This paper describes an optimal logic partitioning/test points setting by using testability measures in large digital circuits. First, signal lines' testability measures (controllability and observability) in a circuit are computed. Next, the circuit is transformed into a network which consists of nodes (corresponding to circuit elements) and arcs (corresponding to signal lines). Then, after the arcs' capacity is defined as a function of the testability measures, the original logic partitioning/test points setting problem for the circuit is transformed into that for the maxflow in the network flows. This problem is solved by using the maxflow/ mincut theorem. Finally, it is shown that a simple logic circuit is considered using the proposed method.

This paper describes the voice-data hybrid transmission facilities, which can be obtained by using 64 kbit/sec digital line. Instead of using separate transmission facilities for voice and data services, or instead of increasing the digital transmission rate, the silent portion of telephonic speech can be used to transmit the data. The line is available for the data transmission when a pause of the voice is detected, and the line is blocked for the data transmission during a talkspurt of the voice. Two models of the hybrid transmission system are shown. The first model, in which the data arrive randomly in bursts, is useful to describe a kind of interactive process. The second model, in which the data arrive continuously, describes file transfers, facsimile transmissions, etc. The necessary buffers, the blocking probabilities, the data delay, and other factors of both models are calculated.

Polarization evolution and the degree of polarization in twisted optical fiber are measured using an identical fiber sample. Measured polarization degree is consistently explained using independently measured linear birefringence, polarization dispersion and light source spectral data. As the result, polarization characteristics in twisted optical fibers could be comprehensively understood by revealing the mutual relation between several characteristics. Twisted optical fiber is designed based on equations supported by experiment. To get good polarization preserving fiber with a twist rate as low as several turns/m, core ellipticity of starting fiber should be less than about 1%. Linear birefringence and polarization dispersion data are compared with theoretical values derived from fiber parameters and the sources of discrepancies are discussed.

A new switching diversity technique employing a carrier-jitter sensor is proposed for application to mobile radio transmission systems. Performance of the sensor has been examined both theoretically and experimentally, and it is found to respond well to noise as well as interference. In addition, this sensor can be implemented by digital devices. Diversity experiments in which a digital-type sensor was employed in digital mobile radio channels show that diversity effectively reduces performance degradation due to multipath fading.

This paper proposes a new residue number multiplication scheme based on the cylic type of relationship which exists between the entries in the residue number multiplication truth-table when the modulus is any prime number. Using the scheme, multiplication is direct without table consultation and an entire truth-table is realizable. The multiplier circuit is simple and compact and allows pipelined processing of data. The flexibility of the multiplier is exploited in the implementation of an RNS based high-order FIR digital filter by using a programmable low order section. The suitability of the modular digital processor for VLSI is also indicated.

A loop detection is inherent in a context-sensitive parsing. A new detection method is presented for a top-down context-sensitive parsing using a grammar GE. This method requires only two input items, while the previous one requires three.

A measurement technique of chromatic dispersion in single-mode fiber transmission lines is proposed. By using a local signal generator, an optical line to transmit a reference signal is unnecessary in the proposed measurement technique, even if the input and output end points of the fiber are separated by a large distance.

A new type of shaped-beam antenna has been studied as a possible candidate for the antenna for the next generation Japanese broadcasting satellite which succeeds BS-2, launched January 23, 1984. The studied antenna employs an offset paraboloidal reflector with elliptical shape, an elliptical corrugated horn and a rectangular one. The studied antenna covers most part of the Japanese main lands with antenna gain of more than 39 dB, Okinawa more than 35 dB and remote islands more than 28 dB. The sidelobe and cross-polar components radiated outside the service area satisfies the WARC-BS on the basis of power flux density on the earth assuming 200 W output power of the transponder.

Properties of a semi-insulating film deposited by Ar-Beam Sputtering have been investigated. This film was characterized with a substrate temperature lower than 150 during deposition. It was found that this film was as efficient in achieving breakdown characteristics higher than 400 V as were the conventional films.

Performance of self-synchronizing scrambler/descrambler in mobile radio transmission systems is discussed theoretically and experimentally. Multiple-error characteristics in descrambler processing are analyzed in detail.

A self-complementary basis of a finite field corresponds to the orthonormal basis of a vector metric space. This paper presents a theorem that GF (24m) has no self-complementary normal bases over GF (2) if m is odd, which was recently conjectured by one of the present authors.

This letter improves the technique proposed previously for speeding up stack-controlling LALR(1) parsers. The efficient actions of the improved parsers are more than those of the parsers by the previous scheme.

This paper considers a repair system which includes several repair stations, many user sites and a great many identical equipments operated in these sites. The means and the variances of the numbers of the equipments in these user sites and repair stations are obtained using an approximation method. The proposed repair model is applicable to a complex repair system such as a multi-echelon repair system.

A boundary element method is presented for the analysis of shielded microstrip lines with dielectric layers. The formulation is based on (a) the Green's second identity, (b) the method of subdomains, (c) the constant boundary element discretization and (d) the discrete conservation law of total charge. In particular, the above (b) and (d) are originated for dealing with the dielectric layers. Numerical results for the balance-type and coplanar-type striplines are shown in order to examine the validity of the boundary element method. By user of the technique of subdivision into boundary element, it is also found that the calculated values for line characteristics are with the second-order accuracy.

The electromagnetic scattering coefficient of an infinite elliptic cylinder is presented. We have discussed the fundamental properties of the coefficient in the case of the parallel and perpendicular polarization of the incident plane wave.

It has been found experimentally that in double-choked small-aperture circular waveguide antenna, the choke position influences greatly the radiation properties. The cross-polar level is found to be particularly sensitive to the choke positions. When the parameters a, the length between the circular waveguide aperture and the inner choke, and b, the length between the aperture of the inner and the outer chokes, are varied within 0a2.5 mm, 0b7.5 mm, the cross-polar peak values are found to vary by about 10 dB. When, for example, a and b are chosen 0.5 mm and 5.0 mm, respectively, the 45-plane cross-polar value of this double-choked antenna could be reduced to 39 dB. It is also found that the beam circularity of the double-choked feed is improvable by properly choosing the choke-load positions. However, the cross-polar patterns of the test paraboloid with the double-choked feed (a1 mm, b6 mm) produced high cross-polar fields (27 dB). Authors then measured the amount of the reflector reflection, and found that the value of the reflection without a vertex plate was as high as 18 dB. However, by loading a vertex plate 0.65λ from the reflector apex, the cross-polar values of the parabolic reflector was suppressed below 35 dB over the frequency range of 11.4 GHz 12.3 GHz.

This paper presents and analyzes the following queueing model for congestion control. In an M/M (Poisson arrival/exponential service time) type model with finite waiting room, the input rate into the system is gradually controlled by comparing the number of calls in the system with two threshold values. If an arriving call finds the system to be full, the call is lost and the regulation grade is tightened by one level, i.e. the input rate slows down. If a leaving call finds the number of calls in the system to be lower than the lower threshold, input regulation grade is loosened by one level, i.e. the input rate speeds up. The method is called hysteresis" control. An efficient calculation procedure is devised for steady state probabilities. Some numerical results are shown. Here, in the example, mean service time grows linearly with the number of calls in the system. The graphs show that the input regulation method is effective for preventing such a system from falling into a congested state. This analysis can easily be applied to an input regulation model with finite sources.

This paper first defines signal line fault detection testability measure (FDTM) for stuck-at-0 and stuck-at-1 faults. The FDTM is obtained from signal line's 0, 1-controllability and observability measures. This measure is analyzed in terms of the relationships between FDTM and undetected faults under the condition of the D-algorithm ATPG program execution for a certain time. Then, node (element/functional block) testability measure is defined from node's input 0, 1-controllability and observability measures. This measure is also evaluated in terms of the relationships between node testability measure regions and node fault coverage under the condition of the ATPG program execution for a certain time. Finally, the proposed testability measures applications in early design phases and test generation systems are discussed.

Some study was made by the author on stability conditions for the two-dimensional digital filters that are required for image processing. Algorithms for testing the stability of such filters as mentioned above can be obtained by applying Huang's theorem. This theorem, however, has not been proved completely by Huang, and various proofs by use of the maximum principle have been proposed. In this paper is presented a new proof applying the principle of analytic continuation.

We propose a framework for deductive logic program synthesis from the first order specification in conjunction with the definition of total correctness for a synthesized program. The necessity of such definition comes from the fact that logic program synthesis is aimed at a nondeterministic program that computes a relation so that conventional definition of total correctness for the synthesized program, i.e. partial correctness termination seems inappropriate. The point of our approach is the derivation of comp(s), completed definition of a target program S, from the given specification. It enables us to verify the total correctness of a synthesized program. The verification method is based on the recent result about negation as failure rule". Two derivation examples are given.