Fujitsu Corporation

Hiroko Haraguchi

Hideaki Watanabe

Masaru Sawada

Tsunehiko Moriuchi

Akiyoshi Matsuda

A differential amplifier of the present invention comprises transistors where to each of which one of two inputs to said differential amplifier is provided; current mirror circuits where each of which delivers one of the outputs of the differential amplifier to the load side; and cut-off prevention units where each of which is connected to the connecting point of a transistor to which a monitor current of one of the current mirror circuits flows, and one of the transistors to which the inputs are provided, and applies a current for preventing cutting off the transistor to which the monitor current flows, when the input to the transistor to which the input is provided is L.

Differential amplifier

In a differential output signal circuit suitable for restraining voltage overshooting/undershooting at differential output terminals due to lags in input signals and realizing stable and fast switching of differential input signals, a first differential pair of PMOS. transistors connected to a first current source and a second differential pair of NMOS transistors connected to a second current source are mutually connected at the differential output terminals, and a capacitor is connected between the connection nodes of the respective differential pairs and current sources. A transitional current path of the capacitor restrains voltage variations during differential input signal switching. Further in a signal detection apparatus suitable for realizing the detection of fast transmitted differential input signals with less current consumption and at low cost, an edge detect signal is supplied against a differential input of or above a prescribed value, and a setting signal is issued when this edge detect signal has been detected a prescribed number of times during a first prescribed length of time while a resetting signal is issued if none is detected during a second prescribed length of time. A signal-detect signal is generated from these setting signal and resetting signal.

Signal detection apparatus, signal detection method, signal transmission system, and computer readable program to execute signal transmission

In a differential output signal circuit suitable for restraining voltage overshooting/undershooting at differential output terminals due to lags in input signals and realizing stable and fast switching of differential input signals, a first differential pair of PMOS transistors connected to a first current source and a second differential pair of NMOS transistors connected to a second current source are mutually connected at the differential output terminals, and a capacitor is connected between the connection nodes of the respective differential pairs and current sources. A transitional current path of the capacitor restrains voltage variations during differential input signal switching. Further in a signal detection apparatus suitable for realizing the detection of fast transmitted differential input signals with less current consumption and at low cost, an edge detect signal is supplied against a differential input of or above a prescribed value, and a setting signal is issued when this edge detect signal has been detected a prescribed number of times during a first prescribed length of time while a resetting signal is issued if none is detected during a second prescribed length of time. A signal-detect signal is generated from these setting signal and resetting signal.

Differential signal output apparatus, semiconductor integrated circuit apparatus having the differential signal output apparatus, and differential signal transmission system

A servo signal processing apparatus for processing a servo signal corresponding to servo information from a servo area on a recording medium for controlling a head. The servo area includes a servo mark area for storing a servo mark indicative of a head of the servo area, a gray mark area for storing a gray mark indicative of a head of information for position control for the head, and a gray code area for storing information. An A-D converter converts the servo signal to digital data. A digital filter filters the converted data based on a sampling clock, and outputs the filtered digital data. A servo mark detector detects a servo mark based on a continuity of a first predetermined logical value. A gray code decoder detects a gray code based on a continuity of a predetermined logical value. The gray code decoder decodes information stored in a gray code area following the detected gray mark.

Servo signal processing apparatus, recorded data reading apparatus and method for processing servo signal

A signal processing apparatus for reading and writing information to a storage medium includes a power supply control circuit that selectively inhibits and enables power to individual circuits of the signal processing apparatus in order to achieve maximum power conservation. The signal processing apparatus looks ahead to determine a next operation to be performed and, using either read or write information of the next operation, along with information concerning how long it takes to power up individual circuits, determines the optimal time to switch power on to the individual circuits. Power is then supplied to the individual circuits of the signal processing apparatus only when it is required by the individual circuits.

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Kasugai, Japan

Hiroko Haraguchi