Abstract: An interface of the present invention includes a first inverter circuit that inverts a logic level of an input signal given to an external input terminal and outputs the inverted logic level, a second inverter circuit that outputs a potential in which a logic level of an output signal of the first inverter circuit is inverted, that is, a potential higher or lower than a logic of an input signal applied to the first inverter circuit by the amount of a predetermined potential, and a feedback path that positive feedbacks an output signal of the second inverter circuit to the external input terminal. The interface circuit of the invention positive-feedbacks a potential of the output signal of the second inverter circuit and shifts the potential of the external input terminal in a floating state to an H or L level potential.

Abstract: The velocity calculating device includes a semiconductor laser for emitting a laser beam at a web that is the subject to be measured; a photodiode for converting into an electric signal the optical power of the semiconductor laser; a lens for focusing and emitting the beam from the semiconductor laser and for focusing the return light from the web and injecting it into the semiconductor laser; a laser driver for driving the semiconductor laser; a current-voltage converting/amplifying portion for converting the output current from the photodiode into a voltage and then amplifying; a filter portion for removing the carrier wave from the output voltage of the current-voltage converting/amplifying portion; a signal extracting portion for counting the number of interference waveforms included in the output voltage of the filter portion; and a calculating portion for calculating the velocity of the web based on the counting result of the signal extracting portion.

Abstract: A physical quantity sensor has a semiconductor laser, a laser driver for providing, to the semiconductor laser, a driving electric current that is a waveform wherein the maximum portions and minimum portions of a triangle wave have been rounded; detecting means (a photodiode and a current-voltage converting amplifier) for detecting an electric signal that includes an interference waveform that is produced by the self-coupling effect between a laser beam that is emitted from the semiconductor laser and a return beam from a measurement object; and measuring means (a filter circuit, a counting device, and a calculating device) for calculating a physical quantity for the measurement object from interference waveform information.

Abstract: An interface of the present invention includes a first inverter circuit that inverts a logic level of an input signal given to an external input terminal and outputs the inverted logic level, a second inverter circuit that outputs a potential in which a logic level of an output signal of the first inverter circuit is inverted, that is, a potential higher or lower than a logic of an input signal applied to the first inverter circuit by the amount of a predetermined potential, and a feedback path that positive feedbacks an output signal of the second inverter circuit to the external input terminal The interface circuit of the invention positive-feedbacks a potential of the output signal of the second inverter circuit and shifts the potential of the external input terminal in a floating state to an H or L level potential.

Abstract: An interface of the present invention includes a first inverter circuit that inverts a logic level of an input signal given to an external input terminal and outputs the inverted logic level, a second inverter circuit that outputs a potential in which a logic level of an output signal of the first inverter circuit is inverted, that is, a potential higher or lower than a logic of an input signal applied to the first inverter circuit by the amount of a predetermined potential, and a feedback path that positive feedbacks an output signal of the second inverter circuit to the external input terminal. The interface circuit of the invention positive-feedbacks a potential of the output signal of the second inverter circuit and shifts the potential of the external input terminal in a floating state to an H or L level potential.

Abstract: A laser driver (4) causes a semiconductor laser (1) to operate such that a first oscillation period of monotonically increasing the oscillation wavelength and a second oscillation period of monotonically decreasing the oscillation wavelength alternately exist. A photodiode (2) converts laser light emitted from the semiconductor laser (1) and return light from a measurement target (12) into electrical signals. A counting unit (13) counts the number of interference waveform components obtained from an output signal from the photodiode (2) in each of the first oscillation period and the second oscillation period. A computing device (9) calculates the distance to the measurement target (12) and the velocity of the measurement target (12) from a shortest Lasing wavelength and a longest Lasing wavelength in a period during which the counting unit (13) counts the number of interference waveform components and the counting result obtained by the counting unit (13).

Abstract: The counting device includes: a signal counter that counts the number of half cycles of input signals during given counting periods; a signal half cycle measurement unit that measures the half cycles; a frequency distribution generator that generates a frequency distribution of the half cycles; a representative value calculator configured to calculate a representative value of a distribution of the half cycles; a correction value calculator configured to calculate a total number Ns and a total number Nwn so as to correct the number of the half cycles, wherein Ns represents the total of the number of the half cycles that are less than 0.5 times the represent value, and Nwn represents the total of the number of the half cycles that are equal to or greater than 2n and less than (2n+2) times the representative value.

Abstract: A tension/speed measuring device comprises a laser driver for driving the oscillation of a semiconductor laser, and a counter for counting interference waveforms included in the output of a photodiode for converting the output of the semiconductor laser into an electrical signal. The counter measures the periods of interference waveforms during a measuring interval, where a frequency distribution for the periods of the interference waveforms during the measuring interval is generated from the measuring results, where a class value wherein the product of the class value and the frequency is a maximum is used as a representative value D0 at the periods of the interference waveform, to calculate a total Ns of the frequencies of the classes that are less than 0.5 times the representative value T0 and to calculate a total Nwn of the frequencies of the classes that are equal to or greater than (n+0.5) times the representative value T0 and less than (n+1.

Abstract: In a distance/speed meter, first and second semiconductor lasers emit parallel laser light beams to a measurement target. A first laser driver drives the first semiconductor laser such that the oscillation interval in which at least the oscillation wavelength monotonically increases repeatedly exists. A second laser driver drives the second semiconductor laser such that the oscillation wavelength increases/decreases inversely to the oscillation wavelength of the first semiconductor laser. First and second light-receiving devices convert optical outputs from the first and second semiconductor lasers into electrical signals. A counting unit counts the numbers of interference waveforms generated by the first and second laser light beams and return light beams of the first and second laser light beams.

Abstract: An amplitude computing apparatus includes: a mean or median value computing unit configured to compute a mean or median value of a distribution of an input signal that changes sinusoidally; a mode value computing unit configured to compute a mode value of the distribution of the input signal; and an amplitude computing unit configured to compute a difference between the mean or median value and the mode value as an amplitude of the input signal.

Abstract: An interface of the present invention includes a first inverter circuit that inverts a logic level of an input signal given to an external input terminal and outputs the inverted logic level, a second inverter circuit that outputs a potential in which a logic level of an output signal of the first inverter circuit is inverted, that is, a potential higher or lower than a logic of an input signal applied to the first inverter circuit by the amount of a predetermined potential, and a feedback path that positive-feedbacks an output signal of the second inverter circuit to the external input terminal. The interface circuit of the invention positive-feedbacks a potential of the output signal of the second inverter circuit and shifts the potential of the external input terminal in a floating state to an H or L level potential.

Abstract: To reduce the probability of incorrect determination to detect an object reliably. A reflective photoelectric sensor is provided with: a light projecting device for emitting light; a light receiving device for receiving the optical feedback of the light that is emitted from the light projecting device; a determining portion for determining whether or not an object exists in the direction in which the light is emitted from the light projecting device, based on the optical feedback; and a reflection preventing plate of a moth-eye structure, disposed at a position that is on the optical path of the light that is emitted from the light projecting device at a position that is more distant than the location wherein the object is anticipated to appear.

Abstract: A counting device includes a counting unit, period measuring unit, frequency distribution unit, representative value unit, and correction value unit. The counting unit counts signals input during an interval. The signals have a single frequency when the physical quantity is constant. The period measuring unit measures the period of a signal interval. The frequency distribution unit generates the frequency distribution of signal periods from the measurement result. The representative value unit calculates the representative value of the distribution of periods from the frequency distribution. The correction value unit obtains a total sum Ns of frequencies in a class not more than a first predetermined multiple of the representative value and a total sum Nw of frequencies in a class not less than a second predetermined multiple of the representative value from the frequency distribution, and corrects the count result on the basis of the frequencies Ns and Nw.

Abstract: In a distance/speed meter, first and second semiconductor lasers emit parallel laser light beams to a measurement target. A first laser driver drives the first semiconductor laser such that the oscillation interval in which at least the oscillation wavelength monotonically increases repeatedly exists. A second laser driver drives the second semiconductor laser such that the oscillation wavelength increases/decreases inversely to the oscillation wavelength of the first semiconductor laser. First and second light-receiving devices convert optical outputs from the first and second semiconductor lasers into electrical signals. A counting unit counts the numbers of interference waveforms generated by the first and second laser light beams and return light beams of the first and second laser light beams.

Abstract: A laser driver (4) causes a semiconductor laser (1) to operate such that a first oscillation period of monotonically increasing the oscillation wavelength and a second oscillation period of monotonically decreasing the oscillation wavelength alternately exist. A photodiode (2) converts laser light emitted from the semiconductor laser (1) and return light from a measurement target (12) into electrical signals. A counting unit (13) counts the number of interference waveform components obtained from an output signal from the photodiode (2) in each of the first oscillation period and the second oscillation period. A computing device (9) calculates the distance to the measurement target (12) and the velocity of the measurement target (12) from a shortest Lasing wavelength and a longest Lasing wavelength in a period during which the counting unit (13) counts the number of interference waveform components and the counting result obtained by the counting unit (13).

Abstract: A physical quantity sensor has a semiconductor laser, a laser driver for providing, to the semiconductor laser, a driving electric current that is a waveform wherein the maximum portions and minimum portions of a triangle wave have been rounded; detecting means (a photodiode and a current-voltage converting amplifier) for detecting an electric signal that includes an interference waveform that is produced by the self-coupling effect between a laser beam that is emitted from the semiconductor laser and a return beam from a measurement object; and measuring means (a filter circuit, a counting device, and a calculating device) for calculating a physical quantity for the measurement object from interference waveform information.

Abstract: In a distance/speed meter, first and second semiconductor lasers emit parallel laser light beams to a measurement target. A first laser driver drives the first semiconductor laser such that the oscillation interval in which at least the oscillation wavelength monotonically increases repeatedly exists. A second laser driver drives the second semiconductor laser such that the oscillation wavelength increases/decreases inversely to the oscillation wavelength of the first semiconductor laser. First and second light-receiving devices convert optical outputs from the first and second semiconductor lasers into electrical signals. A counting unit counts the numbers of interference waveforms generated by the first and second laser light beams and return light beams of the first and second laser light beams.

Abstract: A counting device includes a counting unit, period measuring unit, frequency distribution generating unit, representative value calculation unit, and correction value calculation unit. The counting unit counts the number of signals input during a counting interval. The number of signals has a linear relationship with a physical quantity. The signals have a substantially single frequency when the physical quantity is constant. The period measuring unit measures the period of a signal every time a signal is input during the counting interval. The frequency distribution generating unit generates the frequency distribution of signal periods from the measurement result. The representative value calculation unit calculates the representative value of the distribution of periods of signals from the frequency distribution.

Abstract: An interface of the present invention includes a first inverter circuit that inverts a logic level of an input signal given to an external input terminal and outputs the inverted logic level, a second inverter circuit that outputs a potential in which a logic level of an output signal of the first inverter circuit is inverted, that is, a potential higher or lower than a logic of an input signal applied to the first inverter circuit by the amount of a predetermined potential, and a feedback path that positive-feedbacks an output signal of the second inverter circuit to the external input terminal. The interface circuit of the invention positive-feedbacks a potential of the output signal of the second inverter circuit and shifts the potential of the external input terminal in a floating state to an H or L level potential.

Abstract: A device includes a coil (11) coupled to a magnetic field having power energy by electromagnetic induction, a rectifier (12) for subjecting the power energy fetched by the coil to full-wave rectification, a smoothing circuit (13) for smoothing a rectified output from the rectifier and forming a fixed internal power source, an MOS transistor (14) having a source and a drain connected in parallel across the coil, and a constant-voltage control circuit (15) adapted to be actuated to control the gate voltage of the MOS transistor in response to the output of the smoothing circuit, thereby limiting voltage (power) applied to the rectifier.