Abstract: A microphone unit includes a substrate. The substrate includes a first face formed with a first recess, a second face opposite to the first face, and a through hole communicating the second face to a bottom part of the first recess. A diaphragm unit includes a diaphragm, and at least a part of which is disposed in the first recess so that the diaphragm opposes the through hole.

Abstract: A sound signal transmitter-receiver includes a differential microphone for receiving sounds respectively at first and second points to convert the receiving sounds into a transmission sound signal; a transmission-reception unit for receiving an incoming signal as a reception sound signal; an addition unit for adding the reception sound signal from the transmission-reception unit and the transmission sound signal to produce an addition signal; and a speaker outputting sound based on the addition signal.

Abstract: A microphone unit includes: a partition member, including a vibration film configured to be vibrated by sound; a housing, defining an inner space, and formed with a first opening and a second opening, the inner space being divided into a first space and a second space by the partition member, the first space adapted to be communicated with an outer space via the first opening, and the second space adapted to be communicated with the outer space via the second opening; and a shutter, configured to close one of the first and second openings; and an amplifier, configured to: amplify an electric signal at a first gain when the shutter closes the one of the first and second openings; and amplify the electric signal at a second gain that is larger than the first gain when first and second openings are opened.

Abstract: A sound input device includes a differential microphone, configured to receive sound including noise, and generate a first signal in accordance with the sound; a detector, configured to detect the noise, and generate a second signal in accordance with the detected noise; and a controller, configured to control at least one of suppression of high-frequency components of the first signal and changing of a frequency band to be suppressed of the first signal based on the second signal.

Abstract: A microphone system, includes: a housing, adapted to be placed in a reference position relative to a sound source; a first microphone, configured to receive sound from the sound source at a first position within the housing; a second microphone, configured to receive sound from the sound source at a second position within the housing; and a differential signal generator, wherein: the first and second positions are arranged on a first line; and the first line perpendicularly intersects a second line that is extended from the sound source at a third position which is not between the first and second positions, and obliquely intersects a third line that is extended from the sound source at a fourth position which is between the first and second positions, when the housing is placed at the reference position.

Abstract: A voice input-output device includes a voice input section and a voice output section. The voice input section includes a microphone unit, the microphone unit including a housing that has an inner space, a partition member that is provided in the housing and divides the inner space into a first space and a second space, the partition member being at least partially formed of a diaphragm, and an electrical signal output circuit that outputs an electrical signal that is the first voice signal based on vibrations of the diaphragm, a first through-hole through which the first space communicates with an outer space of the housing and a second through-hole through which the second space communicates with the outer space being formed in the housing. The voice output section includes: an ambient noise detection section that detects ambient noise during a call based on the first voice signal; and a volume control section that controls volume of the speaker based on a degree of the detected ambient noise.

Abstract: A microphone unit includes: a housing which has an inner space; a partition member which is provided in the housing and divides the inner space into a first space and a second space, the partition member being at least partially formed of a diaphragm; and an electrical signal output circuit which outputs an electrical signal based on vibrations of the diaphragm. In the housing, a first through-hole through which the first space communicates with an outer space of the housing and a second through-hole through which the second space communicates with the outer space are formed.

Abstract: In a light information recording apparatus, a hologram pattern diffracts a reference light such that the reference light which is emitted from an objective lens to a recording medium side, is superimposed on a information light which is emitted from the objective lens to the recording medium side in the vicinity of a light condensing point of the information light, and the reference light is condensed at a different point from the light condensing point of the information light. In a light information reproducing apparatus, the hologram pattern diffracts the reference light in a going path such that the reference light which is emitted from the objective lens in a returning path comes off a light path of the reference light in the going path.

Abstract: A feedback loop structure including an operational amplifier unit (1) for amplifying a reproduction signal of recorded information and a gain/offset control unit (6) for controlling an amplitude and an offset of an output of the operational amplifier unit (1) so that each of the amplitude and the offset becomes a predetermined value is adopted, and accurate information for an asymmetry amount is obtained by a binarization unit (7) for receiving the output of the operational amplifier unit (1) and performing binarization while adjusting a slice level by feedback control so that a duty ratio after the binarization substantially becomes a predetermined value. Based on the asymmetry amount information, a judgment level of a Viterbi decoding unit (15) is changed, thereby reducing a reproduction error rate.

Abstract: An optical disc system comprises a gain offset unit for giving a gain and an offset to an inputted reproduction signal, an A/D converter, a peak detector, a bottom detector, an amplitude detector for calculating a signal, an offset detector for calculating a signal offset, a dropout detector for detecting a dropout in the input signal, and a controller for performing gain control and offset control of the gain offset unit, the controller being able to hold the control operation or switch the control speed by a hold signal that is supplied from the outside, wherein a defect in a recording medium is detected to hold the gain control and offset control or change the control response speed, whereby the signal amplitude and offset at the input of the A/D converter are always kept constant.

Abstract: A feedback loop structure including an operational amplifier unit (1) for amplifying a reproduction signal of recorded information and a gain/offset control unit (6) for controlling an amplitude and an offset of an output of the operational amplifier unit (1) so that each of the amplitude and the offset becomes a predetermined value is adopted, and accurate information for an asymmetry amount is obtained by a binarization unit (7) for receiving the output of the operational amplifier unit (1) and performing binarization while adjusting a slice level by feedback control so that a duty ratio after the binarization substantially becomes a predetermined value. Based on the asymmetry amount information, a judgment level of a Viterbi decoding unit (15) is changed, thereby reducing a reproduction error rate.

Abstract: A wave-shaping apparatus includes a first detection circuit for detecting a reproduction signal reproduced from an optical disk by an optical pickup circuit using a first detection time constant to detect an upper envelope of the reproduction signal; a second detection circuit for detecting the reproduction signal using a second detection time constant to detect a lower envelope of the reproduction signal; an averaging circuit for putting a weight represented by a weighting coefficient to each of the upper envelope and the lower envelope to calculate an average value of each of the upper envelope and the lower envelope; and a subtraction circuit for subtracting a signal corresponding to the average value from the reproduction signal to output a wave-shaped signal.

Abstract: An optical disc system comprises a gain offset unit for giving a gain and an offset to an inputted reproduction signal, an A/D converter, a peak detector, a bottom detector, an amplitude detector for calculating a signal, an offset detector for calculating a signal offset, a dropout detector for detecting a dropout in the input signal, and a controller for performing gain control and offset control of the gain offset unit, said controller being able to hold the control operation or switch the control speed by a hold signal that is supplied from the outside, wherein a defect in a recording medium is detected to hold the gain control and offset control or change the control response speed, whereby the signal amplitude and offset at the input of the A/D converter are always kept constant.

Abstract: An optical information recording and playback apparatus for recording and playing back an optical information recording medium having a transparent protective layer comprises a tilt detection device and an off-track adding device, and includes means for determining an optimum direction in which the center of a light spot is to be displaced from the centerline of an information track on the optical information recording medium to compensate for the tilting of the optical information recording medium relative to the light beam, means for setting the amount of displacement as fixed values, and means for splitting the optical information recording medium into a number of areas and for activating a tilt detection function each time switching is made from one area to another during recording or playback.

Abstract: The present invention has an objective of providing a digital data reproduction apparatus and a method for correcting a reproduced signal digitization level in which the signal quality of a reproduced signal from a recording medium is kept high while ensuring the reproduction stability. The digital data reproduction apparatus includes: reproduced signal digitization means for digitizing a reproduced signal; synchronization means for producing a clock whose phase is synchronized with a leading edge and a trailing edge of the digitized signal produced by the reproduced signal digitization means; and jitter detection means for integrating and thereby converting absolute values of phase errors between the digitized signal and the clock to a voltage value. The apparatus further includes digitization level correction means for correcting a reproduced signal digitization level so as to minimize a signal produced by the jitter detection means.

Abstract: An optical information recording and playback apparatus for recording and playing back an optical information recording medium having a transparent protective layer comprises a tilt detection device and an off-track adding device, and includes means for determining an optimum direction in which the center of a light spot is to be displaced from the centerline of an information track on the optical information recording medium to compensate for the tilting of the optical information recording medium relative to the light beam, means for setting the amount of displacement as fixed values, and means for splitting the optical information recording medium into a number of areas and for activating a tilt detection function each time switching is made from one area to another during recording or playback.

Abstract: An optical disk drive for reading information recorded on a recording surface of an optical disk medium using an optical head to generate a read-out signal, comprises focus position control means for controlling a focal point of a light beam emitted from the optical head so that it is positioned on a focus position that is set as a position in the vicinity of the recording surface of the optical disk medium; equalizing means for performing waveform equalization using a set equalization quantity, to the read-out signal generated by the optical head, and outputting an equalization signal; jitter measuring means for measuring a jitter of the equalization signal output from the equalizing means; and optimum value searching means for searching for a focus position and an equalization quantity, at which the jitter is minimized. In this optical disk drive, for both the focus position and the equalization quantity, the jitter minimized point can be searched accurately.

Abstract: A phase error between an information signal including a reference signal that can be detected asynchronously and a synchronized signal that is synchronously produced from the information signal is detected, and a signal in response to an absolute value of the phase error is produced. Further, a defect detecting signal is produced in response to the absolute value of the phase error. Therefore, whether a pulse signal exceeding a maximum value of the pulse width of the information signal, that is, a pulse signal exceeding the pulse width of the reference signal, is detected or not, it is possible to detect that the signal reproduction enters a defect region immediately after the entry. Accordingly, a defect with noise or a track jumping can be detected rapidly.

Abstract: A reproduced signal is digitized so as to count a time interval of a specified pattern simultaneously with the count of a clock period of a phase lock loop circuit. A phase lock loop clock frequency is subjected to a feedback control based on the information indicated the difference between the time interval and the clock period. In this manner, a frequency loop performs a feedback operation so that a frequency of the reproduced signal falls within a capture range of a phase lock-in, thereby increasing the speed of phase lock-in.

Abstract: The optical disk reproducing apparatus of the invention includes: a waveform equalizing section for emphasizing a predetermined range of frequency band of a reproduced signal; a digitizing section for digitizing the reproduced signal which has been emphasized by the wave equalizing section at a predetermined level, so as to convert the emphasized reproduced signal into a digital signal; a period detecting section for detecting and outputting a period of a predetermined pattern included in the digital signal; a phase lock loop section having a free-run period, for controlling the free-run period based on the output of the period detecting section so that the free-run period becomes substantially equal to a period of a clock component of the digital signal, and for outputting a reproduced clock signal by reproducing the clock component of the digital signal; and a synchronizing section for synchronizing the digital signal with the reproduced clock signal so as to output a synchronized signal as reproduced data.