Measurements on non linear microphones by a speech-like signal

Carbon microphones are non linear and time varying devices, so that their response curve widely depends on the type of excitation signal, To carry our measurements well correlated with the real performance, the transducers must be excitated by a signal as close as possible to real voice. For the artificial signals already proposed, the attention was practically concentrated on both waveform behaviour and long-time characteristics. The speech-like signal here presented, in addition to previous items, also accounts for syllabic-rate of real speech, showing an envelope very similar to real voices. Sensitivity frequency characteristics and distortion measured on 4 microphones (3 carbon and 1 linear) using this signal are presented.