DISTORTION IMMUNITY OF MLS-DERIVED IMPULSE-RESPONSE MEASUREMENTS

Maximum-length-sequence (MLS) measurement of system impulse responses offers a potential enhancement in error immunity over periodic impulse testing, although care must be exercised in setting the MLS excitatio n amplitude in order to realize this potential. The effects of nonline arity in MLS measurement are studied, in particular the way in which i mpulse response errors due to nonlinearity are distributed across the measurement period. The consequences of such errors in cumulative spec tral display plots are also investigated. Finally inverse-repeat seque nces (IRS) are shown to have complete immunity to even-order nonlinear ity while maintaining many of the advantages of MLS.