【発明の名称】同期検出装置

Japanese Patent JPH0758330

B2

An article surveillance system includes a generator of a first inductive magnetic field having on and off duty cycle portions. The generator derives the first magnetic field at a predetermined AC frequency during the on duty cycle portions. The article to be detected includes a structure which responds to the predetermined frequency of the first magnetic field to derive a second inductive magnetic field at a predetermined frequency. The second field is derived as a pulsed wave having a starting time at the expiration of each on-duty cycle portion and a predetermined carrier frequency. A receiver for the predetermined frequency of the second inductive magnetic field derives first and second different responses while an article including the structure is and is not in a detection region magnetically coupled to the receiver and transmitter. The receiver includes a synchronous detector for detecting first and second orthogonal components of the carrier frequency of the pulsed wave relative to a reference wave having a reference phase at the carrier frequency. The responses are derived independently of the amplitude of the carrier frequency components in the pulsed wave. The first and second responses are separately integrated over a predetermined interval, in synchronism with the occurrence time of each pulsed wave. The presence of the pulsed wave is indicated in response to either of the first or second responses having an absolute value in excess of a predetermined value during the interval.

WO/2020/078927

ARCHITECTURE OF TIME SAMPLING DIGITAL SIGNAL PROCESSING DEVICE BASED ON AN APPLICATION OF THE FREQUENCY MULTIPLYING DEVICE

John Jay Torre

JP21911086A

June 21, 1995

September 17, 1986

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Identity Tech Co-Polation

G01R25/00; G08B13/22; G01V3/10; G08B13/24; (IPC1-7): G01V3/10; G08B13/22

JP5940287A
JP6078378A
JP533913B2
JP551640B2

Kyozo Yuasa (5 people outside)

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