Pub Date : 1995-11-07DOI: 10.1109/ULTSYM.1995.495852
K. Katakura, M. Okujima
In conventional ultrasound Doppler systems, the velocity component along the beam axis is obtained from the observed frequency shift. We have proposed two methods that use pure linear procedures to measure all the components of an arbitrary flow vector. In the first method, the first step is a Fourier transform of the received signals in the direction of the transducer array. The second step is also a Fourier transform, but in the polar-axis directions. In the second method, the first step is again a Fourier transform, but in the direction of the time-axis. The second step is not a Fourier transform but a projection integration in the polar-axis direction. In this paper, the identity of these methods in velocity resolution is shown.
{"title":"Identity between two computed velocimetry methods","authors":"K. Katakura, M. Okujima","doi":"10.1109/ULTSYM.1995.495852","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495852","url":null,"abstract":"In conventional ultrasound Doppler systems, the velocity component along the beam axis is obtained from the observed frequency shift. We have proposed two methods that use pure linear procedures to measure all the components of an arbitrary flow vector. In the first method, the first step is a Fourier transform of the received signals in the direction of the transducer array. The second step is also a Fourier transform, but in the polar-axis directions. In the second method, the first step is again a Fourier transform, but in the direction of the time-axis. The second step is not a Fourier transform but a projection integration in the polar-axis direction. In this paper, the identity of these methods in velocity resolution is shown.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130176754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-07DOI: 10.1109/ULTSYM.1995.495804
Qian Zhang, Peter A. Lewin, P. E. Bloomfield
To improve the pulse-echo sensitivity of a piezopolymer transducer while preserving its broad bandwidth property, several multilayer transducer design approaches have been suggested. This paper presents formulae describing three types of multilayer transducers-a Barker code multilayer-, folded multilayer and switchable Barker code multilayer transducer. Based on the formulae derived, the pulse-echo responses of the multilayer transducers under various excitation signals were calculated and compared with those achievable with an equivalent PZT transducer. Also, the influence of a tissue layer on the transducer responses was examined. The simulation results indicated that the switchable Barker code transducer design outperforms all other transducer designs analyzed with respect to the axial resolution and overall sensitivity in the medical imaging frequency range. To verify the simulation results, several prototypes of multilayer transducers were fabricated and tested in water. A good agreement between the experimental results and the corresponding computer predictions was achieved.
{"title":"PVDF transducers-a performance comparison of single layer and multilayer structures","authors":"Qian Zhang, Peter A. Lewin, P. E. Bloomfield","doi":"10.1109/ULTSYM.1995.495804","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495804","url":null,"abstract":"To improve the pulse-echo sensitivity of a piezopolymer transducer while preserving its broad bandwidth property, several multilayer transducer design approaches have been suggested. This paper presents formulae describing three types of multilayer transducers-a Barker code multilayer-, folded multilayer and switchable Barker code multilayer transducer. Based on the formulae derived, the pulse-echo responses of the multilayer transducers under various excitation signals were calculated and compared with those achievable with an equivalent PZT transducer. Also, the influence of a tissue layer on the transducer responses was examined. The simulation results indicated that the switchable Barker code transducer design outperforms all other transducer designs analyzed with respect to the axial resolution and overall sensitivity in the medical imaging frequency range. To verify the simulation results, several prototypes of multilayer transducers were fabricated and tested in water. A good agreement between the experimental results and the corresponding computer predictions was achieved.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128920112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-07DOI: 10.1109/ULTSYM.1995.495772
B. Bijnens, M. Herregods, J. Nuyts, P. Suetens, F. Van de Werf
The value of high resolution integrated backscatter (IB) for use in myocardial tissue characterization during acute ischemia was examined. In closed chest dogs, myocardial ischemia was induced in a small region. Before and after 5, 30 and 60 minutes of occlusion, echocardiography was performed. High resolution digital radiofrequency (RF) data of the complete sectorscan, and of 2 consecutive heart cycles, were acquired using a new acquisition approach. A region of interest was drawn on each image in both the (normally perfused) septum and the (ischemic) posterior wall. IB and cyclic variation (CV) of IB was calculated. Values were expressed using a linear scale. We found a significant increase in mean IB after 5 min in the ischemic region compared to the normally perfused region in all experiments. This increase persisted during the 60 minutes of occlusion. Furthermore, an increase in CV was observed during ischemia. This is in contradiction to the findings of other groups. One of the explanations is that we don't express the values on a logarithmic scale (dB), We can state that comparing the mean IB from different regions within the myocardium can discriminate ischemia in a very early stage in a canine model. The value and the meaning of the change in CV of IB however is not straightforward and remains an issue for further investigation.
{"title":"High resolution integrated backscatter in acute myocardial ischemia","authors":"B. Bijnens, M. Herregods, J. Nuyts, P. Suetens, F. Van de Werf","doi":"10.1109/ULTSYM.1995.495772","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495772","url":null,"abstract":"The value of high resolution integrated backscatter (IB) for use in myocardial tissue characterization during acute ischemia was examined. In closed chest dogs, myocardial ischemia was induced in a small region. Before and after 5, 30 and 60 minutes of occlusion, echocardiography was performed. High resolution digital radiofrequency (RF) data of the complete sectorscan, and of 2 consecutive heart cycles, were acquired using a new acquisition approach. A region of interest was drawn on each image in both the (normally perfused) septum and the (ischemic) posterior wall. IB and cyclic variation (CV) of IB was calculated. Values were expressed using a linear scale. We found a significant increase in mean IB after 5 min in the ischemic region compared to the normally perfused region in all experiments. This increase persisted during the 60 minutes of occlusion. Furthermore, an increase in CV was observed during ischemia. This is in contradiction to the findings of other groups. One of the explanations is that we don't express the values on a logarithmic scale (dB), We can state that comparing the mean IB from different regions within the myocardium can discriminate ischemia in a very early stage in a canine model. The value and the meaning of the change in CV of IB however is not straightforward and remains an issue for further investigation.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125206214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-07DOI: 10.1109/ULTSYM.1995.495786
P. Lewin, R. Bhatia, Qian Zhang, J. Dodick
Describes a measurement technique specially developed to characterize optoacoustic sources. The technique provides a convenient baseline for a comparison of different surgical ultrasonic systems utilizing optoacoustic and ultrasonic transducers. In addition, it provides a well defined tool to optimize the performance of a variety of designs. Attention is focused on the laser assisted devices in which appropriately delivered light energy is converted into acoustic shock wave. A meaningful comparison of such devices with other therapeutic equipment designed for a direct interaction with tissue requires knowledge of energy needed for a successful surgical treatment. It is demonstrated that knowledge of the key shock wave parameters allows the total acoustic energy associated with the shock wave to be determined. The procedure developed to calculate this energy is discussed and it is shown that the value of this energy can be conveniently used as an indicator of efficacy of an optoacoustic converter in a clinical environment. The characterization procedure developed is applicable to surgical ultrasonic systems including conventional and laser assisted phacoemulsifiers.
{"title":"Characterization of optoacoustic surgical devices","authors":"P. Lewin, R. Bhatia, Qian Zhang, J. Dodick","doi":"10.1109/ULTSYM.1995.495786","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495786","url":null,"abstract":"Describes a measurement technique specially developed to characterize optoacoustic sources. The technique provides a convenient baseline for a comparison of different surgical ultrasonic systems utilizing optoacoustic and ultrasonic transducers. In addition, it provides a well defined tool to optimize the performance of a variety of designs. Attention is focused on the laser assisted devices in which appropriately delivered light energy is converted into acoustic shock wave. A meaningful comparison of such devices with other therapeutic equipment designed for a direct interaction with tissue requires knowledge of energy needed for a successful surgical treatment. It is demonstrated that knowledge of the key shock wave parameters allows the total acoustic energy associated with the shock wave to be determined. The procedure developed to calculate this energy is discussed and it is shown that the value of this energy can be conveniently used as an indicator of efficacy of an optoacoustic converter in a clinical environment. The characterization procedure developed is applicable to surgical ultrasonic systems including conventional and laser assisted phacoemulsifiers.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133128241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-07DOI: 10.1109/ULTSYM.1995.495781
U. Cobet, P. Pfundner, M. Walke, M. Schultz, I. Schrodter
Theoretical and experimental results show that ultrasonic scattering of cell suspensions is caused mainly by interaction forces between cells. Therefore, the membrane properties of cells, the electrical charge and the viscoelastic properties, but also the antigen-antibody and receptor-ligand bindings, have a strong influence upon ultrasonic scattering. The theoretical calculation of an autocorrelation function of a scattering region containing statistical isotropical distributed scatterers leads to a closed solution of ultrasonic scattering. Two correcting terms can be calculated in addition to the well known Rayleigh's solution, i.e. the geometry term of the scattering particles and a correcting function dependent on the interaction forces between the particles. Two systems for the measuring of the Doppler-sonographical scattering coefficient were developed, one a recirculating tube system and a Couette-flow cylinder-cylinder system with a sample volume smaller than 0.5 ml. Employing these systems, both the shear rate and scattering coefficient occurring in the flow can be measured simultaneously. It can be shown that with these methods the simple proof of adhesion receptors of erythrocytes, lymphocytes and platelets is possible.
{"title":"Determination of cell interaction forces in suspensions with ultrasonic scattering","authors":"U. Cobet, P. Pfundner, M. Walke, M. Schultz, I. Schrodter","doi":"10.1109/ULTSYM.1995.495781","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495781","url":null,"abstract":"Theoretical and experimental results show that ultrasonic scattering of cell suspensions is caused mainly by interaction forces between cells. Therefore, the membrane properties of cells, the electrical charge and the viscoelastic properties, but also the antigen-antibody and receptor-ligand bindings, have a strong influence upon ultrasonic scattering. The theoretical calculation of an autocorrelation function of a scattering region containing statistical isotropical distributed scatterers leads to a closed solution of ultrasonic scattering. Two correcting terms can be calculated in addition to the well known Rayleigh's solution, i.e. the geometry term of the scattering particles and a correcting function dependent on the interaction forces between the particles. Two systems for the measuring of the Doppler-sonographical scattering coefficient were developed, one a recirculating tube system and a Couette-flow cylinder-cylinder system with a sample volume smaller than 0.5 ml. Employing these systems, both the shear rate and scattering coefficient occurring in the flow can be measured simultaneously. It can be shown that with these methods the simple proof of adhesion receptors of erythrocytes, lymphocytes and platelets is possible.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115573429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-07DOI: 10.1109/ULTSYM.1995.495783
K. N. Bates
The N+N imaging system solves the problem of controlling 2-D arrays with only as many control channels as there are rows and columns of elements in the acoustic array. A 10,000 element array can be controlled with only 200 control channels; a reduction in complexity that allows the possibility of a commercial medical acoustic imaging system capable of rapid 3-D, volume, images and/or real time, arbitrary scan plane, 2-D sector, planar, or curve planar images. In addition, it allows the implementation of multi-dimensional aberration correction which may allow ultrasonic images to finally approach the image acuity of MRI and X-ray CAT imaging systems, and to do so at a fraction of the costs of these imaging modalities.
{"title":"A high acuity 3-D acoustic imaging system","authors":"K. N. Bates","doi":"10.1109/ULTSYM.1995.495783","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495783","url":null,"abstract":"The N+N imaging system solves the problem of controlling 2-D arrays with only as many control channels as there are rows and columns of elements in the acoustic array. A 10,000 element array can be controlled with only 200 control channels; a reduction in complexity that allows the possibility of a commercial medical acoustic imaging system capable of rapid 3-D, volume, images and/or real time, arbitrary scan plane, 2-D sector, planar, or curve planar images. In addition, it allows the implementation of multi-dimensional aberration correction which may allow ultrasonic images to finally approach the image acuity of MRI and X-ray CAT imaging systems, and to do so at a fraction of the costs of these imaging modalities.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"200 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115633806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-07DOI: 10.1109/ULTSYM.1995.495574
D. Penunuri, A. Baghai-Wadji, T. Hickernell
In this paper we construct elemental charge distributions for high precision modeling of interdigital transducers on leaky acoustic wave substrates such as the well known cuts of LiNbO/sub 3/ and LiTaO/sub 3/. To this end we consider geometrically periodic and arbitrarily driven electrodes with infinite or finite aperture length. We define an elemental structure by considering one "hot" electrode neighbored by an infinite number of "grounded" electrodes. Due to the linearity assumption of the problem, the frequency-dependent elemental charge distribution (ECD) on this structure is sufficient to construct the charge distribution on the electrodes of any periodic IDT with the same pitch-to-mark ratio. To calculate the ECD we consider a certain number (say, /spl ap/30) of appropriately defined multi-phase transducers and determine the corresponding charge distributions by employing our recently developed concept of multi-phase periodic Green's functions in a method-of-moments application. The weighted superposition of the resulting auxiliary multi-phase field solutions leads to the ECDs which fully account for the leaky wave interaction with the electrodes. The analysis is then applied to several electrode geometries using 41/spl deg/-cut, X-propagating lithium niobate. We then show how this method can be extended to 2D charge distributions.
{"title":"Two- and three-dimensional elemental charge distributions in leaky acoustic wave devices","authors":"D. Penunuri, A. Baghai-Wadji, T. Hickernell","doi":"10.1109/ULTSYM.1995.495574","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495574","url":null,"abstract":"In this paper we construct elemental charge distributions for high precision modeling of interdigital transducers on leaky acoustic wave substrates such as the well known cuts of LiNbO/sub 3/ and LiTaO/sub 3/. To this end we consider geometrically periodic and arbitrarily driven electrodes with infinite or finite aperture length. We define an elemental structure by considering one \"hot\" electrode neighbored by an infinite number of \"grounded\" electrodes. Due to the linearity assumption of the problem, the frequency-dependent elemental charge distribution (ECD) on this structure is sufficient to construct the charge distribution on the electrodes of any periodic IDT with the same pitch-to-mark ratio. To calculate the ECD we consider a certain number (say, /spl ap/30) of appropriately defined multi-phase transducers and determine the corresponding charge distributions by employing our recently developed concept of multi-phase periodic Green's functions in a method-of-moments application. The weighted superposition of the resulting auxiliary multi-phase field solutions leads to the ECDs which fully account for the leaky wave interaction with the electrodes. The analysis is then applied to several electrode geometries using 41/spl deg/-cut, X-propagating lithium niobate. We then show how this method can be extended to 2D charge distributions.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115781653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-07DOI: 10.1109/ULTSYM.1995.495540
D. Chen, S. Jen, C. Hartmann
An equivalent circuit representation, which has been successfully used in SAW transversely coupled resonator filter (TCF), is extended to longitudinally coupled resonator filters (CRF). In TCF case usually two fundamental modes are accurate enough to represent the passband but more modes (most of them are 'quasimodes' located outside of the stopband of the structure) are needed for CRF. A mode identification method is introduced in terms of equivalent motional parameters, R, L, and C and then applied to two experimental examples, a narrow bandfilter on quartz and a 3% bandwidth filter on 36/spl deg/ YX-LiTaO/sub 3/. The results confirm that it could be a useful tool for system designer as it is compatible property with commercial electronic circuit CAD software. The profiles of the main resonant modes detected by a laser probe are presented in this paper.
{"title":"Resonant modes in coupled resonator filters and the unique equivalent circuit representation","authors":"D. Chen, S. Jen, C. Hartmann","doi":"10.1109/ULTSYM.1995.495540","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495540","url":null,"abstract":"An equivalent circuit representation, which has been successfully used in SAW transversely coupled resonator filter (TCF), is extended to longitudinally coupled resonator filters (CRF). In TCF case usually two fundamental modes are accurate enough to represent the passband but more modes (most of them are 'quasimodes' located outside of the stopband of the structure) are needed for CRF. A mode identification method is introduced in terms of equivalent motional parameters, R, L, and C and then applied to two experimental examples, a narrow bandfilter on quartz and a 3% bandwidth filter on 36/spl deg/ YX-LiTaO/sub 3/. The results confirm that it could be a useful tool for system designer as it is compatible property with commercial electronic circuit CAD software. The profiles of the main resonant modes detected by a laser probe are presented in this paper.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"171 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124150097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-07DOI: 10.1109/ULTSYM.1995.495544
C. Zhang, J. Yin, Q. Lin, Y. Shui
A new adaptive filter for cancelling narrow-band interference in spread spectrum communications systems is described in this paper. The filter employs a SAW injection-locked oscillator (SAWILO) to track CW interference signal in a simulated spread spectrum system. The filter demonstrates a 20 dB interference cancellation over the locking bandwidth of SAWILO in real time. The filter offers the advantage in terms of complexity over other equivalent systems. The adaptive filter is presented with experimental measurements.
{"title":"Adaptive filter based on SAW injection-locked oscillator","authors":"C. Zhang, J. Yin, Q. Lin, Y. Shui","doi":"10.1109/ULTSYM.1995.495544","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495544","url":null,"abstract":"A new adaptive filter for cancelling narrow-band interference in spread spectrum communications systems is described in this paper. The filter employs a SAW injection-locked oscillator (SAWILO) to track CW interference signal in a simulated spread spectrum system. The filter demonstrates a 20 dB interference cancellation over the locking bandwidth of SAWILO in real time. The filter offers the advantage in terms of complexity over other equivalent systems. The adaptive filter is presented with experimental measurements.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"182 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124588266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-11-07DOI: 10.1109/ULTSYM.1995.495660
T. Koike, T. Hirao, T. Nagano
Digital control method for oscillatory frequencies of a magnetostatic wave (MSW) oscillator employing a straightedge resonator without changing the external magnetic field and the circuit parameters of a feedback load circuit is discussed. In this method, additional electrodes are fabricated near or at the edges of the resonator and pin diodes are connected in series. Upon switching the pin diodes on and off, the resonant frequency can be shifted while the oscillation condition is maintained. We constructed an oscillator using a straightedge resonator with one additional electrode near each edge and could observe a shift of the oscillatory peak as predicted by our equivalent circuit model. We also examined a condition for realizing optimum frequency shift when the oscillatory frequency is controlled by the pin diodes.
{"title":"Digital frequency control method for MSW oscillators using straightedge resonators","authors":"T. Koike, T. Hirao, T. Nagano","doi":"10.1109/ULTSYM.1995.495660","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495660","url":null,"abstract":"Digital control method for oscillatory frequencies of a magnetostatic wave (MSW) oscillator employing a straightedge resonator without changing the external magnetic field and the circuit parameters of a feedback load circuit is discussed. In this method, additional electrodes are fabricated near or at the edges of the resonator and pin diodes are connected in series. Upon switching the pin diodes on and off, the resonant frequency can be shifted while the oscillation condition is maintained. We constructed an oscillator using a straightedge resonator with one additional electrode near each edge and could observe a shift of the oscillatory peak as predicted by our equivalent circuit model. We also examined a condition for realizing optimum frequency shift when the oscillatory frequency is controlled by the pin diodes.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117320242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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