Abstract: In a camera having a power source shared between a charging circuit for a strobe emission and a camera function section other than the charging circuit, the charging operation is inhibited during an operation of the camera function section and a battery check is inhibited during the charging operation. As a result, a runaway of a CPU of the camera due to the voltage reduction of the power source in the charging operation is avoided; moreover, inhibition of a shooting operation due to the battery check is prevented, thereby efficiently utilizing the battery capacity.

Abstract: A magnetic head advancing apparatus which advances a magnetic head to be brought into contact with a magnetic recording medium (head loading) in response to a latch-type solenoid when a power supply switch is closed. The magnetic head is separated from the magnetic recording medium (head unloading) in response to a latch-type solenoid when the power supply switch is opened, when the power supply voltage drops below a predetermined level, or when the power supply (a battery) is ejected from the apparatus. This makes it possible to prevent local permanent deformation of a magnetic disk caused by prolonged abutting contact between the magnetic head and the magnetic disk.

Abstract: A recording/playback apparatus is provided with a plurality of controllers (inclusive of CPU's) which, by communicating with one another, share control of each of the components of the recording/playback apparatus or of the entire apparatus. Communication among the controllers is performed in the second half of one period of a signal related to the rotational reference phase of a rotating recording medium. This makes it possible for control requiring high precision to be performed in the first half of the aforementional period without being affected by high-priority interrupts which accompany communication control. Further, in order that the aforementioned communication may be carried out in the second half of the above mentioned period, message editing is performed in the first half of the same period. This enables prompt communication processing during the short time in the second half of the period without an unnecessary waste of time.

Abstract: A search range for detecting the peak position of an envelope on a rotating magnetic recording medium is limited to a predetermined range on either side of an absolute track position of each track on the recording medium. A limitation is also placed upon the number of times a magnetic head is fed within this predetermined range. If a peak cannot be decided even when the magnetic head is fed the limited number of times, the final position of the magnetic head is adopted compulsorily as the peak position. As a result it is possible to reduce the time needed for peak position detection processing. When an envelope cannot be detected with the predetermined range, the absolute track position is adopted as the peak position.

Abstract: The gain of an envelope detector circuit for detecting the envelope of a signal read from a magnetic head is capable of being changed over between two, namely high and low, stages. The gain of the envelope detector circuit is raised when track search processing is performed. When peak position detection processing is executed for detecting the peak position of the envelope of a recorded signal with regard to a designated track, first the gain of the envelope detector circuit is raised. The gain is lowered when the envelope saturates. This makes it comparatively easy to perform envelope detection, shortens the time required and makes it possible to use even a relatively low-precision A/D converter in the envelope detector circuit.

Abstract: In a system including a still video camera and a playback device capable of being connected thereto, the playback device stored track information (such as data representing the field/frame recording and the envelope peak position) detected in a playback operation in a memory thereof corresponding to a track number. When the power of the playback device or the like is turned off, the track information is transferred from the playback device to the camera side and is stored in a memory of the camera side. When the playback device achieves thereafter a playback operation, the track information is again transferred to the playback device so as to be used for the playback operation. The track information can also be used in an erase operation on the camera side or in the playback device. In addition, track information used in a recording operation of the camera is stored in a memory thereof corresponding to a track member.

Abstract: Positioning of a magnetic head for recording a signal on a magnetic recording medium is performed in accordance with an absolute track address system. However, due to mechanical errors, expansion or contraction of the magnetic recording medium caused by changes in temperature or humidity, or small variations between recording apparatuses, a deviation can occur between a position recorded on in the past and a absolute track position thereof. Accordingly, with regard to at least one track that has already been recorded on, the amount of deviation between the peak position of the envelope of a signal on this track and an absolute track position is measured. Then, based upon the measured amount of deviation, the position at which the magnetic head is stopped on the track to be recorded on next is corrected.

Abstract: In a still-video camera, a video signal representing the image of a photographed subject is written in a video floppy during one revolution of the floppy, namely during an interval between one phase pulse PG and the next. Immediately after the phase pulse PG is generated, a field-shift pulse FS for reading the video signal out of an electronic image pick-up device is outputted. Read-out from the electronic image pick-up device by the field-shift pulse FS is inhibited during the time that a shutter is open. Writing is carried out from the moment of the next phase pulse PG after read-inhibit is cancelled. If the inhibition on read-out from the electronic image pick-up device were to be cancelled between the phase pulse PG and the field-shift pulse FS, read-out of the video signal by the field-shift pulse FS would be carried out, but it would not be possible to carry out recording without waiting for the next phase pulse PG.

Abstract: In an electronic still-video camera capable of frame recording using a shutter, read-out is controlled in such a manner that dark currents generated in an imaging device will be equal in both first and second fields. Thereby, the recording of a still-video signal that will provide an excellent and easy-to-view reproduced image that is free of flicker is made possible.

Abstract: A camera having an ordinary automatic exposure function which automatically decides a proper shutter speed and f-stop based on the results of photometry is additionally provided with a slow-photography mode. When the camera is set to the slow-photography mode, a predetermined shutter speed and f-stop outside a range of shutter speeds and f-stops capable of being set by ordinary automatic exposure control is set. This makes it possible to photograph night scenes, fireworks displays and the like. Photography is possible even in a light-value region in which the camera shutter would be locked against release in ordinary automatic exposure control owing to too little light.

Abstract: A magnetic recording/reproducing device which has a track search function to discriminate a recorded track from an unrecorded track for all tracks formed in a magnetic disc. In the magnetic recording/reproducing device, in accordance with signals output from a magnetic head when the magnetic head is moved to positions lying at least adjacent to the central position of a track accessed, with a predetermined position on the magnetic disc designated as a reference position, it is determined whether each accessed track is a recorded track or an unrecorded track. Data representing the check results are stored in memory corresponding to the track numbers respectively given to the tracks. This assures an accurate track search.

Abstract: An apparatus for positioning a recording or playback head over a rotating recording medium, such as a magnetic disk. When access to a desired track is attempted, the head is quickly moved and placed within a range close to the track under open loop control. When the head enters the range close to the desired track, the head control is switched to servo feed under closed loop control. During the servo feed, the head is moved according to a head position signal representing the actual position of the head, the head position signal being given by a head position detector having a portion moving together with the head. The head is thus directed to a predetermined position according to an error signal corresponding to the deviation of the head position. When the head has passed through the desired position, driving force in the reverse direction is generated and the head is forced back toward the desired position. The head thus oscillates around the desired position but converges to it.

Abstract: A data signal is modulated by an exclusive-OR operation applied to a carrier signal and a data signal to be recorded. Demodulation is similarly performed by an exclusive-OR operation applied to the carrier signal and signal indicative of read data. This makes it possible to construct the modulating/demodulating circuit in the form of a digital circuit.

Abstract: A white balance adjusting device for use in a camera which photographs a field and forms a video signal representing the field. In the white balance adjusting device, while a sequential photographing is under way, updating of the color temperature data to be used for adjusting a white balance is prohibited. Therefore, the hues of main objects in the respective frames of still images photographed by the sequential photographic operation remain unchanged, thereby maintaining the homogeneity of the main objects. Also, in the white balance adjusting device, control a device is used to provide a short response time for a quick response property in a still mode and to provide a longer response time in a movie mode when compared with the still mode. As a result, the white balance can be adjusted according to the photographic modes of the camera.

Abstract: A device for tracking a rotary recording medium includes a playback head for reading a signal from any of a plurality of tracks which are formed on the rotary recording medium, which is rotating at a predetermined constant speed, such that a beginning and an end of a recording in each of the tracks coincide with each other, a head support mechanism supporting the head such that the head is movable along the recording medium, an arrangement for detecting an envelope of a signal which is read out of the recording medium by the head, and a controller for controlling the head support mechanism to move the head to a position where a desired one of the tracks is located. An arrangement for detecting a position of the head relative to the recording medium and an arrangement for detecting a rotation phase of the recording medium are provided.

Abstract: A still video camera includes a color temperature sensor for detecting the color temperature of ambient light which is used in the color balance adjustment of video signals outputted from an image pickup system. The camera further includes a strobe emission circuit which produces a signal indicating when strobe emission is capable of being performed. A control circuit controls the adjustment of the color balance of the video signals on the basis of the color temperature detected by the color sensor in the absence of a strobe ready signal. Upon the activation of a shutter release switch, the control unit determines whether or not a strobe ready signal is present. If a strobe ready signal is present, the control unit fixes the color temperature to a predetermined constant value for color balance adjustment.

Abstract: When a disc pack containing a magnetic disc is loaded in a still video camera, all tracks on the magnetic disc are searched to determine whether each track has been recorded on or is blank, and the results of the search are stored in memory. If a continuous picture-taking mode has been set, the magnetic head is fed forwardly from a home position and is positioned on a track next to the last track recorded on. Since all of the remaining tracks from the track at which the head has been positioned to the final track of the disc will be blank, feeding of the magnetic head during the continuous picture-taking operation is simplified. In other words, in the continuous picture-taking mode, it will suffice merely to feed the head one track at a time each time a still picture is taken.

Abstract: An apparatus for positioning a recording or playback head over a rotating recording medium, such as a magnetic disk. When access to a desired track is attempted, the head is quickly moved and placed within a range close to the track under open loop control. When the head enters the range close to the desired track, the head control is switched to servo feed under closed loop control. During the servo feed, the head is moved according to a head position signal representing the actual position of the head, the head position signal being given by a head position detector having a portion moving together with the head. The head is thus directed to a predetermined position according to an error signal corresponding to the deviation of the head position. When the head has passed through the desired position, driving force in the reverse direction is generated and the head is forced back toward the desired position. The head thus oscillates around the desired position but converges to it.

Abstract: A data signal is modulated by an exclusive-OR operation applied to a carrier signal and a data signal to be recorded. Demodulation is similarly performed by an exclusive-OR operation applied to the carrier signal and signal indicative of read data. This makes it possible to construct the modulating/demodulating circuit in the form of a digital circuit.

Abstract: A motor control apparatus includes a driving unit having a motor for rotating a body at a predetermined rotating speed; a reference position detecting unit for determining a reference position in a rotation of the body and for generating a phase signal representing the reference position; a phase controller for controlling the driving unit by use of the bias signal as a reference so that a generation of the phase signal causes the rotation of the body to be brought within a predetermined range with respect to a reference signal; and a bias control unit interconnected to the phase controller for determining a difference in phase of the phase signal from the reference signal to provide the phase controller with the bias signal according to the determined difference.