57results about How to "Constant amplitude" patented technology

An improved interrogator for an inductively coupled identification system is disclosed. The interrogator provides a multidimensional electromagnetic field through a plurality of coils aligned relative to each other. The coils provide a rotating magnetic field having approximately constant amplitude regardless of orientation with respect to the transponder. An additional coil may be utilized to precess the multidimensional electromagnetic field. The interrogator may further provide an impedance matching network that includes a series drive capacitor to match the impedance of a capacitor in parallel with a coil to a driver load impedance.

A method and transmission circuit are provided for generating a transmission signal, wherein the feedback component of the transmission signal is attenuated in accordance with the required mean transmission power and used for regulation, i.e., the mean transmission power is adjusted by variable attenuation between the transmission amplifier and the comparator in the control loop.

A time domain measurement and control system for a hot wire air flow sensor is disclosed in which the air flow sensor is of the type having a resistive heating element with an input end and an output end. The control system includes a fixed frequency variable width pulse generator which generates a pulse train through the heating element. This pulse train, furthermore, has a first predetermined voltage amplitude. The output voltage amplitude of the pulse train is determined at the outlet end of the heating element while a control circuit varies the duty cycle of the pulse train to maintain the output voltage amplitude at a second predetermined voltage level. The duty cycle of the pulse train is proportional to the air flow rate through the air flow sensor. In a modification of the invention, a fixed width variable frequency pulse train is generated through the resistive heating element and the frequency of the pulse train is varied to maintain the output voltage amplitude of the pulse train at the outlet end of the resistive heating element at a second predetermined voltage level. In this modification, the frequency of the pulse train is proportional to the air flow rate through the air flow sensor.

An ultrasonic measuring device for measuring a fluid flowing in a pipe includes a housing and transducers. The housing receives and fixes the pipe, so that the fluid can flow through a central recess in a flow direction. The ultrasonic transducers emit and receive ultrasonic signals. Two first ultrasonic transducers are arranged laterally on a first side of the central recess, and two second ultrasonic transducers are arranged on a second side of the central recess. The second side is opposed to the first side, so that the recess is located between the first and the second ultrasonic transducers, and the ultrasonic transducers are arranged and aligned so that one of the first ultrasonic transducers emits a first measuring signal to one of the second ultrasonic transducers obliquely to the flow direction and receive a second measuring signal emitted by the second ultrasonic transducer obliquely to the flow direction.

In a method and apparatus for generation of magnetic resonance (MR) images based on the TrueFISP sequence with simultaneous acquisition of the MR images of a number of parallel slices of a measurement subject the number of the slices N to be acquired in the measurement subject is established whereby N is at least, the number of the phase coding lines MA per raw data matrix and slice N are established, with the requirement that the quotient of MA and N is a natural number, the repetition time TR, the radio-frequency pulse duration RF and the flip angle α are established, of each raw data matrix is sub-divided into S separate segments to be measured, whereby S is equal to N or a whole-number multiple of N, with the requirement that the quotient Q of MA and S that corresponds to the number of the phase coding lines per segment is a natural number, data are acquired for all segments S of all slices N, whereby the time duration, in msec, T_Seg for the acquisition of the data of each segment is $T_{\mathrm{Seg}}=\mathrm{TR}+\mathrm{RF}+\frac{\mathrm{MA}}{S}·\mathrm{TR},$

and the measurement of all segments S of all slices N is implemented such that the time duration T_Relax is T_Relax=(N−1)·T_Seg [msec] for the relaxation of the magnetization M_Z with the relaxation constant T₁ in a slice N that corresponds to the time span from the end of the measurement of a first segment up to the beginning of the measurement of a second segment of the same slice.

The invention relates to an electrical source transmitter device with a self-adaption dummy load and a control method. The electrical source transmitter device is characterized in that a generator or a battery pack is connected with a direct current voltage stabilizing power supply, the direct current voltage stabilizing power supply is respectively connected to a transmitting branch and a self-adaption dummy load branch through a current sensor, a main controller is connected with a direct current constant current power supply through a constant current power supply control unit, is connected with a current pulse generator through a pulse generator control unit, and is connected with a self-adaption current stabilizing converter through a current stabilizing converter control unit, and the current sensor is connected with the self-adaption current stabilizing converter. Under the condition that the resistance value of the dummy load is unchanged, the generator or the battery pack keeps outputting in constant power, the operation is simple and convenient, the constant pulse current amplitude is ensured, the quality of emission current pulse waveform is improved, the size of the system is reduced, the weight of an instrument is lightened, the working stability of the transmitter is increased, the service life of the alternating current generator or the battery pack and the direct current voltage stabilizing power supply is prolonged, and the device can stably and reliably work in a complex field environment in a long time.

Disclosed is a gyroscope sensor circuit, including a first differential amplifier differentially amplifying signals outputted from first sensing nodes of a gyroscope sensor; a phase shifter shifting a signal from the first differential amplifier by a predetermined shift phase; an amplitude detector detecting the amplitude magnitude of the signal from the first differential amplifier; and a variable gain amplifier amplifying the shifted signal from the phase shifter with gain adjusted depending on the amplitude magnitude from the amplitude detector, and providing the amplified signal to driving nodes of the gyroscope sensor.

The invention discloses a micromechanical gyroscope drive method, which comprises four steps of generating an AC (alternating current) signal, generating a static drive signal, detecting the signals and extracting amplitude and phase. Through the active accommodation to the disturbance inside a micromechanical gyroscope, the micromechanical gyroscope drive method can ensure that the frequency and the amplitude of a drive mode detection signal are kept constant and a phase difference between the drive mode detection signal and the AC drive signal is also kept constant. According to the invention, due to no need of tracking a resonant frequency of a drive mode, the influence to a micromechanical gyroscope system by modules such as a filter relevant to the frequency in the micromechanical gyroscope system is avoided, and the stability of the micromechanical gyroscope system can be enhanced.

In order for keeping the amplitude of the excitation current of a vibrator constant irrespective not only of the temperature variation but also of the manufacturing variation and the variation in frequency, a comparison control circuit for controlling the amplitude of the drive signal for exciting the vibrator includes a comparative voltage supply circuit for supplying the comparative voltage, and the comparative voltage supply circuit generates the comparative voltage with a constant current source and a second resistor made of a material the same as a material of a first resistor included in a current-voltage conversion circuit.

The invention concerns a circuit arrangement for igniting and operating an electrodeless gas discharge lamp by means of a high operating frequency drive voltage, comprising a half-bridge commutator having two switching elements each having an emitter electrode and a control electrode. The said switching elements are alternately switched to a conducting state by means of a resonant control circuit, which is coupled to an oscillator via a transformer. The said resonant control circuit comprises capacitor means forming part of said oscillator and a driver stage driven by an oscillator, the driver being of the class-E type. A DC supply voltage is supplied to the driver via a current-limiting circuit. The amplitude of the high frequency drive voltage is substantially constant in a chosen frequency range.

The invention relates to a three-plasmid whole sealing environmentally friendly vibration fluidized bed dryer which is suitable for drying powder material of regular shape such as Laroflex MP with granularity ranging from 50mu m to 5000mu m. The drier comprises a foundation (9), a lower housing (13), a fluidized bed body (6), an upper housing (18) and a bag type dust collector (24); wherein the lower housing (13) is supported on the foundation (9) by a slantly arranged plate spring (12), a case type vibration exciter (14) is arranged at the front end of the lower housing (13), the fluidized bed body (6) is arranged above the lower housing (13) and internally provided with a hood-shaped fluidized bed plate (7), the upper housing (18) is arranged above the fluidized bed body (6) and internally provided with a plurality of groups of bag type dust collectors (24). An air-reserve tank (24.6) is arranged outside the upper housing (18), a plurality of air branch pipes (24.3) are internally arranged in the air-reserve tank (24.6), wherein each air branch pipe (24.3) is provided with a pulse solenoid valve (24.5), the bottom part thereof is provided with an air source hole (24.7). The drier of the invention features low energy consumption, high production efficiency, good operation stability and good uniformity of products.

The invention provides a vibrational excitation device and belongs to the technical field of medical instruments. The vibrational excitation device comprises a vibrating source, a sensor and a controller, wherein the vibrating source is electrically connected with the controller; the vibrating source comprises a stator and a mover; the mover reciprocates relative to the stator under the action ofan alternating magnetic field or an external electric field; the mover is used for being externally connected with a coagulometer so as to drive the coagulometer to move; the controller controls the vibration amplitude and the accelerated speed of the reciprocation, relative to the stator, of the mover by adjusting the exerted alternating magnetic field and frequency or the external electric fieldstrength and frequency; and the sensor is disposed on the mover and used for collecting the moving vibration amplitude and accelerated speed of the mover. By means of the vibrational excitation device, the vibration amplitude and the accelerated speed of the coagulometer during vibration can be controlled to keep constant.

A jitter generating device for generating a jitter on a carrier signal includes: a carrier signal generator for generating the carrier signal; a modulation signal generator for generating a modulation signal corresponding to the jitter; an orthogonal modulator for modulating a phase of the carrier signal generated by the carrier signal generator using the modulation signal generated by the modulation signal generator as one of modulation input signals; a DC power supply for applying a DC voltage serving as the other modulation input signal to the orthogonal modulator; and a limiter amplifier for setting an amplitude of an output signal of the orthogonal modulator to be constant.

The invention discloses a high-voltage output stage integrated circuit. The integrated circuit comprises a filter circuit and a modulation circuit; the filter circuit is connected with a RC (Resistance-capacitance) circuit in series, so as to filter out medium-high frequency clutters; the voltage is inputted into the modulation circuit after the voltage is stabilized and the proportion is amplified by an operational amplifier; the modulation circuit modulates the amplitude and outputs stable voltage by a thyristor and a three-end voltage-regulator tube; negative electrodes of the thyristor D4 and the thyristor D6 are divided into two paths to receive the voltage of the filter circuit; one path is connected with a capacitor C4 in series, so as to filter out the direct-current voltage in the alternating voltage by using the characteristic of circulating the alternating current and blocking the direct current of the capacitor C4; the other end of the capacitor C4 is connected with a negative electrode of the thyristor D5 and a control electrode of a three-end silicon controlled rectifier Q1; the thyristor D5 protects the circuit; if the potential of the control electrode of the three-end silicon controlled rectifier Q1 is too high, the three-end silicon controlled rectifier Q1 is reversely conducted to be connected with the ground; if the potential is too low, the three-end silicon controlled rectifier Q1 is not triggered to be conducted; in the same way, a same circuit is connected in parallel; the circuit consists of the thyristor D6 and a thyristor D7, a capacitor C5 and a three-end silicon controlled rectifier Q2. The integrated circuit effectively stabilizes the output voltage of the high-voltage integrated circuit, filters the frequency, and effectively regulates the abnormal voltage.

In a method of controlling a reluctance polyphase electric machine (36), in particular an automobile motor, the currents injected into each coil of the stator of the machine (36) are deduced by a transformation of a pair (Id, Iq) of excitation currents (Id) and of armature current (Iq) defined in a reference frame (d, q) rotating with the rotor of the machine, such that: - the excitation current (Id) is composed of a fundamental sinusoidal signal, to which are added successively other odd harmonics of increasing order when the torque setpoint of the machine increases, - the armature current (Iq) is a signal proportional to the estimated or measured electromotive force of the machine.