Patent ID: 6566921
Filing Date: 2003-05-20
Classification: H03L

Abstract:
An apparatus for dynamically making fine adjustments to a frequency output of a multistage frequency synthesizer, the apparatus comprising:a first stage of the multistage frequency synthesizer with an input and an output; one or more intermediate stages, wherein each intermediate stage receives an input from a previous stage and includes a variable frequency divider that generates an output to a next stage; and a final stage with an input from a last intermediate stage and generating the frequency output of the multistage frequency synthesizer, wherein the first stage comprises a first frequency synthesizer, wherein a reference frequency is received at an input to the first frequency synthesizer, and further comprising a first variable frequency divider, wherein the first variable frequency divider receives a signal from the first frequency synthesizer and the output of the first stage is the output of the first variable frequency divider, and wherein the first frequency synthesizer in the first stage of the multistage frequency synthesizer further comprises: a first fixed frequency divider with an input and an output, wherein the input of the first fixed frequency divider is a reference frequency, fref, where the reference frequency is the input to the multistage frequency synthesizer; a forward path in a phase locked loop with a first input, a second input, and an output, wherein the first input of the forward path in a phase locked loop is the output of the first fixed frequency divider; and a second fixed frequency divider with an input and an output, wherein the input of the second fixed frequency divider is connected to the output of the forward path in a phased lock loop and the output of the second fixed frequency divider is connected to the second input of the forward path of a phase lock loop; and the output of the forward path in the phase lock loop is the output of the first frequency synthesizer.