High frequency broad-band mixing circuit including an electrolytic capacitor in parallel with a local oscillator input port
Patent 4979233 Issued on December 18, 1990. Estimated Expiration Date: 
August 17, 2008. Estimated 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.
August 17, 2008. Estimated 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.Patent References 2508048 3913037 Balun transformer High gain balanced mixer Doubly-balanced mixer termination Microwave receiver Frequency conversion apparatus Patent #: 4677692 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 mixerExaminersPrimary: Olms, Douglas W.Assistant: Smith, Leonard E. Attorney, Agent or FirmForeign Patent References
International ClassH04B 001/26Foreign Application Priority Data1987-08-19 JPAbstractA 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
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