MAGNETIC RECORDING/REPRODUCING DRUM DEVICE

摘要

PURPOSE:To improve the balance of a rotor by supplying the wave signal to be modulated and having its modulated erasion signal frequency to the rotor part from a fixed drum part and detecting the wave of said wave signal by the rotor part to give the switch control to the reproduction signal supplied from a rotary head. CONSTITUTION:The erasion signal outputted from an erasion signal oscillating circuit 81 is supplied to an AM modulation circuit 84 to undergo the AM modulation there by a servo signal for output. This modulation output is supplied to an input side coil 71a of a rotary transformer 71 for erasion signal and then sent to the inside of a rotor part 52 by the electromagnetic induction of the coil 71a and an output side coil 71b. Then said modulation output is supplied to a wave detecting circuit 86 to undergo the wave detection from the coil 71b via an erasion signal switch circuit 63b and an erasion head 62. This wave detection output is supplied to a reproduction signal synthesizing circuit 66 as a control signal for head channel switch pulse. As a result, no synchronizing control is needed and the balance of a rotor is improved.