Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Synchronizing
Patent
1998-02-10
2000-01-18
Callahan, Timothy P.
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Synchronizing
327308, 331 4, 331 17, 375373, H03L 700, H03L 7093
Patent
active
060160691
ABSTRACT:
A phase locked loop includes a controlled oscillator that is responsive to a control signal to generate an output signal, the frequency of which is a function of the control signal. A phase detector is responsive to a reference frequency input signal and to the output signal, to produce an error signal. A loop filter filters the error signal, to thereby produce the control signal. An acquisition sweep circuit is responsive to an activation signal, to sweep the control signal and thereby aid to acquire lock in the phase locked loop. Simultaneous increase in the amplitude of the reference frequency input signal is provided during sweep of the control signal. The increase in amplitude may be provided by a variable attenuation circuit that is coupled between a phase locked loop input signal and the reference frequency input signal, and that is also responsive to the activation signal. The variable attenuation circuit, preferably in the form of a tunable resonant tank notch circuit, attenuates the phase locked loop input signal after the sweep of the control signal, to thereby decrease the amplitude of the reference frequency input signal after the sweep of the control signal. Thus, the amplitude of the reference frequency input signal is higher during the sweep of the control signal, to thereby temporarily widen the bandwidth of the phase locked loop, while temporarily sweeping the control signal.
REFERENCES:
patent: 5498998 (1996-03-01), Gehrke et al.
patent: 5651035 (1997-07-01), Tozun et al.
Kroupa, "Frequency Synthesis--Theory, Design & Applications", John Wiley & Sons, 1973, pp. 171-176.
Gardner, "Phaselock Techniques, Second Edition", John Wiley & Sons, 1979, pp. 53-91.
Adolphe Eunja
Callahan Timothy P.
Ericsson Inc.
LandOfFree
Attenuating systems and methods for acquiring synchronization in does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Attenuating systems and methods for acquiring synchronization in, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Attenuating systems and methods for acquiring synchronization in will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-565471