Method for generating a modulated television signal

United States Patent [w]

Bargauan

[54] METHOD FOR GENERATING A

MODULATED TELEVISION SIGNAL

[75] Inventor: Michele Bargauan, Milan, Italy

[73] Assignee: M.B. International S.r.l., Livigno, Italy

[21] Appl. No.: 613,810

[22] Filed: Mar. 6, 1996

[30] Foreign Application Priority Data

Mar. 10, 1995 [IT] Italy MI95A0475

[51] Int. C I. II04N 5/40

[52] U.S. CI 348/724; 348/475; 332/151;

375/298; 455/47; 455/102

[58] Field of Search 375/295, 296,

375/298, 300, 308; 332/103, 108, 149, 151; 455/47, 48, 102, 108, 109; 348/723, 724, 423, 426, 473, 475, 388, 607, 608, 609, 610, 611, 613; H04N 5/21, 5/40

[56] References Cited

U.S. PATENT DOCUMENTS

4,882,614 11/1989 Kageyama et al 358/141

4,882,725 11/1989 Noda et al 358/143

4,918,515 4/1990 Faroudja 358/167

5,122,879 6/1992 Ito 358/191.1

IIIIIIH

US005875005A

[ii] Patent Number: 5,875,005

[45] Date of Patent: Feb. 23, 1999

5,243,304 9/1993 Rixon 455/109

5,534,933 7/1996 Yang 348/475

Primary Examiner—Michael Lee

Assistant Examiner—-Jeffrey S. Murrell

Attorney, Agent, or Firm—Guido Modiano; Albert Josif

[57] ABSTRACT

The method for generating a modulated television signal involves performing a first filtering and a second filtering to obtain two signals, one having a passband that is equal to complete passband and the other one having a passband that is equal to the sideband to be suppressed. The signal having a complete passband is amplitude-modulated with a video carrier, obtaining a first signal. The signal having a passband equal to the sideband to be suppressed is then divided into a first component and a second component, and the first component is phase-shifting by 90° with respect to the second component. The first component is modulated with a video carrier that is phase shifted by 90°, obtaining a second signal. The second component of the signal having a passband equal to the sideband to be suppressed is modulated with the video carrier, obtaining a third signal. The second and third signals are then subjected to an algebraic sum, obtaining a fourth signal. The fourth signal is then subtracted from the first signal, obtaining a fifth signal that represents the television signal having the desired sideband.

8 Claims, 3 Drawing Sheets