US 12,261,637 B2
Method and apparatus for measuring and cancelling local oscillator feedthrough using an observation receiver
Kameran Azadet, San Ramon, CA (US); and Marc Jan Georges Tiebout, Finkenstein (AT)
Assigned to Intel Corporation, Santa Clara, CA (US)
Filed by Intel Corporation, Santa Clara, CA (US)
Filed on Jun. 25, 2021, as Appl. No. 17/358,040.
Prior Publication US 2022/0416822 A1, Dec. 29, 2022
Int. Cl. H04B 1/04 (2006.01); H04L 5/12 (2006.01); H04L 25/06 (2006.01)
CPC H04B 1/0475 (2013.01) [H04B 2001/0433 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An apparatus configured to cancel local oscillator feedthrough (LOFT), comprising:
a transmitter configured to process a transmit signal, the transmitter including a first mixer configured to mix the transmit signal with a first local oscillator signal;
an observation receiver configured to receive a fraction of a power of the transmit signal as a feedback signal and process the feedback signal, the receiver including a second mixer configured to mix the feedback signal with a second local oscillator signal;
a LOFT correction estimation circuitry configured to determine a DC offset to be added to the transmit signal to cancel LOFT at the first mixer in the transmitter based on measurements on outputs of the second mixer; and
a LOFT correction circuitry configured to add the DC offset to the transmit signal,
wherein the LOFT correction estimation circuitry is configured to determine the DC offset based on several measurements obtained by varying the DC offset and/or a phase shift in the second local oscillator signal in the observation receiver.