Robert M Casey

US Patent:

53862430, Jan 31, 1995

Filed:

Jul 22, 1993

Appl. No.:

8/096156

Inventors:

Jinshi Huang - San Jose CA
Robert F. Casey - Santa Clara CA

Assignee:

Zoran Corporation - Santa Clara CA

International Classification:

H04N 5213

US Classification:

348607

Abstract:

A ghost cancellation system for filtering out ghosts in a received video signal including an active filter having a filtering function defined by a first set of coefficients (ak. sub. old) and having a input and a output. A transmitted ghost cancellation reference (GCR) signal is applied to the input of the active filter during a vertical blanking period to generate a filtered GCR signal at the output of the active filter. The filtered GCR signal is compared with a ghostless GCR signal to obtain an error signal, and the filter coefficients are adjusted based on the error signal to obtain a set of new coefficients (ak. sub. new). The active filter includes a feedforward FIR filter and an adder serially connected between the input and the output, a feedback IIR filter and a switch serially connected between the output and-the adder, the feedforward FIR filter and the feedback IIR filter having filtering functions defined by the coefficients. The active filter is reconfigurable as a matched filter by passing the error signal serially through the feedforward FIR filter and the feedback IIR filter, the matched filter receiving the error signal and producing a set of impulses (dk) which represent received ghost delays and coefficients where ##EQU1## where x(j) is time-reversed sequence of the coefficients in the bank (ideal GCR sequence), and e(j+k) is the difference between the received average GCR and the reference GCR.

US Patent:

54165270, May 16, 1995

Filed:

Dec 15, 1993

Appl. No.:

8/168625

Inventors:

Robert F. Casey - Santa Clara CA

Assignee:

Zoran Corporation - Santa Clara CA

International Classification:

H04N 504

US Classification:

348537

Abstract:

A frequency controlled clock circuit for use in a television receiver utilizes a detected sound intermediate frequency (IF) signal for use in controlling a voltage controlled oscillator and thereby provide immunity from ghost signals in the transmitted video signal. A phase locked loop responds to phase errors detected from the voltage controlled oscillator and a reference signal from the sound IF signal to control the frequency of the voltage controlled oscillator.