Abstract: An optical transmitter includes a light source that outputs light superposed with a pilot signal having a predetermined frequency; an optical modulating unit that modulates the light from the light source according to an input electric signal; a detecting unit that detects a high-output-side maximum value of signal light output from the optical modulating unit, a fluctuation width of the high-output-side maximum value, and a fluctuation width of a low-output-side minimum value; a bias-potential adjusting unit that adjusts a bias potential of an electric signal to be input to the optical modulating unit based on the detected maximum value; and an amplitude adjusting unit that adjusts an amplitude of the electric signal to be input to the optical modulating unit based on the fluctuation width of the high-output-side maximum value and the fluctuation width of the low-output-side minimum value.

Abstract: In a case where two constant envelope signals corresponding to an input signal are generated through analog signal processing, variation in detection sensitivities of amplitudes of those signals is suppressed. At least one of a mixer (24) for detecting an amplitude of a first intermediate signal S1 and a mixer (26) for detecting an amplitude of a second intermediate signal S2 detects an amplitude of a given reference signal, and sampling hold circuits (36, 38) hold a voltage related to those amplitudes. Then, detection sensitivities of the mixer (24, 26) are corrected based on the held voltage.

Abstract: Disclosed are an addition circuit that makes it possible to add two vector signals in a high-frequency region, a power amplifier circuit using the same, and a transmission device and communication device using the power amplifier circuit.

Abstract: To provide an adder capable of obtaining an addition signal of a plurality of high frequency signals, and also a power combiner, a quadrature modulator, a quadrature demodulator, a power amplifier, a transmitter, and a wireless communicator, each of which uses the adder. Impedances (Zg, Zh) seen from a common output point (P3) of a plurality of first impedance circuits (110a, 110b) toward respective input terminals (102a, 102b) are set so that high frequency currents (Ig, Ih) are approximately zero. An impedance (Zs) seen from a first connection point (P1) toward the input terminals (102a, 102b) is set so that a high frequency current (Is) is approximately zero. An impedance (Zc) seen from the first connection point (P1) toward a circuit (150) is set so that a high frequency current (Ic) is approximately zero. An impedance (Zm) seen from a second connection point (P2) toward a power supply is set so that a high frequency current (Im) is approximately zero.

Abstract: In a case where two constant envelope signals corresponding to an input signal are generated through analog signal processing, variation in detection sensitivities of amplitudes of those signals is suppressed. At least one of a mixer (24) for detecting an amplitude of a first intermediate signal S1 and a mixer (26) for detecting an amplitude of a second intermediate signal S2 detects an amplitude of a given reference signal, and sampling hold circuits (36, 38) hold a voltage related to those amplitudes. Then, detection sensitivities of the mixer (24, 26) are corrected based on the held voltage.

Abstract: To provide a power amplification device that can amplify an input signal having an envelope variation with high power-added efficiency in a wide frequency range, and a transmission device and a communication device using the power amplification device. A first orthogonal signal (Sd1) is generated by performing vector subtraction between first and second fundamental signals (Su1 and Su2) having the same amplitude and a phase difference ?? (0 degrees<??<180 degrees) therebetween. First and second fundamental signals are generated based on an input signal (Sin). A second orthogonal signal (Sd2) is generated by performing vector addition between the first and second fundamental signals (Su1 and Su2). First and second constant envelope signals (S1 and S2) are generated by performing vector addition between the second fundamental signal (Su2) and first and second constant envelope vector generation signals (e and ?e) obtained based on the first fundamental signal (Su1).

Abstract: To provide a power amplification device having a function of preventing deviation of the amplitude and phase of an output signal having amplified envelope variation from a predetermined value, and a transmission device and a communication device both using the same.

Abstract: In a case where two constant envelope signals corresponding to an input signal are generated through analog signal processing, variation in detection sensitivities of amplitudes of those signals is suppressed. At least one of a mixer (24) for detecting an amplitude of a first intermediate signal S1 and a mixer (26) for detecting an amplitude of a second intermediate signal S2 detects an amplitude of a given reference signal, and sampling hold circuits (36, 38) hold a voltage related to those amplitudes. Then, detection sensitivities of the mixer (24, 26) are corrected based on the held voltage.

Abstract: To provide a power amplifier circuit which is capable of reducing a phase error of an output signal in a case where an amplitude of an input signal is relatively small, as well as a transmitter and a wireless communication device using the same. A constant envelope signal generation circuit (20) converts an input signal (Si) having envelope variation into a first constant envelope signal (Sd1) and a second constant envelope signal (Sd2) having the same amplitude and different phases, and outputs the signals. A first amplifier (11) amplifies the first constant envelope signal (Sd1). A second amplifier (12) amplifies the second constant envelope signal (Sd2). An output adder (13) outputs an amplified output signal having envelope variation based on the amplified signals output from the first amplifier (11) and the second amplifier (12).

Abstract: To provide a power amplifier circuit, which is capable of amplifying a signal having envelope variation with high power added efficiency, and exhibits low power consumption and high versatility, as well as to provide a transmitter and a wireless communication device using the power amplifier circuit, the power amplifier circuit includes: a constant envelope signal generation circuit (20) for converting an input signal (Si) having envelope variation into two constant envelope signals (Sd1, Sd2); a first and a second amplifiers (11, 12) for amplifying the two constant envelope signals to output two amplified signals (Sh1, Sh2); and an output adder (13) for performing vector addition of the two amplified signals.

Abstract: An optical transmitter includes a light source that outputs light superposed with a pilot signal having a predetermined frequency; an optical modulating unit that modulates the light from the light source according to an input electric signal; a detecting unit that detects a high-output-side maximum value of signal light output from the optical modulating unit, a fluctuation width of the high-output-side maximum value, and a fluctuation width of a low-output-side minimum value; a bias-potential adjusting unit that adjusts a bias potential of an electric signal to be input to the optical modulating unit based on the detected maximum value; and an amplitude adjusting unit that adjusts an amplitude of the electric signal to be input to the optical modulating unit based on the fluctuation width of the high-output-side maximum value and the fluctuation width of the low-output-side minimum value.

Abstract: An optical transmitter includes: a modulating unit that modulates an optical signal based on an electric signal; a first detecting unit that detects a first variation width of a maximum output of the modulated optical signal; a second detecting unit that detects a second variation width of a minimum output of the modulated optical signal; a comparing unit that performs a comparison of the first variation width and the second variation width; and an adjusting unit that adjusts a bias potential of the electric signal based on a result of the comparison.

Abstract: A power supply control circuit includes: a conducting part configured to be controllable in its a conducting amount for conducting a power supply current to a load circuit; a current change ratio detecting part detecting a change rate of the power supply current supplied to the load circuit; and a control part controlling the conducting amount of the conducting part according to the change rate of the power supply current detected by the current change detecting part, wherein: the control part carries out feedback control of reducing an increasing rate of the conducting part as the power supply current change rate is larger.

Abstract: An optical transmitter includes: a modulating unit that modulates an optical signal based on an electric signal; a first detecting unit that detects a first variation width of a maximum output of the modulated optical signal; a second detecting unit that detects a second variation width of a minimum output of the modulated optical signal; a comparing unit that performs a comparison of the first variation width and the second variation width; and an adjusting unit that adjusts a bias potential of the electric signal based on a result of the comparison.

Abstract: A power supply control circuit includes: a conducting part configured to be controllable in its a conducting amount for conducting a power supply current to a load circuit; a current change ratio detecting part detecting a change rate of the power supply current supplied to the load circuit; and a control part controlling the conducting amount of the conducting part according to the change rate of the power supply current detected by the current change detecting part, wherein: the control part carries out feedback control of reducing an increasing rate of the conducting part as the power supply current change rate is larger.

Abstract: The invention provides a method for measuring transmission loss in an optical transmission line between a master station and a slave station, and also a slave station, a master station and a star network communication system using this method. Power of an optical signal is measured at a second end of an optical transmission line connected with an added slave station and at a first end other than the second end. The result at the first end is stored in a storing unit or transmitted to an incorporating unit by a transferring unit. The incorporating unit incorporates the result into a downstream optical signal, which is transmitted to the slave station. In the slave station an information extracting unit extracts the result from the downstream optical signal, and a processing unit calculates a difference between the measurement results of the first and second ends to obtain transmission loss therebetween.

Abstract: The invention provides a method for measuring transmission loss in an optical transmission line between a master station and a slave station, and also a slave station, a master station and a star network communication system using this method. Power of an optical signal is measured at a second end of an optical transmission line connected with an added slave station and at a first end other than the second end. The result at the first end is stored in a storing unit or transmitted to an incorporating unit by a transferring unit. The incorporating unit incorporates the result into a downstream optical signal, which is transmitted to the slave station. In the slave station an information extracting unit extracts the result from the downstream optical signal, and a processing unit calculates a difference between the measurement results of the first and second ends to obtain transmission loss therebetween.

Abstract: A laser diode drive circuit comprising a laser diode; a drive pulse current source for emitting light or not emitting light of the laser diode according to an input signal; and a biasing unit for optimally operating the laser diode, the biasing unit having a bias voltage source for applying a bias voltage to the laser diode, which bias voltage can feed an optimum bias current to the laser diode. The laser diode drive circuit can maintain a bias current at a predetermined value with high precision and with high stability.

Abstract: An automatic assembly and inspection system for optical connectors is provided, which is highly reliable and which can produce economical and highly-effective optical cords or cables with optical connectors.

Abstract: A constant range polishing apparatus for polishing an end face of an optical fiber connector ferrule. The apparatus comprises a polishing plate adapted to be rotated about a polishing plate axis for polishing the end face of the connector ferrule. The polishing plate includes a disc-shaped substrate having a circular surface including an outer ring area, an inner ring area disposed radially inwardly with respect to the outer ring area, and an inner portion disposed radially inwardly with respect to the inner ring area.