Hitachi, Ltd.

Hitachi Automotive Engineering, Ltd.

Michiaki Kurosawa

Masaru Kokubo

Hideya Suzuki

Arata Nakagoshi

Masaru Kugo

Yukinari Fujiwara

Yasuaki Kinoshita

Hiroshi Ito

Jun'ichi Nakagawa

Hideo Nakasawa

A frequency synthesizer which comprises a voltage controlled oscillator; a unit for outputting a value corresponding to a differential phase of a reference signal at a predetermined frequency as a first differential phase; a unit for sampling an oscillating signal corresponding to an output of the voltage controlled oscillator K times per period of a repeating frequency f.sub.r (f.sub.r is an arbitrary frequency) and for repetitively generating phase information of the oscillating signal in the form of saw-tooth-like wave; a unit for calculating the difference between adjacent phase information in phase information of the oscillating signal outputted as a saw-tooth-like wave, and for outputting this difference as a second differential phase; a comparator for calculating the difference between the first and second differential phases; a signal processing unit for integrating an output of the comparator; and a unit for converting an output of the signal processing unit to a voltage to control the voltage controlled oscillator.

Frequency synthesizer

With respect to a mobile communication system, intelligence learns a cell boundary where the field strength of adjacent base stations becomes equal, by measuring field strength of communications, and from this data determined and stored over a period of time, the intelligence calculates the position and velocity vector of each mobile unit, from which a priority for hand-off can be determined. Hysteresis of the hand-off is determined with respect to hand-off boundaries located a fixed distance from the measured cell boundary, with hand-off preferably being soft hand-off within the narrow hand-off boundaries. Priority is particularly determined using fuzzy logic and calculation of the time estimated for the mobile unit to reach the cell boundary. Battery consumption of the mobile units is improved by prolonging the interval of checking the position of mobile units, when the mobile units are moving slowly or not moving at all. The determination of the cell boundary is updated continuously, to compensate for environment changes affecting field strength.

Mobile communication switching across cell boundaries

A liquid crystal color display element has striped red, green and blue color filters and comb electrodes corresponding to the respective red, green and blue color filters. At least two of the comb electrodes are connected in parallel and interleaved with an independent electrode composed of the remaining comb electrode.

Liquid crystal display device

Growing community of inventors

Ibaraki, Japan

Michiaki Kurosawa