US 11,811,415 B2
Direct digital synthesizer with frequency correction
Shailendra Srinivas, Nashua, NH (US); Joseph D. Cali, Merrimack, NH (US); and Steven E. Turner, Nashua, NH (US)
Assigned to BAE Systems Information and Electronic Systems Integration Inc., Nashua, NH (US)
Filed by BAE Systems Information and Electronic Systems Integration Inc., Nashua, NH (US)
Filed on Jun. 18, 2021, as Appl. No. 17/351,529.
Prior Publication US 2022/0407524 A1, Dec. 22, 2022
Int. Cl. H03L 7/093 (2006.01); H03L 7/08 (2006.01); G06F 1/08 (2006.01); G06F 1/03 (2006.01); G06F 1/02 (2006.01); H04L 27/00 (2006.01)
CPC H03L 7/093 (2013.01) [G06F 1/022 (2013.01); G06F 1/0321 (2013.01); G06F 1/08 (2013.01); H03L 7/08 (2013.01); H03L 2207/50 (2013.01); H04L 2027/0065 (2013.01); H04L 2027/0073 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A direct digital synthesizer (DDS) circuit, comprising:
a first input to receive a first fixed frequency clock signal having a first frequency;
a second input to receive a second fixed frequency clock signal having a second frequency that is lower than the first frequency;
an output to provide an output frequency, the output frequency based at least in part on a frequency control word; and
a frequency correction circuit having a first input to receive the first fixed frequency clock signal, a second input to receive the second fixed frequency clock signal, and a third input to receive the frequency control word, and an output to provide a frequency error of the first fixed frequency clock signal, the frequency error determined using a ratio of the first fixed frequency clock signal and the second fixed frequency clock signal and the frequency control word;
wherein the frequency correction circuit is configured to correct a frequency error and/or frequency wander of the first fixed frequency clock signal by summing an accumulated phase to the first fixed frequency clock, wherein the frequency error and/or frequency wander is determined based on a known fixed period of the second fixed frequency clock signal.