JPS62212690A - Display circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circuit for displaying an area in a display or the like. Area display means displaying a certain area (b) (hatched area in FIG. 8) of the entire screen as shown in FIG.

[Conventional technology]

FIG. 6 shows an example of a conventional circuit for displaying information on a display. In the figure, ■ is an input signal processing section, haiku is a memory, dan is a timing control section, V1 is a display position detection section, g31 is an output control section, (31 is a display control input terminal, (4) is a display output terminal, (!l) is an oscillator, Ill.

(!1 is the input terminal of the booster which serves as the reference for display position detection.

In the conventional example shown in FIG. 6, data regarding the address of the memory is input from the input terminal (31), and the contents of the memory are transmitted to the output control section. signal and vertical synchronization signal)
The output control section is controlled by the timing control circuit and the output control section.
The data corresponding to the display position is output from the output terminal (41) to the display.

When displaying an area as shown in FIG. 8, the conventional example described above uses a memory and the like, resulting in a large scale. In addition, the display position detection section g1 generally uses a kakunta, controls the kakunta using a reference input signal, and determines the display position by counting the number of clock pulses from the timing control section. Depending on the phase state with the clock signal, the 12072-minute count start time difference may be exceeded and the display position shift may be exceeded.

[・Problem that the invention seeks to solve]

Furthermore, in order to reduce display position deviation, it is necessary to increase the frequency of the clock signal from the timing control section, and in this case, it is necessary to increase the speed of the circuit.

The present invention was made to solve the above-mentioned problems, and it is an object of the present invention to provide an area display circuit that is small in scale and can eliminate display position shift. .

[Means for solving problems]

In this invention, an area display timing signal is generated by counting the number of pulses of an oscillator output that is phase-synchronized with a signal serving as a reference for horizontal sweep timing (hereinafter referred to as a horizontal reference signal). .

[Effect]

The area display timing signal according to the present invention is generated from the reference signal and the phase-synchronized oscillator output, is output to the display, and determines the area display position on the display.

〔Example〕

FIG. 1 shows an embodiment of the present invention. In the figure, the space between is an oscillator, θ is a frequency divider,
4 is a detector, (11 is a horizontal reference signal input terminal, (!1
is the reference signal for the vertical insertion timing (hereinafter,
This is the input terminal for the vertical reference signal.

The frame is a timing generator, into which the horizontal reference signal, the vertical reference signal, and the output of the oscillator (II) whose phase is synchronized with the horizontal reference signal are input, and outputs a timing signal for area display, which is transmitted to the display.

The operation will be explained below with reference to FIGS. 2 and 8. As shown in Fig. 3, a specific area el) (
Assume that the display is performed in the shaded area in FIG. In the horizontal direction, there is a specified time T from the fall of the horizontal direction reference signal Iw.
After IH, the IHz level is output for a certain period of time using the horizontal area position control signal fOH to indicate the area area for a certain period of time. Furthermore, the specified time is 'l'! Similarly 70H after IH
By setting it to an IH label, you can display a frame as shown in Figure 3. Similarly, in the vertical direction, when the vertical reference signal fv falls from 9 to Trv, and further after Tgv, the vertical area position control signal fomat goes to 'H' level to indicate the vertical area area.

The area display position is TIH, TII[, TIT,
Although determined by the time TI'7, the horizontal area display position TIH, Tjl1M is created as shown in Figure 2-a.

27g1 One oscillator (1
11 output and the horizontal reference signal fH1! input from the terminal Il+. : is input, the phases of both signals are compared, positional deviation is detected, and the frequency of the first oscillator (11) is controlled to achieve phase synchronization.
The oscillator (one output f
oaa and the horizontal reference signal fH are phase synchronized, as shown in FIG. 2-a. Therefore, input it to 10sc' and use the kakunta that is reset at fFl to create fol.
If you count the number of pulses on IC, the kakunta input is 10 seconds at the start of counting.

Since the phase of is constant, the accuracy is good ('l
'lH,T21[ can be determined.

The display position of the vertical area on the display screen is also determined by counting the number of pulses of fm using synchronized horizontal reference signal fH and vertical reference signal /V, as shown in Figure s-b. By determining the times 'l'lv and 'l'lV, the area display position in the vertical direction can also be determined accurately with respect to /f.

In addition, although the number of fHIv pulses was counted in the vertical direction, it is also possible to count the signal as long as it is phase-synchronized with the @ rectangular reference signal fH.Also, #H#, II, I of each signal The level of r0@4 is an alternative embodiment of the one shown in FIG. 6, and the one shown in FIG. This is an example of K, and f4
FIG. 5 is an example in which control signal inputs such as the shape of the area display, such as the thickness of the frame and the shape of the frame such as a square and a circle, are added.

〔Effect of the invention〕

As described above, according to the present invention, the reference input signal and the oscillator output are phase-synchronized, and the area display position is determined by counting the clock signal generated by the oscillator output. can be displayed.

[Brief explanation of drawings]

gx diagram is an example of the present invention, FIG. 2 is a timing diagram of a signal according to the present invention, FIG. 8 is an example of area display, FIG.
FIG. 5 shows another embodiment, and FIG. 6 shows a conventional example. In the figure, (11) is an oscillator, H is a frequency divider, α-shi is a phase comparator, α-hiro is a detector, 4 is a timing generator, 11)
(2) is an input terminal for a horizontal timing reference signal, and (2) is an input terminal for a vertical reference signal. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] An oscillator, a frequency divider that divides the oscillator output, a phase comparator that receives the frequency divider output and a reference signal, and detects the phase comparator output and uses the output to control the oscillator. The display is characterized in that an area is displayed in a specific area of a display device using the output of a timing generator that generates a prescribed timing using the oscillator output and a reference signal. circuit.