Abstract: A fully integrated single-loop frequency synthesizer, which can serve as a local oscillator for a broadband tuner, is disclosed, thus allowing the creation of a single-chip solution for broadband applications. The tank circuits are integrated into the tuner chip through the combination of a phase-locked loop and multiple on-chip VCOs comprising narrow-tuning range varactors. Drift in the VCOs caused by heat is overcome by designing the VCOs to overlap each other. Initial tolerance problems associated with the VCOs are overcome by the use of a calibration method. The calibration of the VCOs is accomplished by utilizing the lock detect output of the phase-locked loop and a binary search algorithm. The edges of each VCO are determined with this calibration method, thereby enabling VCO selection based on the desired channel. A sufficient number of VCOs are provided such that whatever the initial tolerance shift, the full broadband spectrum can still be covered after calibration.

Abstract: A fully integrated single-loop frequency synthesizer, which can serve as a local oscillator for a broadband tuner, is disclosed, thus allowing the creation of a single-chip solution for broadband applications. The tank circuits are integrated into the tuner chip through the combination of a phase-locked loop and multiple on-chip VCOs comprising narrow-tuning range varactors. Drift in the VCOs caused by heat is overcome by designing the VCOs to overlap each other. Initial tolerance problems associated with the VCOs are overcome by the use of a calibration method. The calibration of the VCOs is accomplished by utilizing the lock detect output of the phase-locked loop and a binary search algorithm. The edges of each VCO are determined with this calibration method, thereby enabling VCO selection based on the desired channel. A sufficient number of VCOs are provided such that whatever the initial tolerance shift, the full broadband spectrum can still be covered after calibration.

Abstract: A fully integrated single-loop frequency synthesizer, which can serve as a local oscillator for a broadband tuner, is disclosed, thus allowing the creation of a single-chip solution for broadband applications. The tank circuits are integrated into the tuner chip through the combination of a phase-locked loop and multiple on-chip VCOs comprising narrow-tuning range varactors. Drift in the VCOs caused by heat is overcome by designing the VCOs to overlap each other. Initial tolerance problems associated with the VCOs are overcome by the use of a calibration method. The calibration of the VCOs is accomplished by utilizing the lock detect output of the phase-locked loop and a binary search algorithm. The edges of each VCO are determined with this calibration method, thereby enabling VCO selection based on the desired channel. A sufficient number of VCOs are provided such that whatever the initial tolerance shift, the full broadband spectrum can still be covered after calibration.

Abstract: A collector-injector mixer circuit (100) has a first differential pair of transistors having first and second transistors (102, 104) whose emitters are connected to a common first emitter terminal (110), and a second differential pair of transistors having third and fourth transistors (106, 108) whose emitters are connected to a common second emitter terminal (112). The bases of the first and fourth transistors (102, 108) are coupled to a common first base terminal (114) and the bases of the second and third transistors (104, 106) are coupled to a common second base terminal (116) between which a mixing signal is applied.

Abstract: The programmable electronic device, such as a radio, includes a memory for storing program information. A controller, such as a microprocessor, is connected to the memory for programming and reading the memory. A keypad is provided for data entry and is connected to the microprocessor. A magnetic switch, such as a Hall effect switch, is located within the radio and controls the program enable line of the microprocessor. The Hall effect switch is actuated by an externally supplied magnetic field for enabling programming of the memory of the radio.

Abstract: A battery charger includes a first charger for providing a first battery charging current and a second charger for providing a second battery charging current. A switch is provided for manually actuating the second charger. A timer times the second charger cycle. The timer is used to initiate the discontinuation of operation of the second charger. When the second charger is operating, the timer is inhibited from being reset. When the first charger discontinues supplying a charging current, the battery charger is conditioned to again permit actuation of the switch to reset the timer and allow operation of the second charger.