The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 06, 1999
Filed:
May. 27, 1997
Applicant:
Inventors:
Hiroshi Tatsumi, Shiki-gun, JP;
Chiaki Yamawaki, Habikino, JP;
Assignee:
Sharp Kabushiki Kaisha, Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
A02K / ;
U.S. Cl.
CPC ...
318254 ; 318606 ; 318607 ; 318678 ;
Abstract
A differential amplifier amplifies a PG reproduction signal to a level permitting signal processing. A low-pass filter makes the signal waveform of a PG detection signal generated by the differential amplifier substantially uniform irrespectively of the rotational speed of a rotating drum. A comparator outputs a PG pulse by comparing an output of the low-pass filter with a threshold. A magnetic recording and reproducing apparatus having such a structure can detect the PG pulse with accuracy over a rotational speed range requiring a precision control of the rotating drum.