41results about How to "Reduce Noise Sensitivity" patented technology

A method and apparatus for fully integrating a Voltage Controlled Oscillator (VCO) on an integrated circuit. The VCO is implemented using a differential-mode circuit design. The differential-mode implementation of the VCO preferably comprises a differential mode LC-resonator circuit, a digital capacitor, a differential pair amplifier, and a current source. The LC-resonator circuit includes at least one tuning varactor and two high Q inductors. The tuning varactor preferably has a wide tuning capacitance range. The tuning varactor is only used to "fine-tune" the center output frequency f0 of the VCO. The center output frequency f0 is coarsely tuned by the digital capacitor. The VCO high Q inductors comprise high gain, high self-resonance, and low loss IC inductors. The IC VCO is fabricated on a high resistivity substrate material using a trench isolated guard ring. The guard ring isolates the fully integrated VCO, and each of its component parts, from RF signals that may be introduced into the IC substrate by other devices. By virtue of the improved performance characteristics provided by the digital capacitor, the analog tuning varactor, the high Q inductor, and the trench isolated guard ring techniques, the inventive VCO is fully integrated despite process variations in IC fabrication.

A digital audio system including a digital phase-locked-loop circuit for generating a pulse-width-modulation (PWM) clock signal, applied to a pulse-code-modulation to pulse-width-modulation converter, is disclosed. The digital phase-locked loop includes a phase detector for measuring phase error between a reference signal and a feedback signal. A digital version of the phase error, after filtering by a loop filter, is converted to a digital delay control word that is sampled at twice its frequency. Successive samples of the delay control word control the propagation delay of first and second delay cells in an oscillator. The use of successive samples at substantially twice the frequency of change of the delay control word effectively realizes the sum of a sinc filter and a comb filter, which greatly suppresses the effects of jitter in the reference signal to the digital phase-locked loop.

An electronic device for a lighting system, comprising a TRIAC dimmer configured to receive a mains supply voltage and provide a phase cut voltage to the electronic device and having a control loop configured to control a duty cycle of a switched voltage converter that receives the rectified input voltage and provides drive current to a light emitting semiconductor device. The control loop has an error amplifier that is coupled to receive a sense voltage that is indicative of a current through the light emitting semiconductor device, the error amplifier is configured to provide a feedback signal to a pulse width modulation logic configured to control the duty cycle of the switched voltage converter to provide a constant drive current to the light emitting semiconductor device in response to the sense voltage, the error amplifier being coupled to receive a reference voltage that is a function of the input voltage.

A constant ON-time controller for a buck converter utilizes dual symmetrical ramps. The ramps may be generated artificially or by sensing the voltage across a sense resistor in the output. The ramp may also be generated by sensing the voltage across the “ON” resistance of the low side FET in the switching regulator. A modified output voltage has one of the ramps superimposed and a modified reference voltage has the other ramps superimposed. The modified output voltage and the modified reference voltage are compared to determine when to start the ON-time of the buck converter. The dual ramps reduce, noise susceptibility. The ON-time is stopped in response to charging a capacitor with the regulator input voltage. An offset may also be generated representing the difference between the average output voltage and the reference voltage. The offset is used to generate a modified reference to compensate for the offset.

The invention discloses a mean shift and neighborhood information based fuzzy C-mean image segmentation method, and mainly solves the problems of low segmentation accuracy and poor robustness of an existing image segmentation method. The method comprises the steps of (1) inputting a to-be-segmented image; (2) calculating a cluster number and an initial cluster center by adopting a mean shift algorithm; (3) performing initialization; (4) calculating a weight of an neighborhood image block in the to-be-segmented image; (5) calculating a weighted fuzzy factor weight of each pixel point in the to-be-segmented image; (6) performing cluster iteration; (7) judging whether an iterative stop condition is met or not; and (8) generating a segmented image. According to the method, the neighborhood information of the image is fully utilized, so that the method is high in noise robustness and the accuracy of image segmentation is greatly improved.

Methods of using “noise cores” in a PLD design. “Noise cores” are pre-developed blocks of logic included in a PLD design for the purpose of creating noise in other circuits also implemented in the PLD. By gradually increasing the level of noise created by the noise core, the noise sensitivity of the user circuit can be determined. Also, by ensuring that the user circuit functions properly when combined with the noise core, a designer can have confidence that unmodified portions of the user circuit will still function properly when the user circuit is modified. In some embodiments, once the user circuit has been qualified with the noise core operational, the noise core is disabled prior to including the PLD design in a system. Because the user circuit is proven to withstand a certain level of noise, future additions to the design do not necessarily require re-qualification of the user circuit.

High performance memory devices have been realized by applying an Evenly Scaled Multiple Level Architecture (ESMLA) using block select arrangement. A single-bit-line-write mechanism allows us to reduce the number of bit lines by 50% for static memory devices. The resulting memory device can be as fast as registers files while its area is smaller than prior art high-density memory devices. The scaling method of the memory architecture also assures that the speed of the memory devices will scale in the same rate as logic circuits in future IC manufacture technologies.

The invention relates to a visual inspection method of an electron beam welding pool shape parameter. During a current weld pool image processing process, there is strong noise interference, so that a continuous and smooth electron beam edge can not be obtained; however, the above-mentioned problem can be solved according to the invention. According to the method, calibration is carried out on an electron beam welding colored weld pool image visual sensing system; the system is started to collect weld pool images as well as a binary morphological image processing algorithm is employed to extract a weld pool image edge; and a weld pool shape parameter extraction algorithm is utilized to carry out extraction on a weld pool shape parameter. According to the invention, the noise influence on the extracted weld pool edge image is completely eliminated; the edge is smooth continuously and extraction precision of the weld pool shape parameter is high; and it takes about 30ms to complete the whole processing process, thereby completely meeting a real-time detection demand. Moreover, the provided method in the invention can be applied to the welding automation field.

The invention belongs to the technical field of controllers and particularly discloses an active disturbance rejection control method based on a fractional order extended state observer. The method comprises the following steps: S1, comparing an input reference signal with a system output signal to obtain a system error; S2, taking the system error as an input signal of a proportional controller to obtain a system control rate; S3, taking a controlled object as a purely fractional integral transfer function as shown in the description, taking a part except the transfer function as shown in thedescription in the controlled target as disturbance, and observing the disturbance through the fractional order extended state observer to obtain an observation value of the disturbance; and S4, estimating the disturbance to obtain gain estimation of the controlled object, carrying out real-time compensation on the disturbance according to the control rate and the observation value of the disturbance to obtain the stable controlled object. The fractional order active disturbance rejection control method has better robustness on a control parameter, also has good robustness on system gain change, and has better capability of resisting noise interference.

A voltage controlled oscillator is provided in the form of two ring oscillators 30 and 32. Each oscillator stage 14 includes an invertor 16, a level change accelerating circuit 18 and a level change decelerating circuit 20. The level change accelerating circuit 18 is responsive to an input control signal Vctrl to increase the oscillator frequency by decreasing the propagation delay through the invertor 16. The level change decelerating circuit 20 is responsive to the input control signal Vctrl to decrease the oscillator frequency by increasing the propagation delay through the invertor 16. Pairs of opposing invertors 34, 36, 38, 40 and 42 disposed between output signal lines of corresponding oscillator stages 14 in the two ring oscillators 30 and 32 serve to lock the two ring oscillators in antiphase.

A system on chip such as a radio receiver has reduced suceptibility to voltages in the bulk silicon by using gyrator elements in the receiver with each gyrator element including a plurality of current sources interconnected to provide output transconductance voltages, and a variable load for the current sources including first and second load resistors each serially connected with one other plurality of current sources. A variable resistance interconnects nodes of the load resistors with the variable resistance comprising a pair of native MOS transistors having low threshold voltages. In a preferred embodiment the first and second load resistors comprise first and second MOS transistors with the pair of native transistors serially connected between source elements of the first and second MOS transistors.

A voltage controlled oscillator and a method of operating a voltage-controlled oscillator are disclosed. The oscillator comprises a current controlled oscillator having a variable frequency current output, a first control path for generating a first control current having a first adjustable gain, and a second control path for generating a second control current having a second adjustable gain. A summer is provided for adding the first and second control currents to obtain a summed control current, and for applying the summed control current as an input current to the current controlled oscillator. A control sub-circuit is used for controlling the gain of the first control current as a function of a defined voltage on the second control path to maintain constant the gain of the current output of the current controlled oscillator over a given operating range of the current controlled oscillator.

The invention discloses a color image segmentation method based on exponential moment pixel classification. The method includes: in the segmentation process of a color image, the color image is decomposed by employing an exponential moment in RGB three channels, and proper moment values obtained by decomposition are regarded as pixel level characteristics of the image; a threshold is solved by employing a two-dimensional Otsu rapid threshold foremost segmentation algorithm, and training samples are selected; and the obtained pixel level characteristics and the training samples by employing a TSVM classifier are finally classified, and a segmentation result is obtained. According to the system, the description capability for the image by the exponential moment is high, the value calculation is stable, and the noise sensitivity is low so that the characteristics of the image can be well extracted; in this way, characteristic extraction of the image is performed via the exponential moment so that the segmentation effect is greatly enhanced compared with segmentation by employing single color or texture.

The invention discloses an all-digital phase-locked loop frequency synthesizer which comprises a numerical control oscillator, a prescaler, a counter, a time-to-digital converter, a first D trigger, asecond D trigger, a differentiator, a first adder, a second adder and a digital filter. The numerical control oscillator is connected with the prescaler, and the prescaler is respectively connected to the counter, the time-to-digital converter and the first D trigger. The first D trigger and the time-to-digital converter are connected to a reference frequency, and the first D trigger is connectedto the second D trigger and the differentiator. The counter is connected to the second D trigger, the second D trigger and the time-to-digital converter are connected to the first adder, and the first adder is connected to the differentiator. The second adder is connected to the frequency control word, the differentiator and the digital filter. The digital filter is connected to the numerical control oscillator. According to the all-digital phase-locked loop frequency synthesizer, the signal time sequence stability is improved, the noise sensitivity is reduced, the quantization noise is reduced, and the method is suitable for a 60GHz communication system.

The invention discloses a bridge construction stress detection system based on a blockchain. The system comprises an ultrasonic testing device, a WIFI module and a background monitoring center. The ultrasonic testing device comprises an ultrasonic sensor, a signal receiving and processing module and an ARM processor. The signal receiving and processing module comprises an impedance matching circuit, an anti-interference amplifying circuit and a frequency-selecting output circuit; after an output signal of the ultrasonic sensor is processed by the impedance matching circuit, the signal is divided into two paths in the form of differential signals to be sent into the anti-interference amplifying circuit for gain; the anti-interference amplification circuit amplifies the differential signal in the form of a differential composite operational amplifier; after the output signal of the anti-interference amplification circuit is sent to the frequency selection output circuit for band-pass filtering and frequency selection, a processed signal is sent to the ARM processor by using a voltage follower principle, so that the linearity of ultrasonic signal receiving and processing along with the change of stress is high, the system stress resolution is high, and the detection is more accurate.

A speed sensor including at least one sensor element and an analog-to-digital converter that digitizes the output signals of the at least one sensor element, and a Costas loop unit that is connected to the output of the analog-to-digital converter.

The invention discloses a square wave transformation amplitude measuring device based on self-mixing interference. The device comprises a light source unit, a signal processing unit and a data processing unit, wherein the signal processing unit introduces a hysteresis comparator to process signals so as to output required square wave signals, and the data processing unit searches for turning points for the output square wave signals so as to calculate the vibration amplitude of an object according to the number of fringes in the same inclined direction between adjacent turning points. The invention also discloses a square wave transformation amplitude measurement method based on self-mixing interference. According to the invention, the hysteresis comparator circuit with adjustable upper and lower limits is adopted to perform square wave transformation on an obtained laser self-mixing signal, so that the influence of external noise on the measurement stability and accuracy is effectively reduced. The self-mixing interference principle is adopted with no specific requirement on the coherence of the laser light source, so that the laser has large selection freedom. Meanwhile, the amplification factor of the signal is controllable, the measurable minimum amplitude value can reach a nanometer level, and wide-range real-time measurement is easy to realize.