Abstract: A multi-mode circuit can switch an output section between mixer and amplifier modes, with or without variable gain, to create a variable gain amplifier or a variable gain mixer or route an input signal by adjusting a bias current. An input section is controlled by a bias section and connected to the output section. The output section includes a first base-coupled transistor pair adapted to receive an input signal at emitters of the first base-coupled transistor pair, receive a bias signal at bases of the first base-coupled transistor pair, and provide an output signal at collectors of the first base-coupled transistor pair.

Abstract: Emitter-coupled logic circuits and systems that include such circuits are provided. Some emitter-coupled logic circuits include a plurality of fT-doubler circuits. Each fT-doubler circuit includes a plurality of transistors coupled to one another in an arrangement such that the plurality of transistors are configured to behave as a single enhanced transistor that has an effective unity current gain frequency that is higher than if a single transistor were used in its place. The fT-doubler circuits are configured to increase an operating frequency capability of the emitter-coupled logic circuit. Some emitter-coupled logic circuits include a plurality of cascode amplifier circuits. Each cascode amplifier circuit includes multiple transistors. An emitter of at least one first transistor of the plurality of transistors is coupled to a collector of at least one second transistor of the plurality of transistors Some emitter-coupled logic circuits may include both fT-doubler circuits and cascode amplifier circuits.

Abstract: A bridge-stabilized oscillator with feedback control includes an RF amplifier connected to a first bridge path and a second bridge path. Each first and second bridge path has a variable gain amplifier to receive and modify the respective signals to maintain the resistance of a resistor in the first bridge path, so the resonator in the second bridge path oscillates. A power detector provides a control signal to each of the variable gain amplifiers to maintain the phase of the output with respect to the input and constrain the gain in each of the first and second bridge paths.

Abstract: A high dynamic range precision variable amplitude controller includes a gain portion configured to apply a controllable amount of amplitude adjustment to an input signal. The gain portion includes two or more amplification stages each amplification stage having branches that are cross-coupled with branches of the other amplification stage. A control portion controls the current supply to the two or more amplification stages to control the amount of amplitude adjustment by the gain portion. The amplitude controller also includes a load portion that provides balanced impedances to the cross-coupled branches of the amplification stages throughout the amplitude control range.

Abstract: A multiple mode RF circuit includes a switching network to switch the RF circuit between a mixer mode and amplifier mode of operation. Two differential amplifier stages coupled to a differential transistor pair form the core of the circuit. A differential local oscillator (LO) source is selectively coupled to the two differential amplifier stages for mixer operation by the switching network and a feedback loop is selectively coupled between the input of the differential transistor pair and the output of the two differential amplifier stages by the switching network for amplifier operation. Gain is controlled in both modes by varying the DC bias on the two differential amplifier stages so that partial cancellation of the amplified signal from the differential transistor pair occur at the RF output. The multiple mode RF circuit operates over a large dynamic range by adjusting a bias current to scale linearity.

Abstract: A method of separating individual channels from a composite or broadband RF signal that carries the channels on respective frequencies. An RF signal is received from an antenna at a high impedance input port of a plurality of mixers. A local oscillator (LO) signal is received at a high impedance port of the plurality of mixers. The plurality of mixers separately mix the RF signal to produce a plurality of common intermediate frequency (IF) signals. The plurality of common IF signals are output to filters corresponding to the individual isolated channels then processed to derive their information content.

Abstract: An auto leveling circuit suitable for use in an RF receiver. The auto leveling circuit comprises a plurality of automatic gain control (AGC) circuits each having at least one amplifier stage to amplify an RF signal according to at least two incrementally discrete levels. In order to selectively control gain, the AGC circuits further comprise peak detectors to detect the amplitude of the amplified RF signal and comparators to compare the amplitude of the RF signal with a threshold value indicative of a saturation point of the amplifiers.

Abstract: A circuit includes a passive element having an impedance. An active circuit can be configured to receive an impedance signal associated with the impedance. The impedance includes a real portion and an imaginary portion. The active circuit removes at least a portion of the real portion of the impedance signal. The circuit can be utilized in a wide array of applications including radio applications.

Abstract: An ultra wideband interconnect from an external cable to an electric circuit. The interconnect includes an external cable including an external cable pin that projects from the termination of the external cable, an internal circuit, a conductive media coupled to the external cable pin and the internal circuit, and a package wall positioned between the external cable and the internal circuit. The package wall includes a cavity extending between the external cable and the internal circuit, the cavity having a coaxial structure. Further, the pin extends into but not through the cavity. The conductive media is coupled to the external cable pin within the cavity.

Abstract: A transistor commuted double balanced mixer that uses a Gilbert cell mixer quad transistor core. The RF input differential pair is deleted from the standard Gilbert cell mixer configuration. A transformer is used to apply the RF input through resistors to the Gilbert cell mixer quad transistor core.