JPH03198244A - Channel scanner - Google Patents

Abstract

PURPOSE:To shorten the time required to make one round of channel positions by reading no VPS data at a position where a skip is made and no broadcast is received. CONSTITUTION:A synchronizing signal presence/absence discriminating circuit 4 detects whether or not there is a synchronizing signal as to all frequencies at which signals are received. A timer circuit 5 reads no VPS data as to frequencies where no synchronizing signal is present. Thus, the time required to make one round of channel positions, i.e. the time required to decide that a target value becomes equal to an actual value is shortened to shorten the time when the video recording of the starting part of a program which needs to be recorded is disabled.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is directed to VPV (Video Progra
The present invention relates to a channel scanning device in standby mode for scheduled recording by (mw+i'ertVideoheiBerate).

[Prior art] vPv is a system that simplifies the scheduled recording of VTRs. When a program is selected from the program guide page of a teletext service and the necessary information about the selected program is broadcast, It is designed to be recorded.

Control of the VTR is compatible with vPS and is performed using vPS data transmitted in data string 16. In particular, it eliminates the need to enter start time, end time, date, and broadcast station, which can lead to awkward operational errors by inexperienced users. When turned on, the information on the teletext page is read and scheduled recording is automatically performed.

When the desired program (target value) is set by the user, V
The TR scans and compares target values and actual values for all receivable channel positions. The difference between the standby channel scan mode of scheduled recording with VPV and scheduled recording with VPs is that VPS scans only the channel position specified by the user, whereas vPv scans the channel position specified by the user. Since the station code in the value must be found, it is necessary to compare the target value and the actual value in all channel positions that are allowed to receive, ie, in all non-skipped channel positions.

FIG. 3 is a block diagram showing the configuration of a conventional channel scanning device for performing scheduled recording using vPv. In the figure, (1) is a tuner circuit, and (2) is a data string 1 of a video signal output from the tuner circuit (1).
6 is a VPS signal decoder that decodes the PS code, (3) is a teletext signal decoder that decodes the teletext signal, and (5) is a timer circuit. The displayed program guide page stores teletext data such as the start time, end time, date, and broadcasting station code of the desired program, and the function of comparing it with the PS data by the PS signal decoder (2) and the tuner circuit ( 1) It has a function to control tuning. (6)
is a system control circuit that controls the internal circuits and mechanisms of the VTR based on the data from the timer circuit (5).
Switch to recording mode, playback mode, etc.

Next, the operation of the above configuration will be explained.

When the user sets the target value using the program guide page provided by the teletext service, as shown in Figure 4, Ach,
Bch, Cch, Dch, ・-, all the positions that are not skipped are sequentially scanned for channels, and the set broadcasting station code is
Compare with the broadcasting station code included in the PS data. At this time, the time tw from switching the channel to reading the vPS data of each channel is the time tw from when the timer circuit (5) performs tuning control to the tuner circuit (1) until the reception condition becomes sufficiently stable. This value takes into account the time required for reading data, and the time required to read data is tr
It is expressed as

Therefore, if the number of all positions that are not skipped is N, then for one program (target value),
The time required for channel scanning for all non-skipped positions is N (tw+tr).

In this way, if the target value set by the user on the program guide page while performing a channel scan matches the vPS data at that time, that is, the actual value, a recording command control command is issued from the timer circuit (5). The signal is sent to the system control circuit (6) and the VTR is switched to the recording state.

[Problem to be Solved by the Invention] Since the conventional channel scanning device is configured as described above, it is necessary to compare the target value and the actual value for all channel positions that are not skipped. If there are many positions that have not been set or multiple target values are set, it will take a long time for the channel positions to go through one cycle, and therefore it will be difficult to determine that the target value and actual value match. There was a problem in that it took a long time to complete the program and the beginning of the program that was supposed to be recorded was not recorded.

This invention was made to solve the above-mentioned problems, and it eliminates the need to read vPS data for positions where broadcasts are not being received in positions that are not skipped, so that target values and actual values match. To provide a channel scanning device capable of shortening the time required to determine whether a program has been recorded, and shortening the non-recording time of the beginning part of a program desired to be recorded.

[Means for Solving the Three Problems] The channel scanning device according to the present invention detects the presence or absence of a synchronization signal for all received frequencies, and determines whether to read vPS data based on the presence or absence of the synchronization signal. It is characterized by being configured to determine.

[Operation] According to the present invention, the presence or absence of a synchronization signal is detected for all received frequencies, and vPS data is not read for frequencies where there is no synchronization signal, thereby making it possible to complete a cycle of channel positions. It is possible to shorten the time required for determining that the target value and the actual value match, and to shorten the time during which the beginning of a program that must be recorded cannot be recorded.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of a channel scanning device according to an embodiment of the present invention.
1) to (3), (5), and (6) are the same as those in the conventional example shown in FIG. 3, so they are given the same reference numerals and detailed explanation thereof will be omitted.

In FIG. 1, (4) is a synchronization signal presence/absence determination circuit that detects the presence or absence of a vertical synchronization signal of a video signal, and if a synchronization signal is present, sets VsyncH to "H". ) is configured such that the timer circuit (5) compares the vPS data from the vsp signal decoder (2) and the teletext data from the teletext signal decoder (3) only when VsyncH is H''.

Next, the operation of the above configuration will be explained.

When the user sets the target value using the program guide page using the teletext service, the Ach%
A channel scan is performed sequentially as Bch%Cch%Dch, Ech, etc., and compared with the set broadcasting station code or the broadcasting station code included in the PS data.

At this time, channel scanning must be performed for all positions that have not been skipped, but after switching channels, ts
(seconds), the level of VsyncH is determined.

For example, looking at Ach in Figure 2, after ts elapses, the level of Vsync)( is "H", so it is determined that channel position A is receiving a certain broadcast, and such a determination In this case, the vPS data is read at the time tr required for data reading after a value tw has elapsed, which takes into account the time from when the channel is switched until the reception state becomes sufficiently stable.

On the other hand, looking at Bch in Figure 2, V at the appropriate time of ts
Since the level of syncH is "L", it is determined that broadcasting is not being received for channel position B. V! ! Regarding transient level changes of 3FrlCH, it takes tdl time when the vertical synchronization signal goes from presence to absence, and it takes tdl time when the vertical synchronization signal goes from presence to absence.
It takes 2 hours. Therefore, the above ts is ts>td
1, td2<ts<tw.

Similarly, for Cch%Dch, ・, it is determined whether or not broadcasting is being received for each channel by determining the level of VsyncH, and the channel position where it was determined that broadcasting is not being received, i.e. , In Fig. 2, for BchsDch, vPS
Without reading data, after determining the level of Vsync, start scanning the next channel position as quickly as possible.

In the above embodiment, the presence or absence of a broadcast in a channel position that has not been skipped is determined based on the presence or absence of a vertical synchronization signal. , the same effect as the above embodiment can be obtained.

[Effects of the Invention] As described above, according to the present invention, since the reading of vPS data is not performed for positions that are not skipped and where broadcasting is not being received, the target value and the actual value are not the same. The time required to determine a match can be shortened, and the time during which the beginning of a program that must be recorded is not recorded can be shortened.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a channel scanning device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a channel scanning device according to an embodiment of the invention.
FIG. 3 is a block diagram showing the configuration of a conventional channel scanning device, and FIG. 4 is a diagram explaining the conventional vPS data reading timing. (1)...Tuner circuit, (2)...vPS signal decoder, (3)...Teletext signal decoder, (4
)...Synchronization signal presence/absence determination circuit, (5)...Timer circuit, (6)...System control circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) In the standby state for scheduled recording by VPV, a means for decoding the scheduled recording signal, a means for detecting the presence or absence of a synchronization signal of the frequency being received, and a comparison between the set target value and the actual value to be broadcast. A channel scanning device comprising: a timer circuit having a function of determining whether or not scheduled recording data is to be read based on the presence or absence of a synchronization signal.