A unified approach to the derivation of canonical single amplifier circuits capable of realizing second-order filters with finite transmission zeros is proposed. Application of the proposed approach leads to the known circuits, as well as some new ones. Design formulae for the new circuits are presented, and their salient features are pointed out. Finally, design examples are also presented.

The noise properties of directly modulated laser diode influenced by reflected waves are given theoretically. Firstly, the quantum noise enhancement effect due to direct modulation is found theoretically in term of product between the quantum shot noise and the modulation current. Secondly, the high-frequency intensity noise due to reflected waves (often so-called self-coupling effect) is clarified to be due to resonance of the quantum shot noise to the external cavity. According to our theory, it is found that the noise of the narrow stripe laser diode with the stripe width comparable to the diffusion length of carrier is about 10 dB smaller than that of the wide stripe laser. And also, the reverse isolation loss of an optical isolator is estimated theoretically to be 30 dB to reduce the relative high-frequency intensity noise by 40 dB.

Switching threshold characteristics of the shaped Josephson junctions for tree-decoder use were investigated theoretically and experimentally. Side lobe suppression was successfully achieved by a constricted full window junction structure, whose optimum constriction could be predicted by Fourier integral of junction width function. Side lobe suppression ratio as large as 16 was obtaind for constriction ratio K/L1/3, and junction length L/λ₀3.3.

This paper presents some methods for recognition of handprinted Arabid scripts. Arabic scripts are generally structured of curves and hence our recognition method is based on the identification of the component curves in the script. In the paper, first we propose a method for recognition of single handprinted Arabid characters, using the concept of contour tracing and identification of the curves in the character. The identification of a curve is performed through determination of its local directions. Next, we develope the method to the recognition of cursively handprinted scripts, by usage of the identification of the basic shapes. The basic shapes are identified through using the orientation of the curves and the relationships between the feature points in the script. The results of computer simulations show average recognition rates of more than 95% and 90% for singly written and cursively written characters, respectively. The advantage of our method is its powerful recognition of highly distorted shapes, particularly the shapes which are generated through rotation of the original pattern. Although the present method has been developed for the recognition of Arabic scripts, it can be applied equally well for recognizing many other singly and cursively written scripts.

A store and fordward speech interpolation telephonic concentrator system is introduced. This paper presents first the system, describes its main parts and components and using typical parameters the probable system operation is outlined. Following, a study on capacity and delay of transmission of each voice packet is done by supposing that a M/D/1 model can be applied to the system. As voice has special characteristics and packets don't arrive randomly as supposed in the M/D/1 model, an analysis using a computer simulation is done. The source generating speech is closely matched with human voice by using a model with good resolution specially for small pauses of talkers during the active generation of speech. Using this source, simulations representing 120 or 180 sec. of actual time are done. As its results are different of those predicted by the M/D/1 model, the capacity of the system is forecasted again through examples. To increase even more the capacity without impairing the frozen out fraction of the speech or increasing the delay of each packed, a different method to decrease congestion in those short moments of high arrival rate of packets is intended. This method consist in to transmit from each voice sample only 7 bits during the high congestion moments, creating new capacity by shortening packets. Results of parameters obtained by simulation and probable capacity of the system are again shown.

A necessary condition is given for a closed set of k-valued logical functions to be essentially minimal. It is stated in terms of the associated 1-variable function of a generator of the set concerned.

A transient analysis of the electromagnetic field by our new numerical method is shown to be useful for understanding the mechanism by which the electromagnetic field at the stationary state in the waveguide having the H-corner are brought about.