AES E-Library

Tape Flux Measurement Revisited

Analog magnetic recording standards specify recorded signal magnitude in terms of short-circuit flux per unit track width, called fluxivity. Two flux measurement methods are standardized: a direct ac method using a high-efficiency head (AES7/ANSI Standard S4.6); and a transfer-to-dc method using a fluxmeter (German Standard DIN 45 520).: A transfer-to-dc measurement made in the 1950s is used to calibrate the fluxivity of German calibration tapes. When these tapes are measured by the direct ac method, the fluxivity is 10% less than the stated value. Thus the 1950s German transfer-to-dc measurement was 10% more sensitive than the direct ac measurement.: A new comparison of the two measurement methods shows that they actually have the same sensitivity within an experimental error of about 0.5%. Thus we conclude that the German measurement in the 1950s must have had a 10% error, and that the fluxivity on all of the calibration tapes based on the old German measurement is 10% less than the stated value tapes identified as 320 nWb/m are actually 288 nWb/m.

Authors: McKnight, John G.; Cortez, Benito E.; McKnight, Jeffrey A.
Affiliation: Magnetic Reference Laboratory, Mountain View, CA
AES Convention:105 (September 1998) Paper Number:4802 Import into BibTeX
Subject:Instrumentation and Measurement

Click to purchase paper or login as an AES member. If your company or school subscribes to the E-Library then switch to the institutional version. If you are not an AES member and would like to subscribe to the E-Library then Join the AES!

This paper costs $20 for non-members, $5 for AES members and is free for E-Library subscribers.

Learn more about the AES E-Library

E-Library Location: (CD aes14)   /pp9798/pp9809/4692.pdf

Start a discussion about this paper!