A simple method for swept frequency response testing

This paper deals with the design of simple, and relatively inexpensive, dedicated equipment which is tailored to test a 6th-order analogue pitch rate compensation unit using sweep frequencies and return signal processing to estimate gain and phase characteristics. It is shown that the test time required for an optimum swept frequency test compares very favourably with the total test time needed using either automatic test equipment or manual steady state testing at a few frequencies. The test technique provides a `hard-copy¿ signature of the system under test in a form which has found particular favour for maintenance purposes in such diversified areas as electronic circuits, aircraft structures, and air breathing systems. The technique should be regarded as complementary to more flexible frequency domain test methods in forming the complete inventory of equipment needed during system life-cycle testing.