Abstract: A frequency detector is used for detecting a frequency difference of a signal to be tested from a first time point to a second time point. The frequency detector includes: an alternating current coupled capacitor configured to receive the signal to be tested; a rectifying circuit electrically connected to the alternating current coupled capacitor; an analog-to-digital converter electrically connected to the rectifying circuit; a control unit electrically connected to the analog-to-digital converter; and a counter electrically connected to the rectifying circuit and the control unit, wherein the control unit is configured to calculate the frequency difference of the signal to be tested from the first time point to the second time point according to outputs of the analog-to-digital converter and outputs of the counter.

Abstract: An endoscope apparatus includes an endoscope including a cable and a sensor and a processor. The endoscope includes a differential amplifying section configured to differentially amplify an output signal from the sensor. The processor includes a power supply circuit configured to generate a reference voltage supplied to the differential amplifying section. The reference voltage generated by the power supply circuit of the processor is supplied to the differential amplifying section of the endoscope via the cable. An output signal of the differential amplifying section is detected by the processor via the cable.

Abstract: A radar circuit for controlling a radar antenna in a vehicle comprises an antenna connection for connection of a radar antenna, a radar circuit for transmission and reception of a radar signal, wherein the radar circuit is connected to the antenna connection. A test circuit to test the connection of the radar antenna is provided.

Abstract: A tuning device and method for tuning or verifying the tuning of a string of a stringed instrument is provided. The device includes an electromagnetic pickup physically separate from the stringed instrument. The electromagnetic pickup is a noise cancelling pickup. The electromagnetic pickup ultimately provides an electrical signal indicative of a movement of the string in a magnetic field of the electromagnetic pickup to a processor electronic tuner. Optional features of the electromagnetic pickup increase the effective range of the pickup.

Abstract: A centrifuge includes a regenerative braking safety system including an electrical system reversibly coupled to a power source. A motor is coupled to the electrical system. The motor is capable of driving a rotor using power delivered through the electrical system, and is further capable of supplying the electrical system with recovered energy. The recovered energy is electrical energy converted from kinetic energy of the rotor during regenerative braking of the motor. The safety system includes a power cut-off configured to disable the effect of regenerative braking of the motor when the electrical system is decoupled from the power source.

Abstract: There is described a device for removing an offset from a signal, the device comprising (a) a frequency estimation unit (260) for estimating a frequency of the signal, (b) an offset estimation unit (222) for estimating the offset in the signal by applying an adaptive low pass filter to the signal, wherein a cut-off frequency of the adaptive low pass filter is determined based on the frequency of the signal estimated by the frequency estimation unit (260), and (c) a subtraction unit (230) adapted to subtract the offset estimated by the offset estimation unit (222) from the signal. There is also described a filter unit comprising the device. Furthermore, there is described a corresponding method of removing an offset from a signal as well as a computer program and a computer program product for performing the method by means of a computer.

Abstract: A field device comprising a signal processing unit that generates a digital measurement, control or regulation signal, and comprises an output stage that converts the digital measurement, control or regulation signal into an analog voltage or current signal, The field device also includes a monitoring device which comprises a measuring device that detects the analog voltage or current signal and converts this signal into a digital voltage or current measurement signal, a first digital low-pass filter for filtering the digital measurement, control or regulation signal, a second digital low-pass filter having the same cut-off frequency as that of the first digital low-pass filter, a comparator downstream of the low-pass filters, and an evaluation device that generates an error message when the deviation between the compared signals exceeds a pre-determined level.

Abstract: The present invention discloses a sensing circuit including a sensing device, a first amplifier circuit, a high-pass filter, a second amplifier circuit and a determination circuit. The sensing device produces a sensing signal. The first amplifier circuit reduces high-frequency components of the sensing signal and amplifies low-frequency components of the sensing signal to produce a first amplified signal. The high-pass filter removes the direct current of the first amplified signal to produce a filtered signal. The second amplifier amplifies low-frequency components of the filtered signal according to a first predetermined voltage to produce a second amplified signal. The determination circuit determines whether the second amplified signal is higher than a second predetermined voltage and lower than a third predetermined voltage, and produces a detection result when the second amplified signal is higher than the second predetermined voltage or lower than the third predetermined voltage.

Abstract: An RF signal reception device including: a transposition device of signals of frequency fRF to a first intermediate frequency IF1<fRF; a first bandpass filter centered on IF1; a sampler at a frequency fs<IF1; a second discrete-time filter centered on a second intermediate frequency IF2=?·fs/M+fs/(M·n); a decimation device of a factor M; an analog-digital convertor to operate at a frequency fs/M; where ?, n and M are strictly positive real numbers chosen such that: ?<fs/(2·BWch·M), and BWch/2<fs/M·n), with BWch: bandwidth of a channel of the received RF signals.

Abstract: A frequency measuring apparatus includes: a counter section adapted to count a signal including a pulse signal for a predetermined time period, and output a binary count value corresponding to a frequency of the signal including the pulse signal; and a low pass filter section adapted to perform a filtering process on the count value, wherein the low pass filter section includes a first stage filter and a second stage filter, the first stage filter is a moving average filter to which the count value is input, and which provides a binary output with a high-frequency component reduced, and the second stage filter performs an average value calculation on the binary output to provide an output with the high-frequency component reduced.

Abstract: Provided is a measurement apparatus that measures a characteristic of a filter, comprising a first transmission line that has the filter connected therein, the first transmission line receiving a multi-tone signal having signal components at a plurality of frequencies from an input end thereof, passing the multi-tone signal through the filter, and outputting the multi-tone signal from an output end thereof; a second transmission line that receives the multi-tone signal from an input end thereof, propagates the multi-tone signal therein, and outputs the multi-tone signal from an output end thereof; and a measuring section that calculates the characteristic of the filter based on the multi-tone signal output from the output end of the first transmission line and the multi-tone signal output from the output end of the second transmission line.

Abstract: A frequency measuring apparatus includes: a counter section adapted to count a signal including a pulse signal for a predetermined time period, and output a binary count value corresponding to a frequency of the signal including the pulse signal; and a low pass filter section adapted to perform a filtering process on the count value, wherein the low pass filter section includes a first stage filter and a second stage filter, the first stage filter is a moving average filter to which the count value is input, and which provides a binary output with a high-frequency component reduced, and the second stage filter performs an average value calculation on the binary output to provide an output with the high-frequency component reduced.

Abstract: A frequency measurement device for measuring a frequency of a signal to be measured including a pulse signal, includes: a signal multiplier section that multiplies the signal to be measured by n (n is an integer) and outputs a multiplied signal; a counter section that counts the multiplied signal with a predetermined gate time and outputs a count value of the frequency of the signal to be measured at a predetermined period; and a low-pass filter that outputs a signal corresponding to the frequency of the signal to be measured based on the count value outputted at the predetermined period.

Abstract: A method for digital triggering of a digital recording of a digitized measurement signal having a superimposed noise signal. The method includes generating from the digitized measurement signal a digital triggering signal for the digital triggering of the digital recording of the measurement signal, and performing band-limitation of the noise signal superimposed on the digitized measurement signal via a low-pass filtering before the digital triggering signal is generated. The bandwidth of the low-pass filtering is adjusted dependent upon edge steepness of the measurement signal, in order to reduce variance ?t2 in jitter of the digital triggering signal.

Abstract: A frequency measuring apparatus includes: a high-order digit calculation section adapted to measure an input signal and output a high-order digit value of a frequency value of the input signal; a low-order digit calculation section adapted to measure the input signal and output a low-order digit value of the frequency value of the input signal; and an adding section adapted to add the high-order digit value and the low-order digit value to each other to output the frequency value of the input signal.

Abstract: Transmit equalization over high speed digital communication paths may be compensated in a receiver for a probe on that path. In one example, a probe input provides a signal from an electronic communications path, the signal having been processed by a transmit equalizer. A filter circuit processes the signal to compensate for the transmit equalizer, and a decoder decodes the processed signal and produces an output for use by test equipment.

Abstract: A unit cell of a narrow band filter is provided. The unit cell includes a matrix body having a first permittivity and an inclusion body having a second permittivity and disposed in the matrix body. The matrix body and the inclusion body are configured to reflect electromagnetic radiation incident on electromagnetic radiation facing surfaces of the matrix body and the inclusion body. A bandwidth of the reflected electromagnetic radiation is based on a difference between the first permittivity and a third permittivity, which is an average permittivity between the first permittivity and the second permittivity based on volumes of the inclusion body and a portion of the matrix body. The inclusion body is configured such that the second permittivity is adjustable to adjust the third permittivity, thereby adjusting the difference between the first permittivity and the third permittivity. A narrow band filter and a method are also disclosed.

Abstract: A variable speed drive for an electric motor has an inverter for receiving pulse width modulation controls. The inverter communicates power signals to a poly-phase electrical motor. A resolver communicates signals from the poly-phase motor back to a motor control. The motor control includes a speed control, a field-oriented control, and a pulse width modulation drive for driving the inverter. The resolver is connected to the speed control and to the field-oriented control, and further communicates with a synchronous compensator. The synchronous compensator is configured to drive the harmonic content at a target frequency or frequencies in a selected signal towards zero over time.

Abstract: A system and method for determining a received signal frequency by sampling the received signal at a rate less than twice a predefined nyquist rate. The system includes a distorting component configured to distort the received signal in a frequency dependent manner, at least one analog to digital converter configured to sample the received signal and the distorted signal at a rate less than twice a predefined nyquist rate, and a processing component configured to determine a frequency of the received signal based on the sampled received signal and the sampled distorted signal. The method includes distorting the received signal, sampling the received signal and the distorted signal at a rate less than twice a predefined nyquist rate, and determining a frequency of the received signal. In an embodiment, distorting includes at least one of distorting an amplitude or a group delay of the received signal.

Abstract: A personal alerting device and method for detecting an approaching sound source includes a sound detector for detecting environmental sounds and for providing an electrical signal to a sound analyzer. The sound signal is analyzed to determine a baseline sound pattern comprising a plurality of distinct sounds corresponding to sounds emitted from a reference sound source. The distinct sounds in the baseline sound pattern may have substantially the same amplitude and time interval. The sound signal is monitored and compared against the baseline sound pattern to determine whether a target sound pattern is present in the sound signal, the target sound pattern corresponding to sounds emitted by the approaching sound source. When it is determined that the target sound is present in the sound signal, one or more of an audible, visual and tactile alert may be emitted to provide warning of the approaching sound source.

Abstract: An apparatus for determining a resonant frequency of a wind turbine tower is provided. The apparatus includes a processing unit configured to receive an acceleration measurement value, the acceleration measurement value representative of the acceleration of the wind turbine tower in the direction parallel to a rotor rotational axis of the wind turbine and/or in the direction perpendicular to both the rotor rotational axis and the tower axis of the wind turbine. The apparatus includes a memory configured to store a series of acceleration measurement values, and the processing unit includes a Fourier transform module configured to calculate a spectral vector based on calculating a convolution-based fast Fourier transform of the series of acceleration measurement values, and includes a resonant frequency calculation module configured to calculate the tower resonant frequency based on the calculated spectral vector.

Abstract: A device, in particular, a multi-channel oscilloscope, for the analysis of at least one measured signal transmitted via a multi-channel system, with several measurement channels. The device includes in each case a sampling device, a baseband mixing device, and a filter device, and an analysis device. The measured signal is supplied to the measurement channels and to the respective sampling devices for simultaneous sampling. The sampled measured signal is supplied to the baseband mixing devices connected downstream of the sampling devices for the mixing of the measured signal down into the baseband, to the filter devices connected downstream of the baseband mixing devices for the decimation of the sampled values of the measured signal in the baseband and to the analysis device connected to the filter devices for the analysis of the measured signal.

Abstract: A method for measuring active power of alternating current (AC) using a digital phase-locked loop (DPLL) includes the steps of (1) generating via the DPLL a pair of substantially mutually orthogonal sinusoid signals in response to an input voltage data signal, (2) mixing a first sinusoid signal of the pair with a current data signal of the alternating current via a first low-pass filter, (3) mixing the first sinusoid signal of the pair with a voltage signal of the alternating current via a second low-pass filter, and (4) computing an active power of the alternating current based on an output from the first low-pass filter and an output from the second low-pass filter.

Abstract: A data system 102 permits bus encoding based on frequency of the bus; an encoding scheme may be implemented to avoid undesirable frequency conditions such as a resonant condition that may lead to degradation in system performance. The device or integrated circuit will typically include an encoder; in one embodiment, the encoder is a data bus inversion (DBI) circuit that selectively inverts all lines of a data bus. A detector that may include a band-pass or stop-band filter that, for example, evaluates data for transmission on the bus to detect frequency, for example, a predetermined frequency or a frequency range. The detector provides a control signal for the encoder to selectively apply an encoding scheme as a function of frequency.

Abstract: A signal acquisition system has a signal acquisition probe having probe tip circuitry coupled to a resistive center conductor signal cable. The resistive center conductor signal cable of the signal acquisition probe is coupled to a compensation system in a signal processing instrument via an input node and input circuitry in the signal processing instrument. The signal acquisition probe and the signal processing instrument have mismatched time constants at the input node with the compensation system having an input amplifier with feedback loop circuitry and a shunt pole-zero pair coupled to the input circuitry providing pole-zero pairs for maintaining flatness over the signal acquisition system frequency bandwidth.

Abstract: A signal acquisition system has a signal acquisition probe having probe tip circuitry coupled to a resistive center conductor signal cable. The resistive center conductor signal cable is coupled to a compensation system in a signal processing instrument via an input node and input circuitry in the signal processing instrument. The signal acquisition probe and the signal processing instrument have mismatched time constants at the input node with the compensation system having an input amplifier with feedback loop circuitry and a compensation digital filter providing pole-zero pairs for maintaining flatness over the signal acquisition system frequency bandwidth.

Abstract: Provided is a measurement apparatus that measures a characteristic of a filter, comprising a first transmission line that has the filter connected therein, the first transmission line receiving a multi-tone signal having signal components at a plurality of frequencies from an input end thereof, passing the multi-tone signal through the filter, and outputting the multi-tone signal from an output end thereof; a second transmission line that receives the multi-tone signal from an input end thereof, propagates the multi-tone signal therein, and outputs the multi-tone signal from an output end thereof; and a measuring section that calculates the characteristic of the filter based on the multi-tone signal output from the output end of the first transmission line and the multi-tone signal output from the output end of the second transmission line.

Abstract: A power meter having complex quadrature output current and voltage filters provides power measurements in high amplitude and frequency variation and/or high jitter environments without requiring high computational overhead. A pair of filters, one for voltage and one for current each have a response determined by complex non-conjugate poles. The response of the filters is such that only the positive or negative half plane of the complex frequency spectrum is passed and provide complex outputs representing the real and imaginary parts of both the current and voltage. At least one indication of a power delivered to a load is computed from the complex current and voltage outputs, which may be the real and/or reactive power.

Abstract: A method of instantaneously determining or estimating the frequency of an input signal includes mixing a digitally sampled and quantized input signal (12) by a time shifted replica of the input signal (12), where the time shift equals an integer multiple of a sampling period of the input signal (12), thereby producing a mixed signal. The mixed signal is filtered with a low-pass filter producing a filtered signal, which is used to obtain an estimate of the frequency of the input signal. The invention extends to an apparatus (8) for implementing the method in accordance with the invention. The invention also extends to a method of determining or estimating the amplitude of an input signal (12).

Abstract: A frequency stability measuring apparatus for measuring a frequency fluctuation of a signal outputted from a given signal source includes: a reference signal output unit that outputs a reference frequency signal; a mixer that mixes a signal outputted from the signal source with the reference frequency signal outputted from the reference signal output unit and outputs a resultant signal; a filter that allows a low-frequency component of the signal outputted from the mixer to pass therethrough; a waveform-shaping circuit that shapes a waveform of a signal outputted from the filter; a counter that counts a number of pulses of a signal shaped by the waveform-shaping circuit; and a control unit that calculates average frequencies of the signal outputted from the filter within respective measurement periods of a predetermined length, and calculates and outputs a standard deviation of the average frequencies calculated

Abstract: A method and apparatus for estimating the changing frequency of a signal received by a satellite receiver from, illustratively, positioning system satellites is disclosed that enables a more accurate measurement of the change in frequency of that signal due to movement of the satellite receiver relative to those satellites. The system includes a PLL having a numerically controlled oscillator (NCO) and a filter of frequency estimates (FFE). In operation, an analog signal is received at the satellite receiver and the PLL tracks the changing signal frequency and outputs non-smoothed frequency estimates into the FFE. The FFE then smoothes noise in the signal to produce a more accurate smoothed frequency estimate of the input signal. Comparing multiple estimates over time allows Doppler shift of the signal frequency received by the satellite receiver to be calculated more precisely, thus resulting in more accurate satellite receiver velocity vector determinations and, hence, position measurements.

Abstract: A power metering apparatus meters a power signal in a powered system. A low-pass filter receives the power signal and outputs a filtered signal. The filter implements a corner frequency programmable based on a first clocking signal and anti-aliases high frequency components of the power signal. An A/D converter receives the filtered signal and outputs a digital signal. The A/D converter samples the filtered signal according to a system clock based on a second clocking signal. A clocking element generates and outputs each of the first clocking signal and the second clocking signal. The first clocking signal is synchronous with the second clocking signal.

Abstract: Signal processing techniques and systems and, in particular, an apparatus, system, algorithm and method of extraction of sinusoidal signals of time-varying nature is described. The apparatus, system, algorithm and method provide for extraction of a specified single sinusoidal component of an input signal, potentially containing other components and noise, and tracking variations of the amplitude, phase and frequency of such a sinusoid component over time. A “tool” or “core unit,” embodying the apparatus, system, algorithm or method may be used in isolation or as the fundamental building block of single-core or multi-core systems.

Abstract: An alternating voltage detector having a sensor for the detection of an electric alternating field, an electrical signal transducer connected to the sensor for signaling an electrical alternating field detected by the sensor, and an indicator unit connected to the electrical signal transducer for the indication of the signaled electrical alternating field, has an interference pulse filter arranged between the sensor and the electrical signal transducer which filters out electrical pulses or pulse packets detected by the sensor which have an average pulse duration or average pulse packet duration less than a predetermined time.

Abstract: An error-suppression signal measurement system and method therefor is provided. The system transmits a test signal from a first probe, through a device under test, and into a second probe. The probes extract normalization signals from reference signals therein, exchange specific ones of the normalization signals, and combine the normalization signals with data signals derived from the test signal to form receiver signals. The probes propagate the receiver signals to a receiver, where the signals are gain-ranged, digitized, normalized, and compensated for phase-noise.

Abstract: An analog filter in an integrated circuit is tested by placing the filter in a feedback loop. The filter is tested by determining whether the analog filter, while in the feedback loop, provides a signal that oscillates within a predetermined tolerance of an expected frequency.

Abstract: A method is provided to process system test data to determine certification parameters of the system based on the test data. For a torpedo launch system, the velocity data is generated by a Pressure/Velocity/Displacement housing interfaced with a computer based data acquisition system and known launch system and test parameters, such as sample rate, muzzle exit length, time of acquisition, decimation factor and low pass cutoff frequency are provided as inputs. The method forces assigns a value of zero to any data less than a predetermined threshold in order to eliminate non-zero levels contributed by ambient noise. The method then passes the data through a filter chosen to agree with hand fit smoothing methods, so as to obtain a smoothed velocity profile. The smoothed data is processed to obtain and display an acceleration profile and a displacement profile, as well as data points for peak acceleration, time at peak, acceleration pulse width, muzzle exit velocity and time at exit.

Abstract: The invention describes two alternative methods and corresponding devices for producing an energy signal yn whose amplitude values represent the energy of an electrical signal sn.

Abstract: A pre-conditioner for enabling high-speed time interval measurements in an ATE system having a relatively low-bandwidth pathway between a UUT and a timer/counter includes a frequency divider and a D flip-flop located near the UUT. The frequency divider receives a first input signal from the UUT and produces a first output signal having a frequency equal to 1/N times the frequency of the first input signal. The first output signal connects over the low-bandwidth pathway to a first channel of the timer/counter. The first output signal also connects to the D input of the D flip-flop. The pre-conditioner receives a second input signal from the UUT that drives the CLOCK input of the D flip-flop. The Q output of the D flip-flop supplies a second output of the pre-conditioner. The second output connects over the low-bandwidth pathway to a second channel of the timer/counter.

Abstract: The invention describes two alternative methods and corresponding devices for producing an energy signal yn whose amplitude values represent the energy of an electrical signal sn.

Abstract: A method and apparatus for measuring the frequency of a desired resonant mode of a crystal arrangement, or other two-port device, during an automated operation. The crystal arrangement, or other two-port device, is placed into a test circuit and subjected to a sinusoidal test signal of known frequency. Based upon the output response of the crystal arrangement to the test signal, the frequency of the test signal is changed such that the test signal rapidly converges on a desired mode of operation of the crystal arrangement. This is accomplished by first noting a desired increase in amplitude of the output response of the crystal arrangement, followed by measuring an error signal related to the desired crystal arrangement mode of operation. When the error equals a predetermined value the frequency of the sinusoidal test signal is the frequency of the desired mode.

Abstract: An inverse modulator 21, a Fourier transform circuit 22 and a power converter 23 are provided for obtaining a power-frequency spectrum of the carrier wave of a received signal, which is subjected to the influence of fading in the transmission line. A peak detector obtains a peak power level from the power-frequency spectrum and also obtains a peak power level frequency corresponding to the peak power level. A first and a second lower power level frequency detector 25 and 26 receive the power-frequency spectrum, the peak power level and the peak power level frequency. The first lower power level frequency detector detects a frequency which is higher than the peak power level frequency and corresponds to a power level lower than the peak power level by 120 dB, as a first lower power level frequency.

Abstract: The invention describes two alternative methods and corresponding devices for producing an energy signal yn whose amplitude values represent the energy of an electrical signal sn.