54results about "Multiple resonant circuits tuned to same frequency" patented technology

An integrated electronic circuit comprises at least first and second variable resonator elements that can be tuned by means of an electric signal (Vtune) and that are arranged on the same silicon substrate, and that are respectively integrated into a Master circuit and a Slave circuit. Each resonator element is associated with a first inductive partner element set in the vicinity of the resonant and antiresonant frequencies; and with a second capacitive partner element, at least one of said partner elements being adjustable by means of said electric signal (Vtune). Controlling both partner elements could be done either by means of an adjustable capacitor, as a varactor, or by means of an inductor, passive or active, fixed or variable.

A fluid sensor comprises a sensor housing (12), a sensor package (14), an actuator (16) and a switch (18). The sensor package (14) is disposed within the sensor housing (12) and includes first and second screens and at least one sensing membrane. The sensing membrane is disposed between the first and second screens (36) and is adapted to expand when exposed to a predetermined quantity of a first predetermined fluid. The actuator (16) is disposed proximate the sensor package (14) within the sensor housing (12) and moveable between a first position and a second position through an intermediate position. The switch (18) is disposed proximate the actuator (16) and is operable between closed and open positions. When the actuator (16) is in the second position at least a portion of the actuator (16) depresses the switch (18) to control an-electrical, circuit connected therewith.

A tuner and a transformer formed by printed circuit board thereof are provided. The transformer includes a first winding and a second winding. In which, the first winding forms a first inductor and the second winding forms a second inductor. The transformer is formed by the first and the second inductors, wherein the first winding and the second winding are formed by conducting wires of a printed circuit board.

A single conversion tuner suitable for receiving RF signals having different requirements as to selectivity, linearity and image rejection is presented. Tuners of this kind are particularly useful for digital terrestrial as well as cable reception, where different modulation schemes require very high image rejection ratios on one hand and high linearity or pass band flatness on the other hand. The inventive tuner features a double-tuned tuneable filter in combination with an image reject mixer. The double-tuned filter provides excellent pass band flatness, while the image reject mixer provides a high intrinsic image rejection. The image rejection ratio of the combination of image reject mixer and tuneable filter is very high and fulfils the requirements of commonly used modulation schemes such as 8VSB, while the pass band flatness is compliant with the requirements for modulation schemes such as QAM.

A high frequency signal receiver can prevent higher harmonics other than a necessary higher harmonic from being subjected to frequency conversion so as to interfere with the base band signal in a broadcasting channel frequency band. The receiver has a high frequency signal receiving circuit 1 that comprises an input circuit 3 to which a high frequency signal (RF signal) subjected to frequency conversion from a 12 GHz band to a 1 to 2 GHz band is input, a mixer circuit 4 adapted to frequency convert the signal of 1 to 2 GHz band output from the input circuit 3 into a base band signal, a local oscillation output circuit section 5 adapted to supply a signal of a frequency band to be mixed with the signal output of the input circuit 3 to the mixer circuit 4 and a PLL circuit section 6 to which the source oscillation output signal from the local oscillation output circuit section 5 is input. The local oscillation output circuit section 5 has an oscillation circuit 51, a higher harmonic output circuit 52 that generates the fourth harmonic of the output signal of the oscillation circuit 51 and a resonance circuit 53. It controls both the resonance frequency of the resonance circuit 53 of the local oscillation output circuit section 5 and the frequency characteristic of the input circuit 3 by means of the control voltage output from the PLL circuit section 6 so as to boost the higher harmonic of an order that corresponds to desired broadcasting channel frequency and attenuate higher harmonics of all other orders that appear in other frequency bands that overlap the broadcasting channel frequency in the input circuit 3.

The invention provides a variable tuning circuit capable of extending a variable range in a high frequency band, ensuring the value of L of an inductor to increase the value of Q of a circuit in a low frequency band, and preventing a reduction in gain, an increase in noise, and unstable oscillation.A variable tuning circuit includes: a first parallel resonance circuit that includes a varactor diode, a capacitor connected in series to the varactor diode, and a first inductor connected in parallel to the varactor diode and the capacitor; and a second parallel resonance circuit that includes a second inductor connected in parallel to the varactor diode with a direct current cut-off capacitor interposed therebetween. When the varactor diode has a maximum capacitance, a resonant frequency of the second parallel resonance circuit is set about a lowest frequency in a variable frequency range.