REMANENT STATE NOISE MEASUREMENTS ON MAGNETIC RECORDING MEDIA

Media noise has been investigated as a function of both the isothermal remanent magnetisation (IRM) and DC-demagnetisation (DCD) processes o n a modified audio transport. Captured noise time series from a given remanent state has been analysed for spectral content using signal pro cessing software. These noise spectra display changes in magnetic micr ostructure of the tested media with remanent state. Measurements have been made on a range of commercial and laboratory produced tapes. The paper concentrates on examples of commercial samples which have been c hosen to indicate various noise characteristics. Conventional media us ually show similar features, but changes in remanent state noise has b een observed in tapes for new formats and in recent manufacture of con ventional formats. This indicates changes in magnetic microstructure a ssociated with new particles and dispersion techniques. (C) 1998 Elsev ier Science B.V. All rights reserved.