# Measurement method of harmonic distortion of fm signal generated by the direct digital synthesis method

FIELD: measurement equipment.

SUBSTANCE: invention can be used for frequency modulated (FM) signal nonlinear distortion measuring. Measurement method of harmonic distortion of fm signal generated by the direct digital synthesis method, consists in measuring the changes in the parameters of the central and the first side lateral component of FM signal by the spectrum analyzer during modulation entering and frequency modulation harmonic coefficient calculating on the results of measurements.

EFFECT: increase of the resolution capability of the measurement of harmonic distortion of FM signals source frequency modulation generated by direct digital synthesis method.

1 dwg, 1 tbl

**Same patents:**

FIELD: electricity.

SUBSTANCE: on the basis of measurements of frequency of a power system the dependence of average of crossings of frequency deviation levels per unit of time from values of levels of these deviations is determined, and using the calculation formulas the dependence of average of crossings of levels of deviations of load power per unit of time from the value of load power deviations. Mutually equating the obtained dependences, the frequency characteristic of the power system is obtained.

EFFECT: obtaining the total frequency characteristic of the isolated power system with limited power.

1 dwg

FIELD: physics.

SUBSTANCE: method is based on decomposing signals into empirical modes, which includes: a) sampling; b) selecting process extrema; c) constructing upper and lower envelopes; d) calculating a smoothed component as an average value between the envelopes; e) extracting a sign-variable component as the difference between the initial and the smoothed components; f) estimating current frequencies and amplitudes or power values for each component using Hilbert spectral analysis; g) repeating steps (b) through (f) over the smoothed component, wherein construction of the upper and lower envelopes is performed based on the maxima and minima of the selected extrema, without subsequent calculation of envelopes at points between like extrema; selecting the smoothed component directly from the sequence of process extrema, wherein formation of a smoothed sequence of extrema is carried out by calculating an average of the average values of the current and previous extrema and average values of the current and next extrema; selecting the time-variable component by subtraction from the initial smoothed sequence of extrema. An apparatus which carries out said method is also disclosed.

EFFECT: easier digital signal processing.

3 cl, 5 dwg

FIELD: measuring instrumentation.

SUBSTANCE: method of frequency measurement involves count of reference frequency periods per measured frequency period and calculation of respective codes saved in the order of evolvement, thus obtaining a source code sequence which is analysed by determining continued fraction factors for reference to measured frequency periods ratio starting from zero factor; after calculation of next codes of continued fraction a_{i} factor and continued fraction denominator p_{i}, continued fraction denominator code q_{i}, matching continued fraction for reference frequency period to measured frequency period under number i and relative maximum error of measurement reference to measured frequency period ratio are calculated.

EFFECT: reduced maximum relative error of method for frequency measurement.

1 dwg

FIELD: measurement equipment.

SUBSTANCE: method to determine parameters of a wideband signal consists in the fact that the signal is transformed into a digital form with the help of ADC, quadrature components are received A(ω), B(ω) at the specified frequency, quadrature components are transformed into the amplitude U(ω) and the initial phase φ(ω) of the signal, they form the amplitude-frequency spectrum and the phase-frequency spectrum of the signal, then they assess frequency ω=ω_{0} and amplitudes U_{0} of the signal by the maximum of the amplitude-frequency spectrum, they assess the initial phase φ of the signal using the phase-frequency spectrum of the signal in the point ω=ω_{0}.

EFFECT: increased accuracy of assessment of parameters of wideband sinusoid signals.

5 dwg

FIELD: measurement equipment.

SUBSTANCE: method implies procedure of synchronisation on the signal carrier frequency, detection of the section of the signal carrier and determination of its boundaries with the specified accuracy. Further the phase sampled information is analysed in respect to the reference oscillation of k-frequency at the specified time interval for sliding window monitoring and the signal is detected. Numbers of the initial and end phase samples, which correspond to the beginning and the end of the interval, are recorded. The analysis window duration is less than the sending duration. One frequency channel is analysed. Phase samples for other reference frequencies are defined on the basis of the initial phase sample by introducing necessary corrections. Each of these phase samples is analysed for signal delivery by sliding window method. This procedure is repeated many times along with the reduction of the analysis window duration. The device for the method implementation comprises an antenna-feeder device, a phase sample generator, a memory unit, a frequency channel generation unit, a unit for quadrature processing of signals, a unit for output data processing. The unit for quadrature processing of signals consists of the first and the second generators of quasisine and quasicosine channels, the first and the second adders, a weight function creating unit, two multipliers.

EFFECT: reducing time for signal reception and processing, improved accuracy.

3 cl, 5 dwg

FIELD: measurement equipment.

SUBSTANCE: method to measure nominal frequency of sinusoidal signals contemplates realisation of tuning of measured nominal frequency with a phase changer controlled by a sawtooth voltage generator. Tuning is carried out until equality of phases with a frequency that arrives directly to the second input of the comparator, the actuation time of which is proportionate to the number of pulses measured by a counter and processed by a microcontroller. At the same time the phase changer comprises RC-links, in which the role of capacitance C is played by capacitor diodes, and the microcontroller comprises a program that provides for the possibility to calibrate different types of sensors for linearisation of dependences of values of physical parameters on frequency. Results of measurements are displayed on an indicator. The device for measurement of nominal frequency of sinusoidal signals comprises a generator of reference frequency, a key, an "AND" circuit, a pulse counter, an indication unit, a microcontroller, the input of which is connected to the output of the pulse counter, and the output - with the indicator, a phase comparator, a gate multivibrator, which starts the generator of sawtooth voltage, which controls the phase changer until equality of phases on the comparator.

EFFECT: provision of high reliability, accuracy of the method, efficiency and universality of application.

2 cl, 3 dwg

FIELD: physics.

SUBSTANCE: method involves performing direct Fourier transformation of the analysed discrete signal in form of 2^{n} dimensional fast Fourier transformation, determining complex conjugate values of the results of direct Fourier transformation of the analysed discrete signal, pairwise multiplication of the obtained complex signals of direct Fourier transformation of the analysed discrete signal with complex conjugate values of direct Fourier transformation of the analysed discrete signal; from the obtained product P_{j}, values are selected and m M^{k} signals are formed; the obtained M^{k} signals are subjected to inverse Fourier transformation Z^{k}=F^{-1}[M^{k}]; a frequency-time autocorrelation function is determined. The obtained results are used to plot the curve of the frequency-time autocorrelation function R(f, t), from which presence of harmonic components and frequencies thereof in the analysed discrete signals are determined.

EFFECT: detecting harmonic components and frequencies thereof in a discrete signal from an autocorrelation function.

4 dwg, 1 tbl

FIELD: measurement equipment.

SUBSTANCE: method includes digitisation of an analogue signal, representation of its fragment with three digital codes S_{1}, S_{2}, S_{3}, generated at the moments of time t_{1}, t_{2}, t_{3} and used to calculate the signal frequency f according to the formula _{2} is not zero. In process of frequency variation the same codes are used to calculate the amplitude U, the phase φ and the initial phase of the signal φ_{0} in accordance with the following expressions: _{0}=φ-2πft_{2}, where the phase φ corresponds to the moment of time t_{2}.

EFFECT: accelerated measurements.

FIELD: radio engineering, communications.

SUBSTANCE: device to calculate values of signal and noise amplitudes, comprising the following serially connected components: an antenna, a mixer, an intermediate frequency amplifier (IFA), and also a heterodyne, the output of which is connected with the second input of the mixer, the antenna input is the device input. The device comprises the following serially connected components: the first unit of signal processing, the first analogue-to-digital converter (ADC) and a calculator of signal and noise amplitude values, the output of which is the device output, serially connected the second unit of signal processing, the second ADC, the output of which is connected with the second input of the calculator of the signal and noise amplitude values, inputs of the first and second blocks of signal processing are combined and connected with the IFA output. At the same time the first unit of processing comprises serially connected an accumulating circuit and the first amplitude detector, and the second processing unit represents the second amplitude detector.

EFFECT: increased accuracy of signal amplitude assessment with availability of noise.

3 dwg

FIELD: measurement equipment.

SUBSTANCE: signal frequency measurement method involves signal reception with further analogue-to-digital conversion, quick Fourier transformation, transformation of numerical massif in time area to numerical massif in frequency area, determination of j_{max} number of numerical massif element, which corresponds to maximum signal amplitude in frequency area, determines approximate value of the quantity of signal periods at observation interval, creation of 2k+1 reference signals in time area, which correspond as to the shape to initial massif in time area, the quantity of periods of which are offset in relation to the quantity of initial signal periods by j_{max }*(s/k-1)*b, where s=0,1,2, …2k, where coefficient b determines the neighbourhood size, b=0…1 near approximate quantity of signal periods j_{max} at observation interval, calculation of correlation coefficients 2k+1 of reference signals with initial one, approximation of ratio of correlation coefficients 2k+1 of reference signals and initial signal from number m in frequency area KK[m], where m=j_{max}+j_{max}*(s/k-1)*b, oversampling based on the determined approximating dependence with increase in the quantity of massif elements by R times, i.e. formation of massif KK1[m_{1}], where m_{1}=j_{max}+j_{max}*(s_{1}/(k*R)-1)*b, s_{1}=0,1,…2k*R, R - oversampling coefficient of more than 1, determination of element m_{1max} of numerical massif, which corresponds to maximum value of correlation coefficient KK1. Value m_{1max} is accepted as a specified value of the quantity of reference signal periods instead of j_{max}. Then, all the previous signal processing operations are repeated, thus decreasing each time the value b that determines the neighbourhood size near the determined quantity of signal periods at observation interval. After the required approximation accuracy of evaluation of reflected signal centre position is achieved, frequency value f=m_{1max}/(N*dt) is calculated.

EFFECT: higher measurement accuracy.

5 dwg

FIELD: electric engineering.

SUBSTANCE: method includes estimation of quality coefficients of electric energy in electric energy system, determining degree of matching of these coefficients to normal values, forming of control signal for correcting devices and predicting electric energy characteristics expected after effect of these devices. On basis of analysis of predicted characteristics quality coefficients are newly estimated and if necessary control signals for correction devices are formed. Estimation of not only voltage and frequency is provided, but also current. Whole cycle is repeated for each node of electric energy system.

EFFECT: higher efficiency.

1 dwg

FIELD: measuring equipment.

SUBSTANCE: method includes measuring instant average frequency of harmonic oscillations selected in couples, determining dispersion of frequency of researched generator, calculation of relative non-stability of frequency of researched oscillation. In device for measuring non-stability of frequency of researched generator three mixers are inserted, three amplitude detectors and three analog-digital converters, while outputs of generators are in couples connected to inputs of mixers, outputs of which are connected to inputs of amplitude detectors, outputs of which through analog-digital converters are connected to appropriate inputs of processor, to output of which device for recording measurement results is connected.

EFFECT: higher precision, higher efficiency.

2 cl, 2 dwg

FIELD: radio electronics.

SUBSTANCE: method comprises seeking the signal in a given frequency range by adjusting super-heterodyne receiver, forming frequency sweep on the screen of the tube, converting the frequency of the received signal, amplifying the voltage of the signal, decoding, and sending the signal to the vertically deflecting plates of the tube. The screen displays the pulse whose position on the frequency sweep determines the carrier frequency of the received signal. The root-mean-square coefficient of amplitude modulation, root-mean-square deviation of the frequency, the spectrum width of the received signal, and ratio of the spectrum width to the specific frequency deviation are then determined. The root-mean-square coefficient of the amplitude modulation is then compared with the ratio of the spectrum width to the root-mean-square deviation of frequency, and the type of modulation of the received signal is determined by the criteria proposed.

EFFECT: expanded functional capabilities.

3 dwg

FIELD: radio engineering, possible use as panoramic super-heterodyne receiver with frequency analysis function, operating under conditions of receipt in broad dynamic and frequency ranges.

SUBSTANCE: super heterodyne receiver and frequency meter contains amplifier of input signals, to output of which two receiving channels are connected, each one of which consists of serially connected mixer, band filter of intermediate frequency, amplifier of intermediate frequency and meter of intermediate frequency, two heterodynes on basis of digital frequency synthesizer, circuit for controlling frequency of heterodynes, code comparison circuit and solving device. Utilization of heterodynes with fixed shift by frequency during their readjustment, selection of relation between bands of intermediate frequency filters allows to stop using specialized channel for preventing receipt at mirror frequency and to perform receipt and measurement of signal parameters simultaneously in both main and mirror frequency bands.

EFFECT: increased band of simultaneous receipt and measurement of signal parameters with given band of intermediate frequency route.

4 dwg

FIELD: the invention refers to measuring technique and may be used for measuring of a carrier frequency and a vector analysis of signals in the system of radio control.

SUBSTANCE: for achieving such result a line of delay, a phase shifter till 90^{0}, two multipliers, two filters of low frequencies and the second electron-ray tube are additionally added. At that the line of delay, the first multiplier, whose second input is connected with the output of the amplifier of an intermediate frequency, the first filter of low frequencies and vertical-deflection plates of the second electron-ray tube are in series connected to the output of the amplifier of an intermediate frequency. The phase shifter till 90^{0} and the second multiplier are in series connected to the output of the amplifier of an intermediate frequency.

EFFECT: expansion of functional possibilities.

4 dwg

FIELD: tool-making industry, possible use for determining bearing frequency within given range of frequencies and during generation of aimed noise interference at this frequency.

SUBSTANCE: to achieve effect in seizing mode singular video pulse is generated, adjustment of super-heterodyne receiver is halted for time, equal to duration of video pulse. Then voltage of intermediate frequency is formed and multiplied with voltage of heterodyne. Voltage of total frequency is selected, modulated by amplitude by noises, power-amplified and broadcasted.

EFFECT: expanded functional capabilities on basis of generation of aimed noise interference for radio-electronic suppression of radio-electronic equipment.

3 dwg

FIELD: radio engineering, possible use as panoramic super heterodyne receiver with frequency analysis, working under conditions of receipt in wide dynamic and frequency ranges.

SUBSTANCE: super heterodyne receiver and frequency meter contains amplifier of input signals, to output of which two receiving channels are connected, each one of which consists of serially connected mixer, narrowband filter of intermediate frequency, intermediate frequency amplifier, amplitude detector and amplitude comparator, two heterodynes based on digital frequency synthesizer, circuit for controlling frequency of heterodynes, source of supporting voltage and solving device. Usage of heterodynes with fixed frequency shift during their adjustment, selection of ratio of filter bands of intermediate frequency makes it possible to abolish use of specialized channel for protection from receipt at mirror frequency and to realize receipt and measurement of signal parameters simultaneously in main and mirror frequency bands.

EFFECT: increased band of simultaneous receipt and measurement of signal parameters with given band of intermediate frequency route.

3 dwg

FIELD: measuring technique.

SUBSTANCE: system comprises signal input, unit for processing measurement results, computing device, and signal output. The internal cadence signal is supplied to the unit for processing the measurement results. The measuring signal is supplied to the signal input, and computing device generates output signal on the basis of cadence signal and measuring signal. The reference signal generated on the basis of the cadence signal is supplied to the unit for processing the results of measurements and is used for correction of the output signal.

EFFECT: enhanced accuracy of measurements.

3 cl, 11 dwg

FIELD: measuring equipment, possible use for measuring carrier frequency of radio signals.

SUBSTANCE: device contains input, block for rough estimation of frequency, first multiplier, phase shifter for 90°, second multiplier, signal/noise ratio evaluation block, block for evaluating signal duration ratio, first key, first low frequency filter, second low frequency filter, boundary computation block, supporting signal generator, block for computing current phase, block for computing frequency shift, comparator, second key, block for computing frequency, third key, delay line, fourth key.

EFFECT: increased precision when measuring carrier frequency of radio signal due to compensation of shift in frequency estimation, resulting from influence of noise with even energy spectrum; iteration processing of phase of carrier oscillation of signal occurs, making it possible to provide for compensation of shift in frequency value estimation, resulting from effect of noise with even power spectrum.

5 dwg

FIELD: radio-electronics, possible use for determining carrier frequency, type of modulation and manipulation of signals received in given range of frequencies.

SUBSTANCE: the known method for determining frequency, type of modulation and manipulation of received signals is complemented with, in case of phase manipulation of received signal, multiplication of signal phase by two, four and eight in three processing channels respectively, width of spectrum of second, fourth, and eights harmonics of frequency of received signal are determined, ratio of width of spectrum of received signal to width of spectrum of its harmonics is determined in each processing channel, resulting ratios are compared to one, and if these ratios are substantially more than one, logical unit are formed, outputs of all three channels are connected to first inputs of coincidence elements "AND" respectively, second input of first coincidence element "AND" is connected directly to output of second processing channel, second input of second coincidence element "AND" is connected through inverter to output of first processing channel, second input of third coincidence element "AND" is connected through inverter to output of second processing channel, if logical unit appears at output of first coincidence element "AND", conclusion is drawn about double phase manipulation of received signal, if logical unit appears at output of second coincidence element "AND", conclusion of quadruple phase manipulation of received signal is drawn, if logical unit appears at output of third coincidence element "AND", conclusion is drawn about octuple phase manipulation of received signal.

EFFECT: expanded functional capabilities of the method due to determining of multiplicity of phase manipulation of received signal.

3 dwg