Oscillators – Automatic frequency stabilization using a phase or frequency... – Plural oscillators controlled
Patent
1998-06-24
2000-04-18
Pascal, Robert
Oscillators
Automatic frequency stabilization using a phase or frequency...
Plural oscillators controlled
331 25, 327156, H03L 700
Patent
active
060520345
ABSTRACT:
An all-digital phase-locked loop (ADPLL) device includes a primary ADPLL circuit and a controller which allow an in-phase output signal to be generated even when the incoming reference signal is lost. The primary ADPLL loop includes a phase detector, a digital loop filter, a first digital control oscillator (DCO) for generating a loop signal which is phase-locked to a received reference signal, and a frequency divider. The controller generates control signals to be used by a secondary DCO or the first DCO to generate a synchronized system output signal. The controller includes an accumulator which accumulates the number of phase-hopping events performed by the first DCO for a certain time period, a first-in-first-out (FIFO) buffer which stores a number of consecutive phase-hopping samples from the accumulator, and a calculator for determining an average of the consecutive values stored in the FIFO buffer. The control signals generated by the controller may be used by the secondary DCO to achieve a synchronized system output signal during both normal and holdover operating modes, or may be used by a single DCO only during the holdover mode.
REFERENCES:
patent: 4972442 (1990-11-01), Steierman
patent: 5043677 (1991-08-01), Tomassetti et al.
patent: 5072195 (1991-12-01), Graham et al.
patent: 5485484 (1996-01-01), Williams et al.
patent: 5572167 (1996-11-01), Alder et al.
patent: 5675620 (1997-10-01), Chen
patent: 5883533 (1999-03-01), Matsuda et al.
Wang Bor-Min
Yang Shu-Fa
Choe Henry
Industrial Technology Research Institute
Pascal Robert
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