Method and apparatus for providing moire effect correction based on displayed image resolution

Claim 2

A circuit for correcting a moire effect on a display comprising: a first circuit to receive a horizontal synchronization signal having a horizontal scanning frequency; a second circuit to receive a vertical synchronization signal having a vertical scanning frequency; a divider circuit, coupled to the first and second circuits, that generates a moire correction signal having a value substantially proportional to the horizontal scanning frequency divided by the vertical scanning frequency, the moire correction signal being provided to the display for correcting the moire effect; and a horizontal driver circuit, coupled to the divider circuit to receive the moire correction signal, the horizontal driver circuit generating a flyback pulse having a first frequency substantially equal to the horizontal scanning frequency and a flyback phase that is shifted from a synchronization phase of the horizontal synchronization signal substantially in proportion to the moire correction signal on alternate cycles of the horizontal synchronization signal, the flyback phase controlling a horizontal position of lines on the display and thereby correcting the moire effect.

Claim 3

The circuit of claim 1, wherein the divider circuit generates the moire correction signal having the value substantially proportional to the horizontal scanning frequency multiplied by the horizontal scanning frequency divided by the vertical scanning frequency.

Claim 4

The circuit of claim 1, wherein the horizontal driver circuit further comprises receiving a horizontal adjustment signal and generating the flyback phase substantially in proportion to the horizontal adjustment signal added to the moire correction signal on alternate cycles of the horizontal synchronization signal.

Claim 5

The circuit of claim 1, wherein the horizontal driver circuit is further coupled to the second circuit to receive the vertical synchronization signal, and where the horizontal driver circuit shifts the flyback phase of a first cycle of the flyback pulse after receiving the vertical synchronization signal if a preceding first cycle of the flyback pulse after receiving a preceding vertical synchronization signal was not shifted.

Claim 6

The circuit of claim 1, further comprising: a horizontal position control circuit, coupled between the divider circuit and the horizontal driver circuit, to generate a horizontal reference signal having a second frequency substantially equal to the horizontal scanning frequency and a reference phase that is shifted from the synchronization phase of the horizontal synchronization signal substantially in proportion to the moire correction signal on alternate cycles of the horizontal reference signal; and the horizontal driver circuit generating the flyback pulse having the flyback phase that is substantially equal to the reference phase.

Claim 7

The circuit of claim 1, wherein the moire correction signal is generated by a microcontroller.

Claim 8

A cathode ray tube display system for receiving and displaying a video signal comprising a horizontal synchronization signal and a vertical synchronization signal, the cathode ray tube display system comprising: a moire correction circuit that receives the horizontal synchronization signal and the vertical synchronization signal, having respectively a horizontal scanning frequency and a vertical scanning frequency, and the moire correction circuit generates a moire correction signal, having a correction value substantially proportional to the horizontal scanning frequency divided by the vertical scanning frequency; a display that receives the video signal and displays a corrected video signal based on the moire correction signal, and a moire adjustment circuit that receives the horizontal synchronization signal, that receives a moire adjustment signal substantially proportional to a level of moire correction, and generates a horizontal position signal having a first frequency proportional to the horizontal scanning frequency and an adiustment value substantially proportional to the moire adjustment signal and the moire correction signal; a horizontal driver circuit that receives the horizontal position signal, that receives the horizontal synchronization signal, and generates a flyback pulse having a second frequency substantially equal to the horizontal scanning frequency and a flyback phase that is shifted from a synchronization phase of the horizontal synchronization signal substantially in proportion to the horizontal position signal; and the display that further receives the flyback pulse having the flyback phase controlling a horizontal position of lines on the display to correct the moire effect.

Claim 9

A cathode ray tube display system for receiving and displaying a video signal comprising a horizontal synchronization signal and a vertical synchronization signal, the cathode ray tube display system comprising: a moire correction circuit that receives the horizontal synchronization signal and the vertical synchronization signal, having respectively a horizontal scanning frequency and a vertical scanning frequency, and the moire correction circuit generates a moire correction signal, having a correction value substantially proportional to the horizontal scanning frequency divided by the vertical scanning frequency; a display that receives the video signal and displays a corrected video signal based on the moire correction signal, and a moire adjustment circuit that receives the horizontal synchronization signal, that receives a moire adjustment signal substantially proportional to a level of moire correction, and generates a horizontal position signal having a first frequency proportional to the horizontal scanning frequency and an adiustment value substantially proportional to the moire adjustment signal and the moire correction signal; a horizontal driver circuit that receives the horizontal position signal, that receives the horizontal synchronization signal, and generates a flyback pulse having a second frequency substantially equal to the horizontal scanning frequency and a flyback phase that is shifted from a synchronization phase of the horizontal synchronization signal substantially in proportion to the horizontal position signal; and the display that further receives the flyback pulse having the flyback phase controlling a horizontal position of lines on the display to correct the moire effect.

Claim 10

The cathode ray tube display system of claim 7, wherein the moire correction circuit generates the moire correction signal having the correction value substantially proportional to the horizontal scanning frequency multiplied by the horizontal scanning frequency divided by the vertical scanning frequency.

Claim 11

The cathode ray tube display system of claim 7, wherein the horizontal driver circuit further receives a horizontal adjustment signal and generates the flyback pulse having the flyback phase substantially in proportion to the horizontal adjustment signal added to the moire correction signal on alternate cycles of the horizontal synchronization signal.

Claim 12

The cathode ray tube display system of claim 7, wherein the horizontal driver circuit further receives the vertical synchronization signal, and shifts the flyback phase of a first cycle of the flyback pulse after receiving the vertical synchronization signal if a preceding first cycle of the flyback pulse after receiving a preceding vertical synchronization signal was not shifted.

Claim 13

The cathode ray tube display system of claim 7, further comprising: a horizontal position control circuit that receives the horizontal position signal, that receives the horizontal synchronization signal, and generates a horizontal reference signal having a third frequency substantially equal to the horizontal scanning frequency and a reference phase that is shifted from the synchronization phase of the horizontal synchronization signal substantially in proportion to the horizontal position signal; the horizontal driver circuit generating the flyback pulse having the flyback phase that is substantially equal to the reference phase.

Claim 14

The cathode ray tube display system of claim 7, wherein the moire correction circuit comprises a microcontroller.

Claim 17

The method of claim 13, wherein generating the moire correction signal comprises generating the moire correction signal having the correction value substantially proportional to the horizontal scanning frequency multiplied by the horizontal scanning frequency divided by the vertical scanning frequency.

Claim 18

The method of claim 13, further comprising receiving a horizontal adjustment signal and generating the flyback phase substantially in proportion to the horizontal adjustment signal added to the moire correction signal on alternate cycles of the horizontal synchronization signal.

Claim 19

The method of claim 13, wherein generating the flyback pulse further comprises receiving the vertical synchronization signal, and shifting the flyback phase of a first cycle of the flyback pulse after receiving the vertical synchronization signal if a preceding first cycle of the flyback pulse after receiving a preceding vertical synchronization signal was not shifted.

Claim 20

The method of claim 13, further comprising: generating a horizontal reference signal having a third frequency substantially equal to the horizontal scanning frequency and a reference phase that is shifted from the synchronization phase of the horizontal synchronization signal substantially in proportion to the horizontal position signal; generating the flyback pulse in the horizontal driver circuit, the flyback pulse having the flyback phase that is substantially equal to the reference phase.

Claim 21

The method of claim 13, wherein the moire correction signal is generated by a microcontroller.