Abstract: The delay and distortion characteristics of an optical detector can be improved with a comparator having tailored offsets and hysteresis. The comparator is controlled by the output of a transimpedance amplifier, coupled in part through a delay mechanism. The delay mechanism provides a dynamic reference level to one terminal of the comparator.

Abstract: Fast switching may be achieved in a comparator by driving a comparator stage with a gain amplifier and feeding back the output signal from the comparator to the gain amplifier.

Abstract: The response time of a driver for an LED optocoupler is improved by adding a pedestal current component (IP) to the LED drive on turn-on. The pedestal current speeds up or accelerates the turn-on process by providing an additional amount of current for a short period of time.

Abstract: An improved peak detector for an audio limiter is disclosed where the audio limiter comprises preferably a voltage controlled amplifier and the feedback detector in a feedback arrangement. The peak detector has a resistive capacitive load and either charges or discharges more rapidly when the difference between the output of the peak detector and the output of the voltage controlled amplifier increases. As a result, over much of the range of operation of that difference, the charging or discharging current is linear with the output of the amplifier to provide a constant transconductance gain. However, when the difference exceeds a predetermined maximum, the circuit limits that current, thereby, decreasing the transconductance gain of the circuit.

Abstract: An arrangement for adjusting the intensity of an electrodeless discharge lamp is described. In one embodiment the high-frequency signal delivered to the induction coil is interrupted during a predetermined portion of a full duty cycle. This function is provided by a dimmer control unit which may be in an analog or digital form and may respond to a control signal provided by a potentiometer, a three-way lighting fixture or an addressable, remote controlled interface with data transmitted over the power lines or over a radio or infrared communication channel. In another embodiment the dimmer control unit alters the amplitude of the high-frequency signal supplied to the lamp's induction coil.

Abstract: A push-pull Class E amplifier is used to provide an efficient transfer of power to the induction coil in an electrodeless discharge lamp and to reduce the amount of radio frequency interference emitted by the lamp into the surrounding environment. A bifilar or other type of multifilar induction coil, preferably center-tapped, is used to further reduce the radio frequency interference problem.

Abstract: A push-pull Class E amplifier is used to provide an efficient transfer of power to the induction coil in an electrodeless discharge lamp and to minimize the amount of radio frequency interference emitted by the lamp into the surrounding environment.

Abstract: An electrodeless discharge lamp includes a discharge vessel containing an ionizable vapor, a generator for providing a high frequency signal, and an induction coil adjacent the discharge vessel and connected to the generator. The induction coil is shaped in the form of a planar spiral. The spiral coil is formed of wire or made of metal etched in a spiral pattern onto a substrate. The electrodeless discharge lamp having a spiral induction coil shows low lumen depreciation, a high linear relationship between light output and power input and produces low radio frequency interference.

Abstract: A complementary differential amplifier comprising a first and a second pair of complementary bipolar transistors, each of said transistors having a base, emitter and a collector, a resistor network for coupling said emitters, a first and a second level shift bias network, a resistor network for coupling said first and said second level shift bias networks to the bases of said first and said second pair of complementary transistors, a constant current source coupled between the level shift bias networks and a source of a first reference potential and a reference current generator coupled to the current source for generating a reference bias current for said first and said second level shift bias networks which is proportional to absolute temperature.

Abstract: A current variable shunt impedance with a non-linear control characteristic intended to functionally imitate and replace a field effect transistor responsive to a control voltage applied to its gate electrode having a source-drain path connected as a variable impedance shunt resistor in the variable frequency high pass filter section of the commercially popular Dolby B noise reduction system. The invention allows a large part of the Dolby B encode decode circuitry to be embodied in low-cost integrated circuit form while maintaining performance characteristics which closely match existing standards. These standards were previously established using noise reduction systems fabricated from discrete circuit components. The complementary nature of the encode and decode operations used to process a signal makes such matching of performance characteristics to the established standards critical.