Pulse or digital communications – Receivers – Automatic frequency control
Patent
1995-09-08
1998-10-27
Chin, Wellington
Pulse or digital communications
Receivers
Automatic frequency control
455119, H04L 2706
Patent
active
058287094
ABSTRACT:
An apparatus and a method for improving the stability of the transmitting frequency by using a costas loop section in a communication system of a half duplex transmitting method is disclosed, in which a receiving terminal is provided with an A/D converter, a D/A converter, a switching circuit, and a central processing unit, and thus, during a data transmission, a reference frequency is extracted through the costas loop section without installing a separate reference frequency extracting facility, thereby improving the stability of the transmitting frequency. In the conventional technique, in forming a reference frequency for a transmitting frequency, additional devices such as a pilot signal detector, a transmission reference frequency oscillator and the like are required, with the result that the cost for establishing the system becomes high, and that too much man hours and too many additional components are required. However, in the present invention, low cost facilities such as A/D and D/A converters, a switch circuit and a central processing unit are installed to the costas loop of the currently used receiving terminal, so that a transmitting reference frequency can be extracted from the data carrying carrier waves through the costas loop without using the high cost conventional reference frequency extracting facility, thereby improving the stability of the transmitting frequency.
REFERENCES:
patent: 4816769 (1989-03-01), Ma et al.
patent: 4980652 (1990-12-01), Tarusawa et al.
patent: 5233626 (1993-08-01), Ames
patent: 5271039 (1993-12-01), Suzuki
patent: 5454009 (1995-09-01), Fruit et al.
patent: 5550871 (1996-08-01), Lee
patent: 5701602 (1997-12-01), Shimoda
Ralph Eschenbach Application of spread spectrum radio to indoor data communication, IEEE, 34.5-1-34.5-2, Mar. 1982.
Chin Wellington
Corrielus Jean B.
Hyundi Electronics Industries Co., Ltd.
LandOfFree
Apparatus and method for improving stability of transmitting fre does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for improving stability of transmitting fre, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for improving stability of transmitting fre will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1620046