Abstract: A high performance radio frequency receiver includes a low noise amplifier with large binary and stepped gain control range, controlled impedance, and enhanced blocker immunity, for amplifying and converting a radio frequency signal to a current; a pulse generator for generating in-phase and quadrature pulses; a crossover correction circuit and pulse shaper for controlling a crossover threshold of the pulses and interaction between in-phase and quadrature mixers; and a double balanced mixer for combining the RF signal with the pulses to generate an intermediate frequency or baseband zero intermediate frequency current-mode signal. The in-phase and quadrature pulses have a duty cycle of 20-35%. The intermediate frequency signal and second order harmonics may be filtered with a high frequency low pass filter and a current injected complex direct-coupled filter.

Abstract: A high performance radio frequency receiver includes a low noise amplifier with large binary and stepped gain control range, controlled impedance, and enhanced blocker immunity, for amplifying and converting a radio frequency signal to a current; a pulse generator for generating in-phase and quadrature pulses; a crossover correction circuit and pulse shaper for controlling a crossover threshold of the pulses and interaction between in-phase and quadrature mixers; and a double balanced mixer for combining the RF signal with the pulses to generate an intermediate frequency or baseband zero intermediate frequency current-mode signal. The in-phase and quadrature pulses have a duty cycle of 20-35%. The intermediate frequency signal and second order harmonics may be filtered with a high frequency low pass filter and a current injected complex direct-coupled filter.

Abstract: A VCO circuit including a VCO, a voltage supply and a control circuit. The VCO has a supply voltage input and a gain that changes with its supply voltage. The voltage supply has an adjust input and an output coupled to the supply voltage input of the VCO. The voltage supply adjusts the voltage level of its output in response to changes of the adjust input. The control circuit has a first adjust output coupled to the adjust input of the voltage supply to adjust the gain of the VCO. The VCO may include a frequency range adjust input controlled by the control circuit so that the gain of the VCO is adjusted when the frequency range is changed. For a multi-band VCO, the gain is adjusted for different frequency bands to maintain a relatively constant gain for each frequency band.

Abstract: A VCO circuit including a VCO, a voltage supply and a control circuit. The VCO has a supply voltage input and a gain that changes with its supply voltage. The voltage supply has an adjust input and an output coupled to the supply voltage input of the VCO. The voltage supply adjusts the voltage level of its output in response to changes of the adjust input. The control circuit has a first adjust output coupled to the adjust input of the voltage supply to adjust the gain of the VCO. The VCO may include a frequency range adjust input controlled by the control circuit so that the gain of the VCO is adjusted when the frequency range is changed. For a multi-band VCO, the gain is adjusted for different frequency bands to maintain a relatively constant gain for each frequency band.

Abstract: Ultrasonic calibration material produced by polymerization of acrylamide with N,N'-methylene-bis-acrylamide in vacuum-degassed liquid solutions such as water, ethylene glycol, emulsions of non-miscible liquids with water and blends of liquids in which a homogeneous and permanent suspension of solid and liquid particles (e.g.: alumina, boron nitride, graphite, water-filled phenolic microspheres, glass microspheres, polyethylene, turpentine oil) is chemically achieved by polymerization of an acrylic acid polymer.