Abstract:
A frequency adjustable surface acoustic wave oscillator uses circuitry in which the phase relationship between the corresponding input and output signals and the voltage applied to or received by transducer fingers is controlled in such a manner that the frequency of the surface acoustic wave oscillator is arbitrarily controlled over a wide range by digital means. This provides an oscillator that exhibits a wide tunable frequency range while providing low phase noise.
Abstract:
The invention proposes a device for high-frequency and/or radio-frequency tuning comprising within one IC-package a first variable capacitor (C1) and at least one second capacitor (C2), each of the at least one second capacitor (C2) being fixed or variable respectively, at least one signal path connected to the first variable capacitor (C1) and providing at least one input and one output port (rf-port1, rf-port2) and at least one controllable switching means (SC2) for individually connecting and disconnecting at least one of the at least one second capacitor (C2) into the signal path or from the signal path, in particular in parallel to the first variable capacitor (C1).
Abstract:
An apparatus comprising a digitally controlled oscillator and a frequency tuning array. The digitally controlled oscillator may be configured to finely tune an output signal having a frequency in response to a digital signal. The frequency tuning array may be configured to generate the digital signal.
Abstract:
A frequency synthesizer has a voltage controlled oscillator comprising a voltage controlled capacitor having a first terminal and a second terminal. A positive control voltage is applied to the first terminal of the voltage controlled capacitor and a negative control voltage is applied to the second terminal of the voltage controlled capacitor, causing the varactor to operate in a reverse biased state. A circuit for generating a negative control voltage is provided in a phase-locked loop circuit. The circuit includes a negative DC generator for generating a negative DC voltage from an AC signal, and a programmable variable attenuator for selectably attenuating the negative control voltage.
Abstract:
A transmitter for use with a receiver responsive to a function request signal transmitted by said transmitter for performing a requested function. The transmitter includes a controller for providing a function command and an LC oscillator for providing the request signal at a fixed frequency in response to the command from the controller. The oscillator includes a semi-conductor having first, second, and third electrodes and a tank circuit including first, second, and third impedances. A surface acoustic wave resonator is connected from the first electrode to ground. A feedback capacitor is connected from the second electrode to said first electrode for reducing spurious frequency signals.
Abstract:
An oscillation circuit is provided which is easily adjusted with a high degree of accuracy. The oscillation circuit including a filter having a time constant and an inverting amplifier which feeds back the output of the filter to the input side of the filter so that an oscillation condition is fulfilled. The filter includes a gm amplifier formed of a differential amplifier, and a capacitor. The constant current source of the differential amplifier is connected to a free running oscillation frequency adjusting circuit. The adjusting circuit includes a microcomputer, a decoder which decodes the output data of the microcomputer and a switching circuit driven by the output of the decoder and varying the current value according to the output of the decoder. A current in accordance with a current value depending on the setting of the switch flows through the constant current source.
Abstract:
The invention provides a piezoelectric oscillator including a semiconductor integrated circuit and a piezoelectric resonator or a voltage-controlled oscillator including a semiconductor integrated circuit, a piezoelectric resonator and another electronic component. The piezoelectric resonator has a cross-sectional shape of an ellipse or a track. The semiconductor integrated circuit and the electronic component are molded with a resin into a very thin unit.
Abstract:
An injection locking oscillator (ILO) comprising a tank circuit having a digitally controlled capacitor bank, a cross-coupled differential transistor pair coupled to the tank circuit, at least one signal injection node, and at least one output node configured to provide an injection locked output signal; a digitally controlled injection-ratio circuit having an injection output coupled to the at least one signal injection node, configured to accept an input signal and to generate an adjustable injection signal applied to the at least one injection node; and, an ILO controller connected to the capacitor bank and the injection-ratio circuit configured to apply a control signal to the capacitor bank to adjust a resonant frequency of the tank circuit and to apply a control signal to the injection-ratio circuit to adjust a signal injection ratio.
Abstract:
An injection locking oscillator (ILO) comprising a tank circuit having a digitally controlled capacitor bank, a cross-coupled differential transistor pair coupled to the tank circuit, at least one signal injection node, and at least one output node configured to provide an injection locked output signal; a digitally controlled injection-ratio circuit having an injection output coupled to the at least one signal injection node, configured to accept an input signal and to generate an adjustable injection signal applied to the at least one injection node; and, an ILO controller connected to the capacitor bank and the injection-ratio circuit configured to apply a control signal to the capacitor bank to adjust a resonant frequency of the tank circuit and to apply a control signal to the injection-ratio circuit to adjust a signal injection ratio.
Abstract:
There is provided a crystal oscillator including an oscillating unit outputting an oscillating signal; a driving unit driving the oscillating unit, a waveform converting unit shaping a waveform of the oscillating signal, a current supplying unit applying an operating signal to the driving unit and the waveform converting unit, and a controlling unit applying a control signal to at least one of the oscillating unit and the current supplying unit based on an output of the waveform converting unit.