Abstract:
In a phase-lock-loop circuit a frequency detector measures a frequency error between an oscillatory signal and a synchronizing signal in alternate horizontal line periods for generating a frequency error indicative signal. The frequency error indicative signal is applied to an oscillator for correcting the frequency error in other alternate horizontal line periods in a manner to prevent frequency error measurement and correction from occurring in the same horizontal line period.
Abstract:
An integrated oscillator circuit comprises an oscillator configured to be switched between a first frequency and a second frequency. A switching circuit receives an input representing a target frequency and switches the oscillator between the first and second frequencies at intervals determined by the input, so as to cause the average output frequency of the oscillator to approximate the target frequency.
Abstract:
In various embodiments, the invention provides a clock generator and/or a timing and frequency reference using an LC-oscillator topology, having a frequency controller to control and provide a stable resonant frequency, which is integrated with other, second circuitry such as a processor or controller. Frequency stability is provided over variations in a selected parameter such as temperature and fabrication process variations. The various apparatus embodiments include a sensor adapted to provide a signal in response to at least one parameter of a plurality of parameters; and a frequency controller adapted to modify the resonant frequency in response to the second signal. In exemplary embodiments, the sensor is implemented as a current source responsive to temperature fluctuations, and the frequency controller is implemented as a plurality of controlled reactance modules which are selectively couplable to the resonator or to one or more control voltages. The controlled reactance modules may include fixed or variable capacitances or inductances, and may be binary weighted. Arrays of resistive modules are also provided, to generate one or more control voltages.
Abstract:
The electronic device comprises an oscillation circuit (1, 2, 3, 10, 11, C1, C2, C3) included in a phase-locked loop which comprises a phase detector (17) and a variable divider (15) depending on a certain quantity. A check circuit is provided which either or not melts a fuse (25) as a function of the magnitude of the output of said phase detector (17) for each quantity of said divider indicating a bad or good locking respectively, of said loop. Application: Determination of wideband radio receiver/transmitter.
Abstract:
An integrated oscillator circuit comprises an oscillator configured to be switched between a first frequency and a second frequency. A switching circuit receives an input representing a target frequency and switches the oscillator between the first and second frequencies at intervals determined by the input, so as to cause the average output frequency of the oscillator to approximate the target frequency.
Abstract:
A frequency synthesizer applied to a digital television tuner includes: a voltage controlled oscillator (VCO), a phase locked loop (PLL), a frequency divider unit, and a multiplexer. The maximum oscillated frequency of the VCO is twice its minimum frequency. The PLL controls and locks the VCO output frequency by a frequency control signal. The frequency divider unit includes a plurality of first dividers which form a cascade connection. The frequency divider unit receives the VCO output frequency, and subsequently divides the output frequency one by one. The multiplexer receives the dividing signals, and then chooses one of the dividing signals by a frequency selection signal, and generates a local oscillation signal. Hence, the present invention can implement the frequency synthesizer by simple architecture and cover the frequency ranges of Digital Video Broadcasting standard.
Abstract:
Eine LC-Oszillatorschaltung einer Hörvorrichtung soll dauerhaft in einem gewünschten Frequenzbereich betrieben werden können. Hierzu wird eine Hörvorrichtung mit einem Oszillator (L, C res ) und einer Trimmeinrichtung (11, 12) zum Trimmen der Oszillationsfrequenz des Oszillators vorgeschlagen. Eine Regeleinrichtung (19) regelt die Oszillationsfrequenz des Oszillators mit Hilfe der Trimmeinrichtung (11, 12) entsprechend einem vorgegebenen Sollwert. Damit ist ein automatisches Selbsttrimmen eines drahtlosen Übertragungssystems in einer Hörvorrichtung und insbesondere in einem Hörgerät möglich.