SIGNAL-BIASED MLS-BASED HEARING-AID FREQUENCY-RESPONSE MEASUREMENT

Two new signal-biased maximum-length-sequence (MLS)-based frequency re sponse measurements have been developed for the electroacoustic charac terization of hearing aids. These methods measure the frequency respon se of an automatic signal-processing (ASP) hearing aid when various ty pes of bias signals are present. Such biased measurements can be used to identify the type of processing used by a hearing aid. Two methods of signal biasing are presented: subtractive and adaptive. Both method s apply a biasing signal and a low-level MLS simultaneously. The adapt ive method requires that the biasing signal be periodic; for the subtr active method, any bias signal may be used. Measurement results are pr esented for two ASP hearing aids.