Rca Inc.

Thomson Consumer Electronics Inc.

Rca Licensing Corporation

William L Lehmann

David J Carlson

Michael Anthony Pugel

Leroy S Wignot

William Hoffmann Bose

A signal selecting circuit including a first, second and third inductors coupled in series in the order named, a fourth inductor coupled between an output terminal of the third inductor and a reference potential, and varactor diodes responsive to a tuning signal for varying the frequency response of the signal selecting circuit. The signal selecting circuit includes bandswitching circuitry for changing the configuration of the signal selecting circuit in response to the frequency band of the selected signal.

Television receiver tuning circuit

A television receiver powered by an alternating current power source includes an electrically conductive chassis coupled to one side of the AC source, a radio frequency tuner coupled to the chassis, and a coaxial cable having an inner conductor and an outer shielding conductor for supplying filtered radio frequency signals to the tuner. The outer conductor is comprised of an electrically conductive housing circumposing the inner conductor for at least a portion of its longitudinal length, and providing electrical connection and mechanical support for the cable assembly. Filtering of the signal is provided by one or more ferrite beads disposed about the outer conductor, and capristor/capacitor devices.

Antenna isolation assembly for hot chassis receiver

A television receiver includes a single tuner for tuning both television channels and broadcast FM stations. The tuner is operated at a fixed gain setting in FM reception mode. The tuner serves as the first conversion stage of a double conversion FM receiver, wherein the mixer of an FM radio integrated circuit serves as the second conversion stage. The arrangement operates at a specific and non-arbitrary first IF frequency. The FM receiver is also capable of automatically receiving National Weather Service broadcasts on that one of NWS's seven allocated frequencies which is operating in a listener's area. The receiver provides an on-screen display of the currently tuned FM channel number.

Fixed RF AGC of a television tuner for FM reception in a television

FM trap for a television tuner permitting both TV and FM reception

Antenna coupling components including a coil and a static discharge resistor are mounted on a separate printed circuit board within a tuner that is positioned by means of projecting tabs on each end so as to self-center the coil with the inductor. A first tab extends through an aperture in the tuner wall and carries foil patterns for connecting an antenna to the coil and one end of the resistor. The other tab is secured to a slot in an internal shield to provide mechanical support for the board, electrical connection to ground for the other end of the resistor and which facilitates lateral movement of the coil during assembly. A connector block, fixed to the outside of the tuner enclosure, provides mechanical support and electrical insulation for the first tab and additionally provides electrical connection to a pair of antenna terminals and a right angle bend in the antenna circuit.

Tuner with insertable antenna coupler

A radio frequency (RF) amplifier including a resonant circuit having a peaked response is tunable in response to a tuning voltage to select RF carriers over a wide range of frequencies and includes an additional resonant circuit for improving its response at the low frequency end of that range. The additional resonant circuit has a peaked response tunable in response to the tuning voltage in tracking relationship to that of the first resonant circuit. The tracking relationship is desirably selected so that the additional resonant circuit does not become tuned to a frequency which is an integral sub-multiple of the frequency of a selected RF carrier.

Television receiver tuning circuit tunable over a wide frequency range

In a multiband tuner, an input arrangement for selectively applying first and second local oscillator signals to a single input of a prescaler of a phase locked loop tuning system includes a first capacitor connected in series from the output of a first local oscillator to the prescaler input, a second capacitor and inductor connected in series from one output of a second local oscillator to the same prescaler input and a diode switching arrangement for selectively coupling a third capacitor between the junction of the second capacitor and the inductor and signal ground when the first local oscillator is enabled to operate. The first capacitor, inductor and third capacitor comprise a matching network for the output of the first local oscillator. The second capacitor and inductor form a series tuned circuit in the frequency band of the second local oscillator which rejects signals in the frequency band of the first local oscillator. The arrangement is particularly advantageous for allowing the UHF input of a prescaler intended for a VHF/UHF tuner to be used for dividing the frequency of a superband cable local oscillator signal as well as for dividing the frequency of a UHF local oscillator signal.

Input selection arrangement for applying different local oscillator

In a phase locked loop tuning system including a prescaler for dividing the frequency of the local oscillator signal by a factor selected to make the resultant frequency divided signal compatible with digital processing portions of the tuning system, a frequency selective network is coupled to the prescaler to tune the self-oscillation frequency of the prescaler to a frequency not corresponding to the local oscillator frequency of any legitimate channel. In this manner, when a new channel is selected and the amplitude of the local oscillator signal is below the threshold at which the prescaler will respond to it, the phase locked loop will properly control the local oscillator, rather than respond to a self-oscillation signal which may otherwise correspond to the local oscillator frequency for the selected channel.

Phase locked loop tuning system including a prescaler conditioned to

An isolation device coupled between an antenna network and a fixed tuned VHF/UHF signal splitter includes a first bifilar transmission line and a second bifilar transmission line wound with multiple turns about separate toroidal portions of a magnetic core. Each of the bifilar transmission lines has first and second conductors. At an input port of the device, the first conductor of the first transmission line and the second conductor of the second transmission line are coupled to respective antenna terminals of the antenna network and the second conductor of the first transmission line and the first conductor of the second transmission line are coupled together. At an output port of the device, the second conductor of the first transmission line and the first conductor of the second transmission line are coupled to respective input terminals of the signal splitter and the first conductor of the first transmission line and the second conductor of the second transmission line are coupled together. The number of turns of each of the transmission lines about its respective toroidal portion is selected to provide sufficient amplitude response in the UHF range. The permeability of the core is selected to provide sufficient amplitude response in the VHF range.

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Indianapolis, IN, United States of America

William L Lehmann