Abstract: An array of photosensitive devices, including photovoltaic cells is controlled to provide adequate output voltage for continued use when light conditions are sensed as dropping below a predetermined level for normal operations. Control is made of the internal connections between banks of devices or cells by switching normally parallel connected banks of series connected devices or cells to series connected banks. Stepped switching of an increased number of banks can be made as the light continues to drop, in order to extend and maximize the output of the array during reduced light conditions. The output can be further controlled to limit application of the output voltage to a load during times of diminished light conditions in order to not overdraw the diminished current capacity characteristics when the series connections are made.

Abstract: An output stage of a double balanced mixer having a first intermediate port and a second intermediate port includes an operational amplifier, an impedance and first and second current source devices. The operational amplifier has a first input port, a second input port and an IF output port, and the impedance is coupled between the first input port and the second input port. The first current source device has a first terminal coupled to both the first input port and the first intermediate port, which are coupled to one another. The second current source device has a second terminal coupled to both the second input port and the second intermediate port, which are coupled to one another.

Abstract: A space diversity, multiple-tuner radio receiver obtains substantially noise free reception under most signal conditions. The tuner outputs are mixed in proportion with the signal quality as determined by detecting noise in each tuner output signal. Long-time-delay multipath distortion, adjacent channel interference, and co-channel interference are reduced by selecting predetermined antenna pattern combinations in response to high noise levels being present from both tuners.

Abstract: A dual-band radio receiver utilizes a single transformer to provide impedance matching between signal mixers from separate signal paths to their respective intermediate frequency filters. Thus, a dual-band radio receiver can be made eliminating one transformer and the printed circuit board space of one transformer. In addition, only one transformer needs to be frequency aligned or adjusted during manufacturing.

Abstract: An improved tuner for a varactor-tuned local oscillator in a radio receiver includes a winding of a pair of magnetically coupled inductors, preferably constructed in the form of a transformer. Preferably, the first and second windings are magnetically coupled with reduced inter-winding capacitance by axially separating the windings on a common core. The second winding is selectively coupled by a switch to a capacitive load in order to change the inductance of the first winding. The tuning range of the resonant circuit formed by the varactor diode set and the first winding is changed when the capacitive load is coupled. The magnetic coupling between the transformer windings provides DC isolation between the oscillator and the switching circuit. Preferably, a tuning actuator has overlapping ranges of movement for selection of a signal within both the AM and FM frequency bands as the intermediate frequencies for the local oscillator are generated.