Patent ID: 7243255

Claim:
An apparatus comprising a restartable clock configured to instantaneously start generating and instantaneously cease generating a restartable clocking signal, the restartable clock including: an oscillating source configured to continuously generate a plurality of oscillating signals regardless of whether or not the clocking signal is being generated; and a restartable clocking signal generator configured to generate the restartable clocking signal based on said oscillating signals and configured to asynchronously instantaneously restart in response to one or more control signals; wherein the restartable clocking signal generator includes: a quadruple sample and hold element coupled to the oscillating source and configured to receive said oscillating signals and to generate captured oscillating signals; a plurality of four quadrant multipliers, coupled to the quadruple sample and hold element for receiving said captured oscillating signals and to the oscillating source for receiving said oscillating signals, configured to generate a plurality of sinusoidal signals; and differential circuitry, coupled to the plurality of four quadrant multipliers, being responsive to said control signals and configured to generate the restartable clocking signal based on the sinusoidal signals.