A history of crystal filters

Kinsman, R.G.

doi:10.1109/freq.1998.717956

Cited by 14 publications

(7 citation statements)

References 23 publications

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“…The availability of affordable operational amplifiers suitable for filtering in the megahertz range is another constraint. However, using a second-order quartz-crystal bandpass ladder filter can achieve a flat response for narrow passbands, making it a suitable filter type for this application [37].…”

Section: B Frequency Domain Methodsmentioning

confidence: 99%

Induced Voltage Estimation From Class EF Switching Harmonics in HF-IPT Systems

Pucci

Arteaga

Kwan³

et al. 2022

IEEE Trans. Power Electron.

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One of the advantages of high-frequency inductive power transfer systems is the high tolerance to misalignment and large air-gaps. However, the inherently large magnetic field volumes can lead to coupling of additional foreign objects with the primary, causing possible detuning of the system and heating of the objects. These foreign objects and the conditions of the local environment can load the transmitter, which changes the induced voltage on the primary side. Unfortunately, the induced voltage is not directly measurable in an operating transmitter and the most straightforward way of calculating this variable, through a measurement of primary coil current and voltage, can cause a significant decrease in quality factor which reduces system performance. An integrated solution capable of estimating the induced voltage through other less invasive measurements in the primary is needed to ensure safety of operation through foreign object detection. Knowledge of the induced voltage can also be used to correct tuning mismatches where both sides of the link are active (i.e., in synchronous rectification and bidirectional systems). In this article, multiple candidate variables for estimating the induced voltage are assessed based on factors such as measurement practicality and estimation accuracy. It is demonstrated for the first time that a solution which is based on the measurement of only two variables, the amplitude of the fundamental frequency of the switching waveform and input current, can achieve state-of-the-art induced voltage estimation accuracy. These two variables, which can be obtained using simple cost-effective analogue circuitry, are used in a Gaussian process to generate a regression model. This is used to estimate induced voltages at any angle in an approximate magnitude range of 0-20 V with a normalized root-mean-square error of 1% for the real part and 1.5% for the imaginary part. This corresponds to detecting a plastic container with 1 kg of saline solution (0.4% concentration, to emulate the electromagnetic profile of muscle) at a distance of 15 cm (1.5 coil radii). The results Manuscript

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Section: B Frequency Domain Methodsmentioning

confidence: 99%

Induced Voltage Estimation From Class EF Switching Harmonics in HF-IPT Systems

Pucci

Arteaga

Kwan³

et al. 2022

IEEE Trans. Power Electron.

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“…The typical frequency response of a DMS filter is shoulder behavior in the higher stopband and excellent far-end out-of-band rejection [ 19 ]. At the 1998 IEEE International Symposium on Frequency Control, Kinsmann presented an overview of crystal filters, including trapezoidal and lattice structures, in his invited paper [ 20 ].…”

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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“…Quartz crystal has a valuable tradition in the history of electronic devices [1]. From the first uses as a high stability signal generator [2] or in the realization of radio frequency filters [3], the quartz crystal has always been a key device. The quartz crystal, respectively the QCM sensor, is important from an applications perspective for its unique value of having a very high-quality factor (Q) or equivalent a very low dissipation factor.…”

Section: Introductionmentioning

confidence: 99%

A Study on Regenerative Quartz Crystal Microbalance

Burda

2022

Chemosensors

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The quartz crystal microbalance with dissipation (QCM-D) represented a substantial breakthrough in the use of the QCM sensor in diverse applications ranging from environmental monitoring to biomedical diagnostics. To obtain the required selectivity and sensitivity of a volatile organic compounds (VOC) sensor, it is necessary to coat the QCM sensor with a sensing film. As the QCM sensor is coated with the sensing film, an increase in the dissipation factor occurs, resulting in a shorter and shorter ring-down time. This decrease in ring-down time makes it difficult to implement the QCM-D method in an economical and portable configuration from the perspective of large-scale applications. To compensate for this effect, a regenerative method is proposed by which the damping effect produced by the sensing film is eliminated. In this sense, a regenerative circuit as an extension to a virtual instrument is proposed to validate the experimental method. The simulation of the ring-down time for the QCM sensor in the air considering the effect of the added sensing film, followed by the basic theoretical concepts of the regenerative method and the experimental results obtained, are analyzed in detail in this paper.

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A history of crystal filters

Cited by 14 publications

References 23 publications

Induced Voltage Estimation From Class EF Switching Harmonics in HF-IPT Systems

Induced Voltage Estimation From Class EF Switching Harmonics in HF-IPT Systems

Development and Application of SAW Filter

A Study on Regenerative Quartz Crystal Microbalance

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