This thesis presents the design and simulation of a digital frequency demodulator applied to a Michelson interferometer-based scanning laser vibrometer. The laser vibrometer is a velocity transducer that produces frequency-modulated signals that have traditionally been optically or electronically frequency shifted from baseband to an intermediate frequency. This shifting produces a narrow band modulation that may be demodulated with standard analog frequency demodulators. This thesis proposes replacing these traditional optics or electronic circuits with a digital frequency demodulator. The optics of a laser vibrometer can be constructed such that a near-perfect baseband quadrature representation is available for the frequency modulation. It will be seen that this representation is well suited for use by a digital frequency demodulator. This thesis applies the arctangent-type digital frequency demodulator to a laser vibrometer and demonstrates its superiority over other digital demodulation techniques. In addition some specialized signal processing to handle the special case of sine-dwell vibration tests is presented. / Master of Science