US 7,365,580 B2 | ||
System and method for jitter control | ||
Kenneth William Martin, Toronto (Canada); and David J. Cassan, Toronto (Canada) | ||
Assigned to Snowbush Inc., Toronto (Canada) | ||
Filed on Sep. 30, 2005, as Appl. No. 11/239,200. | ||
Claims priority of provisional application 60/644994, filed on Jan. 21, 2005. | ||
Prior Publication US 2006/0164132 A1, Jul. 27, 2006 | ||
Int. Cl. H03L 7/06 (2006.01) |
U.S. Cl. 327—156 [327/147] | 56 Claims |
1. A device for synthesizing a frequency comprising:
a forward portion having a reference input for receiving a reference clock signal and a feedback input for receiving a feedback
signal; said forward portion having a forward portion output; said forward portion operable to generate an oscillating signal
based on a phase or a frequency or a phase and frequency difference between said reference and feedback inputs; said oscillating
signal being delivered from said forward portion output;
a delta-sigma modulator (DSM) having a DSM clock input for receiving a first driving clock signal; said DSM having a DSM input
for receiving a high resolution input signal; said first driving clock signal having a frequency greater than said reference
clock signal; said DSM having a DSM output; said DSM operable to generate a quantized bit-stream signal from said high resolution
input signal that is delivered from said DSM output;
a fractional divider having a fractional divider input connected to said forward portion output for receiving said oscillating
signal; said fractional divider having a control input connected to said DSM output for receiving said bit-stream signal;
said fractional divider having a fractional divider driving clock input for receiving a second driving clock signal; said
fractional divider having a fractional divider output for delivering a fractionally divided signal; said fractional divider
operable, according to said bit-stream signal, to generate said fractionally divided signal having a frequency that is a fraction
of said oscillating signal's frequency; and,
a feedback integer divider (FID) having a first FID input for receiving a representation of an integer value; said FID having
a second FID input connected to said fractional divider output for receiving said fractionally divided signal; said FID having
an FID output connected to said feedback input; said FID operable to frequency divide said fractionally divided signal by
said integer value in order to generate said feedback signal.
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