Frequency Response

A graph of a system′s response to a different frequency input signals.

An important parameter in specifying the performance of measuring or recording devices (e.g. accelerometers or tape recorders). Ideally, the frequency response of a transducer or recorder should be linear over the range of frequencies likely to be present in the physical quantity being investigated (e.g. bearing acceleration or waveheight). In other words, the voltage produced by the transducer for a given size of input (acceleration, displacement, etc.) should be independent of frequency. In practice, transducers have to be carefully chosen so that their frequency responses are good enough for the measurement application. For example, piezoelectric accelerometers would not be used for building vibration applications because they are not sensitive to low frequency vibration.

SystemFrequency Response
Public Switched Telephone Network300Hz to 3kHz
AM Radio100Hz to 5kHz
FM Radio50Hz to 15kHz
Consumer stereo system20Hz to 20kHz
Professional audio equipment5Hz to 24kHz

The frequency response of a system is usually measured with an input signal that is -20dB below full scale.

See also: Frequency Response Function.

Previous PageView links to and from this pageNext Page

Subjects: Noise & Vibration