公开(公告)号：US4074325A

公开(公告)日：1978-02-14

申请号：US770785

申请日：1977-02-22

申请人： Yoshiaki Sakai ,  Kuniki Murayama

发明人： Yoshiaki Sakai ,  Kuniki Murayama

IPC分类号： G11B20/10 ,  H03K5/1532 ,  G11B5/09 ,  G11B5/02

CPC分类号： G11B20/10009 ,  H03K5/1532

摘要： For sensing the peaks of an electric signal reconverted by a magnetic head from a digital signal stored on a magnetic tape or other recording media, a half-wave rectifying diode is connected to the magnetic head via an amplifier. The output of the half-wave rectifying diode is connected directly to a resistance-capacitance differentiating circuit, without interposition of a slicer therebetween. An output from the differentiating circuit is compared with a variable level-setting reference voltage in a substantially connected comparator circuit, and the latter produces output pulses the trailing edges of which substantially correspond in time to the peaks of the output from the magnetic head. A pulse trailing edge sensing circuit connected next to the comparator circuit produces output pulses of comparatively short durations corresponding to the trailing edges of the comparator output pulses. The comparator circuit has a switching transistor for selectively varying a differential between the levels of its reference voltage in accordance with the output amplitude of the differentiating circuit.