Abstract: A method of determining calibration test patterns to be utilized to calibrate a model for simulating the imaging performance of an optical imaging system. The method includes the steps of defining a model equation representing the imaging performance of the optical imaging system; transforming the model equation into a plurality of discrete functions; identifying a calibration pattern for each of the plurality of discrete functions, where each calibration pattern corresponding to one of the plurality of discrete functions being operative for manipulating the one of the plurality of discrete functions during a calibration process; and storing the calibration test patterns identified as corresponding to the plurality of discrete functions. The calibration test patterns are then utilized to calibrate the model for simulating the imaging performance of an optical imaging system.

Abstract: An inspection method for an image reading apparatus where image information of an original is imaged on light receiving element lines arranged in a main scanning direction to read the information on different colors. The method includes: acquiring a first color misregistration from image information based on a first striped pattern located at a position optically equivalent to a surface of the original with respect to the light receiving element lines, the first pattern having white and black lines aligned, and having longitudinal directions of the white and black lines aligned in a sub-scanning direction; acquiring a second color misregistration from image information based on a second striped pattern having white and black lines aligned, and having longitudinal directions of the white and black lines aligned at an angle from the main scanning direction; and calculating a color misregistration in the sub-scanning direction based on the measured color misregistrations.

Abstract: An image forming apparatus includes an automatic acquiring unit which forms a mark for detecting at least one of positional deviation and density deviation and acquire a degree of deviation by measuring the mark, a manual acquiring unit which receives a user input to acquire a correction value; an image forming unit which forms an image based on an actual correction value determined by an automatic correction value specified based on the degree of deviation and a manual correction value which is the correction value acquired by the manual acquiring unit, and a changing unit which executes at least one of a first changing process of applying a weight to at least one of the automatic correction value and the manual correction value and the second changing process of changing at least one of the automatic correction value and the manual correction value into a past correction value.

Abstract: The method of storing profile set storage method according to the present invention comprising (a) selecting as reconstruction data that enables to reconstruct a profile set, either size prioritized data, which is smaller than said profile set, or reconstruction speed prioritized data, which enables to be reconstructed within a shorter time period than is required for reconstructing the size prioritized data, and which is smaller than the profile set but is larger than the size prioritized data; (b) for generating the selected reconstruction data based on the profile set; and (c) storing the reconstruction data generated in the step (b) in a storage device.

Abstract: An optical reflection element includes a frame, a meandrous vibrating part having an outer end connected with an inside of the frame, and a mirror part supported by an inner end of the meandrous vibrating part. The meandrous vibrating part has a meandrous shape that includes curved portions and vibrating beams alternately connected with the curved portions. A curvature of respective one of the curved portions is smaller than a curvature of at least one of the curved portions which is located closer to the inner end than the respective one of the curved portions. This optical reflection element has a large deflection angle of the mirror part.

Abstract: An actuator includes a movable section swinging around a predetermined swing axis, a connecting section extending from the movable section, and being torsionally deformed in accordance with swing of the movable section, a support section supporting the connecting section, a magnet being disposed on a plate surface of the movable section, and a coil generating a magnetic field acting on the magnet to thereby swing the movable section, and the movable section has a cross shape in a plan view.

Abstract: A micromechanical component having a displaceable part connected to a residual substrate by at least one spring, and including first and second subunits, between which an insulating intermediate layer and at least one semiconductor boundary layer is formed; an inner region of the first subunit, which inner region is aligned with the second subunit, being patterned out of a substrate using at least one cavity etched in a first etching direction; an outer region of the first subunit of the displaceable part, which outer region faces away from the second subunit, being patterned out of the substrate using at least one hollowed-out section etched in a second etching direction; the second subunit being patterned out of a semiconductor layer deposited onto the insulating intermediate layer and/or on the at least one semiconductor boundary layer using at least one continuous separating trench. Also described is a related manufacturing method.

Abstract: A scalable apparatus and a network environment dynamically changes the light transparency of a single SPD device, a small number of SPD devices or thousands of such SPD devices installed in windows in automobiles, aircraft, trains, marine vehicles, residential homes, commercial buildings and skyscrapers. A scalable apparatus and a network environment dynamically changes the light transparency of a single SPD device or thousands of such SPD devices in the presentation of a multi-media special effects display. Textual messages, graphical images and simulated motion effects are driven. Such scalable apparatus being capable of driving and using several operational parameters of SPD's such as frequency range, AC voltage and temperature so as to provide fine control of SPD characteristics such as switching speed and power consumption.

Abstract: In some example embodiments, a demodulator may include an input polarization beam splitter (IPBS), input half waveplate (IHWP), cubical polarization beam splitter (CPBS), first reflector (R1), second reflector (R2), first quarter waveplate (QWP1), second quarter waveplate (QWP2), beam displacer (BD), output half waveplate (OHWP), and output polarization beam splitter (OPBS). The CPBS may be positioned to receive an output from IPBS. The IHWP may be positioned between IPBS and CPBS. The R1 may be positioned to receive and return a first output from CPBS. The QWP1 may be positioned between CPBS and R1. The R2 may be positioned to receive and return a second output from CPBS. The QWP2 may be positioned between CPBS and R2. The BD may be positioned to receive a third output from CPBS. The OPBS may be positioned to receive an output from BD. The OHWP may be positioned between BD and OPBS.

Abstract: An illumination system is disclosed for providing dual-excitation wavelength illumination for non-linear optical microscopy and micro-spectroscopy. The illumination system includes a laser system, an optical splitting means, a frequency shifting system, and a picosecond amplifier system. The laser system includes a laser for providing a first train of pulses at a center optical frequency ?1. The optical splitting means divides the first train of pulses at the center optical frequency ?1 into two trains of pulses. The frequency shifting system shifts the optical frequency of one of the two trains of pulses to provide a frequency shifted train of pulses. The picosecond amplifier system amplifies the frequency shifted train of pulses to provide an amplified frequency-shifted train of pulses having a pulse duration of at least 0.5 picoseconds.

Abstract: In a light amplification system, a fiber-based oscillator, amplifier, and cascaded Raman resonator are coupled together in series. The oscillator output is provided as an input into the amplifier, the amplifier output is provided as a pumping input into the cascaded Raman resonator, and the cascaded Raman resonator provides as an output single-mode radiation at a target wavelength. A loss element is connected between the oscillator and amplifier, whereby the oscillator is optically isolated from the amplifier and cascaded Raman resonator. A filter is coupled between the isolator and the amplifier for filtering out backward-propagating Stokes wavelengths generated in the cascaded Raman resonator. The oscillator is operable within a first power level range, and the amplifier and cascaded Raman resonator are operable within a second power level range exceeding the first power level range.

Abstract: Methods and systems for generating femtosecond fiber laser pulses are disclose, including generating a signal laser pulse from a seed laser oscillator; using a first amplifier stage comprising an input and an output, wherein the signal laser pulse is coupled into the input of the first stage amplifier and the output of the first amplifier stage emits an amplified and stretched signal laser pulse; using an amplifier chain comprising an input and an output, wherein the amplified and stretched signal laser pulse from the output of the first amplifier stage is coupled into the input of the amplifier chain and the output of the amplifier chain emits a further amplified, stretched signal laser pulse. Other embodiments are described and claimed.

Abstract: A device for use in optical signal control is presented. The device comprises an amplification waveguide, including a pumpable medium, and a reference and a control inputs and an output selectively allowing transmission of light respectively into and out of said amplification waveguide. The reference input, the amplification waveguide and the output define together a transmission scheme for reference light through the pumpable medium. The control input and the amplification waveguide define a depletion scheme for the pumpable medium and control light. The device thus allows for controlling an output signal, formed by the transmission of the reference light, by controllable depletion of the pumpable medium.

Abstract: Provided is a light-emitting device including (a) a layer structure obtained by sequentially growing on a base substrate a first compound semiconductor layer of a first conductivity type, (b) an active layer formed of a compound semiconductor, and (c) a second compound semiconductor layer of a second conductivity type; a second electrode formed on the second compound semiconductor layer; and a first electrode electrically connected to the first compound semiconductor layer. The layer structure formed of at least a part of the second compound semiconductor layer in a thickness direction of the second compound semiconductor layer. The first compound semiconductor layer has a thickness greater than 0.6 ?m. A high-refractive index layer formed of a compound semiconductor material having a refractive index higher than a refractive index of a compound semiconductor material of the first compound semiconductor layer is formed in the first compound semiconductor layer.

Abstract: An optical polarizer positioned before a light source for use in semiconductor wafer lithography including an array of aligned nanotubes. The array of aligned nanotubes cause light emitted from the light source and incident on the array of aligned nanotubes to be converted into polarized light for use in the semiconductor wafer lithography. The amount of polarization can be controlled by a voltage source coupled to the array of aligned nanotubes. Chromogenic material of a light filtering layer can vary the wavelength of the polarized light transmitted through the array of aligned nanotubes.

Abstract: A microscope including an illumination device for a light sheet having an approximately planar extension along an illumination axis of an illumination beam path with a transverse axis to the illumination axis. Light emitted from the sample region on axis of detection the illumination axis and the axis of detection as well as the transverse axis and the axis of detection being oriented relative at an non-zero angle. The illumination device includes structure deflecting light to different beam path and thus produces an additional sheet of light, together illuminating the sample region on common illumination axis, and with switches between beam paths. Detection device has a detection lens system for light from by the sample region. The switches include a rapidly switching element with a time <10 ms, a predetermined integration of the surface detector synchronized so the sample region is illuminated twice during integration.

Abstract: In one or more embodiments, a beam control apparatus and method for correcting aberrations include an off-aperture telescope configured to receive a beam of electromagnetic energy, wherein the telescope includes a first optical element and a second optical element. The second optical element is configured to be translated in three orthogonal axes, and a wavefront error sensor is configured to detect aberrations in the beam and to provide a wavefront error signal in response thereto. A processor is configured to provide a correction signal in response to the wavefront error signal, and an actuator is coupled to the second optical element and configured, in response to the wavefront error signal, to selectively translate the second optical element in one or more of three substantially orthogonal directions corresponding to the three orthogonal axes.

Abstract: A polarizing plate, a fabrication method thereof, and a display device using the same are provided. The polarizing plate includes a polarizing element, a first adhesive layer formed on one surface of the polarizing element, a second adhesive layer formed on the other surface of the polarizing element, a protective film attached to an upper portion of the first adhesive layer, a bonding layer attached to a lower portion of the second adhesive layer, and a luminance enhancement film attached to the bonding layer.

Abstract: A reflective film includes interior layers that selectively reflect light by constructive or destructive interference, the layers extending from a first to a second zone of the film. The interior layers include a first set of layers composed of a first material and a second set of layers composed of a different second material. The first and second sets of layers are both birefringent in the first zone, but at least some of the layers have reduced birefringence in the second zone. The reduced birefringence produces a second reflective characteristic in the second zone that differs from a first reflective characteristic in the first zone, this difference not being substantially attributable to any thickness difference between the first and second zones. The film may also incorporate absorbing agents to assist in the manufacture or processing of the film.

Abstract: An image blur correction apparatus includes a base, a movable holding member, a support mechanism that supports the movable holding member to be movable within a plane vertical to an optical axis of a lens, a driving means for driving the movable holding member, a position detecting unit, and a returning unit for returning the movable holding member to a pause position, wherein the driving unit includes coils fixed to the base and drive magnets fixed to the movable holding member, the returning unit includes return magnets fixed to the base to face the drive magnets, the position detecting means includes magnetic sensors fixed to the base, and the support mechanism includes at least three concave portions provided on the base, at least three spheres rollably arranged in the concave portions, and at least three abutment surfaces provided on the movable holding member to abut on the spheres.

Abstract: A monolithic or hybrid integrated optical information processor or optical information processing system having a plurality of non-quadratic phase optical elements, at least one LED array, and plurality of light modulating array elements, each controlled by respective control signals, the system arranged so that each light modulating array element lies in a different plane. In some implementations, at least a portion of the resulting system is implemented in a stack of component materials. In an implementation, an LED array is used as an image source and another LED array is used as an image sensor to transform the processed image into an electrical output.

Abstract: The optical system includes plural lens groups, a negative lens included in one lens group among the plural lens groups and formed of a first medium, a diffractive grating formed on at least one lens surface of the negative lens and being in contact with a second medium different from the first medium, and a positive lens included in the one lens group and formed of a third medium different from the first medium and the second medium. The first medium satisfies ndA?1.7 and 40??dA?55 where ndA represents a refractive index of the first medium for a d-line, and ?dA represents an Abbe number of the first medium for the d-line. The third medium satisfies ndC?1.55 and ?dC?60 where ndC represents a refractive index of the third medium for the d-line, and ?dC represents an Abbe number of the third medium for the d-line.

Abstract: Described herein are diffraction gratings and methods for the manufacture thereof. One method comprises applying a force to a substrate to strain the substrate, disposing a thin film on at least a portion of the substrate, and reducing the force applied to the substrate, thereby causing the thin film to buckle.

Abstract: Imaging device and method, the device including receiver optics, a diffractive and focusing surface, and a pair of diffractive and focusing arrangements, the receiver optics receiving radiation including a first wavelength selected from a first spectral band, and a second spectral band, where the first wavelength is substantially a multiplicative factor less than the midpoint of the second spectral band, the diffractive and focusing surface diffracting the first wavelength at an order of diffraction substantially equal to the multiplicative factor, and diffracting the second spectral band at a first order of diffraction, each of the diffractive and focusing arrangements diffracting, in turn, the first wavelength at a first order of diffraction, such that the first wavelength and the second spectral band emanating from the second diffractive and focusing arrangement focuses at a substantially common focal length and at a substantially common focal plane width.

Abstract: A phase grating includes a substrate and a first dielectric layer. The first dielectric layer is disposed on the substrate and includes a column and a plurality of rings. The top sides of the column and the top sides of the rings align with one another to form a flat plane. The column and the rings are concentric.

Abstract: A light guide member includes a first light guide film, a second light guide film, a diffuser film and an atomization film superposed together one by one. The first light guide film includes a plurality of first light guide dots and the second light guide film includes a plurality of second light guide dots staggered with the plurality of first light guide dots. The plurality of first light guide dots and the plurality of second light guide dots reflect the light towards any directions and then make the light uniformly and brightly emit out from the first light guide film and the second light guide film. The diffuser film controls the luminance and improves the uniformity of the light. The atomization film atomizes the light and solves the problem of visible dots.

Abstract: A changeable liquid lens array and a method of manufacturing the same. The changeable liquid lens array includes a substrate, a plurality of partition walls arrayed on the substrate and having a fluid travel path, cells defined by the plurality of partition walls, a first fluid comprised in the cells, a second fluid arranged on the first fluid, a first electrode arranged on at least one side surface of each of the partition walls, and a second electrode disposed to be separate from the partition walls. A shape of shape of an interface between the first fluid and the second fluid changes based on a voltage that is applied to the first electrode and the second electrode.

Abstract: The invention relates to a microlens array with integrated illumination, an imaging system with such a microlens array, an image detection device and also a method for producing the microlens array.

Abstract: A virtual image display system includes a display device that outputs image light, a projection lens that projects the image light from the display device, a first holding member that holds the projection lens, a light guide plate that takes in the image light from the projection lens, and then, guides the light to an external predetermined position, and a second holding member that holds the light guide plate. A positioning structure for positioning the light guide plate with respect to the projection lens is provided in the first holding member and the second holding member.

Abstract: A projection device for use with a night vision goggle system includes: a display source; a projector lens assembly positioned to accept light from the display source and provide a projector optical path having a plurality of projector rays; and a folding device comprising at least two folding surfaces positioned to split an exit pupil of the projector optical path into two or more separated segments. Each folding surface captures and redirects a portion of the projector rays to be parallel and coincident with corresponding rays produced by an external scene which pass through an objective lens of the night vision goggle system.

Abstract: A head-up display includes a first display device, and a second display device which is provided at a position which is different from a position of the first display device. An optical axis identifying device outputs light beams, which are respectively input from the first display device and second display device, in the identical direction. An enlarged-image forming device enlarges respective images which are formed by the light beams which are output from the first display device and the second display device, based on the light beams which are input from the optical axis identifying device, and forms an image by overlapping the images which are enlarged. A moving device moves at least one of the first display device and the second display device along respective optical axis directions thereof.

Abstract: A thickness of a tapered part provided at the deeper side (?X side) in a light guide direction of a light transmission member is smaller toward the deeper side, and thus, a reflection angle of ghost light that has passed through a fourth reflection surface provided with a half mirror layer and reached the light transmission member gradually becomes smaller within the tapered part and no longer satisfies a total reflection condition, and the light is ejected to the outside in the position diverging from an eye of an observer. That is, the tapered part may prevent the ghost light from reaching the eye and good see-through observation can be realized.

Abstract: A system and method of aligning a micromirror array to the micromirror package and the micromirror package to a display system. One embodiment provides a method of forming and utilizing a package that exposes regions of an alignment reference plane. The device within the package is mounted on the reference plane such that the exposed regions allow precise alignment with the device in a direction perpendicular to the reference plane. Alignment surfaces formed in a display system or other system contact the reference plane at the exposed regions to position the packaged device relative to other components of the system. One embodiment of the package 400 taught has laminated layers forming the package substrate 402 and providing a precision reference plane 416 relative to the position of the micromirror device 404. The package may be formed by laminating several layers of material in sheets to form several package substrates simultaneously.

Abstract: Provided are a wafer lens production method, an intermediate die, an optical component, a molding die, and a molding die production method. The production method of a wafer lens (1) includes a first intermediate die production step using a die (7), a second intermediate die production step using the first intermediate die (8), and a wafer lens production step using the second intermediate die (9). A first intermediate-die substrate (80) is provided with a depressed section (85) on the surface facing the die (7). When photo-curable resin (84A) is pressed, at least a portion closer to the first intermediate-die substrate (80) among the top (71a) and the peripheral section (77) of the die (7) is arranged in the depressed section (85), and a gap is provided so that the die (7) does not contact with a depressed plane (85a) of the depressed section (85).

Abstract: A zoom lens includes, in order from an object side to an image side, first to fifth lens units respectively having positive, negative, positive, negative, and positive refractive powers. During zooming from a wide-angle end to a telephoto end, each of the lens units moves in such a way that a distance between the first and second lens units increases, a distance between the second and third lens units decreases, a distance between the third and fourth lens units increases, and a distance between the fourth and fifth lens units increases. The distances D34w and D34t between the third and fourth lens units, the distances D45w and D45t between the fourth and fifth lens units, focal lengths fw and ft of the entire zoom lens, and focal lengths f1 and f4 of the first and fourth lens units are appropriately set.

Abstract: A zoom lens including a first lens unit having a positive refractive power, a second lens unit having a negative reflective power, a third lens unit having a positive refractive power, and a rear lens group including one or more lens units in this order from an object side to an image side, wherein distances between the respective lens units vary during the zooming operation, wherein the first lens unit consists of three lenses including one negative lens, and a partial dispersion ratio of a material for the negative lens of the first lens unit, an Abbe number of the same, a focal length of the entire system at a wide angle end and a focal length of the first lens unit are set individually and adequately.

Abstract: An embodiment of this invention provides a zoom lens that primarily comprises, in order from an object side to an image-forming side, a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power. The second lens group comprises several lenses, in which the focal length of the first lens from the object side is efl3, the focal length of the second lens from the object side is efl4, and efl3 and efl4 satisfy: 0<efl3/efl4<0.3.

Abstract: An image-capturing lens includes, in order from an object side: a meniscus-shaped first lens which has positive power near an optical axis; a second lens which has positive power near the optical axis and has negative power in the periphery of the second lens; and a meniscus-shaped third lens. The image-capturing lens satisfies the following conditional formulas: TL/f<1.10, 2.00<(r2+r1)/(r2?r1)<4.00, and 0.07<D2/f<0.19, where TL: the air-converted distance from the object-side surface of the first lens to the image-side surface thereof, f: the focal length of the entire system, r2: the radius of curvature of the first lens on the image side thereof, r1: the radius of curvature of the first lens on the object side thereof, D2: the distance between the first lens and the second lens.

Abstract: An image lens system includes, in order from an object side to an image side, a first lens element with negative refractive power including a concave image-side surface; a second lens element with positive refractive power including a convex object-side surface; a third lens element with negative refractive power including an object-side surface and a concave image-side surface, the object-side surface and the image-side surface being aspheric; a fourth lens element with positive refractive power including a convex object-side surface and a convex image-side surface; and a fifth lens element with negative refractive power including a convex object-side surface and a concave image-side surface, the object-side surface and the image-side surface being aspheric, the fifth lens element having at least one inflection point.

Abstract: An imaging lens includes a first lens; a second lens; and a third lens arranged from an object side to an image plane side. The first lens has an object-side surface having a positive curvature radius R1f and an image plane-side surface having a negative curvature radius R1r. The second lens has an object-side surface and an image plane-side surface with negative curvature radii. The third lens has an object-side surface and an image plane-side surface with positive curvature radii and formed as aspheric surfaces having inflexion points. When the whole lens system has a focal length f, the first lens has a focal length f1, the second lens has a focal length f2, and the third lens has a focal length f3, the imaging lens satisfies the following conditional expressions: f1<f2<f3 1.0<f1/f<1.5 ?0.

Abstract: An imaging lens includes plastic-made first, second, third, and fourth lens elements arranged in the given order from an object side to an imaging side. The first lens element has a positive focusing power and is biconvex. The second lens element has a negative focusing power, is biconcave, and has an abbe number not greater than 30. The third lens element has a positive focusing power and has a convex imaging-side surface facing toward the imaging side. The fourth lens element has an imaging-side surface formed with a concave area in a vicinity of an optical axis of the fourth lens element. The imaging lens further includes an aperture stop disposed between the first and second lens elements.

Abstract: An imaging lens includes first, second, third, and fourth lens elements arranged from an object side to an image side in the given order. The first lens element has a positive refractive power. The second lens element has a negative refractive power, and concave object-side and image-side surfaces. The third lens element has a positive refractive power. The fourth lens has a curved object-side surface with a convex portion and a concave portion. The imaging lens satisfies AAG/CT3?1.3, where AAG is a sum of distances between any adjacent two of the lens elements, and CT3 is a thickness of the third lens element.

Abstract: A personal media viewing device has a frame that adjustably holds a pair of lenses. The frame has tracks along a bottom inside portion that guides the lenses as a lens adjustment knob is turned. The adjustment knob is attached to a translating screw shaft that has opposingly threaded portions that interact with a left and right traveling nut attached to each lens and moves each lens in an opposite direction. An elastic strap is used to removably hold a personal media device to the frame and a head attachment portion is provided to allow a user to operate the personal media viewing device hands free. The adjustment knob allows a user to adjust the lenses to an off-axis position selected to reduce eyestrain, headaches and other non-desirable effects associated with viewing a device in front of the user's eyes.

Abstract: In a method for manufacturing a lens, a substrate which has a recess in a first surface thereof is provided. A sacrificial material is provided in the recess which has shape in accordance with a first desired lens surface. A lens material is applied to the substrate and to the sacrificial material and cured so that the lens material has a shape in accordance with the first desired lens surface, and then the sacrificial material is removed.

Abstract: A two-axis, optical mount provides two flexural elements monolithically and homogeneously formed of a single material with, and interconnecting, three rigid segments. Between each pair of rigid segments, beginning with the first and second, a set of extensions is formed to have a cross section that permits simple, easy, independent adjustment therebetween. Likewise, a flexural element exists between the second and third rigid elements. Meanwhile, the rigid elements have section moduli sufficiently great as to be orders of magnitude larger than the flexural stiffness or section modulus of the flexural elements, thus providing flexures that operate in the elastic mode and introduce no joint type accuracy errors in adjustment.

Abstract: A lens barrel includes a barrel wall disposed about a longitudinal axis, an external thread continuously formed on the barrel wall and having a continuous crest, and two parting lines that are longitudinally formed on the external thread and that are symmetrical about the longitudinal axis. A projection of the crest of the external thread on a plane orthogonal to the longitudinal axis has a maximum diameter and a minimum diameter. A difference between the maximum and minimum diameters is between 0.04 mm and 0.18 mm. Each of the two parting lines is disposed on portions of the external thread that define the minimum diameter.

Abstract: A magnetic media tester comprising a Laser Doppler Vibrometer (LDV) head; and a magnetic read head; the LDV head and the magnetic read head being configured for obtaining correlatable data of a region on a magnetic disk.

Abstract: A magnetic recording element records information by applying a recording magnetic field to a magnetic recording medium having an information recording area to form a plurality of recording columns extending in a first direction. Recording by the magnetic recording element is performed so that a first recording column and a second recording column formed before the first recording column partially overlap each other in a second direction perpendicular to the first direction, and that a recording start position of the first recording column is positioned upstream, relative to the recording direction, of a recording start position of the second recording column.

Abstract: Techniques are described for constructing maximum transition run (MTR) modulation code based upon a multi-level (ML) run-length limited (RLL) finite state machine (FSM) that implements different sets of penalties. A processor is configured to receive information from a hard disk drive (HDD) via a read channel and recover data from the HDD using MTR modulation code. A memory has computer executable instructions configured for execution by the processor to model a magnetic recording channel as a partial response channel, model a source of information to the magnetic recording channel to provide an optimized Markov source, and construct an MTR modulation code to mimic the optimized Markov source based upon an FSM having a limited transition run length and a multi-level periodic structure. The FSM provides at least two different sets of penalties in a period.

Abstract: A disk drive is disclosed comprising a head actuated over a disk, and control circuitry comprising a read channel comprising an analog filter and an equalizer. Data is read from the disk to generate a read signal, and the analog filter filters the read signal. The filtered read signal is sampled, and the read signal samples are input into the equalizer in order to equalize the read signal samples according to a target response. A response of the read channel based on the read signal samples input into the equalizer is identified to generate an identified response. Expected samples are generated based on the identified response, wherein the expected samples correspond to the data written to the disk, and an estimated noise sequence is estimated based on the expected samples and the read signal samples.