Abstract: An accelerometer senses a machine's vibration resulting from unbalance of its internal rotors and outputs an electrical signal which is then conditioned by means of an amplifier and uniform level filter. The resulting output signal has individual vibration (frequency) components which are adjusted to match the machine's specified vibration limit extending over each of the rotors' frequency range to achieve a uniform level. A storage oscilloscope is employed to display the conditioned signal.By utilizing the uniform level filter a normal operating band for the machine can be specified in terms of oscilloscope divisions regardless of the machine's operating frequencies. When a signal exceeds the specified band on the oscilloscope the rotor causing the excessive vibration may then be determined by analyzing the individual components. Utilizing relatively uncomplicated electronics, a limit exceedance warning may also be incorporated.