Title:
CIRCUIT FOR THE ACQUISITION OF A CARRIER SIGNAL BY APPLYING A SUBSTITUTE PILOT TO A SYNCHRONOUS DEMODULATOR
Document Type and Number:
WIPO Patent Application WO/1995/018508
Kind Code:
A1
Abstract:
A synchronous demodulator is controlled by a phase locked loop for tuning to a pilot in a television signal. A start-up interval is commenced upon initiation of tuning (either after power-up or a channel change) during which a substitute signal at the pilot frequency is supplied to the phase locked loop to rapidly bring the VCO close to its lock-up frequency. Thereafter the IF signal is supplied. The start-up interval is defined by an AFC Defeat signal from a microprocessor and controls an IF switch. The substitute signal is from a crystal oscillator.
Inventors:
KRISHNAMURTHY GOPALAN
MYCYNEK VICTOR
SGRIGNOLI GARY J
MYCYNEK VICTOR
SGRIGNOLI GARY J
Application Number:
PCT/US1994/014393
Publication Date:
July 06, 1995
Filing Date:
December 15, 1994
Export Citation:
Assignee:
ZENITH ELECTRONICS CORP (US)
International Classes:
H03D1/22; H03D3/00; H03G3/20; H03J7/02; H03L7/10; H04L27/02; H04N5/44; H04N5/455; H04N5/50; H04N21/2383; H04N21/438; (IPC1-7): H04N5/455; H03L7/14; H04L27/02; H04N5/50; H04N7/24
Domestic Patent References:
| WO1992014343A1 | 1992-08-20 | |||
| WO1992016072A2 | 1992-09-17 |
Foreign References:
| US5175626A | 1992-12-29 | |||
| DE3841512A1 | 1989-06-29 | |||
| DE2456742A1 | 1975-06-26 | |||
| US5087975A | 1992-02-11 | |||
| US4918718A | 1990-04-17 |
Other References:
PATENT ABSTRACTS OF JAPAN vol. 17, no. 6 (E - 1302) 7 January 1993 (1993-01-07)
Download PDF:
Previous Patent: VIDEO SIGNAL CONTROLLER
Next Patent: METHOD AND DEVICE FOR THE RECORDING AND REPRODUCTION OF STEREOSCOPIC VIDEO IMAGES
Next Patent: METHOD AND DEVICE FOR THE RECORDING AND REPRODUCTION OF STEREOSCOPIC VIDEO IMAGES