A new pulse-interferometric system which introduces the Maximum Entropy Method (MEM) has been constructed to measure sound velocity in liquids. With this system, a measurement accuracy better than 0.1% with a sample volume of 3 cc at a frequency of 5 MHz has been attained.

A nobel Hilbert transformer is realized by adapting instantenuous spectrum analysis, namely short time discrete Fourier transform (ab. in ST-DFT). The ST-DFT Hilbert transformer is substantiated to be almost ideal in both phase shifting and amplitude characteristics via experiments for unit sample response and analyzing its power spectrum.

Decimation filter plays significant roles in the short time DFT Hilbert Transformers. The longer window introduces the sharper cut-off characteristics in contrast with delay of increase response. Therefore, the decimation filters with sharp cut-off response have been keenly investigated to reduce the window length. This paper shows a new decimation filter optimized by the steepest gradient method in the mean of minimizing maximum ripple on the passband.

The effect of frame truncation error is discussed with emphasis on difference between existing DFT and new short time DFT. Existing DFTs suffer from fluctuations on spectrum analysis results caused by limitations to their input signals. In this paper, short time DFT is discussed to be free from frame truncation error and to introduce various profit into new spectrum analyzers.

Sufficient conditions are given for the transient response of a class of MOS digital circuits composed of inverter-type logic gates, transfer gates and RC ladder networks to vary monotonically with the variations in the characteristics of circuit elements.

GaAs MESFET characteristics in the temperature range of 300 K to 500 K have been investigated using a two-dimensional device simulator. The temperature dependence of the threshold voltage, K-value, subthreshold current, source-to-gate capacitance, and cutoff frequency is theoretically explained.

A traveling-wave semiconductor laser amplifier with a thick, short active layer is optimum for achieving insensitive signal gain to polarization while maintaining high-output power and low-noise characteristics.

A method of designing digital FIR transmitter and receiver filter pairs for classes and partial response systems is presented. The truncated ideal impulse response of a specified class is used as an initial response of the filter pair in cascade. For class I filter, the impulse response has an even symmetry, then its transfer function is a linear phase lowpass function of case 1 or case 2. Therefore, the passband zeros occur in mirror image quadruplet (and doublet) and the stopband zeros occur on the unit circle. The initial stopband attenuation slopes gradually up as frequency increases. To get an equiripple stopband attenuation for both filters, the passband zeros inside and outside the unit circle are assigned to transmitter and receiver filters respectively, then the stopband zeros of each filter are redetermined. Both filters form a matched filter pair. Next, the passband zeros of the filter pair are adjusted to give minimum intersymbol interference (ISI) in the overall response. For class filter, the impulse response has an odd symmetry and its transfer function is a linear phase lowpass function of case 3. In this case, the filter pair are designed to have equiripple and nearly the same stopband attenuation. Zero ISI approximation is performed similarly. Two design examples are shown. One is a 57th order class I filter pair having 0.05% ISI. The other is 61st order transmitter and 57th order receiver class filter pair whose ISI is 0.2%.

A direct procedure to realize pipelinable low-sensitivity digital filters is developed only in the z-domain. It is possible to realize arbitrary digital transfer functions using this procedure. The key concept for the low-sensitivity property lies both in the matching concept in doubly-terminated lossless networks and in the localization of transmission zeros. The synthesis procedure is based on successive extractions of transmission zeros by means of lossless but not always reciprocal transfer scattering matrices. Since a transfer scattering matrix involves the transmission zeros as its poles, such a matrix is suitable for their localization. Furthermore a universal first/second-degree section is derived explicitly.

This paper studies the model reduction of separable denominator multi-dimensional (SD M-D, M is used as an integer) linear, shift-invariant systems (systems for short). First, it shows that the controllability, observability and stability of an SD M-D system are completely determined by M 1-D multi-input multi-output systems, which are referred to as the characteristic systems in this paper. Then the balanced realizations of SD M-D systems are defined, and a synthesis method of such realizations is given. Finally, a model reduction method based on the balanced realizations is proposed. Validity of this method is illustrated by a numerical example of a 3-D system.

This paper presents an implementation model for efficient state dependent processing on data flow machines, and some results from evaluation on NTT's data flow machine simulator. In this model, which is based on communicating processes with streams, each element of a stream is sent directly from an instance of a stream-producing function to a corresponding instance of a stream-consuming function. The order of elements in the stream is preserved by schemata for sequentializing instances of the functions. There is no need for data structure on memory for a stream. Therefore, it is expected that the same number of instances of a stream processing function as the number of elements in the stream are invoked and executed nearly in parallel. A nondeterministic processing is realized in the same framework. Evaluation results show that this model can attain about 80% improvement in speedup compared with a conventional model which exploits parallelism by a non-strict data structure constructor, eager evaluation of element data, and a memory with synchronization capability. It is also shown that a mutually exclusive processing in a sample program, i.e. a functional level simulator of a data flow machine as implemented by this model, does not constrict parallelism.

The telegram analysis problem posed by P. Henderson and R. A. Snowdon has been repeatedly taken into account. This paper adds yet another contribution to this problem. We propose a rigorous specification method, and describe how programs can be derived from it. This method functional programming by which procedural programs can be easily derived from a formal specification in the form of an abstract sequential machine. The method has been applied to sorting, file handlers and High Level Data Link Control Procedures.

To employ Computer Graphics (CG) technology in the production of CG holograms or similar applications where the generation of consecutive pictures with rotated viewing directions is demanded takes a lot of time and money. This paper presents a two-pass surface rendering method for fast creating such animated pictures from a single view image structure. Instead of generating display data for a single picture, the first pass program constructs a Position Oriented (PO) frame buffer that contains the information of control points on every order of visible surfaces. A display program of second pass manipulates the frame buffer structure to generate surface rendered pictures with spatial and perspective transforms. Experiments proved the method is effective to create high quality surface rendered images with rotation capability. Various usuful facilities for CAD visualization have also been developed within the technique. The improvements on memory consumption and picture quality are also discussed in this paper.