Models 4001A and 4003A are 4 MHz sweep function generators. Model 4003A has an added feature of a 20 MHz digital counter. The function generator generates sinusoidal, triangular, ramp, square, and pulse waveforms. The type of function is selectable through a rotary switch. The frequency is settable from 0.5 Hz to 4 MHz of the function with range selector switch and the frequency control knob for variable adjustments with multiplication factor of 0.04 to 4.0 of the selected frequency range.