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US Patent 4979233 - High frequency broad-band mixing circuit including an electrolytic capacitor in parallel with a local oscillator input port
US Patent Issued on December 18, 1990
Estimated Patent Expiration Date:
August 17, 2008Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
Estimated Patent Expiration Date:
August 17, 2008Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.AbstractA broad-band mixing circuit comprises a transmission line transformer connected between a port adapted to receive a radio frequency signal and a double balanced mixing section, the transformer serving to convert an unbalanced radio frequency signal into a balanced signal, a transmission line transformer connected between a local oscillation signal port and the mixing section, the transformer serving to convert an unbalanced local oscillation signal into a balanced signal, and a transmission line transformer connected between the mixing section and an intermediate frequency signal port, the transformer serving to convert the balanced signal from the mixing section into an unblaanced signal. The noise figure is improved by connecting an electrolytic capacitor in parallel with the balanced output end or the input end of the transmission line transformer for the local oscillation signal.Other References
| InventorAssigneeApplicationNo. 233210 filed on 08/17/1988US Classes:455/330, With nonlinear impedance (e.g., diode)455/317, Unwanted oscillation or radiation prevention455/318, With specified local oscillator structure or coupling455/326With balanced mixerField of Search455/326, With balanced mixer455/330, With nonlinear impedance (e.g., diode)455/318, With specified local oscillator structure or coupling455/319, With particular coupling455/317, Unwanted oscillation or radiation prevention331/36C, Capacitor controlled AFC331/22Plural significant heterodyne stagesExaminersPrimary: Olms, Douglas W.Assistant: Smith, Leonard E. Attorney, Agent or FirmUS Patent References2508048, 3913037, 4193048, Balun transformerIssued on: 03/11/1980 Inventor: Nyhus4449245, High gain balanced mixer Issued on: 05/15/1984 Inventor: Rabe4601063, Doubly-balanced mixer termination Issued on: 07/15/1986 Inventor: Price4677691, Microwave receiver Issued on: 06/30/1987 Inventor: Scott4677692Frequency conversion apparatus Issued on: 06/30/1987 Inventor: Sakashita , et al. Foreign Patent References
International ClassH04B 001/26Foreign Application Priority Data1987-08-19 JP |
