Abstract: A magnetic disk recording and reproducing apparatus including a unit for inserting an error correcting code relating to control information in the control information, the control information relating to data, a recording control unit for recording the control information and the data in a recording area of a magnetic disk, the recording area having a plurality of sectors, each of the sectors having an ID area for recording the control information and a data area for recording the data, the data area corresponding to the ID area and being provided adjacent to and behind the ID area in the same sector as the ID area, and an error correcting unit for correcting errors in the control information in the ID area using the error correcting code before the data in the data area corresponding to the ID area and provided in the same sector as the ID area is read or recorded.

Abstract: A phase locked loop circuit having a voltage controlled oscillator for generating a clock signal with a frequency determined by a voltage control signal supplied to the voltage controlled oscillator, an AD-conversion circuit for sampling a target signal with a timing determined by the clock signal and for converting sampled values into digital data, a phase locked loop control circuit for generating control data with values representing values of the digital data, and a DA-conversion circuit having an adjustable conversion characteristic for converting the control data into an analog signal and for outputting the analog signal to the voltage controlled oscillator as the voltage control signal.

Abstract: A recording and reproducing apparatus is provided with a recording circuit to record information on a recording medium rotated and a reproducing circuit to reproduce the information from the recording medium rotated. In the mode of reproducing the information from the recording medium, the reproducing circuit retries reproduction if any error has occurred to the data reproduced. The reproducing circuit is provided with a characteristic changing circuit to change its reproduction characteristic. In the mode of reproducing information from the recording medium, the reproducing characteristic of the reproducing circuit is changed by the characteristic changing circuit if any error has occurred to the reproduced data. The reproducing circuit uses the changed reproducing characteristic to retry the reproduction.

Abstract: A recording and reproducing apparatus is provided with a recording circuit to record information on a recording medium rotated and a reproducing circuit to reproduce the information from the recording medium rotated. In the mode of reproducing the information from the recording medium, the reproducing circuit retries reproduction if any error has occurred to the data reproduced. The reproducing circuit is provided with a characteristic changing circuit to change its reproduction characteristic. In the mode of reproducing information from the recording medium, the reproducing characteristic of the reproducing circuit is changed by the characteristic changing circuit if any error has occurred to the reproduced data. The reproducing circuit uses the changed reproducing characteristic to retry the reproduction.

Abstract: A sheet feeding device comprising a plurality of pickup rollers for exerting a feeding force P (gf) on thin sheets which have ream weights K (kg) less than 55 kg and one or more friction rollers for offering resistance to the thin sheets fed by the pickup rollers. A distance L (mm), in a feeding direction, between the pickup rollers and the friction rollers is set in a range defined by the relationship ##EQU1## so as to enable a feeding of the thin sheets with no buckling.

Abstract: A phase locked loop IC comprising a voltage controlled oscillator which generates a clock signal in accordance with a control voltage, a first ECL input buffer which is an input buffer for a signal to be synchronized, a phase-lock capture circuit for producing a current determinative of the control voltage in accordance with the phase difference and the frequency difference between the signal to be synchronized and the clock signal, and a phase-lock follow-up circuit for producing a current determinative of the control voltage in accordance with the phase difference between the clock signal and the signal to be synchronized; wherein the supply voltage system of the first ECL input buffer is so disposed as to be isolated from any of the supply voltage systems of the voltage-controlled oscillator, the phase-lock capture circuit and the phase lock follow-up circuit, while the ground system of the first ECL input buffer is so disposed as to be insolated from any of the ground systems of the voltage-controlled osc

Abstract: A sheet feeding device comprising a plurality of pickup rollers for exerting a feeding force P (gf) on thin sheets which have ream weights K (kg) less than 55 kg and one or more friction rollers for offering resistance to the thin sheets fed by the pickup rollers. A distance L (mm), in a feeding direction, between the pickup rollers and the friction rollers is set in a range defined by the relationship: ##EQU1## so as to enables a feeding of the thin sheets with no buckling.

Abstract: An automatic sheet feeding device for feeding sheets of low rigidity and high coefficient of friction, such as documents of small thickness and thin sheets with carbon backing, including feeding rollers, separating rollers, a rotating mechanism for rotating the separating rollers, and a regulating mechanism for regulating a torque applied to the separating rollers. A torque tending to rotate the separating rollers in a direction in which the sheets are fed is applied thereto by the feeding rollers, and a torque tending to rotate the separating rollers in a direction opposite the direction in which the sheets are fed is applied thereto by the separating roller rotating mechanism through the regulating mechanism for regulating the torque applied to the separating rollers which is a friction clutch.

Abstract: In a thermal transfer recording system for use in a facsimile machine for a line-printer, a carrier such as a transfer film on which a heat transferable ink or any other record forming material is applied and a recording medium such as a recording paper are used. The carrier and the recording medium are wound in advance in a roll independently of each other. The carrier and the recording medium are brought into pressure contact with a thermal head in a recording section with the carrier and the recording medium overlapping one on another. Heat from the recording section causes the ink or any other record forming material on the carrier to be transferred onto the recording medium to thereby carry out the recording. The carrier and the recording medium may be conveyed in the normal direction or in the reverse direction.