US Patent No: 4,453,136

Number of patents in Portfolio can not be more than 2000

AFC System for controlling an oscillator according to an input frequency

Stats

ATTORNEY / AGENT: (SPONSORED)

Importance

Loading Importance Indicators... loading....

Abstract

See full text

An automatic frequency control system includes a frequency measuring unit (IFM), which produces a frequency quantity representing the frequency of its input signal, and a controllable-frequency signal generator (VCO), which produces an output signal whose frequency depends on a control signal supplied to its control input. In a normal mode of operation, IFM derives its input signal from an external source connected to an input terminal (T), and the system derives from the frequency quantity produced by IFM, a control signal for VCO, using a predetermined transfer characteristic, so that the output frequency of VCO is dependent on the frequency of the input signal to IFM, being, for example, equal to the frequency of the signal at T. In order that the system may have an accurate and rapid response, said transfer characteristic is predetermined in a calibration mode of operation in which different control signals for VCO are derived from a calibration signal generator (CSG), resultant input signals for IFM are derived from the output of VCO, and different resultant frequency quantities produced by IFM are associated with respective control signals for VCO by storing digital words representing these control signals in a random-access memory (RAM) at respective addresses which are resultant frequency quantities from IFM. The system may be recalibrated at intervals to take into account drifts in the system.

Loading the Abstract Image... loading....

First Claim

See full text

all claims..

Related Publications

Loading Related Publications... loading....

Patent Owner(s)

Patent OwnerAddressTotal Patents
THORN EMI ELECTRONICS LIMITEDHAYES17

International Classification(s)

  • [Classification Symbol]
  • [Patents Count]

Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Kelland, Martin J Horsham, GB2 1 12

Cited Art Landscape

  • No Cited Art to Display

Patent Citation Ranking

Forward Cite Landscape

Patent Info (Count) # Cites Year
 
AT&T Information Systems Inc. (1)
4,528,521 Precision control frequency synthesizer having an unstable, variable frequency input signal 8 1984
 
ERICSSON INC. (1)
5,983,077 Systems and methods for automatic deviation setting and control in radio transmitters 41 1997
 
IFR LIMITED (1)
5,079,522 Variable frequency signal generator 31 1990
 
ITT MANUFACTURING ENTERPRISES, INC. (1)
7,720,451 Methods and apparatus for calibrating oscillators in a receiver 1 2004
 
KABUSHIKI KAISHA TOSHIBA (1)
4,613,826 Frequency synthesizer for CATV tuner 7 1985
 
KOREA AEROSPACE RESEARCH INSTITUTE (1)
7,457,599 Frequency transceiver for controlling intermediate frequency 0 2004
 
MOTOROLA, INC. (1)
4,893,087 Low voltage and low power frequency synthesizer 95 1988
 
NEC ELECTRONICS CORPORATION (1)
6,052,419 Frequency adjusting method for use with digital receiver and frequency adjusting circuit thereof 9 1997
 
Pioneer Electronic Corporation (1)
5,367,269 System for producing an oscillating jamming signal utilizing a phase-locked loop 7 1993
 
ROBERT KAZUO KIMURA BENEDICT ANIELLE ITRI (1)
4,568,888 PLL Fast frequency synthesizer with memories for coarse tuning and loop gain correction 71 1983
 
TEXAS INSTRUMENTS INCORPORATED (1)
4,810,974 Drift compensated digitally tuned voltage controlled oscillator 9 1987
 
The United States of America as represented by the Secretary of the Army (1)
4,494,079 Microprocessor controlled phase locked loops 4 1981