US 9,813,267 B1
Communicaton unit, circuit for quadrature sampling error estimation and compensation and method therefor
Frederic Georges-Ferdinand Barghi, Le Rouret (FR)
Assigned to NXP USA, Inc., Austin, TX (US)
Filed by FREESCALE SEMICONDUCTOR, INC., Austin, TX (US)
Filed on Nov. 3, 2016, as Appl. No. 15/342,198.
Claims priority of application No. 16305619 (EP), filed on May 27, 2016.
Int. Cl. H04B 1/38 (2015.01); H04L 5/16 (2006.01); H04L 27/00 (2006.01); H04L 27/26 (2006.01); H04B 17/336 (2015.01); H04L 25/02 (2006.01); H04L 7/00 (2006.01)
CPC H04L 27/0002 (2013.01) [H04B 17/336 (2015.01); H04L 7/0025 (2013.01); H04L 7/0041 (2013.01); H04L 25/0204 (2013.01); H04L 27/2626 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A communication unit comprises:
a modem configured to generate a first test digital quadrature signal;
a transmitter coupled to the modem and comprising at least one digital to analog converter, DAC, configured to convert the first test digital quadrature signal to a first test analog quadrature signal;
a receiver comprising at least one analog to digital converter, ADC, configured to receive the first test analog quadrature signal via a first quadrature path and convert to a first received test digital quadrature signal; and
an analog loop back path that connects the transmitter to the receiver;
wherein the transmitter is further configured to generate a second test analog quadrature signal; and the receiver is further configured to receive the second test analog quadrature signal from the transmitter via a second quadrature path and convert to a second received test digital signal;
wherein the modem is configured to:
estimate a first sampling error performance associated with the first quadrature path from the first received test digital quadrature signal;
estimate a second sampling error performance associated with the second quadrature path from the second received test digital quadrature signal; and
generate at least one sampling error compensation signal based on the first estimated performance and second estimated performance to be applied to at least one of the receiver and transmitter.