Abstract: Model DHF-1 variable-phase versatile function generator is an apparatus in which positive or negative slope and pulse width could be adjusted continually. The versatile function generator can produce continuous waveforms such as sinusoidal, square, triangular, trapezoidal, positive and negative saw-tooth etc. It can also produce ramp, step waves and single-cycle arbitrary wave independently adjustable to both positive or negative slope and pulse width. The versatile function generator is specially designed as a programmer for dynamic triaxial closed-loop servo-controlled testing systems. It may be specifically applied to the following tests: tensile, fracture mechanics, low-cycled fatigue, fatigue, stress relaxation ,creep, high-velocity shock and vibration.