US 4,792,768 AGranted

Fast frequency settling signal generator utilizing a frequency locked-loop

AssigneeHewlett-Packard Company

InventorsRaymond L. Fried, David M. Hoover

Life of this patent

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Abstract

Signal generating apparatus including a phase-locked loop (PLL) utilizing a voltage-controlled oscillator (VCO) and a frequency-locked loop (FLL) to generate an output signal whose frequency jumps from one value to another in a selectable sequence. The signal generator further includes a delay line discriminator to provide an error signal to compensate for FM noise in the VCO. The frequency-locked loop is implemented by utilizing the FM error signal from the delay line discriminator to stabilize the center frequency of the VCO. The inherent wide bandwidth of the FLL provides a fast settling time when the loop is switched to a new frequency. In a learn mode, the gain parameters of the loop are determined and stored each of a plurality of frequencies. The gain parameters and a corresponding pretune signal for each selected frequencies are the applied to the FLL in a selectable sequence to provide a fast-switching signal generator.

Claims5

Dependent claims

A frequency-locked loop signal generator for generating an output signal having a controllably selectable frequency, comprising:

voltage controlled oscillator means for generating an output signal having a frequency that is controllably variable over a predetermined frequency range;
delay line voltage discriminator means coupled to the output of said voltage controlled oscillator means for detecting a change in the frequency of said output signal and providing an error signal having a magnitude representing said frequency change, said error signal being coupled to said voltage controlled oscillator means to controllably vary the frequency of said output signal so as to reduce said frequency change;
pretune means coupled to said voltage controlled oscillator means for providing a pretune signal, said voltage controlled oscillator means responsive to said pretune signal;
memory means coupled to said pretune means for storing pretune information indicative of the value of said pretune signal required by said voltage controlled oscillator means to generate each output signal frequency in said predetermined frequency range;
and
control means responsive to input information for generating a frequency select signal indicating the selected output frequency and for supplying the pretune information corresponding to said selected output frequency to said pretune means.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/118,118Filed 6 Nov 1987
Granted: 20 Dec 1988
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

H03L 7/113
For assuring initial synchronisation or for broadening the capture range: using frequency discriminator
H03L 7/189
Using means for coarse tuning the voltage controlled oscillator of the loop: comprising a D/A converter for generating a coarse tuning voltage
H03L 7/197
Using a frequency divider or counter in the loop: a time difference being used for locking the loop, the counter counting between numbers which…
H03L
Automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or