• Half Speed Recording with Ferrite Heads and High Energy Tape

      Price, R. L.; Youngquist, R. J.; Minnesota Mining and Manufacturing Co. (International Foundation for Telemetering, 1971-09)
      This paper describes the results obtained with several new techniques which are being used to extend the frequency bandwidth limits and the signal to noise ratios of instrumentation magnetic tape record/ reproduce systems. During the past decade, wideband magnetic tape information recording densities have advanced in several stages to the currently used 60 to 80 micro inch wavelengths. The new techniques described in this paper now make it practical to record and reproduce wavelengths in the order of 30 to 40 micro inches. This results in a frequency bandwidth of 1.0 MHz at a tape speed of 30 inches per second. In comparison with present wideband systems this means an improvement of 2X in bandwidth, or a reduction of tape speed by one half is now possible while maintaining approximately 20 dB broadband signal to noise ratio with a track width of .025 inches. This width provides 28 tracks per inch of tape width. This improved performance has been obtained by combining recent improvements in "High Energy" tape, narrow gap ferrite record heads and ferrite reproduce heads. Using a systems approach, electronic signal processing circuits have been developed which coordinate these improvements in tape and heads, resulting in optimized "high performance" record/ reproduce systems.