Itsuo Sasaki

Switched-capacitor non-recursive lowpass filter

A new switched-capacitor realization of a non-recursive filter based on the digital filter theorem is proposed. A switched-capacitor realization of the delay circuit is described first. A switched-capacitor coefficient multiplier and adder are based on the integral feedback capacitance circuit. This circuit has the feature that the voltage across the integral feedback capacitance is used for the output voltage, whereas, in an ordinary circuit, the output voltage is used at the output terminal of an operational amplifier. Agreement between experimental and theoretical values is confirmed.

Switched-capacitor realization of a Walsh transform circuit and its application to sequency filtering

A novel switched-capacitor discrete Walsh transform circuit is proposed. The Walsh hardware transformation is improved in simplicity by using the proposed circuit, and this circuit has a speed advantage because of analog processing. Furthermore, a switched-capacitor inverse Walsh transform circuit is constructed. A switched-capacitor sequence filter is also proposed which combines the Walsh transform circuit and its inverse.<<ETX>>

A proposal of synchronized chaotic communication system using M-ary/SS

It is well known that M-ary spread spectrum (M-ary/SS) system is superior to direct-sequence spread spectrum (DS/SS) system under additive white Gaussian noise (AWGN), and can achieve high spectral efficiency. In this paper, we propose use of M-ary/SS for the purpose of improving the anti-noise performance in synchronized chaotic communication system. However, in the M-ary/SS system, since the transmitted sequences change with each frame, synchronization is difficult. In this system, frame synchronization performance is improved by using chaotic synchronization. The validity of the proposed system is shown by computer simulations