Pressure pulsations excited by a centrifugal compressor or fan at blade passing frequency may cause severe noise and vibrations in piping systems. Therefore, the practical evaluation method of pressure pulsations is strongly required. In this study, a one-dimensional excitation source model for a compressor was proposed based on the equation of motion. An experiment was performed for the validation of this model. As a result, the relation of the maximum pressure amplitude in piping systems to the location of the excitation source under resonant conditions can be evaluated by introducing the equivalent resistance of the compressor and that of piping systems. The role of the system resistance to the response of pressure pulsations is discussed in detail.