Lucent Technologies Inc.

Peter R Kinget

David Esley Long

Robert C Melville

Venugopal Gopinathan

Nagendra Krishnapura

We have recognized that the design and programming complexity associated with conventional frequency divider configurations can be significantly reduced by a configuration of functionally identical, modular division blocks which are each able to swallow at least one input cycle of a input signal by switching to a phase-lagging output once per output cycle. The number of input pulses swallowed when a division block switches to a lagging waveform is a direct function of the division block's location in the chain, such that the number of input cycles swallowed per phase switch increases moving down the chain of division blocks. Therefore, the chain of division blocks has discrete elements for achieving most-significant to least-significant division factor increments. The total number of input cycles swallowed by the chain of division blocks equals the sum of cycles swallowed by each division block. Thus, to achieve a variety of division factors, a controller controls which, if any, division blocks switch to a phase-lagging waveform once each output cycle. Furthermore, we have recognized that the range of division factors which may be achieved by the chain of frequency dividers can be increased by controlling at least one division block to switch to a phase-leading waveform once each output cycle.

Programmable frequency divider

Two or more equal amplitude periodic output signals which are mutually shifted in phase by an integer fraction of 360 degrees, such as 90&deg;, are generated by injection locking a ring type oscillator circuit arrangement with a periodic low phase noise signal source. More particularly, a first ring oscillator is injection locked by a low phase noise signal source, one having a noise characteristic which meets the GSM radio standard of at least &minus;132 dBc/Hz at a 3 MHz offset. An identical second ring oscillator is then driven with the output of the first ring oscillator. In one circuit configuration, an even numbered, e.g., a four stage ring oscillator is injection locked to a low-phase noise oscillator having a predetermined noise specification which is application specific and wherein a second even numbered stage, e.g., a four stage ring oscillator is coupled to the first ring oscillator. In a second circuit configuration, a first odd numbered, e.g., three stage ring oscillator, is injection locked to a low phase-noise oscillator and a second odd numbered, e.g., three stage ring oscillator, is injection locked to the first ring oscillator.

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Aliso Viejo, CA, United States of America

Peter R Kinget