Abstract: A magnetic recording and reproducing apparatus for recording a desired sound or picture signal to a magnetic tape by a magnetic head. At the time of normal-speed recording and reproduction, the magnetic tape is taken up at a constant speed, but by changing the tape travelling speed of the tape on the rotary drum, DTF control and high-speed noiseless reproduction are enabled. The tension of the tape on the entrance side of the rotary drum is controlled to a desired value. This apparatus includes a tape tension actuator and a tape drawing actuator on the entrance side and on the exit side, respectively, of the rotary drum. In DTF control, both tape actuators correct a tracking error of the tape in cooperation with each other. In high-speed noiseless reproduction, both tape actuators are differentially driven so as to lower the tape travelling speed on the rotary drum. Both tape actuators are driven in feedback control using the modern control.

Abstract: A method and apparatus for controlling surface pressure exerted on a movable magnetic head by a recording medium to provide optimum contact between the movable magnetic head and the recording medium with high precision in a wide frequency range. An estimated surface pressure exerted by the recording medium on the movable magnetic head is determined based upon an electrical simulation of the characteristics of the movable magnetic head. The estimated surface pressure exerted is compared to a reference surface pressure in order to develop a surface pressure control signal. The surface pressure tension of the magnetic recording medium and the position of the movable magnetic head may be controlled in accordance with the surface pressure control signal.

Abstract: A movable head position controlling device for magnetic recording and reproducing apparatuses. The position of a magnetic head is detected. The magnetic head is driven by an actuator in accordance with a driving signal. The driving signal is corrected on the basis of the estimated speed of the magnetic head, the absolute height of the movable head, the displacement of the magnetic head, or the output of an equivalent coil. The speed of the magnetic head is estimated by a speed estimating observer. The absolute height is detected by a magnetic field detecting element. The displacement of the magnetic head is detected by non-contacting sensors attached to a member which moves together with the magnetic head and a member which does not move together with the magnetic head, respectively.

Abstract: It is an object of the invention to realize a DTF control in a wide frequency range and a noiseless high-speed replay at several tens of times the normal relay speed without degradation of picture quality. It is also an object to provide an optimum contact between the head and the tape at all times by performing the tension control with high precision and in wide frequency range.A pair of supply side stationary pins 10a.sub.1, 10a.sub.2 and a supply side movable pin 9a driven by a supply side tape actuator 11a are provided on the magnetic tape supply side of the head cylinder that has a rotary head H. By controlling the supply side tape actuator 11a to move the movable pin 9a, the tension of the magnetic tape T at the head cylinder can be controlled. When the tape is replayed at speed different from the recording speed, the supply side tape actuator 11a and a takeup side tape actuator are operated differentially from each other to perform a good tracking.

Abstract: A movable head position controlling device for magnetic recording and reproducing apparatuses. The position of a magnetic head is detected. The magnetic head is driven by an actuator in accordance with a driving signal. The driving signal is corrected on the basis of the estimated speed of the magnetic head, the absolute height of the movable head, the displacement of the magnetic head, or the output of an equivalent coil. The speed of the magnetic head is estimated by a speed estimating observer. The absolute height is detected by a magnetic field detecting element. The displacement of the magnetic head is detected by non-contacting sensors attached to a member which moves together with the magnetic head and a member which does not move together with the magnetic head, respectively.

Abstract: A magnetic recording and reproducing apparatus that realizes a DTF control in a wide frequency range and a noiseless high-speed replay at several tens of times the normal replay speed without degradation of picture quality. Optimum contact between the head of the apparatus and the tape is provided at all times by performing tension control with high precision and in a wide frequency range. A pair of supply side stationary pins and a supply side movable pin driven by a supply side tape actuator is provided on the magnetic tape supply side of the head cylinder that has a rotary head. By controlling the supply side tape actuator to move the movable pin, the tension of the magnetic tape at the head cylinder can be controlled by taking into account the acceleration of the deck. When the tape is replayed at a speed different from the recording speed, the supply side tape actuator and a takeup side tape actuator are operated differentially from each other to perform good tracking.

Abstract: In a magnetic recording and reproducing apparatus having a solenoid-driven actuator to move a magnetic head in the tracking direction, a magnetic head position controller includes a state estimator for estimating the moving speed of the actuator from a drive voltage and a drive current supplied to the actuator; and a damping control loop for feeding back the estimated speed signal estimated by the state estimator to the actuator drive voltage. The state estimator is formed of a combination of equivalent circuits that electrically simulate modeled characteristics of the solenoid-driven actuator and receives the drive voltage and the drive current of the actuator and produces the estimated speed signal representing the speed of the actuator.

Abstract: In a magnetic recording/playback system having a magnetic head drive device for moving a movable head disposed within and mounted to a rotating upper drum in parallel with the axis of the drum, and a fixed drum supporting the upper drum so that the upper drum can rotate, an AC magnetic field generator is disposed along the peripheral surfaces of the drums at a location at which the magnetic tape is not wrapped on the drums. The AC magnetic field generator applies an AC magnetic field to the movable head that varies in the direction of the axis of the drums. Information on the position of the movable head is detected in accordance with the detection signal of the AC magnetic field derived by the movable head and the position of the movable head is controlled by feeding the detected positional infromation back to the magnetic head driving device.

Abstract: A magnetic recording and reproducing apparatus for performing automatic tracking in a video tape recorder of a helical scan type. A magnetic head is wobbled by an electromagnetically driven actuator in a transverse direction of a recording track, a tracking error signal is obtained by extracting a signal component attributable to this wobbling from a signal reproduced by the magnetic head, and the extracted signal component is fed back to the electromagnetically driven actuator. By setting the magnetic head width to 1-1.5 times the recording track width, a dead zone is made small, and the tracking error signal is obtained positively. In addition, by setting the frequency for driving the electromagnetically driven actuator at a level between a primary resonance frequency and a secondary resonance frequency and by subjecting the driving frequency to phase conversion, the driving frequency is converted into a high frequency to permit highly accurate tracking.

Abstract: The present invention relates to a reformer for producing a hydrogen rich gas by reaction of natural gas with steam by a catalytic action with heating, and particularly to the heater in the reformer, where the heating section of the heater is composed of a heating section by burner combustion and a heating section by catalytic combustion, and a stable combustion less susceptible to fluctuations in the feed rate or pressure of fuel or air can be obtained by the catalytic combustion.

Abstract: A power generator containing a fuel cell (or cells) characterized by a fuel supply means designed to supply hydrogen gas and oxygen gas to the hydrogen and oxygen feed lines leading to the cell in response to a rapid rise of power load connected to the cell. This power generator suffers from no shortage of output power due to a delay of action and is excellent in responsiveness to sharp rise of load. In a preferred embodiment of this invention, the electrolyte is electrolyzed to produce hydrogen gas and oxygen gas by DC power generated by the fuel cell, and the produced gases are led to the hydrogen and oxygen feed lines leading to the fuel cell.

Abstract: In a shift converter for catalytically converting carbon monoxide and steam to carbon dioxide and hydrogen through exothermic reaction in a phosphoric acid fuel cell apparatus, the heat generated at the shift reaction is absorbed in vaporization of a liquid in a vessel provided with a reactor tube as a heat source. The catalytic exothermic reaction is carried out with cooling in the present invention, and thus it is not necessary to provide coolers at a plurality of stages in contrast to the conventional shift converter.

Abstract: Screw fluid machines are for use as a compressor for generating high pressure gas, a cooling-medium-compressing compressor for use in a refrigerator or an air conditioner. The fluid machine includes a rotor casing, two side-casings, a pair of screw rotors, and accessories such as silencer, a gas cooler, an oil cooler, and an oil tank. The rotor casing includes an outer wall, an inner wall and interconnecting members or ribs which interconnect the outer wall and the inner wall, with a space being provided between the outer wall and the inner wall. This space is partitioned into two or more spaces by means of the aforesaid interconnecting members. A working chamber or space is provided inwardly of the inner wall and has an inlet port and a discharge port. Both side-casings are secured to the opposite end faces of a rotor casing through the medium of flanges and are provided with a passage adapted to bring two or more spaces thus partitioned, into communication with each other.