摘要:
Disclosed is an optical disk apparatus having a zero-cross signal generating unit for differentiating a reproduced signal read from an optical disk and outputting a zero-cross signal when the differentiated signal crosses the zero level, and a gate signal generating unit for generating a gate signal using the reproduced signal, wherein a data pulse is outputted when the zero-cross signal is generated while the gate signal is being produced. A clamping circuit clamps the peak of a reproduced signal from an optical disk, an amplitude comparator compares the amplitude of a clamped signal, which is outputted by the clamping circuit, with a reference voltage, and an AGC control unit controls the gain of a variable-gain amplifier by generating a control voltage signal in dependence upon an amplitude difference. The gate signal generating unit generates the gate signal upon comparing the clamped signal outputted by the clamping circuit with a prescribed signal level. A data-pulse output unit outputs the data pulse when the zero-cross signal of the differentiated reproduced signal is generated while the gate signal is being produced.
摘要:
The present invention relates to processes for producing α,β-unsaturated aldehyde compounds and unsaturated alcohols with a good yield. There is provided a process for producing and α,β-unsaturated aldehyde compound including the step of subjecting a raw aldehyde compound to an intermolecular condensation reaction in the presence of an amine and a protonic acid having 4 to 20 carbon atoms or a salt thereof; and a process for producing an unsaturated alcohol including the step of subjecting the α,β-unsaturated aldehyde compound to a reduction reaction.
摘要:
The present invention relates to processes for producing α,β-unsaturated aldehyde compounds and unsaturated alcohols with a good yield. There is provided a process for producing and α,β-unsaturated aldehyde compound including the step of subjecting a raw aldehyde compound to an intermolecular condensation reaction in the presence of an amine and a protonic acid having 4 to 20 carbon atoms or a salt thereof; and a process for producing an unsaturated alcohol including the step of subjecting the α,β-unsaturated aldehyde compound to a reduction reaction.
摘要:
A process for producing a 5-arylpentanol of formula (2): wherein R1 represents an aryl group which may be substituted with one or two or more of an alkyl or alkoxy group and has 6 to 12 carbon atoms in total, R3 represents a hydrogen atom, or an alkyl or alkenyl group of 1 to 6 carbon atoms, and R4 represents R2 defined below when R2 is a monovalent group or represents R2H when R2 is a divalent group, which comprises effecting hydrogenolysis of a pyran compound of formula (1): wherein, R1 and R3 are as defined above, R2 represents a hydrogen atom, an alkyl or alkenyl group of 1 to 6 carbon atoms, or an alkylidene or alkenylidene group of 1 to 6 carbon atoms, and a dotted line represents a possible bond and any one of the three bonds represented by dotted lines and solid lines is a double bond, in the presence of one or more catalysts selected from (a) a catalyst carrying two or more elements selected from noble metals in Group VIII in the periodic table and (b) an acid type palladium-supporting catalyst. 5-arylpentanols can be prepared in a high yield with low production of hydrocarbons without causing a problem with regard to corrosion of process equipment.
摘要:
This invention discloses a substance which is a betaine ester of a functional alcohol that has an amido bond in its molecule and releases the functional alcohol.
摘要:
There is provided an optical storage device that can position a lens carriage and objective lens even when position sensors for the lens carriage and objective lens are excluded in an effort to make an optical disk unit thinner. In the optical storage device, immediately after an optical disk is loaded in a main body, the cutoff frequency of a filter lying on a path of a reproduction signal is temporarily changed to a lower frequency. A spacing of sectors of the optical disk is detected using a signal sent from the filter. A type of an optical storage medium and a position of a current reproduction track are detected on the basis of the detected sector spacing and data stored in a memory.
摘要:
A positioning control system for performing recording/reproducing operations by irradiating an optical beam on a predetermined position on an optically recording medium includes a photo-detector constituted by at least two-divisional units and a servo-error signal generating circuit which can generate at least one servo-error signal in accordance with a difference between detection currents measured at the collectors of selected transistors in two pairs of transistors.
摘要:
The present invention relates to alcohol compounds having a scent of natural lily of the valley substantially without any woody scent limiting their applications to raw materials of perfume preparations, and a process for producing the alcohol compounds. The alcohol compounds are represented by the following general formula (I): wherein R1 is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms; and any one of dotted lines represents a double bond, and the remaining three dotted lines each represent a single bond.
摘要:
This invention discloses a substance which is a betaine ester of a functional alcohol that has an amido bond in its molecule and releases the functional alcohol.
摘要:
A frequency synthesizer generates, through setting of a frequency control value, a reference clock having a frequency necessary to read data from a medium. When reading data from an arbitrary position on the medium, a setting control unit sets in the frequency synthesizer a frequency control value corresponding to the zone position, thereby allowing the frequency synthesizer to control a reference clock frequency, and sets in a single or a plurality of processing units other than the frequency synthesizer a predetermined control value corresponding to the read position on the medium. A settling wait processing unit calculates a settling time T1 required for a frequency of the frequency synthesizer to become stable and a setting processing time T2 necessary for the setting control of the other processing unit, and defines as a wait time Tw a difference (T1-T2) between the settling time T1 and the setting processing time T2, during which wait time Tw a migration to the subsequent processing is kept waiting.