Invention Grant
- Patent Title: Notched saw image frequency rejection filter system
- Patent Title (中): 缺陷锯图像频率抑制滤波器系统
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Application No.: US12589431Application Date: 2009-10-23
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Publication No.: US08169279B2Publication Date: 2012-05-01
- Inventor: Orest Fedan
- Applicant: Orest Fedan
- Applicant Address: US MA Canton
- Assignee: Lojack Operating Company, LP
- Current Assignee: Lojack Operating Company, LP
- Current Assignee Address: US MA Canton
- Agency: Iandiorio Teska & Coleman, LLP
- Main IPC: H03H9/64
- IPC: H03H9/64 ; H03H9/52 ; H04B1/12

Abstract:
A notched SAW image frequency rejection filter system includes a SAW filter having an input, an output and a ground output and an impedance matching network including a first matching inductance connected to the SAW filter output and a second matching inductance connected to the ground output of the SAW filter; the SAW filter having an inherent internal capacitance that produces a predetermined capacitive leakage current at the image frequency; an inherent internal inductance that produces an inductance leakage current at the image frequency; and a boosted inherent parasitic ground inductance at the ground output of the SAW filter for generating a voltage across the second matching inductance to produce a compensation current which is substantially opposite in phase and substantially matched in magnitude with the capacitive leakage current for reducing the capacitive leakage current and increasing the image frequency rejection.
Public/Granted literature
- US20110095850A1 Notched saw image frequency rejection filter system Public/Granted day:2011-04-28
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