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.

An acoustic resonator circuit to be integrated into a semiconductor product including: a resonator comprising first and second resonant frequencies; an inductive resistor tuned to said second resonant frequency so as to cancel the latter and to allow tuning of the resonator to said first resonant frequency; an tunable capacitive tuning element allowing to tune the resonator to said first frequency. A method is also provided for manufacturing an integrated circuit comprising an acoustic component allowing sufficient control of resonator characteristics.

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.

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.

A television receiver includes a tuner stage, a selective filter stage connected to the tuner stage, and a intermediate-frequency stage connected to the selective filter stage. A field-strength-detection stage is also provided, which generates a field strength signal proportional to the field strength of the received signal. The selective filter stage includes a transfer function that is modifiable by a control signal derived from the field strength signal.

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.

In an AM radio receiver, a radio-frequency tuning circuit comprises a tuning coil, and variable capacitance diode elements connected to the tuning coil; a local oscillator circuit comprises an oscillator coil, a variable capacitance diode element connected in parallel with the oscillator coil, and a capacitance element connected in series with the oscillator coil; and tuning voltage is applied from a variable voltage source to the variable capacitance diode elements of the high-frequency tuning circuit, and to the variable capacitance diode element of the local oscillator circuit through a voltage adjustment circuit connected to the variable voltage source and a reference voltage source.

A receiver such that the period required for tracking adjustment, temperature compensation is not needed, and tracking errors due to fluctuation of the power supply voltage are prevented from increasing, and a tracking adjusting method for the receiver. A DAC 4 generates a voltage according to the value of data (Do) inputted from an MPU 81 by using a control voltage outputted from a low-pass filter 35 in a local oscillator 3 as a reference voltage used during digital-analog conversion. A multiplier circuit 5 analog-multiplies the output voltage of the DAC 4 by a predetermined multiplier. The output voltage of the multiplier circuit 5 is applied as a tuning voltage to a high-frequency tuning circuit 20. In an EEPROM 84 stored is the value of the input data (Do) of the DAC 4 which has been measured in advance and corresponds to the tuned voltage of when the tracking error is the minimum at the central value of the local oscillation frequency, and the MPU 81 reads the data (Do) from the EEPROM 84 and inputs it to the DAC 4.

A receiver such that the period required for tracking adjustment, temperature compensation is not needed, and tracking errors due to fluctuation of the power supply voltage are prevented from increasing, and a tracking adjusting method for the receiver. A DAC 4 generates a voltage according to the value of data (Do) inputted from an MPU 81 by using a control voltage outputted from a low-pass filter 35 in a local oscillator 3 as a reference voltage used during digital-analog conversion. A multiplier circuit 5 analog-multiplies the output voltage of the DAC 4 by a predetermined multiplier. The output voltage of the multiplier circuit 5 is applied as a tuning voltage to a high-frequency tuning circuit 20. In an EEPROM 84 stored is the value of the input data (Do) of the DAC 4 which has been measured in advance and corresponds to the tuned voltage of when the tracking error is the minimum at the central value of the local oscillation frequency, and the MPU 81 reads the data (Do) from the EEPROM 84 and inputs it to the DAC 4.

A wideband bandpass filter includes an RF input terminal, an RF output terminal, a plurality of electrically tunable coupling capacitors coupled in series between the RF input and output terminals, and a plurality of resonating circuits each including an electrically tunable resonator capacitor coupled to one of the coupling capacitors. At least one resistance is coupled in series between at least one of the coupling capacitors for providing enhanced out of band rejection of the filter.

A double-tuned circuit includes a primary side tuned circuit having a first air-cored coil and a secondary side tuned circuit having a second air-cored coil. The first air-cored coil and the second air-cored coil are opposed to each other so that one opening end of the first air-cored coil and one opening end of the second air-cored coil are capable of being coupled to each other on a coil mounting surface. The coil mounting surface is provided with a first conductive pattern formed adjacent to the first air-cored coil in a direction perpendicular to an arrangement direction of the first and second air-cored coils, and both ends of first conductive pattern are connected to a ground.

The invention discloses an automatic tuning type downhole wireless signal transmission system, which comprises a downhole sending module and a well mouth antenna, wherein the downhole sending module is independently connected with a drilling tool and a logging-while-drilling tool in an oil pipe; the logging-while-drilling tool is placed on the drill bit of the drilling tool; the drilling tool comprises an insulated pup joint, wherein the insulated pup joint is laterally placed below a drilling tool motor and is positioned between the drill pipe and the drill collar of the drilling tool for realizing the electric isolation of the drill pipe and the drill collar; the positive pole of the downhole sending module is connected with one end, which is near the drill pipe, of the insulated pup joint; the negative pole of the downhole sending module is connected with one end, which is near the drill collar, of the insulated pup joint; the well mouth antenna is placed on a well mouth, one end isconnected with the oil pipe, and the other end is subjected to ground connection; the downhole sending module is adopted to receive logging-while-drilling data measured by the logging-while-drillingtool, a direct-driven way is adopted to convert the obtained logging-while-drilling data into an electric signal, and the electric signal is transmitted to the well mouth antenna through the oil pipeafter the electric signal is subjected to automatic tuning amplification. The automatic tuning type downhole wireless signal transmission system carries out transmission through the direct-driven way,and transmission efficiency is high.

A power line communication device including a current path provided between a first terminal and a second terminal. A coupling circuit includes a first circuit of a first inductor connected in parallel with a first capacitor and a first resistor, wherein the coupling circuit is connected between the first and second terminals. A sensor is configured to sense a communication parameter of the coupling circuit. The communication parameter may be a resonance of the first circuit, the quality (Q) factor of the resonance, the bandwidth (BW) of the coupling circuit, the resistance of the first resistor, or the impedance of the first circuit. A transceiver is adapted to couple to the first and second terminal to transmit a signal onto the current path or receive a signal from the current path responsive to the parameter of the coupling circuit and a level of current in the current path sensed by the sensor.

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.