251 results about "Negative peak" patented technology

In a method for deciding the level of an input signal, positive and negative signals are provided in response to the input signal. A peak of the positive signal is detected to provide a positive-peak value. A peak of the negative signal is detected to provide a negative-peak value. The positive signal and the negative-peak value are combined to provide a first combination signal. The negative signal and the positive-peak value are combined to provide a second combination signal. The first and second combination signals are compared to provide an output signal of zero or one.

A proximity detector employs a first peak detector circuit and a second peak detector circuit, both responsive to a magnetic field signal. The second peak detector circuit includes a positive peak detector circuit and a negative peak detector circuit, each of which have a predetermined excursion limit in an outward direction away from a center voltage of the magnetic field signal so as to be less affected by a large signature region in the magnetic field signal. The proximity detector also includes an output control circuit. The output control circuit is configured to provide an output signal, which, during a determined time period, changes state in response to the first peak detector circuit, and which, after the determined time period, changes state in response to the second peak detector circuit.

Apparatus and methods for detecting passing magnetic articles including an offset adjustment circuit for adjusting the DC level of the magnetic field signal based on a dynamically adjustable offset threshold signal. The detector includes a PDAC for tracking the positive peaks of a magnetic field signal and an NDAC for tracking the negative peaks of the magnetic field signal. In one embodiment, the offset threshold signal includes a positive offset threshold signal and a negative offset threshold signal that are initially set at fixed respective signal levels and that become the level of the PDAC signal and NDAC signals, respectively, in response to a counter, that counts a number of increments of the PDAC signal and decrements of the NDAC signal, reaching a predetermined count value.

The disclosed embodiments provide a system that operates a flyback converter. During operation, the system senses an input voltage for the flyback converter. Next, the system uses the input voltage to determine a negative peak current that enables zero voltage switching for a primary switch in the flyback converter. Finally, the system uses the negative peak current to perform the zero voltage switching for the primary switch based on the input voltage, wherein the negative peak current reduces a power loss of the flyback converter.

A distributive encoder for receiving and processing digital error signals representing variations in peak values of an equalized incoming digital data signal and in accordance therewith encoding error signals which represent signal peak errors in data signals for purposes of identifying erroneous signal baseline, peak and equalization conditions. The digital error signals represent variations in peak values of an equalized incoming digital data signal which includes a data signal baseline intermediate to its positive and negative peaks. Two sets of the digital error signals identify when present positive and negative levels transcend prior positive and negative levels, respectively, of the equalized incoming digital data signal. Using various subsets of these digital error signals, the distributive encoder generates encoded error signals which identify erroneous signal baseline, peak and equalization conditions. Using various ones of these encoded error signals, a baseline control circuit can generate a baseline control signal for use in controlling a correction of the equalized incoming digital data signal baseline, a peak control circuit can generate a peak control signal for use in controlling compensation for the positive and negative peaks of the equalized incoming digital data signal, and an equalization control circuit can generate a set of equalization control signals for use in controlling the equalization of the incoming digital data signal.

A device implements a method of tracking objects on a touch surface of an FTIR based touch-sensitive apparatus. An interaction map is generated that indicates local changes in interaction on the touch surface. The interaction map is processed for identification of positive and negative peaks that represent a locally increased and decreased interaction in the interaction map, respectively. To suppress the impact of interferences, a dedicated first heuristic and / or second heuristic is applied to identify potentially false peaks among the positive peaks. The first heuristic designates a positive peak as a potentially false peak when the positive peak is deemed to be associated with one or more of the negative peaks. The second heuristic designates a positive peak as a potentially false peak when the positive peak is deemed to be located along one of the movement trajectories. Movement trajectories of all objects deemed to exist on the touch surface at a preceding time point are then updated while taking the potentially false peaks into account.

A data-pattern feedback mechanism is introduced into the peak detection process of an automatic frequency compensation system in a Gaussian Frequency Shift Keying (GFSK) modulated system, providing fast and accurate fine-stage automatic frequency compensation (AFC). Maximum positive and negative peak registers are updated with new values as necessary based on detection during a sequence of identical binary bit values (e.g., during a "00" for detection of maximum negative peak frequency, or during a "11" for detection of maximum positive peak frequency), in a particular data frame. As soon as an initial value is determined for both the maximum positive and negative peak frequencies (e.g., after the first occurrence of a "11" and a "00", in any order), fine-stage automatic frequency compensation can be initiated. Subsequent adjustments to the VCO of the local oscillator will further refine the frequency offset towards the ideal of zero. Quick determination of the maximum positive and negative peak frequencies is made based on data pattern feedback in accordance with the principles of the present invention, allowing for a fast and accurate fine-stage automatic frequency compensation adjustment of a local oscillation clock signal.

A current sensing circuit for use in a switching regulator having a high-side switch. The current sensing circuit includes a first sensing circuit coupled to the high-side switch for measuring current flowing in a positive direction through the high-side switch. The first sensing circuit includes a first replica device for generating a current which is a scaled version of the positive current flowing through the high-side switch. The current sensing circuit further includes a second sensing circuit coupled to the high-side switch for measuring current flowing in a negative direction through the high-side switch. The second sensing circuit includes a second replica device for generating a current which is a scaled version of the negative current flowing through the high-side switch.

The invention discloses an asymmetric half-bridge converter and a control method thereof. A one-way clamping network is additionally arranged and is connected in parallel with a primary side, a secondary side or a third winding of a transformer, an auxiliary switch is controlled to be switched off when an excitation inductance current reaches a set value, the one-way clamping network is conducted,a clamping current passes through the one-way clamping network, the clamping current is clamped and maintained to be basically unchanged by the one-way clamping network, the one-way clamping networkis controlled to be switched off within a certain time before a main switch is conducted, the clamping current is released, voltages of two ends of the main switch are reduced to zero or be approximate to zero, and zero-voltage conduction of the main switch is achieved. By the asymmetric half-bridge converter, effective control of negative peak of the excitation inductance current can be achieved,a current effective value of a power device under light load of a converter is reduced, the light-load efficiency of the converter is substantially reduced under the condition that the advantages ofzero-voltage conduction of an existing technical scheme is maintained, the no-load loss is reduced, and control implementation is simple and efficient.

The invention discloses a self energy supply lightning current detection system, which is used for being matched with a lightning rod device for use to realize the defection on relevant parameters of lightning current. The self energy supply lightning current detection system comprises a signal sampling maintaining device, an energy taking device, a single chip control unit, a hardware clock unit and a data storage unit, wherein the signal sampling maintaining device comprises a current sensing unit, a first voltage limiting protection unit and a positive / negative peak value maintaining unit which are connected in sequence, and the energy taking device comprises an energy taking coil, a front end protector, a rectifying and wave-filtering unit, a second voltage limiting protection unit, a voltage stabilizing unit and a DC / DC unit which are connected in sequence. The self energy supply lightning current detection system of the invention can continuously realize the monitoring on whether a transmission line or a building lightning rod suffers with the lightning strike or not, and can accurately record the time, the amplitude value in the occurrence of the lightning strike and the polarity, a special triggering circuit is not needed, and the invention has the characteristics of high precision, simple structure, small size, low cost, high safety and the like.

The invention relates to an apparatus and a method for referencing an optical frequency of a tunable laser. Light from a reference laser and the tunable laser is injected into a length of an optical waveguide from opposite ends thereof. When the optical frequency of the tunable laser is swept, SBS induced positive and negative peaks in the optical power of light transmitted through the waveguide are used to provide an accurate frequency change reference.

The invention provides a dual loop voltage regulator based on an inverter amplifier and a voltage regulating method thereof. A voltage regulator includes a pass element, a buffer, and an error amplifier. The voltage regulator further includes a fast push-pull driver that has an inverter type amplification structure, is connected between a power output and a control input of the pass element, and reduces positive and negative peaks of the power output at a speed faster than a speed of a main feedback loop.

The present invention relates to real-time monitoring of photodynamic tumor treating effect, and the photoacoustic blood vessel imaging method is that during laser irradiation of tumor tissue for photodynamic treatment, the photoacoustic chromatographic images of the tumor tissue before and after photodynamic action are compared and the blood vessel diameter change is reflected with the positive and negative peak-to-peak width of the photoacoustic blood vessel signals. The equipment for the real-time monitoring of photodynamic tumor treating effect includes laser generator assembly, acoustic signal acquiring assembly and computer successively connected electrically, as well as rotating scan mechanism connected electrically to the computer, sample fixing assembly and connected acoustic assembly. The present invention is sensitive and quick in real-time monitoring of photodynamic tumor treating effect.

The invention discloses a high-precision and fast optical fiber grating spectrum peak-searching method. Taking searching a positive peak in the reflection spectrum of a reflection type optical fiber grating as an example, a threshold value which is adopted during peak search is first determined according to the maximum value among a plurality of peak values in the reflection spectrum of the optical fiber grating and the signal-to-noise ratio, whether a wave crest is the reflected crest of the optical fiber grating or the crest generated by noise is then judged according to the width and the shape characteristics of a set reflection spectrum, and the horizontal coordinate values of the start point and the end point of the reflected crest are recorded; finally, a left point and a right point on both sides of the reflected crest of the optical fiber grating, which are 3dB lower than the maximum value, are found, the horizontal coordinate values corresponding to the two points are summed up, the sum is then divided by 2, and thereby the position of the peak value is obtained. When a negative peak in the transmission spectrum of the reflection type optical fiber grating is searched, the method is still applicable as long as the method is simply changed; and the method is also suitable for searching the negative peak of the reflection spectrum of a transmission type optical fiber grating and the positive peak of the transmission spectrum of the transmission type optical fiber grating. The method solves the problems of the conventional method, i.e. low peak-searching precision and high computation load.

For a signal waveform to be processed, the continuous wavelet transform is performed with various scale factors, and a wavelet coefficient at each point in time is calculated. On an image showing the strength of the wavelet coefficient with respect to the scale factor and time, ridge lines are detected, and based on these ridge lines, positive and negative peak candidates are extracted, after which an error in the position and width of the peak due to the influence of a neighboring peak is corrected. Subsequently, the degree of non-symmetry of the peak shape or other features are examined to remove false negative peaks due to negative peak artifacts. Subsequently, a true peak cluster, a false peak cluster resulting from the removal of high-frequency components of a high-frequency noise or other causes, and other kinds of peaks are identified, and the obtained result is used to remove false peaks.

The invention relates to a pulse width modulation frequency variable power supply and a dead zone compensation method thereof. In the technical scheme, a comparison point level is arranged at the positive and negative semi-periods of a phase current respectively. When an output phase voltage reaches a predetermined value, a feedback signal level actuates to obtain a required compensation amount. The time of the positive and negative semi-periods of the phase current is determined by sampling the phase current, and the comparison point is switched around the positive and negative peaks of the phase current. The method has the following advantages that: the zero-crossing clamping problem of current can be effectively solved and the width of an output pulse can be precisely measured so as to precisely regulate the on / off time of an upper and a lower bridge arm power switching device in an inverter circuit; therefore, a desired output pulse width is obtained, and a current waveform sine degree and a control effect are improved.

A controller for a switched mode power converter is disclosed, the switched mode power converter comprising a transformer defining a primary side circuit and a secondary side circuit, the primary side circuit comprising a primary switch, the secondary side circuit comprising a synchronous rectification switch, the controller comprising: a baseline off-set circuit configured to provide a baseline timing off-set between opening the synchronous rectification switch and closing the primary switch; a peak current detector configured to detect a peak negative current in the secondary side circuit ; and a feedback circuit configured to add an off-set adaptation to the baseline timing off-set to provide an adapted timing off-set, wherein the feedback circuit is configured to adjust the off-set adaptation to minimise the negative peak current. A switched mode power converter and electronic equipment using such a controller is also disclose, as is a method for controlling a switch mode power converter.

Methods and systems for detecting a rotating target are disclosed herein, wherein a biasing magnet is associated with a rotating target in association with a dual peak detector. The rotating target generally comprises a plurality of teeth and at least one slot formed between at least one tooth of the rotating target. In general, the biasing magnet and the rotating target generate a magnetic signal having positive and negative peaks thereof. The dual peak detector includes a tooth detector and a slot detector, such that the dual peak detector detects a minimum and maximum peak of the magnetic signal generated by the biasing magnet and the rotating target. Additionally, a clamping circuit can be associated with the dual peak detector, wherein the clamping circuit can provide a true power on (TPO) functionality.

The invention provides a method for testing an LVDT sensor signal. The method is characterized in that when an output signal is sampled, the sampled signal and an excitation signal are subjected to the clock synchronization; and by performing a rough adjustment and an accurate adjustment for the phase of the excitation signal, finally, four times' sampling of the sampled signal each period can accurately align to zero, a positive peak, zero and a negative peak of the output signal. The technical proposal provided by the method can acquire a sensor location signal by directly testing an output signal without secondary treatments for the output signal such as sorting, filtering and the like, thereby effectively reducing the error caused by the secondary treatments of the signal, and increasing the accuracy of a feedback position signal of the sensor.

A high-voltage power source includes a high-voltage power source unit configured to apply high voltage obtained by superposing a high alternating-current voltage on a high direct-current voltage to a charging member, an output unit configured to output a first direct-current voltage having a first voltage value according to an externally input pulse-width modulation signal, a direct-current voltage conversion unit configured to convert the first direct-current voltage into a second direct-current voltage, a generation unit configured to boost the second direct-current voltage to generate a high direct-current voltage, a peak value detection unit configured to detect a positive peak value and a negative peak value from an alternating-current component of the high direct-current voltage, and a voltage difference output unit configured to output a third direct-current voltage having a third voltage value to the direct-current voltage conversion unit.

Where a tape is subject to lateral shift excursions from one side of a head to another, a coarse actuator is positioned laterally to enable a fine actuator to follow lateral motion of a longitudinal tape having at least one longitudinal defined servo track. A position error signal loop is configured to sense servo sensor(s) and to determine position error between the head and a desired position related to the defined servo track(s). A servo control senses the lateral shift excursion of the defined servo track(s); determines a maximum positive peak and a maximum negative peak of the lateral shift excursion; and positions the coarse actuator substantially at a midpoint of the maximum positive peak and the maximum negative peak of lateral shift excursion of the defined servo track(s). Thus, the fine actuator follows the lateral shift excursion, while the coarse actuator remains at the midpoint.

The invention relates to an IGBT narrow pulse suppression method for a three-level converter. The method comprises the following steps: (1) detecting a present current direction and an output voltage state of each phase of the three-level converter in real time; (2) when an output voltage is located at a positive peak point, if a phase current is set to be positive, turning off a switch tube s3 of a phase bridge arm all the time, if the phase current is set to be negative, calculating turn-on time T<on> of the corresponding switch tube according to the volt-second balance principle, if the T<on> is smaller than a set value, making the T<on> equal to T<D>, removing a narrow pulse after passing through a dead zone logic, wherein the T<D> is the dead zone time of an IGBT; and (3) when an output voltage is located at a negative peak point, if the phase current is set to be negative, turning off a switch tube s1 of the phase bridge arm all the time, if the phase current is set to be positive, calculating the turn-on time T<on> of the corresponding switch tube according to the volt-second balance principle, if the T<on> is smaller than the set value, making the T<on> equal to the T<D>, and removing the narrow pulse after passing through the dead zone logic. The IGBT narrow pulse suppression method has the advantages of being simple to achieve and high in narrow pulse suppression capability.

A modulated optical system with anti-clipping reduces or corrects clipping that might occur in the laser as a result of negative spikes or peaks in a multichannel RF signal. The system generally detects an envelope of the RF signal to generate an anti-clipping signal that follows at least a portion of the envelope and prevents one or more negative peaks from causing clipping by adjusting a bias current in response to the anti-clipping signal. The system may also reduce cross modulation by clamping the anti-clipping signal at an anti-clipping limit during lower power periods of the RF signal.

The application provides a downhole string leak point locating method and device. The method comprises: acquiring an acoustical signal from an oil-gas well annulus, subjecting the acoustical signal to autocorrelation analysis, and acquiring an autocorrelation function of the acoustical signal; using time corresponding to a first negative peak point of a time positive axis of the autocorrelation function as first feature time, and using time corresponding to a first positive peak point of the time positive axis of the autocorrelation function as second feature time; acquiring parameter information of an oil-gas well, and calculating along-travel speed of the acoustical signal in the annulus of the oil-gas well to be detected according to the parameter information; locating a downhole string leak point according to the first feature time, the second feature time and the along-travel speed. By using the downhole string leak point locating method and device according to the embodiments of the application, it is possible to quickly and accurately locate a downhole string leak point; economic loss due to well shutoff and production halt is avoided, the cost is low, the precision is high, and the method and device are well applicable to oil-gas wells.

The invention discloses a simultaneous and rapid detection method for benzo(a)pyrene, benzo(k)fluoranthene and anthracene in tea, relating to a tea detection method. The method comprises the following steps of: grinding tea, carrying out ultrasonic extraction by adding n-hexane, separating to obtain a supernate, and carrying out ultrasonic extraction by adding dimethylsulfoxide to separate a dimethylsulfoxide extraction liquid to obtain a solution sample to be tested; scanning a first-order derivative non-linear variable angle synchronous fluorescence spectra of benzo(a)pyrene, benzo(k)fluoranthene and anthracene in the solution sample to be tested according to a scanning path by using a fluorospectro photometer with a derivative variable angle synchronous scanning function; reading a peak value with a scanning sequence between 84 and 87 for the benzo(a)pyrene, reading a peak value with a scanning sequence between 365 and 372 for the benzo(k)fluoranthene and reading the absolute value of positive and negative peak values with a scanning sequence between 930 and 1050 for the anthracene; and quantificationally calculating the concentrations of the benzo(a)pyrene, the benzo(k)fluoranthene and the anthracene in the tea solution to be tested by adopting a continuous standard adding method or a method for matching a matrix with a calibration curve.

A circuit for generating video synchronization timing signals includes a negative peak detector (FIG. 5) for following variations of a composite video signal (FIG. 1), rather than clamping the most negative voltage of the composite video signal. The negative peak detector provides a voltage level VTIP representative of the voltage at the synchronization tip of the composite video signal. A sample and hold circuit (700, 702, 704) is used to add an offset VSLICE to VTIP, VSLICE being a voltage level of the breezeway, color burst, or back porch segments of the composite video signal, or a combination of these segments. The sample and hold circuit generates a signal VREF, and is connected by a resistor divider (708,710) to the negative peak detector to form the signal VTIP+VSLICE provided to an amplifier (606) functioning as a comparator. The signal VSLICE+VTIP is compared in comparator (606) with the composite video signal to provide an overall circuit output. Buffering is provided at the input of the negative peak detector by amplifier (600) to reduce any DC offset from the diode of the negative peak detector. To prevent amplifier DC offset error voltages from affecting the perceived VSLICE level, an amplifier (800) can be connected in a first position TTIP as part of a negative peak detector to store VTIP on a capacitor, in a second position TH as part of a sample and hold circuit to store VREF on a capacitor, and in a third position TCOMP to compare VSLICE+VTIP measured from the capacitors with the composite video signal to generate the overall circuit output.