Abstract: When a plurality of storage batteries is used by connecting them in parallel, since the progress of degradation differs among the storage batteries, a power conversion system includes a degradation information acquisition device for acquiring the degradation information of the storage batteries, a temperature information acquisition device for detecting the temperature information of the storage batteries, and a control device for controlling the storage battery power converter based on the degradation information of the storage batteries by the degradation information acquisition device and the temperature information of the storage batteries by the temperature information acquisition device so that the degradation states of the plurality of the storage batteries can be matched.

Abstract: An apparatus and a method for efficiently converting, by means of mixdown, audio signals recorded in multiple tracks into stereo signals. A plurality of audio signals input from an input terminal are recorded into a plurality of tracks of a recording medium. A mixer reads the audio signals recorded in the multiple tracks, subjects the audio signals to mixdown according to a mixer parameter set by an operation section, and records the processed signals as audio signals in the recording medium without reproducing the processed signal in real time. A plurality of mixer parameters are set, and a user can select a desired mixer parameter.

Abstract: A multitrack recorder capable of setting one track or more to a monaural type or a stereo type has a storage unit that stores a history of track-type changing-and-setting operations and operations entailing erasure or changing of audio data stored on each track and that stores specifics of the track-type changing-and-setting operations and the audio data erased or changed along with performance of operations in association with each operation, and a change unit that changes audio data stored in each track, and a type of the track, to audio data that were stored in each track, and a type of the track, before performance of a specified operation.

Abstract: A media recording element having capabilities to facilitate recording media for subsequent playback. The recording element further including features associated with limiting operations of a hard drive or other similarly mechanical memory under certain operating conditions so as to limit power consumption and/or memory degradation.

Abstract: Provided is an optical recording medium, including a recording target track that is a track on which small record carriers are arranged and on which information recording is performed by modulating the small record carriers through light irradiation; and a wobbling track on which the small record carriers are arranged in a wobbling manner, wherein a single wobbling track is formed to run parallel to a set of a plurality of recording target tracks.

Abstract: An optical disc apparatus comprising an optical disc drive for recording on and/or playing back an optical disc; a storage part for storing information; and a save control part for accumulating and saving error information in the storage part, the error information including information that indicates specific error contents in a case in which an error has been generated in the optical disc drive.

Abstract: An information reproduction device sets, from among a plurality of estimated rotation speeds previously estimated, a set rotation speed in accordance with request-specification information specifying a piece of data requested by an external device and a specified rotation speed specified by the external device for a disc-shaped storage medium storing data, rotates the storage medium at the set rotation speed, reads out data from the storage medium at a readout speed that is determined by the set rotation speed of the storage medium, stores the data in a data storage section, and supplies, from among the stored data, the piece of data corresponding to the request-specification information to the external device.

Abstract: Example embodiments provide various techniques for playing data from an optical media drive. The optical media drive may detect certain media access information for use in accessing optical media. This media access information is stored a non-volatile memory. The optical media drive then retrieves the media access information from the non-volatile memory once the optical media drive is reactivated after deactivation. The optical media drive may then read from the optical media using the provided media access information.

Abstract: Method and apparatus for adaptive arrangement of data on storage media, such as in a multi-device storage array across which data are stored. A virtual hot space is formed to store frequently accessed data. The virtual hot space comprises at least one hot data zone which extends across storage media of a plurality of arrayed storage devices over a selected seek range less than an overall radial width of the media. The frequently accessed data are stored to the hot data zone(s) in response to a host level request, such as from a host level operating system (OS) or by a user which identifies the data as frequently accessed data. Alternatively or additionally, access statistics are accumulated and frequently accessed data are migrated to the hot data zone(s) in relation thereto. Lower accessed data sets are further preferably migrated from the hot data zone(s) to another location of the media.

Abstract: The present invention enables a comprehensive evaluation from both of data read from a disk and a servo signal of a servo controller. The present invention provides a semiconductor integrated circuit mountable to a disk recording and reproducing drive, which comprises a signal processor of an RF signal read from a pickup, a servo controller responsive to a servo error signal read from the pickup, a memory controller, and an external interface. The memory controller is supplied with read data and a servo signal and stores the read data and the servo signal in a buffer memory according to a time division process. The read data and the servo signal stored in the buffer memory can be transferred to an external device via the external interface by the memory controller.

Abstract: Provided is an orbiting memory capable of suppressing residual deviation even when a phase difference is caused between a signal to be compensated and information stored in a memory to be fed back and a disc device using the orbiting memory. The disc device includes: an adder to which a signal (s10) to be compensated and having a cyclic frequency component such as a control system error signal is inputted; and a feed back signal system for successively updating and storing an output signal of the adder for each cycle in a memory and inputting one-cycle information stored in the memory to the adder.

Abstract: The present invention provides a recording medium and a recording/reproducing apparatus which enable the number of data units of recording pulse information to be reduced by dividing the recording pulse information into 1 byte-parameter information and differences from a value thereof, and the recording pulse information to be recorded on an existing DI area.

Abstract: A buffer control system for generating a buffered signal having reduced buffer delay time between playback of tracks includes a controller module for providing an end target and for selection of a servo data signal corresponding to a desired track; a compare circuit coupled to the servo data signal for comparing a timestamp of the servo data signal to the end target, and asserting an end match signal when the timestamp of the servo data signal matches the end target; and a data buffering unit for storing the servo data signal as stored data to fill a capacity of an internal memory, and streaming out the buffered signal from the stored data in the internal memory when the capacity has reached a predetermined level; wherein the controller module is for updating selection of the servo data signal according to a next desired track upon assertion of the end match signal.

Abstract: A turntable having multiple-point touch function for a digital sound-signal device includes a base formed with a central insert hole having a lower side provided with a load sensor, with a photo-sensor installed at one inner end of the base. A multiple-point touch-induction circuit is fixed on the base, having different sensing regions and bored with a central through hole. A touch-control turntable assembled on the circuit board has a central post protruding downward to be inserted through both the through hole and the insert hole for combining the base, the circuit board and the turntable together, the combining post having its lower end touching the load sensor. The turntable has its outer end edge provided with lots of light-obstructing plates protruding downward for obstructing light with the photo-sensor. The touch-control turntable is preset with plural memory regions to be touched for outputting different sound effects.

Abstract: When receiving the reproduced data from the optical disc and buffering same, the buffering from the correct position can be started on the basis of the synchronous signal and the address information included in the sub data which was received simultaneously. There is provided a method for controlling the buffering of the main data which is reproduced from the optical disc, in which the main data and the sub data are received with taking word clocks which are partitioning timings having plural bits of the main data as a unit as references, a synchronous signal which is in synchronization with the main data is generated, and the buffering of the main data is started on the basis of the synchronous signal.

Abstract: An object of this invention is to measure the tilt quantity of, and perform a tilt control on, an optical disc accurately without depending on the rotation control method. An optical disc drive includes: a motor for rotating an optical disc; an optical system for irradiating the optical disc with a light beam; a moving mechanism for moving the optical system along the radius of the optical disc; a focus control section for controlling movement of the optical system perpendicularly to the optical disc based on drive values, thereby focusing the light beam onto a storage layer of the optical disc; and a tilt control section for measuring the tilt quantities of the storage layer at multiple different radial locations on the optical disc based on drive values for the respective radial locations when the focus control section focuses the light beam there.

Abstract: A method and apparatus for determining an optimal writing power for recording data on a recording medium such as an optical disk, are discussed. The method according to an aspect of the present invention includes (a) performing a plurality of OPC operations on a plurality of areas of the recording medium, the plurality of OPC operations being performed in mutually different manners, the plurality of areas being areas within a power calibration area (PCA) allocated in the recording medium; and (b) determining an optimal writing power for recording data on the recording medium based on writing powers detected via the plurality of OPC operations.

Abstract: An information recording apparatus such as an optical disc that can avoid an unrecordable condition between a power-on operation and an available state for recording thereby to solve a problem that an image taking chance is missed in a recording step, wherein its constitution is such that: receiving a command to turn on the apparatus after switching, a system controller drives a power-supply circuit to activate a drive controller and a memory controller; if the optical disc is not replaced while in power-off operation by a sub-battery, the system controller issues a request for high-speed activation, based on information stored in an EEPROM, to the drive controller, and drives plural drive control units one after another thereby to establish an activation period confirmedly, allowing the memory controller to accept a request for a recording start from the system controller without waiting for a report of activation completion to be issued by the drive controller.

Abstract: An apparatus and method for recording data on an optical disc, are discussed. In an embodiment of the present invention, when recording of real-time input data in a high quality mode is requested, an Optimum Power Control (OPC) operation for recording is performed while input data is encoded in a quality mode, which is downwardly adjusted, for example, to a standard quality mode, and is then buffered in a buffer memory. After the OPC operation has been completed, the buffered data is recorded on the optical disc while the data is encoded in the requested high quality mode and is then buffered. Further, the input data is encoded in the requested high quality mode, but may be buffered in a hard disc, rather than the buffer memory, during the performance of the OPC operation.

Abstract: A device for recording records blocks of information on logical addresses on a record carrier at corresponding physical addresses. The logical addresses are translated into the physical addresses in dependence on defect management information that includes defect information on a defective status of physical addresses and remapping information on translating a logical address initially mapped to an initial physical address to an alternate physical address. The device has a real-time storage unit for writing real-time information blocks (77) to respective initial physical addresses irrespective of the defective status. When recording at a defective status location (76), the real-time information block is temporarily stored in a memory (80). In a separate period, when the writing of real-time information blocks is suspended, said temporarily stored real-time information blocks are additionally written to alternate physical addresses (81).

Abstract: A recording method, particularly suitable for use in a digital video-camera, is described according to which a digital signal (10), deriving from the encoding of an audio-video signal is temporarily stored in a buffer (11) and from there recorded in a dual layer DVD (12) in successive recording intervals (22) or packets. The start/stop of a recording interval is normally controlled according to the level (15) of filling of the buffer. The digital signal is partitioned in portions that need to be entirely recorded on one single layer, and this triggers the need for a layer jump independently from the level of filling of the buffer. In order to avoid starting a layer jump with the buffer already partly filled, and therefore having a short non-recording interval (23) when time is mostly needed for calibrations, it is proposed to adjust the resolution in the encoding of the audio-video signal so as to have the buffer close to empty when the layer jump occurs.

Abstract: A reproduction data recording method for an optical storage medium. The method comprises storing additional data to a first temporary region of a memory device; reading the first recorded data from the optical storage medium and storing the first recorded data to the first temporary region; reading a data segment of the second recorded data from the optical storage medium and storing the data segment to a second temporary region of the memory device; reading the first recorded data from the first temporary region and the data segment from the second temporary region, and decoding the first recorded data and the data segment to confirm accuracy of the first recorded data; reading the first recorded data and the additional data from the first temporary region, and encoding the first recorded data and the additional data to generate encoded data; and writing the encoded data to the optical storage medium.

Abstract: The present techniques provide systems and methods for decoding a data signal with a control bit to improve bit estimation. The techniques in one embodiment involve using decoding algorithms to estimate the a posteriori state probabilities and the a posteriori transition probabilities of the data encoding, and estimating bit state probabilities. The techniques further involve using a control bit in the bit stream and comparing the estimation of the control bit state in the segment of the bit stream with a test control bit determined based on an average of bit states from the encoded segment of the bit stream. If the estimation of the control bit and the test control bit are not equal, the state of the bit estimate with the lowest confidence probability will be changed.

Abstract: A semiconductor storage device including a memory cell and having a function of refreshing the memory cell, includes a clock generation circuit configured to receive a first clock, generate a second clock based on an inversion of the first clock, and output the second clock. The semiconductor storage device performs operation of the refresh function in synchronization with at least one of the first and second clocks.

Abstract: According to one embodiment, an information processing apparatus, has a reading unit which, if a transfer delay address is found, stores data in the transfer delay address, in a memory, and stores data in a range from the transfer delay address to an additional address located at an outer periphery in a certain distance and which, if the address to be read on the optical disc is present in the transfer delay address, reads data corresponding to the address to be read as stored in the memory, and a control unit which, if the address to be read on the optical disc is present in the additional address, reads the data corresponding to the address to be read as stored in the memory, by the reading unit, and increases a rotation rate of the optical disc up to a predetermined number of revolutions.

Abstract: An optical storage medium playback apparatus includes an optical storage access device, a connection port, and a controller. The optical storage access device is implemented for reading a multimedia content from an optical storage medium. The controller is coupled to the optical storage access device and the connection port, and is implemented for storing a portion of the multimedia content read from the optical storage medium into an external storage via the connection port when the external storage is electrically connected to the connection port, and for accessing the portion of the multimedia content which is stored in the external storage electrically connected to the connection port and performing a playback operation upon data read from the optical storage medium concurrently.

Abstract: A recording apparatus includes a write unit to write information data read from a memory by irradiating a disk medium with a beam in accordance with the information data, and a control unit to, upon the amount of information data stored in the memory reaching a threshold, instruct the write unit to start writing of the information data. In response to the write instruction, the write unit reads the information data stored in the memory and writes the read information data onto the disk medium while it is rotating. Upon the amount of information data in the memory decreasing to a predetermined value, the write unit stops reading and writing of the information data from the memory and onto the disk medium. The control unit sets a value of the threshold in accordance with the number of times the write unit has performed writing of the information data.

Abstract: A method and apparatus for determining an optimal writing power for recording data on a recording medium such as an optical disk, are discussed. The method according to an aspect of the present invention includes (a) performing an optimal power calibration (OPC) operation on a first area of the recording medium, and detecting a first writing power based on the OPC operation performed on the first area; (b) performing an OPC operation on a second area of the recording medium after erasing data on the second area, and detecting a second writing power based on the OPC operation performed on the second area; and (c) determining an optimal writing power for recording data on the recording medium based on the detected first and second writing powers.

Abstract: A CD-Audio System includes a CD-module and a host unit. The CD-module reads audio data from a disc, checks the audio data for errors, and provides the checked audio data to the host unit at greater than 1 times CD audio rate. The host unit stores the received audio data in an electronic shock protection memory included in the host unit. When the CD-module determines an error in the audio data, the CD-module notifies the host unit of the position in the audio data of the error and when notified of a position in the audio data of an error, the host unit replaces stored audio data at that position and all subsequently already received data with retransmitted audio data. Then the host outputs only validated audio data via speakers.

Abstract: A record and reproduction apparatus includes: a CPU; a memory; a recording medium control unit configured to read out data from a recording medium; a reproduction buffer configured to temporarily store stream data such as an image and an audio out of the data read by the recording medium control unit; a reproduction processing unit configured to decode and reproduce the stream data temporarily stored in the reproduction buffer; and an access control unit configured to control the timing by which the access control unit switches between access to the memory and access to the reproduction buffer so that the reproduction processing does not break off during reproduction of the stream data while supervising the state of the reproduction buffer, and to manage the memory and the recording medium control unit in each transaction.

Abstract: The writing in of the reproduced data from the optical disc 101 or the reproduced data from the external USB device 103 into the memory 106 is carried out in such a manner that the data storage formats on the memory 106 of the both writing in are the same storage formats with each other, and the writing in control into the memory 106 and reading out control from the memory 106 are carried out by the similar methods with each other. Thereby, in a data reproduction method having a function of reproducing data which is recorded in the optical disc 101 and a function of reproducing data from an external USB device, a reproduction device which provides no complicated control method as well as gives no large load to the system and is of a high efficiency can be provided.

Abstract: A pickup control device includes a servo system which processes a first signal for error control read from an optical disk to generate a servo control signal. A clock signal is synchronized with the rotation of the optical disk. Two memories store a frequency component at or lower than a predetermined frequency contained in the first signal and a rotational frequency component contained in the first signal. A first adder adds data from the first memory to the first signal and a second adder, in synchronization with the clock signal, data from the memories to generate a second signal. A correction unit writes into the second memory the frequency component or the rotational frequency component and reads data and supplies data to the first adder, and reads and updates data stored in the first memory.

Abstract: An information recording medium includes a lead-in area and a data area for storing contents information. The lead-in area includes a first lead-in information area and a second lead-in information area. The first lead-in information area corresponds to a first playback mode. The second lead-in information area corresponds to a second playback mode different from the first playback mode. The first lead-in information area has a first depth and is designed for storing lead-in information related to the contents information stored in the data area. The second lead-in information area includes pre-pits having a second depth greater than the first depth. The pre-pits represent predetermined information, such as information of copyright protection, related to the contents information stored in the data area.

Abstract: A data processing apparatus for outputting a plurality of picture data forming reproduced data to a reproduction apparatus for reproduction, the data processing apparatus having a processing circuit for judging if the reproduction rate of the picture data by the reproduction apparatus is slower than a transfer rate for transferring the picture data to the reproduction apparatus and outputting all of the picture data forming the reproduced data to the reproduction apparatus when judging as a result of the judgment that the reproduction rate is slower than the transfer rate.

Abstract: A coder codes an information signal. A rate controller controls a coding rate of the coder in accordance with complexity of the information signal. The rate controller controls a coding amount per unit time in the coding process so that an average value of the coding amount can be approximate to an average rate. The coded data is temporarily memorized in a temporary memory unit and processed by an information processing unit such as a recorder and a transmitter. The information processing unit measures an information processing rate in processing the information. The rate controller adjusts the average rate so that the average rate is lower than the information processing rate measured by the information processing unit, or the rate controller compares a threshold value of a used amount of the temporary memory unit which is previously set and an actually used amount of the temporary memory unit and reduces the average rate when the used amount exceeds the threshold value.

Abstract: The present invention relates to a reproducing apparatus which, in a case where a burst error has occurred, corrects an error preceding a synchronization pattern detected thereafter to have less errors. A bit slip judging section 81 in a bit slip correcting section 53 calculates a bit slip correction amount and a bit slip correction position on the basis of phase error signals detected by a phase error detecting section 51, synchronization pattern signals detected by a synchronization detecting section 52, reproduced clocks and detected data. A FIFO control section 82 controls a FIFO buffer 83 on the basis of the bit slip correction amount and the bit slip correction position, to perform bit slip correction. As a result, in the case where a burst error has occurred, an error preceding a synchronization pattern detected thereafter is corrected, whereby an error reduction can be implemented. The present invention is applicable to a reproducing apparatus.

Abstract: A reading unit for reading data from a digital data carrier, the reading unit comprising: a reading head including a sensor for sensing data from the data carrier and generating a sensor signal indicative for the sensed data; head positioning apparatus for positioning the head relative to the data carrier in response to a head positioning control signal; a head positioning controller for receiving the sensed data and being operable in accordance with a stored instruction set to process the sensed data to generate the head positioning control signal; and a data decoder for decoding the sensed data to form a digital output signal.

Abstract: In an information recording method, information is recorded to semiconductor memory when at least a specified amount of free space exists in the semiconductor memory. Information is recorded to magnetic memory when the free space in the semiconductor memory is insufficient but at least a specified amount of free space exists in the magnetic memory. Information is recorded to optical memory when the free space in both the semiconductor memory and the magnetic memory is insufficient. When retrieving recorded information, an access count is incremented, and information with a comparatively high access count is moved to the semiconductor memory, while information with a comparatively low access count is moved to the optical memory. Information is thus recorded to a recording medium suitably selected from among semiconductor memory, magnetic memory, and optical memory, thereby making effective use of each memory type.

Abstract: A reproduction data recording method for an optical storage medium. The method comprises storing additional data to a first temporary region of a memory device; reading the first recorded data from the optical storage medium and storing the first recorded data to the first temporary region; reading a data segment of the second recorded data from the optical storage medium and storing the data segment to a second temporary region of the memory device; reading the first recorded data from the first temporary region and the data segment from the second temporary region, and decoding the first recorded data and the data segment to confirm accuracy of the first recorded data; reading the first recorded data and the additional data from the first temporary region, and encoding the first recorded data and the additional data to generate encoded data; and writing the encoded data to the optical storage medium.

Abstract: A hybrid recording device having a non-volatile semiconductor memory and a recording magnetic disk includes a mapping unit that maps a first recording area in the recording magnetic disk and a second recording area in the non-volatile semiconductor memory, and a controller that controls an access to the second recording area mapped by the mapping unit when there is an access instruction to the first recording area.

Abstract: A hard disk recorder 1 is capable of performing fast-forward reproductions at 120× speed, 60× speed and 30× speed, and reproduces video images and audio sounds in a series of periodic reproduction zones in a video and audio file, each reproduction zone being for a predetermined reference time interval (e.g. 1 second), while skipping video images and audio sounds in other than the reproduction zones according to a ratio of the fast-forward speed to the predetermined reference time interval (skipping for 119 seconds at the 120× speed, 59 seconds at the 60× speed, and 29 seconds at the 30× speed, respectively). Each of the series of reproduction zones for the 120× speed, the series of reproduction zones for the 60× speed, and the series of reproduction zones for the 30× speed, each reproduction zone of which is for the reference time interval, is so set as to be free from overlap with the other series of reproduction zones.

Abstract: A method for decoding encoded data around a specific area on an optical storage medium, wherein the specific area has discontinued data. The method includes: detecting at least one type of sync patterns within the encoded data; determining an offset value corresponding to the specific area according to the detected sync patterns; and decoding the encoded data according to the offset value for generating decoded data.

Abstract: In an optical disk apparatus, when the write-in process to the optical disk is interrupted, a data processing part and an encoder part are set to be in the waiting state after an access to a data storing part is completed, so as to stop accessing the data storing part and also to stop storing data that is to be written. Thus, the interleave can be managed and the DSV calculation can be properly conducted without any irregular calculation. Even in a case in which the write-in process to the optical disk is restarted after temporarily interrupted, it is possible to read data similar to a case in which data to be written is successively written without an interruption.

Abstract: An optical disk reproducing apparatus configured to reproduce an optical disk of a hybrid type having CD and HD layers, including a system controller. Preferably, the system controller includes a disk discriminating unit which discriminates a loaded optical disk, an access list acquisition unit which obtains first access list information, a reproduction information setting unit which sets reproduction information when a reproduction area change request is issued, a reproduction request determining unit which determines whether or not a reproduction request is issued after the reproduction information is set, an access list request unit which requests second access list information when the reproduction request is issued, and a reproduction control unit which obtains the second access list information, when the second access list information is required, replaces the first access list information by the second access list information, and starts reproduction.

Abstract: A recording method for an optical disk drive is implemented as follows. First, at least one of the level of the focusing error signal, the level of the tracking error signal, a wobble synchronization pattern loss, the error rate of demodulating a wobble signal and the frequency of buffer under-run occurrence is detected. If at least one detected value exceeds the preset value, the recording will be ceased. Then, the rotation speed of the optical disk drive is decreased, and the recording is resumed with the decreased rotation speed.

Abstract: According to one embodiment, an information recording device comprises, when writing asynchronous data not recorded in a disk-like recording medium among data recorded in a non-volatile memory by a control module, a setting module is configured to place priority order of writing the asynchronous data to the disk-like recording medium in response to a state of each recording area with the asynchronous data of the non-volatile memory recorded therein.

Abstract: A disk apparatus includes: a kind discrimination unit for discriminating the kind of a loaded disk; a designation unit by which the user designates the prior order for discriminating the kind of the disk; and a frequency of use of storage unit for counting and storing a frequency of use of each kind of disks used in the past, wherein the kind discriminating unit is adapted to discriminate when the frequency of use of each kind of disk stored in the frequency of use storage unit exceeds a preset reference level indicating the predetermined tendency of use the kind of the disk in accordance with a priority order according to the tendency of use thereof, and discriminate when the tendency of use is not higher than the mentioned reference level the kind of the disk in the priority order designated by the designation unit.

Abstract: An information storage apparatus records, reproduces and/or erases information with respect to a recording medium. The apparatus includes a servo error generation detector for detecting a generation of a servo error based on at least one of servo signals including a focus error signal and a tracking error signal which are derived from output signals of a light receiving element, and a data recording resuming section for temporarily interrupting a data recording with respect to the recording medium, temporarily turning OFF a servo and then turning ON the servo again, to thereafter synchronize recording data to recorded data already recorded on the recording medium, and resume recording of the recording data continuing without a discontinuity to an end of the recorded data recorded immediately before the interruption of the data recording, when the generation of the servo error is detected while recording data on the recording medium.

Abstract: An optical disk in which data is interleaved and recorded in physically discontinuous interleaved units and a size of the interleaved unit is not less than a product of a maximum value of a jumping interval and a minimum value of the reproduction rate Vo of the data.

Abstract: A rotation control apparatus which can maintain an accurate rotating state even in a high density optical disk (DVD) having a structure such that parts of the sync signal are recorded at an interval different from that of the other sync signal parts. The apparatus has: a unit period signal generator for generating a period signal of a unit period; a pre-pit detector for detecting a pre-pit from the DVD; a phase difference detector for detecting a phase difference between the detection timing of the pre-pit and the unit period signal; and a holding circuit for holding the phase difference detected. The rotation of the DVD is controlled on the basis of the phase difference held at the holding circuit.