[54] SYNC SIGNAL PROCESSING DEVICE FOR COMBINED VIDEO APPLIANCE
[75] Inventor: Sang Geun Bae, Kyoungsangbuk-Do, Rep. of Korea
[73] Assignee: LG Electronics, Inc., Seoul, Rep. of Korea
[21] Appl. No.: 08/827,992 [22] Filed: May 9, 1997
[51] Int. C I. II04N 5/04
[52] U.S. CI 348/510; 348/500; 348/525;
348/521; 348/516; 348/542; 348/554; 345/213
[58] Field of Search 348/510, 500,
348/525, 521, 524, 516, 522, 552, 529, 530, 542, 543, 544, 554, 555, 558; 345/213, 204; H04N 5/04, 5/05
[56] References Cited
U.S. PATENT DOCUMENTS
4.425.581 1/1984 Schweppe et al 348/510
4,464,679 8/1984 Wargo 348/510
4.554.582 11/1985 Wine 348/510
4,631,585 12/1986 Wine 348/510
4,670,774 6/1987 Tokui 348/505
4,670,785 6/1987 Medin 348/510
4,684,987 8/1987 Tsutsui 348/543
4,896,214 1/1990 Dieterle et al 348/510
5,068,732 11/1991 Satoh 348/748
5,394,171 2/1995 Rabii 345/213
5,469,220 11/1995 Kumada 348/529
5,486,869 1/1996 Cooper 348/525
5,502,503 3/1996 Koz 348/552
5,526,055 6/1996 Zhang et al 348/510
5,550,594 8/1996 Cooper et al 348/513
5,610,663 3/1997 Nan et al 348/554
5,754,250 5/1998 Cooper 348/525
5,808,692 9/1998 Lee 348/542
5,812,204 9/1998 Baker et al 348/453
Primary Examiner—-John K. Peng
Assistant Examiner—-Jean W. Desir
Attorney, Agent, or Firm—Fish & Richardson PC.
[57] ABSTRACT
A sync signal processing device for a combined video appliance capable of directly processing a personal computer (PC) signal through a television (TV) receiver circuit to achieve the horizontal and vertical driving and deflection. The device can prevent the vertical trembling phenomena of the displayed picture and on-screen display by compensating for the sync frequency difference between the PC signal and the TV signal. According to the devices either a TV sync signal or a PC sync signal is selected in accordance with a selected TV/PC mode after the PC sync signal is frequencyconverted and the selected PC sync signal is processed through the TV sync signal processing circuit. Either the horizontal driving pulse signal form the TV sync signal processing circuit or the horizontal driving pulse signal produced from a separate horizontal oscillation circuit is selected and outputted to a horizontal output circuit in accordance with the selected TV/PC mode.
3 Claims, 3 Drawing Sheets
