This paper describes high-temperature operation of nMOSFET on bonded SOI. A long-channel nMOSFET is fabricated on bonded SOI (Si layer thickness 0.3 µm), SOS (Si layer thickness 0.3 µm), and bulk Si, Bonded SOI is produced using pulse-field-assisited bonding and resistivity-sensitive etching. The high-temperature operation of bonded SOI nMOSFET is demonstrated and compared with SOS and bulk MOSFETs. The leakage current variation with temperature is signnificantly smaller in bonded SOI and in SOS than in bulk MOSFETs. At high temperatures, the drain current to leakage current ratio is 100 times higher in bonded SOI than in SOS and bulk devices. At 300, a ratio of 104 is obtained for the bonded SOI nMOSFET. The ratio is expected to be even higher if a reduced channel length and ultrathin (less than 0.1 µm) bonded SOI is used.

Most communication cables are laid underground. In order to make construction and maintenance works easier, systems to detect buried objects have already been developed using the electromagnetic pulse radar technique. However, existing detection systems are not really practical due to their rather limited processing speed. To achieve sufficient processing speed, two dedicated custom FFT LSI's are designed and realized with 0.8 µm-CMOS technology. The two chips have an equivalent processing capacity of 200 MOPS. An efficietn hardware algorithm for address generation and 2 word parallel processing are introduced. In addition, an enhanced system organization is developed together with an improved pattern recognition scheme and aperture synthesis hardware. The new processor executes a FFT/parameter extraction operation in 4 seconds and aperture synthesis in 1 second. This speed meets the design target, and a real time detection system for underground objects becomes possible.

A passive double star (PDS) optical subscriber system which employs a newly proposed flexible access and frequency division duplex transmission system has been reported. For the flexible access and efficient channel usage in subscriber PDS system, a modified pipe-line polling with a call-by-call basis channel assignment has been proposed. This access system has a wide covering range which exceeds 10km or more. A newly proposed pulsed PSK transmission and a baseband transmission are used for a single wavelength bi-directional transmission for to and from the central office. A pulsed FM single subcarrier transmission system is also proposed for the analog CATV distribution system, which is overlaid with wavelength division multiplexing on the bi-directional transmission system. The equipments for the pulsed PSK and the pulsed FM transmission can be realized with all digital circuits. Moreover, the pulsed signal's modulation nature has eased the requirement for the laser diode characteristics, such as linearity and RIN. These features are effective for the compact and cost effective transmission systems.

Quantization of the impulse response coefficients due to finite word length causes the moments to deviate from their ideal values. This deviation is found to have a linear variation with the output roundoff noise of the filter realized in direct form. Since the zeros and poles of a given filter also move away from their designed locations due to quantization, we show a relation between the zeros and poles and the moments of the impulse response.

A random pulse stream (RPS) generator was developed for the noise immunity test of various digital system including communication system. By using this RPS generator along with the composite noise generator (CNG) developed formerly, the Middleton's "Class A" noise could be generated, and the total system (RPS+CNG) became more general noise simulator. In this paper, the configuration of CNG with newly developed RPS generator, and a typical example of Class A noise generated by this system are shown.