The present invention provides a transmitter for an electromagnetic survey system for transmitting signals having a waveform comprising at least a first pulse and a second pulse, wherein the first and second pulses are different in at least one of shape and power. Embodiments of the invention enable combining various distinct pulses that may have been optimized for respective applications to form a transmitter waveform for conducting a geological survey. In effect, the embodiments of the present invention provides an EM system that is substantially equivalent to multiple EM systems operating at the same time for collecting data in relation to different aspects of the geology of interest. Advantageously, the benefits of the present invention can be obtained without the undesirable complexity and cost associated with the simultaneous deployment of multiple EM systems.