A Frequency Demodulation Technique Based on Sliding DFT Phase Locking Scheme for Large Variation FM Signals

Sumathi, P.

doi:10.1109/lcomm.2012.092812.121133

Cited by 11 publications

(6 citation statements)

References 9 publications

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“…Arterial wall motion parameters are estimated using phase locking schemes in [10]. A sliding discrete Fourier transform (SDFT) based phase locking scheme [62] has been applied for frequency demodulation in [63]. From a vibration measurement system, the received ultrasonic signal S 0 (t) = A 2 cos(ω 0 t + f 0 + βsin(ω L t + f L )) can be fed to the SDFT phase locking scheme.…”

Section: Doppler Signal Extractionmentioning

confidence: 99%

Vibration parameter estimation methods for ultrasonic measurement systems – a review

Singh

Sumathi

2015

IET Science, Measurement & Technology

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A review of vibration signal estimation techniques employed in ultrasonic vibration measurement systems is presented. The review focuses on the Doppler signal extraction methods including the theory and analysis pertaining to the background of ultrasonic vibration measurement techniques. The phase modulated received signal in the vibration measurement system involves constant phase shift because of ultrasonic path length, phase shift introduced by Doppler effect because of vibrating object and the parametric phase shift caused by interaction of high frequency ultrasonic wave and low pressure developed by vibrating object. Among the three phase shifts, the Doppler phase shift contains the vibrating signal information and the extraction of Doppler signal helps in knowing the velocity of the vibrating object, amplitude and phase of the vibration. Various techniques of Doppler phase shift retrieval are categorised based on the modulation index estimation procedures from the received ultrasonic signal. An analysis is made based on the information retrieval methods for estimation of vibration signal parameters, range of the vibration amplitude, frequency and the preferable carrier frequency for transmission. Further, the analysis also presents various applications in which ultrasonic vibration measurements system are employed successfully.

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Section: Doppler Signal Extractionmentioning

confidence: 99%

Vibration parameter estimation methods for ultrasonic measurement systems – a review

Singh

Sumathi

2015

IET Science, Measurement & Technology

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“…The proposed demodulation technique for AM-FM signal demodulation falls under the category of combining the feed-forward and feedback demodulation techniques. In the case of feed-forward demodulation, the FM signal is converted into AM using a filter and the feedback demodulation involves phase locking schemes [23]. In this paper, the application of sliding DFT-based PLL has been extended to mono-component AM-FM demodulation.…”

Section: Iet Communicationsmentioning

confidence: 99%

“…where α is the control signal, which is fed to NCO by the PI controller. Linearised transfer function model of the SDFT-PLL structure 1 is presented in [23,25]. This model is reproduced in Fig.…”

Section: Adaptive Sampling Frequency-based Sdft-based Phase Locking Smentioning

confidence: 99%

Sliding discrete Fourier transform‐based mono‐component amplitude modulation–frequency modulation signal decomposition

Sumathi

Singh

2015

IET Communications

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The sliding discrete Fourier transform-based phase locking scheme (SDFT-PLL) has been adapted for the extraction of message signals from mono-component amplitude modulation-frequency modulation (AM-FM) signals. In the proposed scheme, the SDFT-PLL is designed to track a carrier signal, which has been modulated by sinusoidal message signals both in amplitude and frequency. The sliding DFT filter is prone to windowing effect if input signal frequency drifts from centre carrier frequency. The amplitude and phase errors caused by this effect have been utilised to achieve locking condition by adaptive sampling frequency control. The SDFT-PLL is modified in such a way that the numerically controlled oscillator produces sampling pulses suitable for SDFTbin-1 and SDFT bin-0 for the retrieval of frequency and amplitude modulation signals, respectively. Hence, the frequency and amplitude variation of monocomponent AM-FM could be retrieved simultaneously. Furthermore, Bessel function-based analysis provides an insight to the removal of unwanted spectral components present in error signal. Simulation results prove the capability of PLL in message signal retrieval for large variation in frequency and amplitude. The proposed scheme is implemented in field programmable gate array to validate the performance of SDFT-PLL in decomposition of the mono-component AM-FM signal.

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“…The frequency-domain methods usually refer to Fourier transform-based techniques [12][13][14][15], within which the sliding discrete Fourier transform (SDFT) has gained wide applications in recent years for its efficient iteration and easy digital implementation. In [16], the SDFT was used for harmonic detection in the three-phase grid-tie inverter system; besides, SDFT has been often used in cooperation with the phase-locked loop for the stable operation and control of the grid-connected converters [17,18].…”

Section: Introductionmentioning

confidence: 99%

Rapid Extraction of the Fundamental Components for Non-Ideal Three-Phase Grid Based on an Improved Sliding Discrete Fourier Transform

Li¹,

Nai²

2022

Electronics

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In order to make an effective extraction of the fundamental components for a non-ideal three-phase grid, an improved sliding discrete Fourier transform (ISDFT) has been proposed in this paper. Firstly, the non-ideal signal characteristics are studied in detail, which reveals that there are not only typical harmonic components, but also double frequency components, that exist in dq coordinates when the three-phase grid voltages are unbalanced. Then, the structure form of the conventional sliding discrete Fourier transform (SDFT) has been redesigned to form the ISDFT algorithm, in which a special offset link is introduced to reduce the extraction time while the effectiveness is guaranteed. The experimental results show that this proposed ISDFT is suitable for types of non-ideal signals extraction and can keep a nice dynamical and steady performance in cases of grid or load disturbance. For the average extraction time, ISDFT is saving about 44.56% more of the time than SDFT and about 65.32% more than discrete Fourier transform (DFT).

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A Frequency Demodulation Technique Based on Sliding DFT Phase Locking Scheme for Large Variation FM Signals

Cited by 11 publications

References 9 publications

Vibration parameter estimation methods for ultrasonic measurement systems – a review

Vibration parameter estimation methods for ultrasonic measurement systems – a review

Sliding discrete Fourier transform‐based mono‐component amplitude modulation–frequency modulation signal decomposition

Rapid Extraction of the Fundamental Components for Non-Ideal Three-Phase Grid Based on an Improved Sliding Discrete Fourier Transform

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