Abstract: A pulse frequency modulation type DC-DC converter has first and second voltage level comparators for controlling the frequency of a control signal used to drive an output coil. The first voltage comparator detects a first voltage level and the second voltage comparator detects a second voltage level. A reference voltage circuit produces reference voltages corresponding to the first and second voltage levels and provides the reference voltages to the first and second voltage comparators, respectively. An oscillating circuit generates the control signal under control of the first and second comparators. The control signal has one of a first pulse width and a second pulse width depending upon outputs of the first and second voltage comparators for controlling a switching device used for driving an output coil. The switching device is turned on to drive the output coil during a first pulse width when the first voltage comparator detects that the output voltage coincides with the first voltage level.

Abstract: In any steady-state optimization problem, the output being optimized could be a nonmonotonic function of the controlled variable. Often the output is dependent on the temperature, the load impedance, and other unknown and variable quantities. Thus, it is very useful to have an automatic tuning scheme that will take the system to the desired operating point using only input and output information. The present invention is a generalized tuning scheme that uses the correlation between changes in the input and corresponding changes in the output to tune the operating point. In general terms, the present invention utilizes a correlation function between the controlled variable and a perturbed waveform. When the system reaches the desired operating point, the correlation goes to zero and the system converges. This corresponds to the point at which the derivative of the output with respect to the input is zero. This tuning scheme is appropriate for any tuning problem which has a single maximum or minimum.

Abstract: A digital power factor correction circuit including a digital comparator that compares the actual DC bus voltage of an electric circuit with a desired DC bus voltage to produce a digital attenuation signal in the form of a pulse width modulated signal that is used to attenuate the voltage from a time-varying source. The attenuated source voltage is used as the current demand signal for a current controller that controls the current drawn from the line.

Abstract: An air conditioning device is arranged such that an output voltage from a commercial power source is converted into a direct current by a rectifying circuit and a smoothing condenser. Thereafter, it is further converted into an AC voltage having a variable frequency by an inverter under the control of a microcomputer, thereby supplying it to a power compressor. Between the rectifying circuit and the smoothing condenser, an active filter is provided for shaping an input current to be an approximate sine wave almost in phase with an input voltage by switching a power transistor. The switching control section and the microcomputer for controlling the switching are activated independently by separately provided power sources. The switching control section supplies a high level signal when the active filter is a normal condition, and supplies a low level signal when the active filter is abnormal.

Abstract: An antiseismic static electrical converter installation comprises a valve assembly mounted on a platform, the platform being suspended at each of two opposite ends from a series of rods which are attached in a spaced-out relationship to a horizontal beam, the beam being mounted on the ground via rubber springs. During an earthquakes movement of the ground causes mainly lateral distortion of the rubber springs and elastic bending of the rods, and, since the natural resonant frequency of the suspension system is designed to be low and the rubber springs are deigned to have significant damping, a high degree of isolation is provided for the platform and the equipment mounted on it. During severe earthquakes, the rods are arranged to suffer a plastic bending which causes them to act like pendulums and changes the natural frequency of the suspension system to increase the damping and provide greater protection.

Abstract: A method and apparatus which writes image information into a memory and reads the image information out of the memory using different synchronizing signals. A first synchronizing signal which is used to write scanned image data into the memory is generated to have a predetermined regularity, for example using a clock signal. The second synchronizing signal is based on an output of a photosensor which detects laser light reflecting off a polygonal mirror and is based on the rotating speed of the motor. The image information in the memory is read out in synchronism with the writing of the image information by the laser beam and polygonal mirror onto the photoconductive element using the second synchronizing signal. Therefore, it is not necessary for the polygonal mirror and the motor driving the polygonal mirror to be at a predetermined stable speed during the scanning operation.

Abstract: A multi-tone image processing method and apparatus in which mutually dissimilar tone levels are realized by changing the additive condition of recording energy by means of different recording positions, even when the number of recording operations within a specific range is identical. For example, in an electrophotographic apparatus, when the number of irradiation by a light spot within a specific range remains constant as the irradiation position is changed in the specific range, there is a change in the additive condition of the optical energy within said specific range. Thus, the area rendered visible within the aforesaid specific range also changes, thereby changing the tone level.

Abstract: A single ended forward DC-to-DC converter includes a transformer having a primary winding electrically connected to a primary switch and a secondary winding electrically connected to a secondary switch and a clamping capacitor. The clamping capacitor stores the magnetization energy from the secondary winding when the primary switch is turned off, thus causing the transformer core to be reset during the period that the primary switch remains off. The converter can use mosfets as the primary and secondary switches, such that a change in the voltage at the secondary winding of the transformer, due to the turning off of the primary switch, results in an automatic turning on of the secondary switch. The combination of the clamping capacitor and the mosfet switches increases the simplicity of the DC-to-DC converter while eliminating undesirable characteristics such as dead time and voltage stresses on the switches.

Abstract: A dual mode external DC power supply system for supplying DC power to an electronic device and which operates under the control of the electronic device is provided. The disclosed embodiment of the power supply system includes a first input adapted to receive an input signal of unregulated DC power, a second input adapted to receive a control signal from the electronic device, and an output adapted to provide either a constant voltage DC output signal or a constant current DC output signal depending on the magnitude of the control signal. The control signal also determines the level of constant current delivered to the electronic device when the system is operating in the constant current mode.

Abstract: Herein disclosed are a method and an apparatus for supplying an electrical energy to a pair of discharge electrodes spaced apart from each other to cause an electric discharge in a gap between the discharge electrodes. There are firstly provided an alternating voltage generator for generating, as the electrical energy, an alternating voltage having a frequency, and a capacitor connected to the discharge electrodes in series. The alternating voltage generator has a series resonant frequency. The alternating voltage of the alternating voltage generator is applied to the discharge electrodes through the capacitor. The frequency of the alternating voltage is set approximately to the series resonant frequency of the alternating voltage generator to cause a dielectric breakdown in and allow an electric discharge current to flow through the gap between the discharge electrodes.

Abstract: A tap changer in which a pair of selector contacts can be jointly movable or individually movable to engage stationary tap contacts of an array and one of the selector contacts is in series with a tickler coil and switchover resistor connected to one fixed contact of a bypass switch whose movable contact is connected to the load. The other selector contact is connected to one stationary contact of a switchover switch whose movable contact is connected to a second contact of the bypass switch while another contact of the switchover switch is tied to a point between the tickler coil and the resistor. A pair of oppositely poled parallel thyristors bridges the auxiliary network of the tickler coil and resistor and the main branch passing from the switchover switch to the bypass switch. The movable contacts are operated by an intermittent drive of the Geneva mechanism type.

Abstract: There is provided by the present invention an image forming apparatus including a one-chip microcomputer having white reference data for a first sheet of copy fetched with shading gate arrays in a stable region for a halogen lamp, using said white reference data when forming an image for a first sheet of copy, and also having shading-corrected white data fetched for a second or subsequent sheet of copy each time an image is formed.

Abstract: A power supply device in which an inverter circuit is supplied with power directly from a rectification circuit, the inverter circuit has a pair of switching elements connected in series with each other and connected between both ends of the rectification circuit through an impedance element, a series circuit of the impedance element, two capacitors and an inductor is connected in parallel to one of the switching elements of the inverter circuit connected to positive polarity one of the both ends of the rectification circuit, a load is connected across one of the capacitor, a valley filling circuit receives an output of the inverter circuit through a diode provided in the valley filling circuit and supplies it to a power supply capacitor provided therein and, when a DC output voltage of the rectification circuit drops, the valley filling circuit supplies power to the inverter circuit via the power supply capacitor and another diode provided therein.

Abstract: In an image forming apparatus which combines a plurality of different image forming methods, the image forming operations of the plurality of image forming methods are controlled in accordance with the color of an original image and the color of a recording agent, so that image formation in a desired color can be reliably attained, and copying errors can be eliminated. In another aspect, by appropriately selecting the plurality of image forming methods in correspondence with the feature of an image, high-quality image formation can be attained in correspondence with the image feature.

Abstract: A technique for sensing current that employs an internal current sensing resistor. Two current sources of small and equal magnitude pull currents from two identical PNP transistors. Two PMOS transistors supply current to the PNP transistors. The PMOS transistors are scaled so the transistor on the output side of the circuit has an aspect ratio much greater than that of the transistor on the sensing side of the circuit. The result is that the currents through the PMOS transistors are proportional to each other and the current on the sensing side is much smaller than the current on the output side. The output current is the difference between the current through the PMOS transistor with the greater aspect ratio and the current through one of the small current sources. The sensing current, which passes through the internal sensing resistor, is the difference between the current flowing through the PMOS transistor with the lesser aspect ratio and the current flowing through the other small current source.

Abstract: A voltage stress (e.g., reverse voltage stress) in rectifying diodes of, for instance, an asymmetrical DC-to-DC converter is reduced by using a transformer circuit having multiple power transformers with a composite static transfer characteristic. More specifically, the static transfer characteristic is selected to be monotonic in combination with the transformer circuit including two transformers, having independent isolated cores, coupling an input to output of the converter. A primary to secondary winding ratio of each of the two transformers is selected in such a way as to achieve a reduction in reverse voltage in at least one of the rectifying diodes. The reduction in the reverse voltage and, hence, improved efficiency of the rectifier is directly translatable into an increase in a power density of the converter.

Abstract: This invention is related to a communication terminal device and communication method for communicating with another terminal device in a full duplex manner or a half duplex manner depending upon a function of the another terminal device. A new recommendation V.8 of the International Telecommunication Union was established as a data transmission method for use in telephone exchange networks. This V.8 is suitable for use with telephone sets and data modems and not only facsimile devices. Devices which are in accordance with this new recommendation V.8 will be put on the market in the near future. Presently, half-duplex facsimile devices also exist thus functions which cope with half-duplex communication are also necessary. This invention, while being a terminal device basically adapted for the recommendation V.8, proposes a terminal device that can communicate with previously used half-duplex terminal devices, and a terminal device using that communication method.

Abstract: An active power quality conditioner for compensating reactive power and harmonic distortion in power systems. A pulse width modulated (PWM) inverter (70) for each phase is controlled to produce a harmonic distortion compensation signal that is coupled to an inductor. The inductor is connected in series between a stepped-wave inverter (84) and one phase of the power line. A current produced by the stepped-wave inverter compensates for the reactance of a load coupled to the power line. The PWM inverter operates at a frequency that is substantially greater than the fundamental frequency of the power line and is not exposed to the full power line voltage; it can be constructed using components of relatively low power and voltage rating. In contrast, the stepped-wave inverter, which is decoupled from the PWM inverter, operates at the fundamental frequency and is subjected to most of the stress. Both shunt coupled and series coupled compensators are described.

Abstract: A control unit for controlling devices or assemblies comprises a plurality of control elements located on a control surface. These control elements are provided with correspondingly assigned symbols for visually displaying the function of the respective control element and can be adjusted into at least two positions. In order to make reliable control easier, even under unfavorable light conditions, the control elements or an area directly adjoining them are provided with means for distinguishing the respective control element haptically. The control unit is suitable in particular for controlling a heating and/or air conditioning system in a motor vehicle.

Abstract: An expansion unit for expanding print data from an upper layer device into image data according to predetermined control data, a printing unit for printing the image data on a recording medium according to predetermined process condition control data, and a recording medium conveyor for transporting the medium to the print unit are combined. The expansion unit includes a conversion process unit for receiving an image quality request instruction from an external device and a medium specifying instruction specifying a type of the recording medium transported by the recording medium conveyor, a rational data unit for storing a plurality of expansion control data items and identifying an expansion control data item corresponding to each instruction, and a rational process condition unit for storing a plurality of process condition control data items and identifying a process condition control data item corresponding to each instruction.