Oxygen determination based on luminescence quenching of fluorescent dye is effected by using the frequency output of an offset-phase locked loop (15) to calculate the time constant for the exponential decay of fluorescence. An offset phase angle between a periodic stimulus signal used to excite the dye and a response signal based on fluorescence detection is predetermined to optimize signal-to-noise ration for a wide range of time constants. An offset-phase locked loop (15) is used to vary the frequency of a periodic stimulus signal until the predetermined phase relationship is established, and the frequency forms a measure of the decay rate. Where the stimulus and response signals are substantially sinusoidal, the offset phase angle is ideally about 49.3°, although substantially optimal performance is achieved using a more conveniently generated 45°. The 45° angle offset can also be used with a square-wave stimulus signal.

Es wird ein neues, digital arbeitendes Verfahren vor­gestellt, das die Detektion von Momentanfrequenzen bei Hoch- und Höchstfrequenzsignalen bis zu Pulsbreiten im Pikosekundenbereich ermöglicht. Außerdem ist es zur monolithischen Intergration auf einem oder mehreren Halb­leiter-Chips geeignet. Das reine Parallelverfahren beruht auf dem so genannten "Interferometerprinzip" und kann die Frequenz-Detektion des Eingangssignals direkt im Original-Frequenzbereich vornehmen. Zur Realisierung werden Verzögerungselemente, Komparatoren und einfache Gatterschaltungen (EX-OR/NOR-Gatter) eingesetzt. Als Signalverteiler und Phasenschieber dienen vorzugsweise Anordnungen aus 3dB-Hybridkopplern.

Um z.B. die Leistungsbilanz einer mehrphasigen elektrischen Übertragungsleitung zu überwachen, werden aus am Leitungssystem abgegriffenen Meßwerten die raumfesten Orthogonalkomponenten (g_α, g_ß) des Meßwertsystems gebildet. Aus einer Stellgröße (ω) bildet ein Stellglied Wechselgrößen mit einer stellgrößenproportionalen Frequenz, die einer Transformationsschaltung (9) zur Frequenztransformation der Orthogonalkomponenten eingegeben werden. Die Transformationsschaltung liefert eine die Richtung des Raumzeigers bestimmende Größe, die als Istwert einem mit einem konstanten Sollwert beaufschlagten Regler (14) zugeführt wird. Die Reglerausgangsgröße wird einerseits als frequenzproportionale Stellgröße dem Stellglied (5) zur Bildung der Wechselgröße für die Transformation, andererseits als Frequenzgröße einer Ausgabeleistung zugeführt.

Zum Messen der nur einige Hertz betragenden Frequenz einer Wechselgröße mit schwankender Amplitude, zwischen den aufeinanderfolgenden Nulldurchgängen wird die Wechselgröße über ein Eingangsglied (EG) mit stufenweise steuerbaren Verstärkungsfaktor auf einen Betragsbildner (BB) gegeben, dessen Ausgangsgröße bei Überschreiten eines bestimmten Maximalwertes (Umax) und bis Erreichen des Scheitelwertes (Ü) einen die Verstärkung stufenweise rücksetzenden ersten Zähler (Z1) betätigt und daß ferner aus der Ausgangsgröße (|U|) des Betragsbildners (BB) und dem in einem Proben-Stufenspeicher (SP2) gespeicherten Scheitelwert (Ü) eine Differenzspannung ΔU=Û -|U| gebildet und diese mit einem Quotienten (e) verglichen wird, der aus der Division einer gleichermaßen stufenweise rückgesetzten Gleichspannung (Umin) mit dem Scheitelwert (Ü) erhalten wird, und daß in der Zeit vom Auftreten des Scheitelwertes bis zum Erreichen der Differenzspannung AU=e über ein aktiviertes Gedächnis (RE) einem zweiten Zähler (Z2) eine Taktgeber-Impulsfolge zugeführt ist, die über nachgeordnete wechselweise gelöschte Register (RE1, RE2) einen codierenden Summierer (A) einen Digitalanalogwandler (DAW) mit nachgeordneter Auswerteschaltung (V3, PG1, PG2, PG3, INT) in eine der Frequenz proportionale und zwischen den Nulldurchgängen konstante Gleichspannung (U') verwandelt wird.

A device for measuring the rate of change of a pulse train from a transducer (12) includes first counting means (18, 22) which counts the number of pulses in a first fixed frequency to pulse train during each interval between the signal pulses. A divider (28) receives the count generate in the preceding interval and divides the frequency f₁ of a second fixed frequency pulse train by this number. The divider pulse train is counted by a second counting means (30) for the duration of each interval.

A frequency estimation signal generator component arranged to receive an input frequency signal and to generate therefrom a frequency estimation signal. The frequency estimation signal generator component comprises a counter component arranged to sequentially output a sequence of control signal patterns over a plurality of digital control signals under the control of an oscillating signal derived from the received input frequency signal terns. The frequency estimation signal generator further comprises a continuous waveform generator component arranged to receive the plurality of digital control signals and a weighted analogue signal for each of the received digital control signals, and to output a continuous waveform signal comprising a sum of the weighted analogue signals for which the corresponding digital control signals comprise an asserted logical state. The frequency conversion component is arranged to derive the frequency estimation signal from the continuous waveform signal output by the continuous waveform generator component

[Problem] To make it possible to detect the peak frequency of a signal wave at a desired frequency resolution and in a desired time window length while avoiding a conflicting relationship between the frequency resolution (f₀) and the time window length (T₀).

[Solution] A peak frequency detection device that detects a peak frequency at which the maximum power spectrum is achieved in a predetermined frequency band (f_cl to f_ch), said peak frequency detection device being provided with: an n multiplication unit that multiplies each element of a digital data string by n (n is an integer of 2 or more); an FFT unit that derives, as a virtual peak frequency, a frequency that corresponds to the maximum value of a power spectrum that is obtained by performing a fast Fourier transform of a digital data string of N (N is an integer of a power of 2 and is determined in accordance with a sampling frequency (f_s), a sampling resolution (f_tg), and a time window length (T_tg)) sample frequencies (f_s) that are multiplied by n; and a 1/n multiplication unit that outputs the value of the virtual peak frequency multiplied by 1/n as the peak frequency of the digital data string. The peak frequency detection device satisfies n ≥ 1/(f_tg×T_tg), f_s/(n×f_tg) ≤ N ≤ f_s×T_tg, and f_s > 2×n×f_ch.

A method is provided of determining a time interval between switching events for a switching device in a power converter, the switching device being for coupling a direct current (DC) source to provide an alternating current (AC) output at a particular switching frequency. The method comprises selecting an initial length of a time interval between a first switching event and a second, subsequent switching event for the switching device and obtaining a current measurement value for the switching device when the time interval between the first switching event and the second, subsequent switching event takes said initial length. The method further comprises changing the length of the time interval between the first switching event and the second, subsequent switching event and obtaining a current measurement value for the switching device when the length of the time interval is changed. The current measurement values which have been obtained are used to detect generation of a current in the switching device. It is then determined, from the change made to the length of the time interval and the current measurement values obtained, a length (t_g) of the time interval at which said generation of a current in the switching device occurs.

A transmitter system (100) includes a digital phase rotator (104), a phase rotation controller (106, 900), and a radio-frequency (RF) transmitter (112, 200, 300, 400). The digital phase rotator (104) receives a first constellation data, and applies a digital phase response to the received first constellation data to generate a second constellation data. The phase rotation controller (106, 900) configures the digital phase rotation. The digital RF transmitter (112, 200, 300, 400) receives a digital input data derived from the second constellation data, and converts the digital input data into an analog RF output.

Method and module for measuring the rate of change of frequency of a waveform related to a converter unit of a wind turbine generator, comprising: measuring an instantaneous value of said rate of change of frequency of the waveform, calculating a first filtered value of said rate of change of frequency, said first filtered value having good accuracy but low time response, and calculating a second filtered value of said rate of change of frequency said second filtered value having a good time response but low accuracy, comparing said first and second filtered values and selecting that an output value of said measured rate of change is based on said first or second filtered values depending on said comparison,

Methods are directed towards determining a total measurement uncertainty for LME and LEE UEs. Methods include representing the at least one quantity subject to measurement as a function of at least one physically observably quantity. Methods also include obtaining a value of the at least one quantity subject to measurement. Based on the obtained values, values of the sources of uncertainty are derived.

Disclosed herein is a power consumer approach that monitors the occurrence of grid code events within electric power transmission operations. In one aspect, a grid code event meter (130, 400) is used to detect the occurrence of a grid code event. The grid code meter (130, 400) includes a metering component (205, 510, 515) configured to obtain data for power-related parameters associated with consumption needs. A grid code criteria tracking component (205, 520) tracks the data related to the power-related parameters obtained by the metering component (205, 510, 515) for compliance with grid code criteria required by a transmission company of a consumer for power quality and reliability. A grid code event detection component (210, 520) detects an occurrence of a grid code event in accordance with the tracked data for the power-related parameters.