A test-signal generator for low-frequency instrumentation

An instrument for generating simultaneous sinusoidal test signals m the range of 1–32 Hz for EEG equipment checkout procedures is described. A composite signal is produced by a method that separates the functions of waveform generation and control of output frequencies at which that waveform appears. The general technique may be applicable in a number of situations involving low-frequency instrumentation, as with other types of physiological monitoring. Possibilities and methods for elaboration or modification of the circuit are suggested.