Hout position control circuit

Details Hout position control circuit Hout position control circuit

1999-12-08

2003-04-15

Mengistu, Amare (Department: 2673)

Computer graphics processing and selective visual display system

Display driving control circuitry

Display power source

C345S204000, C348S500000, C348S540000, C348S541000, C348S497000

Reexamination Certificate

active

06549198

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a HOUT position control circuit used to control position where image is displayed in a display.
BACKGROUND OF THE INVENTION
Multisync monitors use a HOUT position control circuit to control the delay amount from input horizontal synchronous signal (hereinafter referred to as ‘Hsync signal’) to output horizontal drive signal (hereinafter referred to as ‘Hout signal’) so as to conduct the control of image display position (hereinafter referred to as ‘position control’).
Conventionally, in the HOUT position control circuit of multisync monitors, an adjustable delay circuit is provided in PLL loop, and the position control is conducted by controlling the delay value of the adjustable delay circuit.
FIG. 1
is a block diagram showing the composition of a conventional HOUT position control circuit.
As shown in
FIG. 1
, the conventional HOUT position control circuit is provided with adjustable delay circuits
24
,
25
at the input stage of a phase comparator
3
. Two input signals to the phase comparator
3
are separately delayed by the adjustable delay circuits
24
,
25
. The position control is conducted by controlling the delay value.
FIG. 2
is a block diagram showing the composition of the adjustable delay circuits
24
,
25
in FIG.
1
.
Multisync monitors need the delay amount to be a same proportion to input Hsync signal. Therefore, sawtooth wave
31
synchronized with input signal
29
of the adjustable delay circuits
24
,
25
is generated by a sawtooth generator circuit
28
, and then delayed output signal
27
is made by using a comparator
32
.
The control of delay value is conducted by using delay control voltage
30
, which is DC voltage.
FIG. 3
is a timing chart showing the process of generating a delay value from sawtooth wave.
However, since the conventional HOUT position control circuit has the adjustable delay circuit in PLL loop, a dispersion in the adjustable delay circuit may cause a deviation in position.
Further, since the adjustable delay circuit is operated in analogue manner, the delay value may vary depending on a noise thereby causing a jitter.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a HOUT position control circuit that can suppress a deviation in position or a jitter.
It is a further object of the invention to provide a position control circuit used to control the vertical position of display image in a multisync monitor that can suppress a deviation in position or a jitter.
According to the invention, a HOUT position control circuit used to control the horizontal position of display image in a multisync monitor, comprises:
a first PLL circuit that is phase-locked with input horizontal synchronous signal;
a second PLL circuit that is phase-locked with output of the first PLL circuit; and
means for generating a delay between outputs of the first PLL circuit and the second PLL circuit to control the delay amount from the input horizontal synchronous signal to output horizontal drive signal.
According to another aspect of the invention, a HOUT position control circuit used to control the horizontal position of display image in a multisync monitor, comprises:
the position control of display image is conducted in digital manner.
According to another aspect of the invention, a position control circuit used to control the vertical position of display image in a multisync monitor, comprises:
a first PLL circuit that is phase-locked with input vertical synchronous signal;
a second PLL circuit that is phase-locked with output of the first PLL circuit; and
means for generating a delay between outputs of the first PLL circuit and the second PLL circuit to control the delay amount from the input vertical synchronous signal to output vertical drive signal.
According to another aspect of the invention, a position control circuit used to control the vertical position of display image in a multisync monitor, comprises:
the position control of display image is conducted in digital manner
Also, the invention offers a multisync monitor using the above-composed HOUT position control circuit or a position control circuit.


REFERENCES:
patent: 4327376 (1982-04-01), Balaban et al.
patent: 4803407 (1989-02-01), Mehrgardt
patent: 5043813 (1991-08-01), Christopher
patent: 5150201 (1992-09-01), Mehrgardt et al.
patent: 5329367 (1994-07-01), Fernsler et al.
patent: 5565928 (1996-10-01), Saeger et al.
patent: 5812210 (1998-09-01), Arai et al.
patent: 56-98122 (1981-07-01), None
patent: 61-76911 (1986-05-01), None
patent: 62-216588 (1987-09-01), None

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