The Mössbauer Drive Unit MRG-500 is designed for controlling the Mössbauer Velocity Trans­ducers MA-260 and MVT-1000. Together with one these transducers, it forms a complete Mössbauer system, providing a precise g-source motion during Mössbauer effect measurements. A built-in digital function generator supplies the reference signal, which determines the waveform of the source motion. With SINE and TRIANGLE (CONSTANT ACCELERA­TION) the two most frequently used waveforms are available. They are stored digitally and are converted by means of a D/A converter to a highly precise analog signal, which is fed to the control circuit. Besides the analog signal, the function generator provides digital control pul­ses (START/CHANNEL ADVANCE), which can be used to synchronise a Multichannel Analyser. The ideal waveform and the deviation of the actual source motion from it can be monitored using the measuring signals available at the analog MONI­TOR and ERROR outputs.