Method and an apparatus for detecting tape speed of recording

摘要

In a helical scanning type VTR utilizing a tracking error signal method using four kinds of pilot signals, a tape speed at recording is detected by comparing a threshold level value with the level difference between the outputs before and after the change in the two kinds reference signals which are supplied to a multiplying circuit within one magnetic head scanning period, the multiplying circuit obtaining sum and difference frequency signals between a reproduced pilot signal and the reference signal.