DC Blocking

Direct conversion receivers often impose a direct current (DC) bias on the in-phase and quadrature components of the signal. DC bias can degrade BER performance for QAM and PSK systems. By enabling DC blocking, you can reduce DC bias in the I/Q channels of a received complex signal. The reduced DC bias better enables robust receiver processing. In addition, this reduction enables you to focus on designing the baseband algorithm without worrying about DC bias that is introduced by the analog front end. DC blocking for the AD9361 RF chip on the USRP®[1] E3xx embedded series radio hardware takes place on the RF transceiver and can be implemented at baseband or RF. For more information, see Baseband DC Offset Calibration and Baseband DC Offset Tracking in Analog Devices® AD9364 Reference Manual - UG-673.

DC Blocking on Receiver Block

DC blocking at RF and baseband is on by default. To disable these parameters, on the Advanced tab of the E3xx Receiver or E3xx Transmitter block masks, clear Enable RF DC correction or Enable baseband DC correction.

DC Blocking in Receiver System Object

DC blocking at RF and baseband is on by default. To see these properties, set the ShowAdvancedProperties property to true. To disable either of these properties, set the corresponding properties to false. For example:

rx = sdrrx('E3xx');
rx.EnableRFDCCorrection = false;
rx.EnableBasebandDCCorrection = false;

See Also





[1] Analog Devices AD9364 Reference Manual - UG-673.

[1] USRP, USRP2, UHD, and Ettus Research are trademarks of National Instruments Corp.