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991.
In this paper, time-efficient systolic and semi-systolic architectures for the implementation of multidimensional DFTs are proposed that allow modularity and easy expansibility while keeping throughput independent of the dimension of the DFT. We shall call an array semi-systolic if the input data is to be preloaded into every cell of the array or if the output data can be calculated not only in the boundary cells of the array. DFT algorithms are represented by FORTRAN-like code, in order to explicitly display the suggested rotational transformations in the index space. After the transformation, multidimensional DFT algorithm can be mapped onto a systolic structure. The area-time2 complexity of the proposed design is within logk factor of the lower bound for ak-point DFT (AT
2=(k
2 log2
k)), i.e. equals 0(k
2 log3
k)=0(N
2M
log3
N) fork=N
2M
point DFT;A is the area complexity andT is the system throughput. 相似文献
992.
Linda Kwai-Lin Lau Rajeev Jain Henry Samueli Henry T. Nicholas III Etan G. Cohen 《The Journal of VLSI Signal Processing》1992,4(2-3):213-226
This paper presents a functional compiler for the automatic design of Direct Digital Frequency Synthesizer (DDFS) integrated circuits (ICs) using a ROM based table look-up architecture. The compiler allows the user to specify high-level specifications such as the acceptable spurious response and it generates the IC architecture, floorplan, and layout. To construct the layout for different specifications, a library of parameterized macrocells has been developed in 1.2 m CMOS technology.A test chip with a quadrature DDFS module has been generated, using the compiler, and fabricated. The chip has two input signals: one is for frequency control while the other is for phase initialization. Input and output word lengths are 16 bits and 6 bits respectively. The chip complexity is approximately 12,000 transistors (DDFS core) and the die size is 4.8×2.9mm
2. A maximum sample rate of 80 MHz has been attained implying a maximum sine (cosine) output frequency of 40 MHz and a frequency resolution of 1.22 kHz. The maximum spurious level measured is –46 dB. 相似文献
993.
A. A. Vertiy A. V. Golik A. P. Korolyuk S. I. Tarapov V. P. Shestopalov 《International Journal of Infrared and Millimeter Waves》1989,10(12):1451-1456
The research technique of amorphous magnetics is described. The paper gives the experimental data obtained by a multifunctional low-temperature radiospectrometer Buran in the mm radiowave range and presents their analysis. 相似文献
994.
K. Matsuishi T. Anzaki S. Onari T. Arai 《International Journal of Infrared and Millimeter Waves》1989,10(7):745-750
Far infrared absorption spectra of amorphous (As2S3)1–x(Sb2S3)x system (x=0.00.6) were measured in the wavenumber region 725 cm–1 with Lamellar grating far infrared Fourier Transform Spectrometer, and the spatial fluctuation of charges and its correlation range were estimated with charge fluctuation model. The charge fluctuation of (As2S3)1–x(Sb2S3)x system increases with Sb2S3 concentration x. On the other hand, the correlation length of the charge fluctuation decreases from 7 A to 4.5 A with an increase in x. As a result, it can be found that the medium range order of As2S3 changes drastically with an incease in Sb2S3 concentration x. 相似文献
995.
X. H. Jiao P. Guillon L. Bermudes 《International Journal of Infrared and Millimeter Waves》1989,10(4):519-528
This paper proposes a new type of high permittivity whispering gallery mode cylindrical dielectric resonators with a geometry which is very suitable for use in microstrip type integrated circuits. These oversized resonators, together with high Q factors and ease of fabrication, are potentially interesting for millimeter wave integrated filters and oscillators. In this paper, we report an experimental investigation of such resonators carried out in Ka band (26.5–40 GHz). Measured results including resonant frequencies and loaded quality factors will be presented. Application to millimeter wave filters will also be demonstrated. 相似文献
996.
Gabriel M. Rebeiz Curtis C. Ling David B. Rutledge 《International Journal of Infrared and Millimeter Waves》1989,10(8):931-936
An accurate monolithic power meter has been developed for millimeter-wave applications. The detector is a large-area Bismuth bolometer, integrated on a fused-Quartz substrate. It simply measures the temperature change caused by the absorption of millimeter-wave radiation. The power meter is simple to fabricate, inexpensive, and can be easily calibrated using a low-frequency network. The measured responsivity for a 50 bolometer, with an area of 1×1cm, at a bias of 1V. and a video modulation of 100Hz, is 1mV/W. The noise spectrum exhibits a 1/f rolloff till 1KHz, and is limited by the Johnson noise for higher frequencies. The NEP of the detector is 3WHz–1/2 at a video modulation of 1KHz. It is possible to decrease the current NEP by fabricating bolometers with higher responsivities. Possible application areas are absolute power calibration and localized power density measurements at millimeter and submillimeter wavelengths. 相似文献
997.
高效液相色谱法分离测定洛伐他汀及其开环酸 总被引:2,自引:0,他引:2
改进了洛伐他汀的分析方法,以甲醇:水=80:20为流动相,采用紫外检测器检测,使用C4色谱柱定性、定量分析了洛伐他汀及洛伐他汀羟基酸,并得出了相关方程.实验证明,采用新的色谱条件可在有效地分析洛伐他汀及其开环酸的基础上,节约分析成本. 相似文献
998.
999.
以典型的轻希土镧和重希土镝及碱土金属锶作为A位离子,以过渡金属锰、铁、钴、镍作为B位离子,合成了K2NiF4型结构的A2-xSrxBO4希土复合氧化物,采用粉末X射线衍射技术考察了反应条件等因素对生成K2NiF4型四方(T)结构上析影响,实现结果表明,四方结构的形成不仅与几何因素有关,而且与各组分的物理化学性质有关。各个不同的组成,生成四方相的温度范围也有所不同。适当地提高反应温度以及延长灼烧时间 相似文献
1000.
采用特制的Fe-Si、Fe-Mn合金系列标样,用电子探针测定了钢或铁基合金中低含量的Si和Mn元素、与用纯元素作标样、经ZAF修正的结果相比较,提高了分析准确度. 相似文献