This letter proposes a simulation of an input part of an LCR filter. The proposed method used voltage followers as an active element. As an example, a realization of a 3 MHz third-order maximally-flat filter is presented.

This paper presents advantages of sputtering technique using a ceramic target instead of a conventional powder target for preparing ZnS: TbF_x emitting layer in electroluminescent devices.

Continuous-time MOSFET-capacitor filters have quite a serious problem, that is, MOS transistors' nonlinearity drastically reduces the filters' dynamic ranges. Czarnul proposed an MOS resistive circuit with high degree of linearity and solved this problem. The method, however, requires two capacitors for each integrator. Consequently, the chip area and manufacturing cost will increase. This paper proposes a new single capacitor integrator which can cancel the nonlinearity of transistors. The integrator is applied to a canonical continuous-time filter synthesis with high linearity. A total harmonic distortion less than 0.33% is obtained by SPICE analysis.

The paper proposes a method of variable-to-fixed length binary data encryption in the class of conventional cryptosystems. An encryption algorithm reduces an interval of the integers that mean candidates of cryptograph according to a key and messages. A decryption algorithm traces the trajectory of reduction of interval according to the key and cryptographs to reproduce the messages. These algorithms are executable with simple arithmetics on several registers. However, wiretappers without knowledge on the key cannot correctly reproduce messages since they cannot trace the trajectory of reduction. The exhaustive cryptanalysis identifies the correct decryption procedure only from cryptographs. The comparing cryptanalysis identifies the correct decryption procedure from some pairs of message and cryptograph. Asymptotic evaluations for the computational complexity of cryptanalysis show a satisfactory endurance against wiretapping.

We have defined the number of degrees of freedom of order n (the n-th order NDF) k_n(T) of a piece of an ergodic stationary random process X(t) of length T by using the variance of an estimate Z_n(T) of the n-th moment of X(t). Z_n(T) is here calculated by averaging Xⁿ(t) over a time interval T. The NDF denotes a quantitative measure of the effective number of independent or uncorrelated random variables Xⁿ(t_i) included in the time interval T. Correlation times and equivalent bandwidths, which are important in random processes and some fields in physics, are deduced from the NDF's. In this paper, we study the NDF's from the viewpoint of information theory. First, a simple information measure J_n(T) based on the uncertainty (Shannon's entropy) of Z_n(T) is defined. It is natural that we introduce such J_n(T) because k_n(T) has been defined based on the variance of Z_n(T). We show that the relation J₁(T)(log k₁(T))/2 and the asymptotic relation (log k_n(T))/(2J_n(T)) 1(n2, 3, ) as T . Second, a measure I_n(T) of the information gained about the n-th moment of X(t) by the observation of the Z_n(T) is defined in the style of Shannon. The relation I₁(T)(log k₁(T))/2 and the asymptotic relation I₂(T) (log k₂(T))/2 as T are deduced. Last, we define a measure F_n(T) as the information in the style of Fisher about the n-th moment contained in the estimate Z_n(T) and we show that F₁(T)k₁(T) and F₂(T) approaches asymptotically k₂(T) as T . As a result, the n-th order NDF k_n(T), which was originally defined by using the variance of Z_n(T), is almost equivalent to one defined by using the entropy of Z_n(T). Further, the 1st and 2nd order NDF's show the amount of information about the 1st and 2nd moment of X(t) which are contained in Z₁(T) and Z₂(T) respectively.

This paper reports a high-speed time division switching system using GaAs ICs. It also describes high-speed switching technologies including the fabrication of a 4-channel time division switch, a multi/ demultiplexer and peripheral circuit ICs, each having more than a 2 Gb/s throughput capability. In addition, such key factors as synchronous LSI operation, optimum circuit board designing and LSI packaging are presented. Finally it reports a great success in High Definition TV (HDTV) time division switching operation.

This paper describes the first realization of the APSK system with a honeycomb constellation (HC) for high capacity digital radio links. Partial Gray coding method to improve receiver sensitivity is also described. It is shown that the 68 APSK modulation can increase receiver sensitivity by 0.7 dB compared with a 64 QAM. Possibility of the system with the HC using the present state of the art is confirmed by theoretical estimation of tolerances for modem impairments. Techniques necessary to realize a system with the HC are also described. Using the techniques, the 68 APSK modem with the HC was experimentally fabricated. The modem we fabricated has a transmission capacity of 90 Mbps within the FCC-authorized bandwidth of 20 MHz in the 4 GHz band. The BER performance and signature for multipath fading have been measured. It is confirmed that the signature of the 68 APSK is almost the same as that of the conventional 64 QAM. The signature improved using 5 tap transversal equalizer correspons to an outage of 2 seconds per year per hop.

A rigorous and systematical analysis of the performance of the power inversion adaptive array is shown where the method of moments is applied to analyze the antenna system and the electric field intensity is used as the descriptive parameter of the incident signals. This method can be easily extended to analyze adaptive arrays with arbitrary array structure and with wire antenna elements other than monopoles and dipoles. To show the adavantages of the method, the performance of adaptive arrays with mutual coupling effect among the array elements is considered and the inverted-F antennas (IFA) are used as the elements. The steering vector in the presence of mutual coupling which differs from that in the absence of the mutual coupling is derived. The output signal-to-interference-plus-noise ratio (SINR) of two kinds of adaptive arrays composed of IFA elements is computed and the importance of properly selecting steering vector is demostrated by means of the quiescent array patterns and the output SINR performance.

Potential Controlled (POCO) Laser is a new type of laser which utilizes a character that the lasing gain effectively increases and the threshold current level can be reduced by putting a large number of holes into the active layer. The basic idea of this laser is very close with the so called modulation doping in the multi-quantum-well structure. In this paper, the optimum configuration of the POCO laser is theoretically examined in detail. Possibility to get a very low threshold current lower than 100µA is predicted.