JPH01188186A - Teletext receiving device - Google Patents

Abstract

PURPOSE:To simplify an adjusting work by controlling the phase of the synchronizing signal or three primary color signal of a display circuit in correspondence to the phase difference of a three primary color signal output and setting the phase difference to a value which is determined in advance. CONSTITUTION:When a display position automatic adjustment start instruction is given to a display position control circuit 16, the display position control circuit 16 instructs a display circuit 11 to output R, G and B signals for picture display for display position adjustment. In a phase comparing circuit 15, phase comparison between a deflecting output pulse and R, G and B output pulses in a picture for display position adjustment is executed. In the display position control circuit 16, the delay part of the display circuit 11 is controlled in order to cause the phase difference from the circuit 15 to be a prescribed value. Thus, regardless of an influence such as the manufacture dispersion of a receiving device, the display picture can be always adjusted so as to be set to the center of a CRT automatically.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides an automatic and The present invention relates to a teletext receiving device that allows the display screen position to be adjusted automatically.

(Prior Art) In teletext broadcasting, information such as text and images is multiplexed onto the currently broadcast television radio waves and then broadcast. If recipients prepare a receiver or adapter that can receive teletext programs, they can select and view a desired program from among many teletext programs.

This teletext signal is transmitted as a digital signal using the time gaps in current television video signals, and at the receiver side, the signal is restored and converted into a television signal, and then displayed on the television screen. You can watch and listen to text programs as additional sounds to the displayed images and music.

Fig. 2 shows a conventional teletext receiving device, in which a display circuit 1 displays R (red), G (green), B (blue) of a teletext screen, etc.
This circuit generates signals and horizontal and vertical synchronizing signals for R, G, and B, and includes a delay part with a synchronizing signal phase adjustment function. By partially adjusting this delay, R, G
, B horizontal synchronization signal and the R, G, and B signal outputs, and the display position of the R, G, and 8 screens can be adjusted. The deflection circuit 2 is a circuit that generates horizontal and vertical deflection signals based on the horizontal and vertical synchronizing signals, and supplies its deflection output to the horizontal and vertical deflection coils of a CRT (cathode ray tube) 3. Further, the R, G, and B signal outputs from the display circuit 1 are supplied to the cathodes of the R, G, and B axes of the CRT 3 through the RGB drive circuit 4.

By the way, in the above conventional configuration, display position adjustment for displaying an RGB screen such as a teletext screen at the center of a CRT is performed by the display circuit 1 for each receiving device.

There was a problem in that the adjustment work was troublesome because some of the days were adjusted.

(Problems to be Solved by the Invention) As described above, conventionally, when adjusting the display position of an 808 screen such as a teletext screen, a part of the delay must be adjusted for each receiving device, which has the problem of poor workability. there were.

Therefore, the present invention is intended to eliminate the above problem i. When displaying a synchronized screen that is different from the normal television video signal, such as a teletext screen, the display position VA is automatically adjusted.
? The purpose of this invention is to provide a teletext receiving device that can perform Ii.

[Configuration of the invention 1 (Means for solving problems) The present invention is applicable to the three primary color signals and the horizontal direction of the character screen.

a character signal display circuit capable of outputting a vertical synchronization signal and varying the phase of the three primary color signals and the synchronization signal;
A deflection circuit that generates horizontal and vertical deflection outputs based on vertical synchronization signals and supplies them to the deflection coil of the cathode ray tube, and three primary color signals from the character signal display circuit that drive the cathode ray tube to display a character screen. a phase comparison circuit that compares the phases of the deflection output from the deflection circuit and the three primary color signal outputs from the drive circuit; The display position control circuit controls the phase of the synchronization signal or the three primary color signals of the display circuit and sets the phase difference to a predetermined value.

(Function) In the present invention, it is possible to automatically adjust the delay part of the display circuit so that the phase difference between the deflection output supplied to the CRT and the R, G, and B signal outputs is set to a predetermined value. ,
The display screen can always be set at the center of the CRT.

(Example) The present invention will be described below based on the example shown in the drawings.

FIG. 1 shows an embodiment of the teletext receiving device of the present invention.

FIG.

In FIG. 1, the display circuit 11 is connected to the R,
This circuit has the function of generating G, B signals and horizontal and vertical synchronizing signals for R, G, and B, the function of generating the screen for adjusting the display position, and the function of adjusting the synchronizing signal phase due to part of the delay. Yes, the deflection circuit 12 outputs horizontal and vertical deflection outputs to the CRT 13 based on horizontal and vertical synchronizing signals for R, G, and B.
horizontal.

This is the circuit that supplies the vertical deflection coil. Note that the screen creation function for display position adjustment and the synchronization signal phase adjustment function in the display circuit 11 are functions built into an IC (integrated circuit) or the like used in a normal teletext receiver.

Further, the RGB drive circuit 14 receives R from the display circuit 11.
. A phase comparison circuit 15 that compares the phases of R, G, and B output horns from the RGB drive circuit 14, and this phase comparison circuit 1
Depending on the output value (phase difference) from 5.

This configuration includes a display position control circuit 16 that adjusts a portion of the delay of the display circuit 11.

The display position control circuit 16 has a function of controlling a part of the Moeki delay so that the phase difference of the phase comparison circuit 15 becomes a predetermined phase difference, and also has the function of automatically controlling the display position from a key manual means (not shown) to the terminal 17. When an adjustment start command is given, an instruction is given to the display circuit 11 to create a display position adjustment screen (test mode instruction),
When there is no start command, it has a function of giving an instruction (standard mode instruction) to the display circuit 11 to display an RGB screen such as a teletext screen.

According to the above configuration, when the display position automatic adjustment start command is given to the display position control circuit 16, the display position control circuit 16
is the R for screen display for display position adjustment with respect to the display circuit 11.
, G, and B signals. Phase comparison circuit 1
5c is R, G of the deflection output pulse and display position adjustment screen;
Compare the phase of the B output pulse. Display position control circuit 16
Now, a portion of the delay of the display circuit 11 is controlled in order to bring the phase difference from the circuit 15 to a predetermined value. the result,
It becomes possible to automatically adjust the display screen so that it is always set at the center of the CRT, regardless of the influence of manufacturing variations in the receiving device.

The display position adjustment start command may be issued when the receiving device is completed in the manufacturing process, but may also be issued when the receiving device is turned on after completion.

Furthermore, in the above embodiment, the display circuit 11 has the function of outputting RGB signals for a teletext screen, etc. in the standard mode, and generating RGB signals for a display position adjustment screen in the test mode. It is also possible for the display circuit to have only the function of outputting RGB signals of a teletext screen, etc., and to adjust the display position using the RGB signals of the teletext screen, etc.

[Effects of the Invention] As described above, according to the present invention, it becomes possible to automatically align the display position of the teletext screen, etc. with the center of the CRT, thereby simplifying the adjustment work.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a teletext receiver according to the present invention, and FIG. 2 is a block diagram of a conventional teletext receiver. . 11... Display circuit, 12... Deflection circuit, 13...
CRT, 14...RGB drive circuit, 15...phase comparison circuit, 16...display position control circuit. Agent Patent Attorney Nori Chika Ken Shu
Ujihiro Figure 1 Figure 2

Claims (1)

[Scope of Claims] A character signal display circuit capable of outputting three primary color signals and horizontal and vertical synchronization signals of a character screen and varying the phases of the three primary color signals and the synchronization signal; , a deflection circuit that generates a vertical deflection output and supplies it to the deflection coil of the cathode ray tube; a drive circuit that drives the cathode ray tube to display a character screen based on the three primary color signals from the character signal display circuit; and from the deflection circuit. a phase comparison circuit that compares the phase of the deflection output of the drive circuit with the phase of the three primary color signal output from the drive circuit; 1. A teletext receiver comprising: a display position control circuit that sets a phase difference to a predetermined value.