Abstract: A process for preparing a purified refolded monomer or dimer of a bone-derived factor, which comprises subjecting an inclusion body of a bone-derived factor produced by genetic engineering to the following steps a) to c) in sequence:

Abstract: An active EMI filter senses current in a ground line or a power transmission line as a voltage cross a capacitor coupled to the line. The EMI filter senses common mode voltage and determines a difference between the common mode voltage and noise to provide an output to drive the difference to zero. The resulting active closed loop EMI filter produces good EMI dampening with greatly increased performance over a current transformer type EMI filter. A voltage regulator for the error amplifier improves noise reduction while increasing filter efficiency. The active EMI filter operates in a wide linear range that is greater than that of an equivalent current transformer circuit, while providing low cost and reliability.

Abstract: An active EMI filter for reducing common mode current in a circuit comprising a rectifier coupled to an AC network, the rectifier supplying DC power to a DC bus, the DC bus feeding an inverter stage for providing AC power to a load, the load having a ground return line to a ground connection of the AC network, the active filter comprising: a transistor switching stage coupled across the DC bus, a current sensor coupled to the DC bus for sensing the common mode current flowing in the DC bus and proportional to the common mode current flowing in the ground return line from or to the load, the current sensor having inputs coupled to respective legs of the DC bus and an output driving the transistor switching stage, the transistor switching stage comprising two transistors driven by said output of the current sensor whereby one of said transistors is turned on by said current sensor output depending on the direction of common mode current in said DC bus, a capacitor coupling said transistor switching stage and sa

Abstract: A process for preparing a purified dimer of a bone-derived factor, which comprises subjecting an inclusion body of a bone-derived factor produced by genetic engineering to the following steps a) to e) in sequence: a) the step of treating an inclusion body of a bone-derived factor with a unfolding agent to prepare a solubilized monomer; b) the step of treating the solubilized monomer with a refolding solution to prepare a dimer; c) the step of subjecting the refolded dimer to ultrafiltration and solvent replacement; d) the step of subjecting the dimer solution prepared above to isoelectric precipitation; and e) the step of subjecting the isoelectrically precipitated dimer to reverse-phase chromatography.

Abstract: Low pass filters at the output stage of a D-class amplifier, in which a high channel separation between adjacent signal amplifying channels, a small size, implementation at a high density can be attained. Induced electromotive forces by a leakage magnetic flux from the adjacent channels are set off by a plurality of pairs of inductors in one low pass filter. The low pass filter of each channel is formed by the same construction and the same circuit. The inductors are arranged in a manner that center axes of coils of the two corresponding pairs of inductors in the adjacent channels are located at vertexes of a rectangular parallelogram, and combinations of the winding directions of the coils of the corresponding inductors of the adjacent channels are set to the same direction and the opposite directions every other inductor.

Abstract: A D-class power amplifier of two channels in which an increase in power voltage due to a regenerative current is prevented and a high efficiency in utilization of electric power is attained. Two D-class power amplifying circuits included in the D-class power aymplifier of the two channels are constructed by opposite phases. A preprocess is performed only to low frequency components of input signals so that they have a substantially equal amplitude in the two channels, and the resultant low frequency components are supplied to the D-class power amplifying circuits, respectively. The other ends of loads connected to the D-class power amplifying circuits are connected to a neutral potential point of the power voltage.

Abstract: A variable signal attenuating circuit which has a function of preventing dropout of an attenuated signal even if a large attenuation value is set. A dynamic range compression processing unit is provided in an input unit of the variable signal attenuating circuit for compressing the dynamic range of an input signal within a predetermined range in accordance with a set attenuation value, such that the signal passing through the compression processing unit is attenuated by the set attenuation value.

Abstract: A class D amplifier is provided with a frequency characteristic compensation function. An automatic frequency characteristic compensation circuit is disposed at an input unit of a class D amplifier. The frequency characteristic of the class D amplifier is automatically measured while a load is connected, using a test signal having a predetermined frequency and signal level. An inverse characteristic is computed for compensating the frequency characteristic to the design frequency characteristic, and the inverse characteristic is set in the automatic frequency characteristic compensation circuit.

Abstract: A power amplifying device promptly detects an abnormal condition of a load and permits protection of an output without causing power loss. A test signal having a predetermined frequency and signal level is supplied to an amplifier, and the output level is measured. The measured level is compared with the output level that is projected when the test signal is supplied with an appropriate load connected to the amplifier so as to detect a load condition. If a determination result indicates that the load is short-circuited or released, then the operation of the amplifier is promptly interrupted.

Abstract: A voltage rectifying and smoothing circuit for use in a regulated power supply circuit which converts an ac voltage to a constant dc voltage. A voltage control circuit, which prevents the production of a voltage higher than a predetermined voltage, is connected to a rectifier circuit which rectifies an input ac current to convert it to a rectified voltage. The voltage smoothing circuit is connected on the output side of the voltage control circuit.

Abstract: A direct current voltages detecting circuit is provided for monitoring output voltage of the power amplifier. A direct current signal is produced when a direct current voltage is detected. A cutoff circuit responds to the direct current signal and renders an output stage of the power amplifier a cutoff state. A failure determining circuit is provided to respond to the direct current signal and to produce an abnormality signal. In response to the abnormality signal, a power supply cutoff circuit operates to cutoff a power supply of the power amplifier.

Abstract: A power detector is provided for detecting closing of a power switch in a power supply, for producing a power-on signal after a predetermined time from detection of the closing of the power switch. An abnormality detector is provided for detecting an abnormal voltage produced in a circuit of a power amplifier, for producing an abnormality signal when detected. In response to the power-on signal, an output stage of the power amplifier is activated, and the output stage is cut off in response to the abnormality signal.

Abstract: First and second power transistors collectors of which are connected with each other, other first and second loss sharing transistors connected to bases of the first and second power transistors at collectors thereof, respectively. A first driver transistor is connected to the emitter of the first loss sharing transistor at the collector thereof, and a second driver transistor is connected to the emitter of the second loss sharing transistor at the collector thereof. The base of each of the loss sharing transistors is applied with a constant voltage at the base thereof.

Abstract: A protective apparatus for a power transistor which detects an abnormal temperature of a power transistor and cuts a load to the power transistor to prevent possible breakdown of the power transistor. The protective apparatus comprises detecting means which detects a junction temperature of the power transistor on the real time basis from a base-emitter voltage of the power transistor. When the junction temperature of the power transistor is excessively high, a protective circuit produces an output signal, and a muting circuit applies muting to an input signal to or a current flow through the power transistor.

Abstract: A karaoke device which automatically returns the level of a microphone volume to a presettled level at the beginning or end of individual music pieces, and which is capable of gradually reducing the gain of the microphone amplifier by a predetermined value when an output volume from the microphone amplifier becomes excessively loud during the playing of a music piece. The karaoke device includes an adjustor for adjusting the level of the microphone volume in accordance with a manual instruction or an instruction from a control circuit; a level detector for detecting when the volume level is greater than a predetermined level; a music piece detector for detecting a beginning or end of each music piece; and a control circuit that compares a standard volume level and the volume level of when a detected signal is outputted from the music piece detector, and controls the adjustor to equalize the output level to the previously stored standard level.

Abstract: A frequency/voltage converting device includes a frequency/voltage converting means for converting a DC voltage corresponding to the frequency of an input signal, a reverse-polarity ripple voltage outputting device for outputting a ripple voltage which is equal in magnitude and reverse in polarity to a ripple voltage contained in the DC voltage output from the frequency/voltage converting means; and an adding device for adding the DC voltage output from the frequency/voltage converting device and the voltage output from the reverse-polarity ripple voltage outputting device. The above arrangement serves to cancel the ripple voltage, thereby obtaining a DC voltage containing no ripple voltage for a sawtooth wave generating device.