A first timing reference signal and a second timing reference signal are sent to a memory device. The second timing reference signal has approximately a quadrature phase relationship with respect to the first timing reference signal. A plurality of serial data patterns are received from the memory device. The transitions of the first timing reference and the second timing reference determining when transitions occur between the bits of the plurality of data patterns. Timing indicators associated with when received transitions occur between the bits of the plurality of data patterns are received from the memory device. The timing indicators are each measured using a single sampler. Based on the timing indicators, a first duty cycle adjustment for the first timing reference signal, a second duty cycle adjustment for the second timing reference signal, and a quadrature phase adjustment are determined and applied.