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:
Jan. 22, 2013
Filed:
Apr. 07, 2010
Isamu Sato, Tokyo, JP;
Hiroshi Ikeda, Tokyo, JP;
Mikio Matsuzaki, Tokyo, JP;
Tetsuya Roppongi, Tokyo, JP;
Noboru Yamanaka, Tokyo, JP;
Tsutomu Aoyama, Tokyo, JP;
Isamu Sato, Tokyo, JP;
Hiroshi Ikeda, Tokyo, JP;
Mikio Matsuzaki, Tokyo, JP;
Tetsuya Roppongi, Tokyo, JP;
Noboru Yamanaka, Tokyo, JP;
Tsutomu Aoyama, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
A measuring circuit system in a magnetic field measuring apparatus of the invention has an amplifier and a band-pass filter connected in sequence on an output terminal side of the TMR element, the band-pass filter is a narrow-range band-pass filter such that a peak pass frequency of the filter that is a center is a basic frequency selected from a range of 10 to 40 GHz and a band width centered around the basic frequency is a narrow range of ±0.5 to ±4 GHz; and with the measuring circuit system, an SIN ratio (SNR) of 3 dB or greater is obtained, the SNR being defined by a ratio of an amplitude S of a high-frequency generated signal induced by the TMR element to a total noise N that is a sum of a head noise generated by the TMR element and a circuit noise generated by the amplifier. With such a configuration, an in-plane high-frequency magnetic field generated by a microwave-assisted magnetic head is reliably and precisely measured.