| 摘要 |
<p>PURPOSE:To reproduce the entire signal in an excellent way by implementing vari-speed reproduction with an optional speed multiple ratio. CONSTITUTION:A reproduction signal from rotary magnetic heads 1a, 1b is fed to envelope detection circuits 71, 72 through BPFs 61, 62 and fed to a sampling pulse generating circuit 9, from which sampling pulses PS, PL corresponding to a pilot signal period of upper and lower tracks are extracted and fed to AND circuits 10aL-10bs. Furthermore, a switching pulse SWP is fed to monostable multivibrators 11a-13b, selected by switch circuits 16a, 16b through OR circuits 14a, 14b and changeover switch circuits 15a, 15b and the selected pulse is fed to the AND circuits 10aL-10bs. Moreover, the pulse SWP is fed to a mode control circuit 17 and the gain of reproduction amplifiers 2a,2b and the changeover switch circuits 15a-16b are controlled according to the control signal and a gate signal fed to the AND circuits 10aL-10bs is formed.</p> |
