Читать книгу Engineering Acoustics - Malcolm J. Crocker - Страница 27

Using the mathematical property e^jθ = cos θ + j sin θ, we can write

. Then, Eq. (1.6) is

The impulse response and its Fourier spectrum are shown in Figure 1.7. We notice that replacing α and λ by the corresponding values in terms of the stiffness K, mass M, and damping constant R, of the damped mass‐spring system, the Fourier spectrum becomes (compare with Eq. (2.18))

Figure 1.7 Time and frequency domain representations of the transient response of the impulse response of a damped vibration of a mass‐spring system.