Apparatus for shifting the phase of transmitter and receiver analog baseband signals in an NMR system

Apparatus for shifting the phase of a phase-quadrature signal pair, in at least one of the transmitter and receiver of an NMR system, uses a circuit for shifting the phase of each of the pair of signals by a substantially similar amount responsive to a control signal, and a microcontroller for programmably establishing the control signal data to provide a desired phase shift. Typically, the control signal is of digital data nature and the phase shifter operates to shift signal phase through an angle equal to a selected multiple N of a basic angle. The basic angle is selected such that a plurality of equal angle increments are established by the resolving properties of the data signal. A plurality of phase shifters can be controlled by a single microcontroller.