Abstract: A conventional DC/DC converter with both a step-up function and a step-down function has a drawback that its output voltage will be discontinuous when its operations are switched. An error signal, which is representative of a difference between a target voltage and a present voltage, is inputted to both a step-down switching control circuit and a step-up switching control circuit. When the difference between the target voltage and the present voltage is below a predetermined value, the switching of the step-down and step-up converters by the step-down and step-up switching control circuits, respectively, are caused to concurrently run in a time division manner.

Abstract: A conventional DC/DC converter with both a step-up function and a step-down function has a drawback that its output voltage will be discontinuous when its operations are switched. An error signal, which is representative of a difference between a target voltage and a present voltage, is inputted to both a step-down switching control circuit and a step-up switching control circuit. When the difference between the target voltage and the present voltage is below a predetermined value, the switchings of the step-down and step-up converters by the step-down and step-up switching control circuits, respectively, are caused to concurrently run in a time division manner.

Abstract: During the playback operation for freezing and storing a specific frame of a picture in a memory and thereafter printing the frame, the recording medium is turned reversely for a prescribed amount according to an instruction from a printer in response to the entry of the freeze command in order to accurately search the frame at the entry of the freeze, and thereafter the recording medium is played back in normal mode. The amounts of reverse turn and the successive forward turn in normal playback are counted and compared, and when the difference has become a prescribed value, a freeze signal is produced and the frame of the picture selected by the freeze command is stored in the memory and printed when required. This control method for use in a video print system is designed so that the recording medium is turned reversely for a prescribed amount according to an instruction from the printer and then stopped until the next command is entered.

Abstract: White balance adjusting apparatus for controlling the levels among RGB signals of the video signals and adjusting the white balance of the video image is provided in a color video printer apparatus which receives the video signals and prints out. Prior to color printing, the white balance is adjusted, thereby enabling a good color reproduction to be obtained.

Abstract: A video printer is disclosed. An input video signal is converted into a digital signal and stored in a memory. The write/read operation and memory addresses of the memory are controlled by a memory control unit. The signal read out of the memory is converted into print data, and an image is printed by a printer. The print data and the printing operation are controlled by a print control unit, and at least a part of the memory areas of the memory is controlled in the write operation by an area control unit.

Abstract: A video signal processing circuit for a video printer operating to sample an analog video signal, to convert the video signal into digital data, to store the data in a memory, and to read out the contents of memory to a printer for printing. The circuit includes an oscillation circuit which generates a pixel clock in response to the horizontal sync signal in the video signal, a frequency division phase shift circuit which divides the frequency of the pixel clock provided by the oscillation circuit and shifts the frequency divided clock with the pixel clock, a selection circuit which selects one of frequency divided clocks having different phases provided by the frequency division phase shift circuit, and a selection control circuit which operates on the selection circuit to alter the clock selection at each arrival of vertical sync signal, so that the sampling of the video signal is implemented in response to the clock output of the selection control circuit.

Abstract: A video printer comprises a main memory unit for storing data of a first picture, a sub-memory for storing data for an overlay region to be overlaid on the first picture and also indicative of a second picture to be displayed in the overlay region, a memory data processing unit for generating a synthesized picture by selectively controlling the picture data for the overlay region on the basis of the data stored in the sub-memory, a system control circuit for controlling the data storage in the main memory unit, the data storage in the sub-memory circuit and operation of the memory data processing circuit, and a print circuit for producing a hard copy on the basis of the output of the memory data processing circuit.

Abstract: In a video printer, a suffer memory for memorizing picture data corresponding to one line includes a memory addressed by a first address and a second address. And the video printer includes a memory write circuit having a first address generation circuit for generating a first address depending upon gradation of picture data on the basis of inputted picture data and for supplying said first address to the memory and a second address generation circuit for generating an address signal depending upon the number of printing dots of the thermal head and for supplying said address signal to the memory. The video printer also includes a memory read circuit for successively generating the second address for each of the first address and supplying the second address to the memory.

Abstract: A thermal-transfer recording method and an apparatus used for this method in which ink on an ink tape is heat-transferred in the form of a mirror image of a desired image to an intermediate recording sheet having a base film and an ink absorbing adhesive layer formed on the base film, and in which the intermediate recording sheet to which the mirror image has been heat-transferred is bonded to a desired recording medium at the surface of the ink absorbing adhesive layer.

Abstract: A video printer having color signal interpolation circuit including a first memory which stores a color signal requiring the largest amount of information among signal of three primary colors in a video signal, a second memory which stores both of the other two color signals sampled alternately, and a data interpolation circuit with a signal edge detecting part and signal level detecting part and which reproduces the other two color signals on the basis of the signals stored in the second memory by interpolation. Color signals delivered from the first memory and the data interpolation circuit are successively sent to the printer so as to be printed.

Abstract: A signal-processing circuit of a heat-sensitive recording apparatus comprising a temperature detector for detecting the temperature near a heat-sensitive head is disclosed, in which an energization code train read from a ROM for storing the energization time-concentration characteristics corresponding to the .gamma. characteristic of the inking paper is corrected in accordance with the head temperature, and a print is produced in accordance with the energization code train thus corrected.

Abstract: Disclosed is a video image printer for printing a video image of an input video signal onto a printing paper, in which a medium, such as a magnetic sheet disc or magnetic tape for a video cassette recorder, capable of recording/reproducing the information of the video image is employed. In order to obtain a reproduced video signal from the recording/reproducing medium with normal-operation, the video image printer is provided with a mechanical vibration-absorbing mechanism and an electrical reproduced signal correction circuit. Depending upon the requirements of the situation, a plurality of recording/reproducing heads are provided so as to make it possible to record a video image to be printed on the recording/reproducing medium during the printing operation of a previously selected video image.

Abstract: An apparatus for driving a brushless motor, in which a ripple appearing in the rotation torque of the motor is cancelled by driving the motor with a signal current whose phase is opposite to that of and which has a waveform symmetrical with that of the torque ripple waveform, so that the motor can rotate accurately without any speed variation. In order to obtain such a signal current waveform, counter-electromotive forces induced in the stator coils of the motor are detected, and the level of the signal indicative of the detected counter-electromotive forces is controlled depending on the load and rotation speed of the motor to provide a control signal for controlling the motor drive current.

Abstract: An auto-tracking method and apparatus of a helical scan type magnetic recording/reproducing apparatus wherein envelope levels of reproduced signals are detected and the running phase of a magnetic tape is controlled so that the envelope level of the reproduced signal becomes maximum after detection is effected roughly and then finely, thereby allowing a video head to scan a track on the magnetic tape.

Abstract: A frequency-voltage converter comprising a feedback frequency generating means associated with controlled means, a saw-tooth wave generating means, a current source for the saw-tooth wave, pulse generating means and sample-and-hold means, the frequency-voltage converter being characterized by further provision of supply voltage switching means for changing the feedback frequency of the controlled means by changing the voltage to be supplied to the current source to change the current from the current source and to thereby the slope of the saw-tooth wave from the saw-tooth wave generating means.

Abstract: An FM signal demodulation circuit comprises a plurality of inverters and a capacitor. Each of the inverters is constituted by an integrated injection logic (I.sup.2 L) including a transistor and an injector current source.

Abstract: A transistor circuit is used as a signal amplifier which has little possibility of oscillation in an IC. The transistor circuit includes a cascade connection of differential amplifiers. Each of the amplifiers comprises a differential pair of bipolar transistors and an enhancement-type MOSFET as a constant current source. The MOSFET of each amplifier is connected in the common source mode, and the drain is connected to the emitters of the differential pair of bipolar transistors. The sources of all the MOSFETs are connected to a common ground-line.

Abstract: Disclosed is a speed and phase control system for a moving apparatus driven by an electric motor, or the like, and provided with a speed control system for controlling the moving apparatus to an initially set speed, a phase control system for synchronizing the phase of the moving apparatus with a reference signal, and an error correction device storing therein a target value of and for comparing an actual speed or a phase of the moving apparatus with the target value to detect an error therebetween to thereby correct the initially set value in accordance with the error, whereby control is made such that the moving apparatus is operated at the target value of speed and phase thereof. Further, the error correction device is cut off from the speed control system when the speed reaches a value near the target value and at the same time the operation of the phase control system is started.

Abstract: A time constant circuit capable of switching the characteristic, which is realized by a combination of an equivalent resistor made up of a switched capacitor and an ordinary capacitor, comprises a capacitor of the switched capacitor or the time constant circuit connected in parallel to a series circuit including a switching device and an additional capacitor. The characteristic is switched by turning on and off the additional capacitor by the switching device. The direct connection of a plurality of equivalent resistors with a plurality of switched capacitors and ordinary capacitors makes up an equalizer. The capacitor making up a switched capacitor is connected with a switching device and an additional capacitor so that the frequency characteristic of the equalizer is switchable by turning on and off the switching device. Each of the capacitors making up the switched capacitors, the capacitors making up the time constant circuits and the additional capacitors has an end thereof grounded.

Abstract: A motor control apparatus for driving and controlling a motor, in which a signal frequency proportional to a rotation number of the motor is converted into a d.c. voltage by a frequency/voltage converter so as to drive and control the motor by the d.c. voltage.