This article presents the use of the analytic signal procedure for processing the large volume of structural vibration data recorded in forced vibration tests. The analytic signal facilitates the computationally laborious task of extracting the steady-state amplitude for each response measure of interest from the recorded accelerations throughout the building at each operated frequency of the forced vibration source. The implementation of the signal processing procedure introduced here is illustrated in deriving the acceleration-frequency response curves from the forced vibration test of the first permanently instrumented building in Turkey. This reinforced concrete building, subsequently strengthened with cast-in-place reinforced concrete infill shear walls, is located in close proximity to the North Anatolian Fault. Later, system identification of the building yields the in situ structural system dynamic properties for the first translational and torsional vibration modes, which are compared with those identified from the ambient vibrations of the building recorded following its forced vibration test. The analytic signal procedure is a convenient tool for the rapid and correct derivation for mode shapes and associated frequencies and damping ratios from forced vibration testing of structural systems.