Up-down frequency converter for cable T.V.
Patent 4352209 Issued on September 28, 1982. Estimated Expiration Date: 
March 23, 2001. 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.
March 23, 2001. 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 3226645 3309613 3742131 Tuner device for a television receiver Patent #: 4214212 InventorApplicationNo. 06/242908 filed on 03/23/1981US Classes:455/315, With plural separate local oscillators455/182.1, With frequency control455/189.1, With plural separate mixer or converter circuits455/301Plural or compartmented shielding structureExaminersPrimary: Bookbinder, Marc E.International ClassesH03D 7/00 (20060101)H03D 7/16 (20060101) H03D 7/12 (20060101) H03D 7/14 (20060101) H03B 5/08 (20060101) H03B 5/12 (20060101) AbstractA cable television up-down tuner includes a first frequency up conversion stage in which a first local oscillator, tunable over a wide frequency range, is coupled to a ring diode mixer having individual biasing networks in series with each diode. A combination high pass and low pass filter provides a bandwidth coupling of input signals to the mixer. An intermediate frequency amplifier couples the up converted signal to a second mixer. A fixed tuned second local oscillator down converts the intermediate frequency signal to a selected television channel frequency. The first local oscillator includes a printed circuit board transmission line resonator which is tuned by a varactor diode. The two local oscillators are positioned adjacent the corners of a quadrilateral housing and are isolated from each other by three wall-type shields. | |
