KR19990085282A - How to implement analog clock in digital TV - Google Patents

Abstract

The present invention relates to a digital TV, and more particularly, to a method of providing a viewer with an accurate current time by displaying a clock on a screen. According to the present invention, there is provided a method of displaying a current time of a digital TV, the method comprising: drawing an analog clock without a hands, reading information corresponding to the current time from additional information included in a broadcast signal received on the digital TV, and according to the current time. Calculating the end point coordinates of the analog watch's hands, drawing the watch hands of the analog watch with reference to the center point and the end point coordinates of the analog watch, stopping the operation for a predetermined delay time, and erasing the hand. ; And updating the current time according to the delay time.

Description

How to implement analog clock in digital TV

The present invention relates to a digital TV, and to a digital TV implementing an analog clock.

A digital TV is a device that receives a digital broadcast signal transmitted from a broadcasting station and provides video and audio to viewers. Most current digital broadcasts follow the MPEG standard. In particular, MPEG-2, which is a broadcast MPEG standard, is set with both system, audio, and video standards. For reference, the MPEG-2 system standard number is ISO / IEC 13818-1, the video standard number is ISO / IEC 13818-2, and the audio standard number is ISO / IEC 13818-3.

The structure and operation principle of a general digital TV receiver according to the MPEG-2 scheme will be described with reference to FIG. 1.

A general digital TV receiver includes a tuner unit 11 that receives a digital broadcast signal, a TP analyzer 12 that detects an audio / video signal by analyzing a TP signal among the digital broadcast signals received by the tuner unit 11, and a TP. The audio / video decoders 13 and 14 for separating and decoding the audio / video signals analyzed by the analysis unit, the audio signal converter 21 for converting the digital audio signals decoded by the audio decoder into analog signals, and the TV system. Decoded in the control TV Micom 18, ROM 19 that stores channels and programs, RAM 20 that stores temporary data by the operation of TV Micom, OSD processor 17 for processing OSD text, video decoder A switch unit 15 for selectively outputting the digital video signal and the OSD text of the OSD processor, and an image for displaying a video signal output from the switch unit on a TV or a monitor And a video signal encoder 16 for converting into a signal.

The tuner unit 11 receives a Quadrature Phase Shift Keying (QPSK) signal or a Quadrature Amplitude Modulation (QAM) signal from the antenna 10, detects the signal, corrects an error, and outputs a transport signal sequence. The transport signal sequence is standardized in the MPEG-2 system.

The transport signal sequence standardized by the MPEG-2 method is a time-multiplexed signal sequence called a transport stream packet. This transport signal string has a header at the beginning of the packet, and the header has a PID (Packet IDentifier) number recorded thereon. The PID number may be used as information for demultiplexing a time multiplexed signal. In addition, the PID number indicates the type of the current packet. The PID number is analyzed to determine whether the current packet is a video packet, an audio packet, or program specific information.

The MPEG-2 video standard and audio standard provide for the signal sequence of compressed video and audio. According to the MPEG-2 standard, a video signal, an audio signal, and an additional information signal are all time-multiplexed and transmitted in the form of several transport stream packets, all of which are distinguished by PID numbers.

The TP analyzer 12 analyzes the signal sequence in the form of a transport stream packet by the PID number and applies it to the respective decoders 13 and 14. That is, the TP analyzer 12 receives the transport signal sequence received in the tuner unit and detects the PID number included in the header of the signal sequence. Thus, the TP analyzer divides the video signal sequence, the audio signal sequence, and the additional information signal sequence according to the PID number. The TP analyzer applies the video signal sequence to the video decoder 14, applies the audio signal sequence to the audio decoder 13, and applies the additional information signal sequence to the microcomputer 18.

The video decoder 14 decodes the video signal string applied from the TP analyzer 12 and outputs the decoded video signal to the NTSC encoder 16. The video signal sequence applied from the TP analyzer is data compressed by the MPEG-2 scheme. Therefore, the video decoder decompresses the compressed video signal sequence and reduces the original video data.

The audio decoder 13 decodes the voice signal string applied from the TP analyzer 12 and outputs the decoded audio signal to the DA to digital converter 21. The speech signal sequence applied from the TP analyzer is data compressed by the MPEG-1 scheme. Therefore, the audio decoder 13 decompresses the compressed speech signal sequence and reduces the original speech data.

The DA converter 21 converts the digital voice data applied from the audio decoder 13 into an analog voice signal that can be processed by an amplifier or a speaker. The analog audio signal is output as voice or sound by a stereo speaker (not shown).

The NTSC encoder 16 converts the digital image data applied from the video decoder 14 into a luminance signal Y and a color difference signal C which can be implemented in a general TV or a monitor. The luminance signal and the color difference signal are implemented as images by the CPT.

The microcomputer 18 controls the operation of the digital TV receiver. The program and OSD information necessary for controlling the microcomputer are stored in a ROM (Read Only Memory) 19, and the temporary information necessary for performing the microcomputer control operation is stored in a random access memory (RAM) 20. . That is, the microcomputer processes the additional information signal sequence applied from the TP analyzer 12 by using a control signal input by the user's input device 22 such as a remote controller or a keypad, and transmits the additional information data to the OSD processor 17. Outputs The OSD information is stored in the ROM 19, but when a control signal is generated from the input device, the microcomputer 18 takes out the OSD information corresponding to the control signal from the ROM 19 and transmits it to the OSD processor 17.

The OSD processor 17 converts the OSD information transmitted by the microcomputer 18 into a video signal that the NTSC encoder 16 can process. The switch unit 15 selects the OSD information converted into the video signal by the OSD processor 17 and the video video signal converted by the video decoder 14 and applies it to the NTSC encoder 16. If the OSD information is not generated by the input device of the user, the switch unit 15 continuously applies the video signal applied from the video decoder 14 to the NTSC encoder 16. If OSD information is generated by the input device 22 of the user, the switch unit 15 applies the OSD information applied from the OSD processor 17 to the NTSC encoder 16.

The TV screen in which both the video signal and the OSD information included in the broadcast signal are implemented by the digital TV receiver of FIG. 1 is as shown in FIG. 2. In the digital TV, an image 30 of a TV broadcast signal is displayed on a background of a screen, and text 40 of OSD information is superimposed on the image.

However, the conventional digital TV has a disadvantage in that it does not make good use of time information included in a broadcast signal transmitted from a broadcasting station. That is, in the conventional clock displayed on the digital TV, time information included in a digital broadcast signal that is periodically transmitted is simply displayed in a small corner of the TV image, and thus poor transmission. In addition, most digital TVs display a clock digitally, that is, a number, and the digital clock has a disadvantage in that it is difficult for a viewer to read well when the letter is small.

Therefore, in order to solve this problem, the present invention implements an analog clock on the OSD screen of a digital TV by using time information periodically received from a broadcasting station, thereby increasing viewers' utilization of time information more than a conventional digital TV. Has its purpose.

1 is a block diagram showing a schematic structure of a typical digital TV.

FIG. 2 is a diagram illustrating a screen implemented by the digital TV of FIG. 1. FIG.

3 is a flow chart showing how the digital TV of the present invention implements an analog clock.

4 is a diagram illustrating a coordinate table used by the digital TV according to the present invention.

FIG. 5a shows a hands-free analog clock implemented by the invention of FIG. 4; FIG.

5b shows an analog clock implemented by the invention of FIG.

Explanation of symbols for main parts of the drawings

100: center point of the clock 110: end point of the second hand

111: end point of minute hand 112: end point of hour hand

a _n : x coordinate point of the hour hand b _n : y coordinate point of the hour hand

c _n : x coordinate point of minute hand d _n : y coordinate point of minute hand

e _n : x coordinate point of the second hand f _n : y coordinate point of the second hand

A feature of the present invention is to implement an analog clock as an OSD function on a digital TV screen using time information periodically included in a broadcast signal.

The present time display method according to the present invention comprises the steps of drawing an analog clock as shown in the flowchart shown in FIG. 3 (s1), reading the information corresponding to the current time from the additional information included in the broadcast signal (s2), and the current time. Calculating the end point coordinates of the hands according to (s3), drawing the hands with reference to the end point coordinates (s4), stopping the operation for a predetermined delay time (s5), and then clearing the hands ( s6), updating the current time according to the delay time (s7).

Hereinafter, the present time display method of the present invention will be described with reference to FIGS. 3, 4, and 5A and 5B.

First, the present invention draws a predetermined analog clock on the screen by a pre-programmed program. The shape of the analog clock can vary depending on the program. However, this step draws only the analog clock plate excluding the clock as shown in FIG. 5A.

The digital TV according to the present invention receives a broadcast signal and reads the current time from the additional information included in the broadcast signal. And, the coordinates (a _n , b _n , c _n , d _n , e _n , f _n ) of the clock hands of the analog clock according to the current time, that is, the end points 110, 111, and 112 where the hour, minute, and second hands are to be located. To calculate. At this time, the present invention calculates the coordinates of the end point by the coordinate table as shown in FIG. Of course, this coordinate table is preset by the manufacturer and stored in a memory built into the digital TV. Alternatively, the microcomputer embedded in the digital TV of the present invention may calculate the coordinates of the end point according to a predetermined program.

Then, the present invention refers to the hands of the analog clock (110 ', 111', 112 ') with reference to the coordinate of the end point calculated according to the coordinate table and the center point 100 of the analog clock already drawn by the above-described steps. Draw. As a result of this step, the analog clock shows the viewer the correct current time on the screen of the digital TV. In this case, according to the present invention, the watch may be drawn to show the time in hours and minutes, or the watch and the hands may be shown to show the time in seconds.

Then, the clock is stopped for a predetermined delay time. At this time, the length of the delay time is set differently according to the type of the analog clock. That is, the delay time is set to about 1 minute if the analog clock drawn by the present invention is displayed only the hour and minute units, the delay time is set to about 1 second if the clock is displayed in seconds as well as hours and minutes do.

This delay time is calculated by the digital TV itself by the vertical synchronization signal Vsync (hereinafter referred to as Vs). The reason is that since the vertical synchronization signal is 60 Hz in the NTSC TV, the time of one second passes each time the vertical synchronization signal Vs becomes 60 in the case of a digital TV receiving the NTSC broadcasting signal.

When the delay time passes in the above-described steps, the clock hands are erased. In the present time display method according to the present invention, if the delay time is in the unit of 1 second, only the clock hands in seconds are erased, and if the delay time is in the unit of 1 minute, the clock hands in minutes are erased. At this time, in the present invention, when the second unit time of the current time becomes 60 seconds, the second unit time is replaced with 0 and the minute unit time is increased by one minute. When the minute time of the current time reaches 60 minutes, the minute time is replaced with zero and the hour time is increased by one hour.

Alternatively, the present invention may be designed to read the new current time from the additional information received on the digital TV, calculate a new end point coordinate of each of the hands, and draw the hands again. However, if the new current time is read every second and the end point coordinate is recalculated every second, the operation speed is considerably slow. In addition, since the current time is not included in the additional information received in the digital TV, it is inefficient to read the new current time every second.

Therefore, in the present invention, it is efficient to read the new current time from the additional information and update the current time whenever the time unit of time changes. That is, when the minute unit time reaches 60 minutes and an increase factor occurs in the hour unit time, the present invention reads new information corresponding to the current time from the new additional information included in the broadcast signal and updates the current time inside the digital TV. It is preferably configured to. As a result, every hour, the present time in the digital TV is adjusted to the actual present time.

In the present time display method of the present invention, reading information corresponding to the current time from the additional information reads all of the time unit, minute unit, and second unit when displaying the first time. When the current time is updated thereafter, it is not necessary to continuously read the time of every unit, and it may be designed to read only the time unit and the minute unit according to a predetermined period to correct the current time.

For example, the digital TV according to the present invention detects the correct time by reading time in all units from the additional information only when the time is initially displayed. Therefore, once the information on the current time is detected, the time is calculated and displayed on the screen using a vertical synchronization signal by a built-in micom. Thereafter, the digital TV according to the present invention redetects the correct time from the additional information at appropriate intervals, compares the redetected time with the current time calculated by the microcomputer of the digital TV itself, and compares the current time with the actual time. Correct to fit. The appropriate period at this time may be in minutes or hours as set by the manufacturer. As a result, the present invention can reduce the load on the microcomputer generated by redetecting the current time every second and provide the viewer with the accurate current time.

The present invention implements an analog clock on an OSD screen using time information included in a digital broadcast signal, thereby providing not only accurate time to the viewer but also an advantage of efficiently using additional information of the digital broadcast signal. . Therefore, the digital TV according to the present invention has an effect of providing additional information to the viewer more efficiently than the conventional digital TV.

Claims (5)

How to implement a digital TV clock, Drawing an analog clock without hands; Reading information corresponding to the current time from additional information included in the broadcast signal received by the digital TV; Calculating an end point coordinate of a clock hand of the analog clock according to the current time; Drawing clock hands of the analog clock with reference to the center point and the end point coordinates of the analog clock; Stopping operation for a predetermined delay time; Erasing the clock hands; And, And updating the current time according to the delay time. The method of claim 1, wherein the hands of the watch include both an hour hand, a minute hand, and a second hand. The method of claim 2, further comprising: replacing the second time with zero when the second time of the current time reaches 60 seconds, and increasing the minute by one minute to the current time; When the minute time of the current time reaches 60 minutes, replacing the minute time with 0, and increasing the time by one hour to the time of the current time. Way. 4. The method of claim 3, wherein increasing the time by one hour comprises reading information corresponding to the new current time from additional information included in the broadcast signal received by the digital TV and updating the current time. How to display the current time of the digital TV. The method of claim 1, wherein the reading of the information corresponding to the current time from the additional information is performed when the time unit of the current time is updated.