the text data decoder circuit 10 is provided to receive the video signal S1 outputted from the tuner circuit 2 and outputs are supplied to the tuning control circuit 5, while the CG circuit 40 is provided between the output of the video signal processing circuit 3 and the video signal output terminal 9. Fig. 14 shows the structure of an automatic tuning apparatus A10 for a VTR according to a third embodiment of the present invention. Referring to Fig. 14, numeral 2A denotes a tuner circuit which is connected to an antenna 1, numeral 3 denotes a video signal processing circuit including a SYNC separation circuit which receives a composite video signal S1 from the tuner circuit 2A for carrying out signal processing, numeral 4 denotes an AFT detection circuit receiving a signal from the tuner circuit 2A for detecting presence/absence of a broadcasting station, numeral 5 denotes a tuning control circuit for controlling the tuning operation of the tuner circuit 2A, numeral 6 denotes a memory which is connected to the tuning control circuit 5, and numeral 100 denotes a sorting control circuit for sorting tuning data stored in the memory 6 along prescribed position numbers, which is controlled by a SYNC signal S2 from the video signal processing circuit 3. A system controller 7D is formed by the tuning control circuit 5, the memory 6 and the sorting control circuit 100. Numeral 10 denotes a text data decoder circuit which receives the video signal S1 and extracts a teletext signal S5, which is information from the broadcasting station, from the video signal S1 for supplying the same to the memory 6. Numeral 8 denotes an input signal system switch for switching the operation of the tuning control circuit 5 in response to the video signal system of the input signal. With reference to Fig. 15, the structure of the sorting control circuit 100 is now described. The sorting control circuit 100, which is formed by software, is indicated as hardware in Fig. 15. Referring to Fig. 15, the sorting control circuit 100 comprises a position number pointer 110 for providing a position number for channel selection, a station number pointer 120 for providing a broadcasting station number (station number), a first register 130 reading broadcasting station information (station ID) from a sorting reference memory 61 which is previously provided in the memory 6, a second register 140 reading the station ID from a tuning data memory 62 stored in the memory 6 by a tuning operation, a comparison part 150 comparing the station IDs read by the first and second registers 130 and 140 respectively with each other, and a determination part 160 determining the result of the comparison and instructing provision numbers to the position number pointer 110 and the station number pointer 120, for storing a sorting result having corresponding position and station numbers by sorting in a sorting result memory 63 provided in the memory 6. With reference to flow charts shown in Figs. 16 and 17, the operation of the automatic tuning apparatus A10 is now described. When a command for auto tuning is received from the user, the system controller 7D sets the memory address of the memory 6 at a station number "0" (step ST1). Then, a tuning control signal S3 is transmitted to the tuner circuit 2A, to control the same in a direction for increasing the tuning frequency by a constant amount (step ST2). At this time, an AFT signal S4 which is outputted from an AFT detection circuit 4 and a SYNC signal S2 indicating presence/absence of a signal separated by the video signal processing circuit 3 are inputted in the tuning control circuit 5 for detecting presence/absence of a broadcasting station transmitting a signal of the frequency, to make a discrimination (step ST3). When both of the AFT signal S4 and the SYNC signal S2 are supplied at this point of time, the tuning control circuit 5 determines that the signal from the broadcasting station can be received, and the current tuning data is stored in the address of the station number "0" in the memory 6 (step ST4). At the same time, the text data decoder circuit 10 decodes text information which is superposed on a blanking period of the signal from the composite video signal S1, so that the decoded teletext signal S5 is inputted in the tuning control circuit 5 (step ST5). The tuning control circuit 5 extracts and discriminates broadcasting station information (station ID) from the teletext signal S5 (step ST6), and stores the same in the address of the station number "0" in the memory 6, similarly to the data related to the frequency (step ST7). Then, the address of the memory 6 is incremented by one to a station number "1" in order to store next tuning data, for entering a next tuning operation (step ST8). If both of the AFT signal S4 and the SYNC signal S2 are not supplied at the step ST3, on the other hand, a discrimination is made as to whether or not the current frequency reaches the upper limit of the tuning frequency, i.e., whether or not the tuning is ended (step ST9). If the current frequency does not reach the upper limit of the tuning frequency, the operation at the step ST2 is carried out again and the operations through the steps ST2 to ST8 are repeated until the upper limit of the tuning frequency is reached. If the upper limit of the tuning frequency is reached at the step ST9, on the other hand, the process enters a sorting operation of the sorting control circuit 100. First, the sorting reference memory 61 in the memory 6 is activated, a station ID corresponding to a previously set position number is read (step ST10), and the station ID indicated by the position number pointer 110 is loaded in the first register 130 (step ST11). Then, the tuning data memory 62 in the memory 6 is activated, a station ID corresponding to the station number is read, and a station ID indicated by the station number pointer 120 is loaded in the second register 140, so that the comparison part 150 compares the station IDs which are loaded in the first and second registers 130 and 140 respectively with each other and the determination part 160 makes a determination (step ST12). When the station IDs match with each other at the step ST12, the station number is stored in the sorting result memory 63 in the memory 6 in correspondence to the position number (step ST13). Then, the position number is incremented by one in the position number pointer 110 (step ST14). Then, the station number pointer 120 determines whether or not the current station number reaches the upper limit (step ST15). Also when the station IDs mismatch with each other at the step ST12, the operation at the step ST15 is carried out. If the current station number does not reach the upper limit at the step ST15, the station number is incremented by one in the station number pointer 120, to carry out the operation following the step ST12 again (step ST16). When the current station number reaches the upper limit, on the other hand, the position number pointer 110 determines whether or not all station IDs are sorted, i.e., whether or not the position number reaches the upper limit (step ST17). If a determination is made at the step ST17 that all station IDs are sorted, the sorting operation is ended. If all station IDs are not sorted, on the other hand, the position number pointer 110 increments the position number by one, to carry out the operation following the step ST11 again (step ST18). The aforementioned automatic tuning apparatus A10 comprises the sorting control circuit 100 so that a broadcasting station of a predetermined station ID is automatically set for each position number by a sorting operation and the user may not set the broadcasting station in correspondence to the position number, whereby the burden imposed on the user can be reduced. When no station ID corresponding to the station number is found in the aforementioned sorting operation, this position is not selected but processing such as skipping is carried out. Fig. 18 shows the structure of an automatic tuning apparatus A11 for a VTR according to an fourth embodiment of the present invention. Referring to Fig. 18, structural parts identical to those of the automatic tuning apparatus A10 described with reference to Fig. 14 are denoted by the same reference numerals, to omit redundant description. Referring to Fig. 18, a user input control circuit 200 provided for the user for setting sorting order is connected to a memory 6, and a system controller 7E is formed by a tuning control circuit 5, the memory 6, a sorting control circuit 100 and the user input control circuit 200. A key input unit 300 for the user for inputting setting is connected to the user input control circuit 200. With reference to Fig. 19, the structure of the user input control circuit 200 is now described. Referring to Fig. 19, the user input control circuit 200 comprises a key interface circuit 210 for transferring signals with the key input unit 300, a position number register 220 and a station name register 230 which are connected to the key interface circuit 210, and a station ID conversion circuit 240 and a display unit 250 which are connected to the station name register 230, while the position number register 220 is connected to a sorting reference memory 61 of the memory 6 through a position number pointer 110 of the sorting control circuit 100 and the station ID conversion circuit 240 is also connected to the sorting reference memory 61. The operation of the user input control circuit 200 is now described. When the user inputs broadcasting station information (the broadcasting station name, the broadcasting station name code etc.) from the key input unit 300 in correspondence to the position number, the position number and the broadcasting information are supplied to the position number register 220 and the station name register 230 respectively, so that the position number is supplied to the sorting reference memory 61 by the position number pointer 110 and the broadcasting station information is converted to a station ID by the station ID conversion circuit 240 and supplied to the sorting reference memory 61 to be stored therein. The broadcasting station information is displayed on the display unit 250. With reference to flow charts shown in Figs. 20 and 21, the operation of the automatic tuning apparatus A11 is now described. First, the user inputs broadcasting station information (the broadcasting station name, the broadcasting station name code etc.) through the key input unit 300 in correspondence to the position number, and sets the sorting order (step ST1). Then, the system controller 7E receives a command for auto tuning and sets the memory address of the memory 6 at a station number "0" (step ST2). Then, a tuning control signal S3 is transmitted to a tuner circuit 2A, to control the same in a direction for increasing the tuning frequency by a constant amount (step ST3). At this time, an AFT signal S4 which is outputted from an AFT detection circuit 4 and a SYNC signal S2 indicating presence/absence of a signal separated by a video signal processing circuit 3 are inputted in the tuning control circuit 5 for detecting presence/absence of a broadcasting station transmitting a signal of the frequency, to make a discrimination (step ST4). When both of the AFT signal S4 and the SYNC signal S2 are supplied at this point of time, the tuning control circuit 5 determines that the signal from the broadcasting station can be received, and the current tuning data is stored in the address of the station number "0" in the memory 6 (step ST5). At the same time, a text data decoder circuit 10 decodes text information which is superposed on a blanking period of a composite video signal S1, so that a decoded teletext signal S5 is inputted in the tuning control circuit 5 (step ST6). The tuning control circuit 5 extracts and discriminates broadcasting station information (station ID) from the teletext signal S5 (step ST7), and stores the same in the address of the station number "0" in the memory 6, similarly to data related to the frequency (step ST8). Then, the address of the memory 6 is incremented by one to a station number "1" in order to store next tuning data, for entering a next tuning operation (step ST9). If both of the AFT signal S4 and the SYNC signal S2 are not supplied at the step ST4, on the other hand, a discrimination is made as to whether or not the current frequency reaches the upper limit of the tuning frequency, i.e., whether or not the tuning is ended (step ST10). If the current frequency does not reach the upper limit of the tuning frequency, the operation at the step ST3 is carried out again and the operations through the steps ST3 to ST9 are repeated until the upper limit of the tuning frequency is reached. If the upper limit of the tuning frequency is reached at the step ST10, on the other hand, the process enters a sorting operation of the sorting control circuit 100. First, the sorting reference memory 61 in the memory 6 is activated, a station ID corresponding to a previously set position number is read (step ST11), and a station ID indicated by the position number pointer 110 is loaded in the first register 130 (step ST12). Then, the tuning data memory 62 in the memory 6 is activated, a station ID corresponding to the station number is read, and a station ID indicated by the station number pointer 120 is loaded in the second register 140, so that the comparison part 150 compares the station IDs which are loaded in the first and second registers 130 and 140 respectively with each other and the determination part 160 makes a determination (step ST13). When the station IDs match with each other at the step ST13, the station number is stored in the sorting result memory 63 in the memory 6 in correspondence to the position number (step ST14). Then, the position number is incremented by one in the position number pointer 110 (step ST15). Then, the station number pointer 120 determines whether or not the current station number reaches the upper limit (step ST16). Also when the station IDs mismatch with each other at the step ST13, the operation at the step ST16 is carried out. If the current station number does not reach the upper limit at the step ST15, the station number is incremented by one in the station number pointer 120, to carry out the operation following the step ST12 again (step ST17). When the current station number reaches the upper limit, on the other hand, the position number pointer 110 determines whether or not all station IDs are sorted, i.e., whether or not the position number reaches the upper limit (step ST18). If a determination is made at the step ST18 that all station IDs are sorted, the sorting operation is ended. If all station IDs are not sorted, on the other hand, the position number pointer 110 increments the position number by one, to carry out the operation following the step ST12 again (step ST19). The aforementioned automatic tuning apparatus A11 comprises the user input control circuit 200 so that the user sorts desired broadcasting stations along the sorting order set by him, whereby the broadcasting stations of the station IDs desired by the user are automatically set at the respective position numbers. Although a burden is imposed on the user in the point that he must set the position numbers and the broadcasting station information, a broadcasting station to be automatically tuned at the user's necessity can be set from receivable broadcasting stations in an area where receivable broadcasting stations are limited.

Claims: Automatic tuning apparatus comprising: tuner means (2A) for tune-selecting a prescribed channel from broadcast electric waves including at least a video signal (51); video signal processing means (3) for receiving said video signal (51) being output from said tuner means (2A) and for separating a synchronizing signal (52) being included in said video signal; AFT detection means (4) for detecting presence/absence of a broadcasting station via a signal received from said tuner means (2A); tuning control means (5) for receiving said synchronizing signal (52) from said video signal processing means (3) and an AFT signal (54) from said AFT detection means (4), for controlling a tuning frequency of said tuner means (2A) successively and for detecting presence/absence of a broadcasting station; memory means (6) connected to said tuning control means (5) for storing data related to at least the tuning frequency of said tuner means (2A); and a text data decoder (10) for receiving said video signal output from said tuner means (2A) and for decoding text data included in said video signal, wherein said tuning control means (5) controls said tuner means (2A) by said decoded text data while separating broadcasting station information specifying said broadcasting station from said decoded text data and storing the broadcasting station information in said memory means (10) along with said data related to the tuning frequency, characterized in that : for channels to which said tuner means (2A) is tuned successively there is decoded text data, which text data is included in the video signal being output from said tuner means (2A). Automatic tuning apparatus in accordance with claim 1, characterized in that it further comprises character generator means (40) being connected to a side of said video signal processing means (3) outputting said video signal for superposing said broadcasting station information being stored in said memory means (10) on said video signal. Automatic tuning apparatus in accordance with claim 1, characterized in that : it further comprises sorting control means (100) automatically sorting storage contents being stored in said memory means (10), including at least said data being related to the tuning frequency of said tuner means (2A), in previously set order, and data being related to said broadcasting station information and corresponding to said tuning frequency being automatically sorted in previously set order. Automatic tuning apparatus in accordance with claim 3, characterized in that it further comprises sorting order set means (200) being connected to said memory means (6) for arbitrarily setting sorting order of said storage contents.

Inventors: ARIKANE NOBORU, HAMADA JUNICHI, HONGOH KIMITOSHI, OKUGAWA ISAMU, SHIMAMOTO KATSUSHI, SHIRAKASHI KEIICHIRO, SUGANO TETSUO, ARIKANE, NOBORU, HAMADA, JUNICHI, HONGOH, KIMITOSHI, OKUGAWA, ISAMU, SHIMAMOTO, KATSUSHI, SHIRAKASHI, KEIICHIRO, SUGANO, TETSUO, Arikane, Noboru, c/o Mitsubishi Elec. Eng. Co., Hamada, Junichi, c/o Mitsubishi Elec. Eng. Co., Hongoh, Kimitoshi, c/o Mitsubishi Elec. Eng. Co., Okugawa, Isamu, c/o Mitsubishi Elec. Eng. Co., Shimamoto, Katsushi, c/o Mitsubishi Elec. Eng. Co., Shirakashi, Keiichiro, c/o Mitsubishi Elec Eng Co., Sugano, Tetsuo, c/o Mitsubishi Elec. Eng. Co.
Applicants: MITSUBISHI ELECTRIC CORP, MITSUBISHI DENKI KABUSHIKI KAISHA
Application year: 1996
Main classification: H04N5
IPC codes: H04N5, H04N9