Record head saturation in AC bias recording

The head core saturation problem in ac bias audio recording is analyzed. An approximate expression, which should be satisfied in order to avoid head saturation, is obtained in terms of head core saturation flux density B
m
, gap length g, tape coercivity H
c
, and tape coating thickness δ. Experimental verification is obtained by using various values of B
m
,g,H
c
, and δ.