Wireless transceiver with tx/fbrx sequential qmc calibration using separate/shared plls

Abstract

A direct conversion wireless transceiver is configured for TX/FBRX sequential QMC calibration (coefficient generation) using separate/shared PLLs. A TX path includes a TX LO driving upconversion, and an FBRX path includes an RX LO driving downconversion. TX/RX digital compensators include TX/RX QMC compensators that perform QMC compensation to compensate for IQ mismatch based on TX/RX QMC filter coefficients, and QMC calibration to calibrate the TX/RX QMC filter coefficients based on a QMC calibration procedure. The TX LO signal source is a TX PLL, and the RX LO signal source is selectively the TX PLL or a separate RX PLL. A QMC controller perform QMC calibration to generate calibrated TX/FBRX QMC filter coefficients, including: disconnecting the TX PLL from, and connecting the FBRX PLL to, the RX LO; generating calibrated TX QMC filter coefficients; generating calibrated FBRX QMC filter coefficients; disconnecting the FBRX PLL from, and connecting the TX PLL to, the RX LO; generating re-calibrated FBRX QMC filter coefficients. The TX digital compensator can be configured to perform DPD compensation (after QMC compensation).

1 . A wireless transceiver circuit, comprising
 a transmit (TX) signal chain including
 an IQ modulator, and 
 an RF upconverter including a TX mixer driven by a TX local oscillator (TX LO), 
 a TX digital compensator, including a TX QMC (IQ mismatch) compensator configured to
 in QMC compensation mode, compensate for IQ mismatch in the IQ modulator based on TX QMC filter coefficients, 
 in QMC calibration mode, calibrate the TX QMC filter coefficients based on a QMC calibration procedure; 
 
   a feedback receive (FBRX) signal chain including
 an IQ demodulator, and 
 an RF downconverter including an RX mixer driven by a FBRX local oscillator (RX LO), 
 an RX digital compensator, including an QMC (IQ mismatch) compensator configured to
 in QMC compensation mode, compensate for IQ mismatch in the IQ demodulator based on RX QMC filter coefficients, 
 in QMC calibration mode, calibrate the FBRX QMC filter coefficients based on a QMC calibration procedure; 
 
   a TX PLL signal source connected to the TX LO, and selectively connectable to the RX mixer;   an FBRX PLL signal source selectively connectable to the RX LO;   a QMC controller configured to perform the QMC calibration procedure to generate calibrated TX and FBRX QMC filter coefficients, including
 disconnecting the TX PLL from, and connecting the FBRX PLL to, the RX LO; 
 generating calibrated TX QMC filter coefficients; 
 generating calibrated FBRX QMC filter coefficients; 
 disconnecting the FBRX PLL from, and connecting the TX PLL to, the RX LO; 
 generating re-calibrated FBRX QMC filter coefficients. 
   
     
     
         2 . The wireless transceiver circuit of  claim 1 , wherein the TX digital compensator further includes a DPD (digital pre-distortion) compensator.