Abstract: A test and measurement device includes one or more ports configured to connect to a device under test (DUT), a time domain reflectometry (TDR) source configured receive a source control signal and to produce an incident signal to be applied to the DUT, one or more analog-to-digital converters (ADC) configured to receive a sample clock and sample the incident signal from the TDR source and a time domain reflection (TDR) signal or a time domain transmission (TDT) signal from the DUT to produce an incident waveform and a TDR/TDT waveform, one or more processors configured to execute code to cause the one or more processors to: control a clock synthesizer to produce the sample clock and the source control signal, and use a period of the TDR source, a period of the sample clock, and the number of samples to determine time locations for samples in the incident waveform and the TDR/TDT waveform, and a display configured to display the incident waveform and the TDR/TDT waveform.

Abstract: A signal post-processing method is described, wherein a time-and-value-discrete signal is read from a memory by a signal post-processing circuit wherein a resolution bandwidth and a frequency range of the time-and-value-discrete signal are predetermined. A window filter is applied to the time-and-value-discrete signal. The window filtered time-and-value-discrete signal is transformed to a full-bandwidth frequency-domain signal. A sub-band is selected from the full-bandwidth frequency-domain signal by a selection unit wherein the rest is discarded by the selection unit. Further, a signal post-processing circuit as well as an oscilloscope are described.

Abstract: Current solutions do not provide for the recognition of anonymous consensus around a desire, particularly in the case of already acquainted individuals. This invention is a method, device, system and online platform which allows two or more people to know when they are in agreement of a particular desire without revealing either participants desire unless there is consensus across the participants. A means is provided for which participants may simply express their desire for engaging in an activity with pre-established partner(s) using a means which is undetectable to the other party(s) unless all participants also share the same desire. At the point where consensus is reached, the invention will inform appropriate participants of their shared desire. Additionally, the invention provides for a means to use this desire data to influence participants in an effort to increase the likelihood of reaching anonymous consensus.

Abstract: A system for measuring an electrical response of a device under test (DUT) includes a reflectometer with reduced heat dissipation used with a vector network analyzer (VNA). The reflectometer is tethered to the VNA using a tether of scalable length which carries low frequencies. The reflectometer has a distributed harmonic generator including a non-linear transmission line (NLTL) for multiplying a frequency of an RF signal received from the VNA to generate a test signal having a frequency in the millimeter wave range at a test port connected to the DUT. A sampler in the reflectometer receives a local oscillator (LO) signal from the VNA and includes another NLTL for receiving the LO signal and generating pulses at a frequency in the millimeter wave range. When the test signal is transmitted to the DUT, the sampler outputs intermediate frequency signals which are transmitted to the VNA for characterization of the DUT.

Abstract: A musical instrument system is described to operate as a human to machine input device. The musical instrument outputs an audio signal that is processed to control the movement of an indicator in a computer.

Abstract: Despite many practical limitations imposed by mobile device platforms and application execution environments, vocal musical performances may be captured and continuously pitch-corrected for mixing and rendering with backing tracks in ways that create compelling user experiences. In some cases, the vocal performances of individual users are captured on mobile devices in the context of a karaoke-style presentation of lyrics in correspondence with audible renderings of a backing track. Such performances can be pitch-corrected in real-time at a portable computing device (such as a mobile phone, personal digital assistant, laptop computer, notebook computer, pad-type computer or netbook) in accord with pitch correction settings. In some cases, pitch correction settings include a score-coded melody and/or harmonies supplied with, or for association with, the lyrics and backing tracks.

Abstract: A device for electro-optical sampling of a microwave frequency signal is disclosed. In one aspect, the device includes a microwave transmission line for transmitting a microwave signal, the microwave line including an interruption zone configured to be rendered conducting under the effect of an optical control signal so as to carry out a function of optically controlled interrupter switch. The device also includes, in the interruption zone, a layer of nanostructured semiconductor material, including a periodic or quasi-periodic tiling of nanostructures. The layer of nanostructured semiconductor material is placed, at the level of the interruption zone, in suspension or on a dielectric material of lower refractive index than the refractive index of the semiconductor material, the layer of nanostructured semiconductor material being able to carry out the function of optically controlled interrupter switch.

Abstract: A method for detecting electromagnetic waves derived from bacterial DNA, comprising extracting and purifying nucleic acids from a sample; diluting the extracted purified nucleic acids in an aqueous solvent; measuring a low frequency electromagnetic emission over time from the diluted extracted purified nucleic acids in an aqueous solvent; performing a signal analysis of the low frequency electromagnetic emission over time; and producing an output, based on the signal analysis, in dependence on the DNA in the sample. The DNA may be extracted from at least one of blood, feces, urine, saliva, tears, seminal fluid, sweat, seminal and vaginal fluids of a patient, or water to determine, e.g., potability. The samples may be frozen. The extracting and purifying may comprise diluting the sample with an aqueous buffer and mixing; degrading proteins in the diluted sample; precipitating DNA from the buffer solution; and resuspending the precipitated DNA in an aqueous solution.

Abstract: A method for determining a sampling time of a signal, the method including: determining a candidate sampling time of a signal for input to a sampling circuit; determining a resultant sampling time at which the sampling circuit samples the signal when input with the candidate sampling time; and determining a sampling time of the signal based on a noise shaping of a difference between the resultant sampling time and the candidate sampling time.

Abstract: An element measurement circuit is provided, comprising a oscillator for generating a first oscillation clock and second oscillation clock, a frequency divider for dividing the first oscillation clock to generate a third oscillation clock and for dividing the second oscillation clock to generate a fourth oscillation clock, a frequency detector for detecting the third oscillation clock to generate a first count value and for detecting the fourth oscillation clock to generate a second count value, and a controller for generating a first oscillation period according to the first count value, for generating a second oscillation period according to the second count value, and for generating a measurement value according to the first oscillation period and the second oscillation period.

Abstract: Disclosed is a probe for an oscilloscope comprising a multi-stage transistor amplifier that acts as an impedance transformer. Said amplifier is a d.c.-coupled emitter follower circuit that is composed of bipolar transistors or a d.c.-coupled source follower circuit which is composed of field effect transistors and the successive amplifier elements of which are dimensioned and tuned to each other in such a way that the resulting offset direct voltage between the input and the output is minimal.

Abstract: A method for multichannel multifrequency analysis of an object, applying a set of excitation signals to the object and sampling the response signal from the object, using uniform and non-uniform undersampling. Non-uniform sampling of the response signal is performed, i.e., the sampling is performed for two or more different frequencies in one observation time slot. Also, uniform sampling of the response signal is performed, i.e., the sampling of a signal, corresponding to one frequency, is performed for two or more channels within one observation time slot and then sampling the same signal for another frequency for two or more channels within the next observation time slot.

Abstract: Methods, systems and other embodiments associated with pre-processing a signal for spectral analysis are presented. A system for pre-processing a digital input signal includes a digital down converter (DDC), an interpolator, and a series of down samplers. The DDC modulates the digital input signal to create a down converted signal. The interpolator re-samples the down converted signal to produce a re-sampled signal. The series of down samplers produces down sampled signals. The multiplexer selects one of the digital input signal, the down converted signal, and the down sampled signals and routes the selected signal to an output line.

Abstract: A method for detecting electromagnetic waves derived from bacterial DNA, comprising extracting and purifying nucleic acids from a sample; diluting the extracted purified nucleic acids in an aqueous solvent; measuring a low frequency electromagnetic emission over time from the diluted extracted purified nucleic acids in an aqueous solvent; performing a signal analysis of the low frequency electromagnetic emission over time; and producing an output, based on the signal analysis, in dependence on the DNA in the sample. The DNA may be extracted from at least one of blood, feces, urine, saliva, tears, seminal fluid, sweat, seminal and vaginal fluids of a patient, or water to determine, e.g., potability. The samples may be frozen. The extracting and purifying may comprise diluting the sample with an aqueous buffer and mixing; degrading proteins in the diluted sample; precipitating DNA from the buffer solution; and resuspending the precipitated DNA in an aqueous solution.

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 providing pole-zero pairs for maintaining flatness over the signal acquisition system frequency bandwidth.

Abstract: A system and method for filtering an input signal with at least a first and a second octave portions is presented. A proportional bandwidth filter system includes a bandwidth reducing filter, a down-sampler, and first and second octave filters. The bandwidth reducing filter reduces the bandwidth of the input signal and the down-sampler rolls the second octave portion represented in the reduced bandwidth signal to a top octave portion of a down-sampled signal. The first and second octave filters are comprised of a plurality of proportional bandwidth filters. The first octave filter partitions and converts the first octave portion of the input signal into output signals representing the frequency spectra of the first octave of the input signal. Similarly, the second octave filter generates outputs representing the spectra of the second octave portion of the input signal represented as the top octave portion of a down-sampled signal.

Abstract: The present invention is directed to a circuit device configured to monitor a sensor device. The sensor device is configured to measure a predetermined physical parameter and provide a sensor output signal corresponding to the predetermined physical parameter. The circuit device includes a sampling circuit configured to sample the sensor output signal to obtain a predetermined number (N) of sensor output signal samples. an analog multiplication circuit to generate one of a plurality of predetermined digital sequences. and an analog integrator circuit. configured to add the N multiplication products to generate an analog signal power estimation value which corresponds to a degree of correlation between the sensor output signal and the selected predetermined digital sequence.

Abstract: Systems and other embodiments associated with synthetic instrumentation are presented. A reconfigurable synthetic instrumentation unit comprises an input module, with dual input/output ports and conditioning logic to condition an input signal. An RF down converter selectively down converts the conditioned input signal. A sampled RF down converter selectively samples the conditioned input signal. A pair of narrowband A/D converters are configured to convert one of the conditioned signal, the down converted signal and the sampled signal to produce a narrowband digital signal. A pair of broadband A/D converters convert at least one of the conditioned signal, the down converted signal and the sampled signal to produce a broadband digital signal. Signal processing logic selectively performs digital signal processing on the broadband digital signal or the narrow band digital signal.

Abstract: A detector of periodic packets of X photons, each packet having a duration shorter than 0.1 nanosecond, comprising a sensor comprising a semiconductor element of type III-V biased in a negative differential resistance region, said sensor being arranged in a resonant cavity tuned to a multiple of the packet repetition frequency.

Abstract: A system is provided using one or more shocklines or non-linear transmission lines (NLTLs) to extend the bandwidth of an RF signal source. Extension of the RF bandwidth is achieved by means of multiplexing as well as frequency scaling. Frequency scaling tailors the performance of each NLTL for operation in a particular output frequency band(s) by adjusting the varactor spacing in the NLTL. Multiplexing amalgamates the output frequency bands of one or more NLTLs, thus resulting in a broad output frequency range.

Abstract: A device (10) for measuring a frequency of an input signal (IN) that is expected to comprise a carrier signal (CS) either being unmodulated (CSU) or being modulated (CSM) according to a predefined signal coding and relates to a Radio Frequency Identification (RFID) transponder.

Abstract: Abnormal conditions within an RF-powered plasma process chamber are detected by detecting whether the frequency of a variable-frequency RF power supply moves outside established lower and upper limits. In a first aspect, a first pair of lower and upper limits are established as a function of the frequency of the power supply sampled after a new process step begins or after a sample control signal changes state. In a second aspect, a second pair of lower and upper limits are not adapted to the frequency of the power supply. Both aspects preferably are used together to detect different occurrences of abnormal conditions.

Abstract: Sets of time domain data of respective frequency bands from Fd-1 to Fd-n of a periodic input signal Fs are acquired. Sets of the time domain data of the common frequency band are extracted from the sets of the time domain data of the frequency bands Fd-1 and Fd-2 in the acquired frequency bands. Correlativity between the sets of the time domain data of the common frequency band is determined while shifting time relationship between the sets each other to identify the sets of time domain data having correspondence relationship. The sets of the time domain data having the correspondence relationship in the time domain data of the adjacent frequency band Fd-1 and Fd-2 are converted to the sets of the frequency domain data respectively, and the sets of the frequency domain data are combined to produce one set of combined frequency domain data.

Abstract: In a method of detecting a repetition frequency of a measured signal, in order to detect the waveform repetition frequency of the measured signal with high accuracy even in the presence of a frequency fluctuation in the measured signal, the repetition frequency of the measured signal acquired by the conventional method is used as a provisional repetition frequency, and the frequency change amount of the specified signal obtained in the case where the measured signal is sampled sequentially with a sampling frequency greatly changed from the provisional sampling frequency to generate a frequency fold at the time of sampling is detected. Based on the detected frequency change amount of the specified signal and the change amount of the sample number indicating how many times the frequency fold has occurred in the process, the error contained in the sampling number with a frequency fluctuation contained in the measured signal is calculated.

Abstract: Power measurements of a signal having a changing frequency are corrected by acquiring samples of the signal, matching the samples of the signal to a sequence of frequencies indexed to correction transforms, and applying the correction transforms to the samples of the signal. Additionally, an apparatus corrects power measurements of a signal having a changing frequency and includes an acquisition block for acquiring samples of the signal, a sequence controller for matching the samples of the signal to a sequence of frequencies indexed to correction transforms and a correction block for applying the correction transforms to the samples of the signal.

Abstract: A system includes a sampling module, a counter module, and a frequency characteristic module. The sampling module samples radio frequency (RF) signals on a first channel for a first predetermined period and a second predetermined period that is subsequent to the first predetermined period. The counter module increments first and second counts when the samples collected during the first and second predetermined periods reverse polarity, respectively. The frequency characteristic module determines a frequency of the RF signal based on at least one of the first and the second counts and determines frequency variation of the RF signal based on the first and second counts.

Abstract: A method for multichannel multifrequency analysis of an object, applying a set of excitation signals to the object and sampling the response signal from the object, using uniform and non-uniform undersampling. Non-uniform sampling of the response signal is performed, i.e., the sampling is performed for two or more different frequencies in one observation time slot. Also, uniform sampling of the response signal is performed, i.e., the sampling of a signal, corresponding to one frequency, is performed for two or more channels within one observation time slot and then sampling the same signal for another frequency for two or more channels within the next observation time slot.

Abstract: In a method of detecting a repetition frequency of a measured signal, in order to detect the waveform repetition frequency of the measured signal with high accuracy even in the presence of a frequency fluctuation in the measured signal, the repetition frequency of the measured signal acquired by the conventional method is used as a provisional repetition frequency, and the frequency change amount of the specified signal obtained in the case where the measured signal is sampled sequentially with a sampling frequency greatly changed from the provisional sampling frequency to generate a frequency fold at the time of sampling is detected. Based on the detected frequency change amount of the specified signal and the change amount of the sample number indicating how many times the frequency fold has occurred in the process, the error contained in the sampling number with a frequency fluctuation contained in the measured signal is calculated.

Abstract: A device (10) for measuring a frequency of an input signal (IN) that is expected to comprise a carrier signal (CS) either being unmodulated (CSU) or being modulated (CSM) according to a predefined signal coding comprises: means (9) for generating a measurement period (MP), an input signal counter (2) which is adapted to count edges of the input signal (IN) during the measurement period (MP), sampling means (4) which are adapted to detect whether the input signal (IN) contains edges, control means (7) which are adapted to read a count value (CNT—2) of the input signal counter (2) on expiration of the measurement period (MP) and to derive the frequency (FR) of the input signal from the count value (CNT—2) of the input signal counter (2), wherein the means (9) for generating a measurement period (MP) are adapted to extend the measurement period (MP) by a time period (EXT) during which the absence of edges in the input signal (IN) is detected.

Abstract: A sequential equivalent-time sampling oscilloscope simultaneously acquires samples of a signal-under-test and a reference clock that is asynchronous with the signal-under-test. The oscilloscope converts the samples of the reference clock into timestamps and uses the timestamps to compensate for the jitter of the oscilloscope and to indicate the absolute jitter of the signal-under-test.

Abstract: In a method for performing a frequency analysis of an AC voltage signal, in particular in a power mains, an upper limit of the period length of a fundamental oscillation in the AC voltage signal is determined. A sequence of sampling values of the AC voltage signal is obtained over a duration longer than the upper limit of the period length, thereby ensuring that more than a period of the fundamental oscillation is sampled. Selected from the sequence of sampling values is a subset of sampling values, with the subset sampling substantially one period of the fundamental oscillation. At least a portion of the sampling values not included in the subset is altered, and a frequency is calculated based on the obtained sequence of sampling values, the subset of sampling values and the altered portion of the sampling values.

Abstract: A “no dead time” data acquisition system for a measurement instrument receives a digitized signal representing an electrical signal being monitored and generates from the digitized signal a trigger signal using a fast digital trigger circuit, the trigger signal including all trigger events within the digitized signal. The digitized signal is compressed as desired and delayed by a first-in, first-out (FIFO) buffer for a period of time to assure a predetermined amount of data prior to a first trigger event in the trigger signal. The delayed digitized signal is delivered to a fast rasterizer or drawing engine upon the occurrence of the first trigger event to generate a waveform image. The waveform image is then provided to a display buffer for combination with prior waveforms and/or other graphic inputs from other drawing engines. The contents of the display buffer are provided to a display at a display update rate to show a composite of all waveform images representing the electrical signal.

Abstract: This invention relates to fault detection in electrical circuits. The invention provides a method and apparatus for testing an input circuit by generating a periodic test signal having a predetermined phase and a predetermined amplitude; summing the test signal and an input signal to provide a summed signal; processing the summed signal to provide an output signal; generating an extracted test signal from the output signal; comparing the extracted test signal with a reference signal representing said periodic test signal; generating an error signal in dependence upon the result of said comparing step. The invention also provides a method and apparatus for testing a plurality of adjacent input circuits.

Abstract: A range of a frequency measuring device having limited range is extended by pre-processing an input signal. The input signal is divided into a plurality of channels. In each channel, the input signal is divided into sub-bands. A frequency of the input signal is determined using a frequency measuring device having limited range. The frequencies are stored in a frequency set. The frequency set is used to determine a frequency associated with the input signal according a set of pre-determined reconstruction rules.

Abstract: A built-in self-test apparatus for a digital-to-analog converter uses a differentiation unit for differentiating a digital-to-analog (DA) signal to obtain the differences between pulses of the analog signal. Next, the analog signal is converted into a digital signal in the light of a threshold voltage by a Schmitt trigger unit. Then, the duty cycles of the digital signal are calculated by a duty cycle retriever, and transmitted into a signature analyzer to calculate the differential non-linearity for error analysis. For processing a high-speed DA signal, the circuit disposed before the differentiation unit may use a test pattern unit, a sample-and-hold circuit and a logic circuit to lower the speed of the DA signal.

Abstract: A method and apparatus for synchronizing presentation of multi-domain measurements using actual or quasi 3-D representation. The synchronization between data streams acquired in different measurement domains is performed by using timestamps, a common trigger event, or a common clock, or a combination of any or all of them. In this way, for example, a transient anomaly in the RF spectrum of a communications signal may be correlated with, and displayed with, a related corrupted data communications packet.

Abstract: A system and method for establishing a plurality of operating parameters of a multiphase motor. The plurality of electrical parameters may be established from stator resistance data and electrical input data. The system and method may be used to decompose the electrical input data into a positive sequence and a negative sequence. The positive sequence may be used to establish a plurality of electrical parameters of the motor. The plurality of electrical parameters may be used with the positive sequence and negative sequence to establish the output power of the motor.

Abstract: When a sample stream is decimated, frequency components from outside of a desired frequency band are aliased into the desired band, causing interference and loss of information. Different decimating ratios result in different frequencies aliasing into the desired frequency band. A current-mode sampling mixer 800 with capacitor banks 811 and 812 that are controlled by a digital control unit 820 with a capability to integrate and decimate an RF current at different decimating ratios is able to measure the frequency spectrum with different decimating ratios. The measured frequency spectrum is then analyzed to detect the presence of interferers aliased into the desired frequency band. The interferers can then be eliminated or avoided.

Abstract: A frequency error detection apparatus and method based on histogram information of an input signal. The apparatus includes an A/D converter for and converting an analog signal into digital values; a zero crossing point detector for detecting sign changes of the digital values, and detecting zero crossing points; a period information detector for detecting period information which is the number of the digital values corresponding to a periodic signal; a histogram information calculator for counting the number of detections for the respective period information based on the period information, and calculating error-detection-target histogram information; and a frequency error calculator for detecting a difference between the error-detection-target histogram information and a reference histogram information, and calculating a frequency error value based on the difference. This can shorten time for frequency error detections and improve accuracy of the detected frequency error value.

Abstract: Sampling is performed. A strobe signal is generated from a first signal. Multiple sampled signals are sampled using the strobe signal. Each of the multiple sampled signals is synchronous with its own clock reference and each of clock references are asynchronous with respect to each other. Analog-to-digital conversion is performed on each sampled value of each of the multiple sampled signals. For each of the clock references that is not synchronous with the first signal, a phase comparison is performed between the clock reference and the first signal to produce a difference value. The difference value indicates a phase difference between the clock reference and the first signal. Analog-to-digital conversion of the difference value is performed at a frequency determined by the strobe signal.

Abstract: Signal sampling is performed. A sampler takes samples of a sampled signal. A first analog-to-digital (A/D) converter receives the samples from the sampler. A clock reference is synchronous with the sampled signal. A phase comparator produces a difference value that indicates a phase difference between the clock reference and an oscillating signal. A second A/D converter receives the difference value. The oscillating signal is used in controlling when the sampler takes samples of the sampled signal.

Abstract: A timebase establishes the timing of samples acquired by a signal sampler relative to a trigger signal that is synchronous with an input signal applied to the signal sampler. The synchronous trigger activates a first pair of samplers included in the timebase to acquire samples of a reference signal and of a shifted version of the reference signal provided within the timebase. A divider receives the reference signal and divides the frequency of the reference signal by a predesignated divisor, and a third sampler included in the timebase acquires samples of this divided reference signal, also according to the synchronous trigger. The samples of the input signal are acquired by the signal sampler according to the divided reference signal. A timing analyzer determines the timing of these acquired samples of the input signal relative to the synchronous trigger, based on the acquired samples of the reference signal, the shifted reference signal and the divided reference signal.

Abstract: A method and apparatus for detecting a stator winding fault in an induction motor includes sampling instantaneous signals from the motor and then deriving sequence components of at least some of the instantaneous signals using a power decomposition technique (PDT), one of the sequence components being a total negative sequence current component. In addition, the method includes calculating an expected negative sequence current based on at least some of the sequence components. Thereafter, the method subtracts the expected negative sequence current from the total negative sequence current to determine a fault negative sequence current, wherein the fault negative sequence current is indicative of the fault.

Abstract: A timebase establishes the timing of samples acquired by a signal sampler relative to a trigger signal that is synchronous with an input signal applied to the signal sampler. The synchronous trigger activates a first pair of samplers included in the timebase to acquire samples of a reference signal and of a shifted version of the reference signal provided within the timebase. A divider receives the reference signal and divides the frequency of the reference signal by a predesignated divisor, and a third sampler included in the timebase acquires samples of this divided reference signal, also according to the synchronous trigger. The samples of the input signal are acquired by the signal sampler according to the divided reference signal. A timing analyzer determines the timing of these acquired samples of the input signal relative to the synchronous trigger, based on the acquired samples of the reference signal, the shifted reference signal and the divided reference signal.

Abstract: A system clock for a system for measuring at least one given quantity having a value which does not vary significantly from a given frequency, the system clock comprises a controller for sampling said given quantity at a rate determined by an oscillator frequency, and a programmable oscillator for generating the oscillator frequency, said programmable oscillator being programmable to produce said oscillator frequency at a frequency which is substantially identical to a high order harmonic of said given frequency of the quantity to be measured.

Abstract: Methods and systems for measuring the reflection coefficient of a network are disclosed. The methods and systems measure the reflection coefficient by exciting a device under test with a driving signal. The driving signal incident on the device under test is measured and the source providing the driving signal is removed thereafter. A signal reflected from the device under test is sampled at a sample rate that may differ from the frequency of the driving signal. The reflection coefficient of the device under test is calculated by dividing the measured level of the reflected signal by the measured level of the driving signal.

Abstract: A bandpass sampling system (10) of this invention employs a conventional mixer (14) driven by a frequency-tunable LO (16) to upconvert a signal frequency band to an IF frequency band that is above the signal frequency band. The IF frequency band is passed through an IF bandpass filter (18) to provide to subsequent digitization stages (20, 24) an IF bandpass range of signal frequency components. In this architecture, the IF bandpass filter acts as an anti-alias filter for the digitization stages. The LO frequency is selected to place the upconverted signal frequency band within the pass band of the IF bandpass filter. The resultant IF bandpass signal is sampled and digitized at a rate that is commensurate with the IF bandwidth, but typically much lower than the IF bandpass center frequency. Signal sampling is carried out by a sample-and-hold or a track-and-hold circuit (20), the output of which is applied to an ADC (24) that is clocked (22) at the same rate as the sampling circuit.

Abstract: A method and circuit for compensation control of offset voltages of a radio receiving circuit integrated in a circuit module that can be used in receiver and transceiver chips for portable mobile radio transceivers, for example in GSM or PCN/PCS systems. In the course of offset voltage compensated in the baseband of a radio receiver, the charge state of a capacitor, which is switched on in a sample-and-hold circuit by predetermined, constant control pulses is evaluated on-chip. The evaluation result is used to match the charging current of a sample operational amplifier to the respective charge state of the capacitor, thereby achieving a minimal compensation time with stable regulation.

Abstract: A method and apparatus for spectral analysis of a sampled signal are provided. According to the method, a first time interval &Dgr;T is determined which represents a sample set over which the signal can be averaged for purpose of decomposing the signal into instantaneous mean and random components. From random component of the signal, the optimal time-dependent time interval AW over which the random component should be averaged to obtain the instantaneous frequency spectrum (IFS) is then calculated based upon the instantaneous signal memory. Signal memory specifies the extent in time beyond which the signal “forgets” its past behavior and thus is a measure of its degree-of-randomness. Defining AW in this way reduces the likelihood that short-lived events are lost (or masked) due to uncharacteristically short (or long) averaging intervals. Importantly, both time intervals &Dgr;T and AW are dynamic and vary randomly with time.

Abstract: A high resolution cross correlation, coherent integration type spectrum analyzer for use in obtaining detailed spectral signatures of subsurface and surface vessels correlates short discontinuous records of the incoming signal with reference signals of known frequencies and accumulates the results to establish cross correlation over a relatively long total record made up of the short discontinuous record segments, with the long combined record being responsible for the high resolution of the system.