In-Phase and Quadrature Analysis for Amplitude and Frequency Modulations Due to Vibrations on a Surface-Acoustic-Wave Resonator

Maskay, A.; Hummels, D.M.; Cunha, M. Pereira da

doi:10.1109/tuffc.2018.2875588

Cited by 12 publications

(3 citation statements)

References 19 publications

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“…TV-IF (television intermediate frequency) SAW filters began mass production in the mid-70 s [ 16 ] Surface acoustic wave resonators change the relative size and elastic properties of the substrate due to external mechanical vibrations, which changes the acoustic wave propagation speed of the device [ 17 ]. In 1992, Morita et al proposed a low-loss filter in the literature, which can achieve wide bandwidth in different LiTaO 3 tangential directions.…”

Section: Saw Filter Technologymentioning

confidence: 99%

Development and Application of SAW Filter

Chen

Zhu

2022

Micromachines

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With the in-depth advancement of the fifth generation (5G) mobile communication technology, the technical requirements for filters are also constantly improving. Surface acoustic wave (SAW) filters are widely used in home TV, mobile communications, radio frequency filters and radar due to their simple structure, few mask layers, easy miniaturization, and low cost. Through the continuous improvement of communication technology, SAW has developed into various high-performance acoustic filters from bulk SAW with the support of some new architectures, new materials and advanced modeling techniques. This paper analyzes and reviews the research situation of SAW filter technology.

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Section: Saw Filter Technologymentioning

confidence: 99%

Development and Application of SAW Filter

Chen

Zhu

2022

Micromachines

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“…The I/Q digital signals are filtered by the finite impulse response (FIR) LPF. The digital quadrature demodulation scheme [21] avoids the imbalance of amplitudes and phases of two-way analogue LO signals, and eliminates the imbalance of tag echo amplitudes and phases of analogue I/Q channels caused by the baseband conditioning circuit, and thus makes the calculation of time delays and phases of the echo pulse train corresponding to all the reflectors on the tag more stable and accurate.…”

Section: Rf Band-pass Sampling and Digital Quadrature Demodulation Scmentioning

confidence: 99%

High‐speed data acquisition of the reader of the SAW RFID system

Chen

Hao

Chen

et al. 2019

IET Science, Measurement & Technology

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“…In-phase and quadrature (IQ) demodulation using two in-phase quadrature channels for demodulation can differentiate movements in opposite directions (towards the sound source and away from the sound source) and for this reason, is widely used in radar detection, telecommunication, and ultrasonic detection. [7][8][9][10] During FHR monitoring, the heart wall moves closer and then away from the probe during systole and diastole. Based on this, IQ demodulation may distinguish these two movements and theoretically resolve false FHR doubling and halving.…”

Section: Introductionmentioning

confidence: 99%

The Efficacy of In-Phase and Quadrature Demodulation in Electronic Fetal Heart Rate Monitoring During Labor

Liang

Liu

Yan

et al. 2021

Maternal-Fetal Medicine

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Objective: To investigate the efficacy of in-phase and quadrature (IQ) demodulation in electronic fetal heart rate monitoring (EFM) to reduce false reports of fetal heart rate (FHR) doubling or halving.Methods: This is a prospective cohort study. A total of 263 full-term pregnant women who delivered at Peking University Shenzhen Hospital between August 2019 and July 2020 were prospectively enrolled in the study. FHR monitoring began when the cervix was dilated to 2-3 cm and continued until delivery. Raw fetal Doppler audio signals and internal and external cardiotocography curves from internal electrode monitoring, EFM with conventional demodulation (external), and EFM with IQ demodulation (external) were acquired to compare FHR doubling and halving time. In cohort 1, FHR was compared between IQ demodulation and conventional demodulation. In cohort 2, FHR was compared between IQ demodulation, conventional demodulation, and internal FHR monitoring. Count data were statistically analyzed using the Chi-squared test, and measurement data were statistically analyzed using t-test for correlation coefficients, and Bland-Altman analysis for concordance ranges.Results: To compare IQ demodulation and conventional demodulation, 225 pregnant women were monitored for a total of 835,870 seconds. The beat-to-beat interval of FHRs in raw fetal Doppler audio signals was used as the reference. The results showed a doubling time of 3401 seconds (0.407%, 3401/835,870) and a halving time of 2918 seconds (0.349%, 2918/835,870) with conventional demodulation, compared to 241 seconds (0.029%, 241/835,870) and 589 seconds (0.070%, 589/835,870), respectively, with IQ demodulation. IQ demodulation reduced FHR doubling by approximately 93% (3160/3401) and FHR halving by approximately 80% (2329/2918) compared to conventional demodulation (P < 0.01).To compare IQ demodulation, conventional demodulation, and internal FHR monitoring, 38 pregnant women were monitored for a total of 98,561 seconds. FHR from internal electrode monitoring was used as the reference. The results showed a doubling time of 238 seconds (0.241%, 238/98,561) and a halving time of 235 seconds 0.238%, 235/98,561) with conventional demodulation, compared with 30 seconds (0.030%, 30/98,561) and 81 seconds (0.082%, 81/98,561), respectively, with IQ demodulation (P < 0.05). No significant difference was observed in doubling or halving time between IQ demodulation and internal FHR monitoring (P > 0.05). IQ demodulation was more closely correlated with internal FHR monitoring than conventional demodulation (0.986 vs. 0.947). The Bland-Altman analysis showed that the concordance range of IQ demodulation vs. internal FHR monitoring was significantly narrower than that of conventional demodulation vs. internal FHR monitoring ((À5.32,6.01) vs. (À10.87,11.46)).Conclusion: EFM with IQ demodulation significantly reduces false FHR doubling and halving, with an efficacy similar to that of internal FHR monitoring.

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In-Phase and Quadrature Analysis for Amplitude and Frequency Modulations Due to Vibrations on a Surface-Acoustic-Wave Resonator

Cited by 12 publications

References 19 publications

Development and Application of SAW Filter

Development and Application of SAW Filter

High‐speed data acquisition of the reader of the SAW RFID system

The Efficacy of In-Phase and Quadrature Demodulation in Electronic Fetal Heart Rate Monitoring During Labor

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