Patent ID: 7042970

Claim:
A phase lock loop apparatus having a reference signal input and an oscillator output, the apparatus comprising: a) a filter element having an input and an output, b) a controllable oscillator device having an input coupled to the output of the filter element and an output adapted to produce the oscillator output, c) a frequency dividing element having a first input coupled to the output of the oscillator output and an output for producing a feedback loop signal, d) a charge pump having two inputs and an output adapted to provide a phase difference signal as an input to the filter element, and e) a phase detection apparatus comprising: i) a first storage element having a clock input coupled to the reference signal input, a reset input and an output, ii) a second storage element having a clock input coupled to the loop feedback signal, a reset input and an output, iii) a logic element for logically combining the outputs of the first and second storage elements, the logic element having two inputs coupled to the outputs of the two storage elements and an output coupled to the reset input of the first storage element and the reset input of the second storage element, and iv) a stretching element for effecting a stretching of the trailing edge of the output of one of the first and second storage elements relative to the other storage element, and wherein the outputs of the first and second storage elements are coupled to the inputs of the charge pump.