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:
A method, system, and apparatus to a selectable drive strength high frequency crystal oscillator circuit are disclosed. In one embodiment, a system includes a crystal oscillator circuit to generate a signal with a specified frequency value, and a programmable amplifier circuit containing a plurality of programmable inverting amplifiers, and wherein certain ones of a plurality of inverting amplifiers are operated to change a gain and/or a bandwidth of the signal according to the specified frequency value of the crystal oscillator circuit. The system may include further comprising a resistor circuit coupled in parallel to the programmable amplifier circuit to set an operating point of the programmable amplifier circuit.
Abstract:
A local oscillator circuit includes an inner conductor to which a pick up coil is inductively coupled. The pickup coil is further connected with a capacitor to form a resonance circuit. The resonance frequency of the resonance circuit is set higher than those frequencies in the frequency band of the local oscillator so as to pick up oscillation signals into steady level over the frequency band.
Abstract:
An improved microwave oscillator wherein the oscillator includes a resonator assembly provided with a movable resonator member for varying the frequency response of the oscillator and which further includes a transistor, the improvement including means for varying the electrical coupling between a lead of the transistor and the resonator assembly to provide optimum coupling between the transistor lead and the resonator assembly for maximum power output; means for compensating for variations in frequency response of the oscillator upon different transistors being positioned different distances from the resonator assembly; coupling means electrically associated with the transistor to assure proper coupling between the transistor and the resonator assembly at the low frequencies; means for providing additional feedback to the transistor to assure sufficient feedback to sustain low frequency oscillation of the transistor which is typically chosen and designed for high frequency oscillation; and a flexible linkage interconnected between the resonator movable member and the apparatus for moving the resonator movable member whereby any lateral misalignment between structural members and apertures is compensated for.
Abstract:
The proposed local oscillation circuit comprises a resonance circuit including a variable capacitance diode to change the resonance frequency and tuning coils for low and high frequency bands, an oscillating transistor connected with the resonance circuit, changeover means for switching the tuning coils between the low and the high frequency bands, biasing means for providing a bias voltage for the oscillating transistor, and means for changing over a collector current of the transistor by changing the bias voltage applied by the biasing means to the transistor, in response to the operation of the tuning coil change-over means. The local oscillation circuit is well adapted to be used in a tuner of a receiver which receives a wide range of frequencies, e.g. a VHF television tuner.
Abstract:
A circuit using a voltage-controlled oscillator with a hyperabrupt junction diode in the series resonant circuit is operated as a variable frequency modulation circuit. An amplifier with an inductor in the base circuit of a common base configuration is used to present an impedance with a frequencydependent real part to the series resonant circuit of the oscillator. The nonlinearities in the characteristic of the hyperabrupt junction diode are compensated by the frequencydependent real input impedance to achieve linear operation.