Abstract: A band switchable double tuned circuit having a balanced secondary is presented. A primary tunable tank circuit with a plurality of first inductances is tuned to a first frequency by a first capacitor coupled in parallel with the first inductances. A secondary tank circuit with a plurality of second inductances inductively coupled to ones of the first inductances has a second capacitor coupled in parallel with the second inductances for tuning the secondary to the first frequency. The DC reference potential for the secondary circuit, is coupled to a nodal junction of the plurality of second inductances with the secondary tank circuit providing a balanced signal output. At least one of the plurality of first inductances and the second inductances are switchable for bandswitching the tuning of the primary and secondary tank circuits to a second frequency.

Abstract: A satellite video receiver (12) for providing output signals to a television signal receiver (52) includes apparatus (10, 15, 16, 20, 45, 60, 65, 70) for operator selection of the modulator output channel frequency of the satellite receiver. The operator may select a modulator main channel, or an alternative manufacturer pre-set modulator default channel. In a first recovery mode, the operator may automatically replace an existing modulator channel with a manufacturer pre-set default channel, e.g., if a chosen main channel is forgotten. In another recovery mode, the operator may automatically re-establish a previously selected modulator main channel recalled from memory.

Abstract: A band switchable double tuned circuit having a balanced secondary is presented. A primary tunable tank circuit with a plurality of first inductances is tuned to a first frequency by a first capacitor coupled in parallel with the first inductances. A secondary tank circuit with a plurality of second inductances inductively coupled to ones of the first inductances has a second capacitor coupled in parallel with the second inductances for tuning the secondary to the first frequency. The DC reference potential for the secondary circuit is coupled to a nodal junction of the plurality of second inductances with the secondary tank circuit providing a balanced signal output. At least one of the plurality of first inductances and the second inductances are switchable for bandswitching the tuning of the primary and secondary tank circuits to a second frequency.

Abstract: 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.

Abstract: Conversion of an RF signal amplifier from an unbalanced signal configuration to a balanced signal configuration is provided while including an image trap for both sides of the balanced circuit. The grounded side of the secondary of a double tuned circuit is lifted from ground to provide a balanced circuit configuration. A trap filter is provided in the balanced circuit configuration by a pair of small capacitors coupled between the balanced secondary leads to appropriate signal nodes.

Abstract: An amplifier loaded with a constant bandwidth tuned circuit is provided with an output series coil, and with a resistance in series with the output coil and a subsequent load to provide attenuation at high frequencies for maintaining the total overall gain of the amplifier and tuned circuit load constant with increasing frequency while simultaneously maintaining the bandwidth of the tuned circuit constant with increasing frequency.

Abstract: The present invention is for a highpass input circuit for a television receiver having an additional trap at a predetermined frequency, e.g. CB frequencies. A M derived constant K high pass filter having an intermediate pi configured filter section is provided with an additional inductor in the shunt leg of the pi section for resonating with the bridge capacitance of the pi section and forming an additional trap at the predetermined frequency. The additional inductor is physically formed by an electrically conductive path etched on a printed circuit board.