Tuner device for a television receiver Patent #: 4214212
ApplicationNo. 06/242908 filed on 03/23/1981
US 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 structure
ExaminersPrimary: 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.