166 results about "Digital reference" patented technology

A power factor correction circuit utilizes a digital controller string comprised of an analog-to-digital converter, which is input to a digital compensator followed by a pulse width modulation circuit for generating a switching pulse. The loop current in a regulator circuit such as a boost regulator is sensed and input to one side of a differential analog-to-digital converter, the other side thereof providing a digital reference current. This digital reference current is derived from comparing the input AC voltage to the regulator with the DC output voltage and processing these two voltages with a PFC algorithm to provide this reference voltage.

An ultrasonic diagnostic apparatus acquires images different in a frequency. The invention is composed of a transducer including plural elements for sending an ultrasonic wave and receiving the reflected ultrasonic wave, analog to digital converters that digitize plural received signals, first mixers that respectively multiply a signal from the converter and a first digital reference signal, first filters that respectively extract a signal having a predetermined center frequency from a signal from each first mixer, digital delay units that respectively delay a signal from each first filter, an adder that adds plural signals from the digital delay units, and a second mixer that multiplies a signal from the adder and a second digital reference signal. An envelope detector detects a signal from the second mixer, and a scan converter converts a signal from the detector to a picture signal for display, so the pass band of the filter is not required to be changed.

An IC card includes a first visible layer including a natural material having a unique visual pattern. A storage device is configured to store a digital reference image of the unique visual pattern to be visually compared with the unique visual pattern for authentication. An authentication method based on the IC card is also provided.

The invention discloses a self-adoptive correcting device of mismatch error of time-interleaved analog-digital converter, comprising an M channel TIADC, a signal recombination, a digital reference signal memorizer, a simulated reference signal generator, a self-adaptive reconstruction filter bank, a clock generation circuit and a subtraction device. Signals after passages are reconstructed are used to correct each passage instead of single correction on each passage, thereby solving the problem that when an input signal bandwidth is larger than the Nyquist frequency of each passage ADC, the time error can not be corrected due to aliasing. Each self-adoptive reconstruction filter is divided into a plurality of sub-filters for concurrent working, thereby not improving the requirement of thetreatment speed for a self-adoptive correcting filter while realizing the effect of signal recombination and ensuring the practicability of the hardware of the structure of the invention. A digital reference signal is internally installed in the device and is taken as a target to carry out the self-adoptive correction, pre-measuring or calculating a passage mismatch error is not needed, and the source of the error is not needed to be discriminated so that various mismatch errors can be corrected.

All digital reference frequency locking. An all digital approach is provided for operation within one or more CMs within a cable modem communication system to lock the upstream of the one or more CMs to the downstream symbol clock provided from a CMTS. The locking of the CM's upstream may be performed using one of at least three different functions: (1) Locking the upstream symbol clock phase to the downstream symbol clock phase, (2) Locking the downstream symbol clock phase to the headend reference clock phase (typically 10.24 MHz or integer multiple thereof), and (3) Locking the upstream carrier frequency to the downstream symbol clock frequency. The all-digital techniques for supporting all digital reference frequency locking functionality provide high performance to support S-CDMA and other synchronous modulation techniques.

One embodiment of the present invention relates to a method and apparatus to perform a low power activation of a system by measuring the slope of a digital signal corresponding to a motion sensor measurement value. In one embodiment, a low power activation circuit is coupled to magnetic motion sensor configured to output a magnetic signal proportional to a measured magnetic field. The low power activation circuit may comprise a digital tracking circuit configured to provide a digital signal that tracks the magnetic field and a difference detector configured to detect a difference between a current digital signal and a prior digital signal stored in a digital storage means. If the detected difference is larger than a digital reference level, an activation signal is output to awaken a system from a sleep mode.

A phase-locked loop (PLL) including an active filter, a voltage-controlled oscillator (VCO), two phase detectors, a charge pump and a digital-to-analog converter (DAC) is provided. The VCO generates an oscillation signal according to a control signal provided at an output of the active filter. The first phase detector generates a phase difference signal according to a reference signal and a feedback signal associating with the oscillation signal. The charge pump provides a charging current to a first input of the active filter according to the phase difference. The second phase detector generates a digital reference signal according to the phase difference between the reference signal and the feedback signal. The DAC converts the digital reference signal to an analog reference voltage and provides the analog reference voltage to the second input of the active filter.

A multi-path digital power supply controller includes a first ADC (ADC1) coupled to the supply's output voltage V_out and arranged to provide an output which varies with V_out's low frequency components, and a second ADC (ADC2) coupled to V_out and arranged to provide an output which varies with V_out's high frequency components. A digital reference value is subtracted from the output of ADC1 to produce a low frequency digital error signal, and a summing circuit sums the low frequency digital error signal and the output of ADC2. Processing circuitry is arranged to produce an output which varies with the summed signal and is suitable for coupling to a power stage for use in regulating V_out. Preferably, ADC1 is a low-bandwidth high-resolution ADC and ADC2 is a high-bandwidth low-resolution ADC, both of which are low-cost components.

The present application describes a battery charger interface architecture suitable for digital applications. According to some embodiment, the parameters of a battery are measured and converted into a digital data stream using various analog-to-digital conversion techniques. The digital data stream is compared with a predetermined digital reference to control a duty cycle of a PWM sequence according to a functional mode of the battery charger interface. If the battery charger provides a controlled current output, then the battery charger interface architecture operates in a pulse mode controlling the duty cycle of the battery charger current. If the battery charger does not provide a controlled current output, then the battery charger interface architecture operates in a linear mode controlling the charging current of the battery charger.

The invention discloses a method for controlling a fuzzy PID digital control DC-DC converter. Based on a control system which comprises an ADC unit, a comparator, a fuzzy PID compensator with a fuzzy control unit and a PID control unit, a digital pulse width modulator and a driver unit, the control system and the main topology of a Buck type DC-DC converter are connected in series to form a closed loop, the analog output voltage of the converter is subjected to A/D conversion and then is input to the comparator to be compared with a digital reference voltage signal, the output voltage error value and the error deviation value are calculated, the fuzzy control unit determines the duty ratio value of the switching period according to the output voltage error value and the error deviation value, and the digital pulse width modulator and the driver unit output corresponding PWM according to the duty ratio value to control a power tube to be connected or disconnected so that the output voltage value can be regulated. The defect of the nonlinear effect of the converter is overcome, the system response is accelerated, overshooting is reduced, and good input disturbance resistance and load disturbance resistance are achieved.

A magnetic resonance imaging (MRI) system includes a transmitter that produces an RF excitation pulse that is applied to a subject positioned in the MRI system to induce emission of at least one of an NMR signal and an ESR signal therefrom, and that produces a reference signal indicative of the phase of the RF excitation pulse. A first analog-to digital converter has an input for receiving the reference signal that is synchronous with the RF excitation pulse. One or more additional analog-to-digital converters/processors have inputs for receiving the at least one of NMR signals and ESR signals produced by a subject placed in the MRI system and produce one or more complex digital signal therefrom. A normalizer is connected to receive and normalize the digital reference signal and a mixer is connected to receive the normalized digital reference signal and the digital signal. Accordingly, the mixer is operable to multiply the normalized complex digital reference signal with the complex digital signal.

An audio amplifier includes a compensation unit, an output unit and a calibration unit. The compensation unit generates a compensation signal based on a digital input signal, a digital reference code, a mode signal and a digital approximation code. The output unit generates an output signal based on the compensated input signal. The calibration unit generates the digital approximation code based on the output signal and the mode signal. The digital approximation code includes a plurality of bits that are generated sequentially.

The invention provides a banking transaction authentication method and system based on image authentication. According to the banking transaction authentication method, a network server obtains reference image information of a user and processes the reference image information to be digital reference image information, wherein feature information of the digital reference image information can be extracted easily; in the process of banking transaction conducted by a user, user equipment requests the user to provide image information for authentication, the image information for authentication is converted to an image sequence, encryption and endorsement are conducted on banking transaction information and the image sequence, and user transaction information is formed; the network server conducts attestation and decoding on the received user transaction information and obtains the image sequence, the image sequence is restored to be analog image information, the analog image information is processed to be digital image information confirming to characteristics of the user, the digital image information is compared with the digital reference image information of the user to enable the identity of the user is confirmed, therefore, security vulnerabilities existing in electronic banking are plugged, and transaction security is improved.

A control circuit includes an input terminal for receiving an input signal, which maybe either a digital input signal or an analog input signal, and the control circuit is configured to provide a digital control signal in response to the input signal. The control circuit may include a mode detection circuit for determining whether the input signal is a digital signal or an analog signal and providing a mode signal, a multiplexer circuit configured to select either a digital reference signal or an analog reference signal in response to the mode signal, and a comparator configured for comparing the input signal with the reference signal selected by the multiplexer to provide the PWM control signal.

The invention discloses an automatic gain control circuit for closed-loop drive of an MEMS gyroscope. The automatic gain control circuit comprises an amplitude comparator, a residual selector and a loop filter. The amplitude comparator automatically determines whether a gyroscope is in an oscillation starting phase or a stabilizing phase based on the magnitude of an output signal of the amplitude detector, and outputs a control signal for controlling an operation mode of the loop filter and the residual selector according to the determination result. The residual selector outputs an input signal required for the loop filter according to the control signal output from the amplitude comparator and a preset digital reference value. The loop filter generates a drive amplitude signal based on the input signal and the control signal output from the amplitude comparator. The invention designs the amplitude comparator in the automatic gain control circuit to realize the self-detection of a drive system and to adaptively adjust the operation mode of an automatic gain controller; and the oscillation starting time can be less at very small loop bandwidth, the stabilizing time is shorter, meanwhile, fewer design parameters are needed, and the system is more concise.

A method for adaptive reconstruction and interpretation of spectra combined with re-calibration of a device providing spectrometric data, consist in carrying out an automatic calibration using the external reference light spectrum and its corresponding digital reference data stored in the internal memory of the device. The continual re-calibration procedure allows for automatic adaptation of the values of the coefficients in a reconstruction sub-procedure as well as the estimation of the values of the coefficients in an interpretation sub-procedure on the bases of a current shape of spectrometric data.

The invention relates to the field of integrated circuits, specifically to a highly integrated low-power reference source. According to the highly integrated low-power reference source provided by the invention, a digital reference voltage source, an analog reference voltage source, a current bias reference source and a band gap reference voltage source are skillfully combined as an integrated circuit for meeting the multipurpose requirement, and the reusable circuit units in the existing reference source are simplified, so that the whole reference source has a simple circuit structure and still has high performances; on the other hand, since an electronic system works stably, a starting circuit is automatically closed to avoid quiescent dissipation, so that the operation is high in reliability and the requirement on greatly reducing the quiescent dissipation is met; and at last, the highly integrated low-power reference source provided by the invention can further adjust the voltage values output by the digital reference voltage source, the voltage values output by the analog reference voltage source, the current values output by the current bias reference source and the reference voltage values output by the band gap reference voltage source according to various requirements.

The present invention discloses a SF6 gas component online real-time monitoring apparatus and a SF6 gas component online real-time monitoring method. The SF6 gas component online real-time monitoring apparatus comprises a processor, a light source circuit and a photoelectric detection circuit, wherein the light source circuit comprises a detection laser source and a reference laser source to generate corresponding detection laser and corresponding reference laser, the processor is connected to the light source circuit to acquire the laser input parameter, the photoelectric detection circuit comprises a first photoelectric detection unit, a second photoelectric detection unit and a data acquisition unit, the data acquisition unit respectively converts a detection electric signal and a reference electric signal into a digital detection signal and a digital reference signal, and the processor determines the laser output parameter according to the digital detection signal and the digital reference signal, and determines the concentration of SF6 gas to be determined according to the laser input parameter and/or the laser output parameter. According to the present invention, with the apparatus, the input and output data of the two lasers can be obtained, such that the concentration or purity of the SF6 gas to be determined can be determined according to the dual-wavelength differential laser absorption spectrum.

The invention is suitable for the optical imaging correction technology field and provides a rapid inclination phase error compensation method and an apparatus based on wavefront rotation. The methodcomprises the following steps of using coaxial digital holographic microscopic system to collect a hologram of an object to be tested and taking as an original hologram; rotating the original hologramfor 180 degrees clockwise or counterclockwise and acquiring a digital reference hologram which is taken as a rotation hologram; using a Fourier transform method in digital holographic microscopy to carry out phase recovery processing on the original hologram, and acquiring an original expansion phase diagram; using the Fourier transform method in the digital holographic microscopy to carry out phase recovery processing on the rotation hologram and acquiring a rotation expansion phase diagram; and subtracting the original expansion phase diagram from the rotation expansion phase diagram and acquiring a phase diagram after compensation for the original expansion phase diagram. By using the method of the invention, rapid and accurate inclination phase error compensation in coaxial digital holographic microscopy imaging is realized.

The invention belongs to the technical field of radars, and discloses a method for detecting a target when a reference signal of an external radiation source radar comprises multipath interference. The method comprises the steps: obtaining a signal received by the external radiation source radar, wherein the signal comprises the reference signal and an echo signal, and the reference signal comprises a multipath interference signal, and the echo signal comprises a direct wave signal and a multipath interference signal; sequentially carrying out the amplification, frequency mixing, A/D sampling and digital downconversion processing of the reference signal and the echo signal, and obtaining a digital reference signal and a digital echo signal; carrying out the blind balance filtering of the digital reference signal, and obtaining the reference signal after multipath interference inhibition; carrying out the time domain interference cancellation of the digital echo signal, and obtaining an echo signal after the time domain interference cancellation; carrying out the pulse compression of the echo signal after the time domain interference cancellation, thereby obtaining a target detection result. The method can achieve the inhibition of multipath interference components in the reference signal, eliminates a false target caused by the multipath interference, and obtains a better target detection result.