A number of physical limitations are inherent to analogue recording media, and for this reason compromises have tobe accepted. In order to widen the frequency range of recordings, mechanical, optical, and magnetic recording haveused pre-emphasis at recording which is then suppressed again by a complementary de-emphasis at replay. Thepaper traces the parallel development in all three fields of analog recording.The paper traces the historically parallel and gradual realization in the different domains of the possibility to performtrade-offs between signal-to-noise ratio, dynamic range and frequency range by suitable combination of preemphasisand de-emphasis of the frequency response of the transducers.For each of the domains a discussion is given of the physical limitations of the media which give rise to the need forpre- and de-emphasis, and typical functions will be presented. The consequences are discussed of mismatch betweenthe pre-emphasis used for recording and the de-emphasis, as well as a historical view of contemporary regrets thatstandardisation had not progressed further. At least in the optical field the results presented to the general publicwere worse than technically possible at the time.
展开▼
