Abstract: A substitute reference signal input is incorporated into a state space controller for a scanning probe microscope to improve tracking efficiency.

Abstract: In accordance with the invention, rapid surface seeks to the measurement surface by a scanning probe microscope are enabled by using an actuator coupled to a position sensor.

Abstract: A substitute reference signal input is incorporated into a state space controller for a scanning probe microscope to improve tracking efficiency.

Abstract: In accordance with the invention, an inverse filter is used to improve scanned images from a scanning probe microscope by removing the effect of the scanning system dynamics from the image data. This may be done in-line or as a post-processing operation.

Abstract: In accordance with the invention, an estimator is used in the controller portion of a scanning probe microscope to provide precise position estimates of the probe tip which is controlled in the vertical direction by a microelectromechanical system (MEMS) actuator. The precise position estimates typically enhance the ability of the scanning probe microscope to follow the surface and typically provide improved measurements of the surface topography.

Abstract: Bit-error-rate (BER) testing includes a data pattern generator transmitting a known data pattern to a device under test (DUT), which processes the data pattern and outputs the processed data pattern to an error analyzer. BER testing of telecommunications systems often uses data patterns in the form of SONET or SDH frames, which have error-checking bytes known as B bytes. The B Bytes computed for a given SONET or SDH frame are inserted into a next SONET or SDH frame. In memory-based BER tests, a fixed number of SONET or SDH frames is input to the DUT by the pattern generator. The last frame of the data pattern is adjusted so that the B bytes calculated using the last frame match the B bytes present in the first frame, which approach avoids parity errors that can occur in response to B byte mismatches between the last and the first frame.

Abstract: A test system that includes a generator and an analyzer acting cooperatively to test a device having a plurality of device communication channels. The device has a plurality of inputs and corresponding outputs, each input being connected to a corresponding one of the outputs. The correspondence between the input and output channels may change if the device is turned off and on or if the device is not actively sending data from the inputs to the outputs. The test system determines a mapping between the device inputs and outputs prior to performing bit error rate testing utilizing a mapping test pattern. The test system can then switch to a bit error rate test pattern without causing the device to drift such that the correspondence between the input and output channels is lost.

Abstract: Correction for harmonic disturbances on rotating storage media in a phase-locked loop. The effects of harmonic disturbances in a phase-locked loop are reduced by employing harmonic correction. Harmonic correction may be present in the loop at all times, or may be switched in once the loop has achieved phase lock. Disturbance within the loop bandwidth is corrected using additional integrating pole or a bump (resonant) filter. Disturbance outside the loop bandwidth is corrected using low pass or a notch (anti-resonant) filter. Alternately, a canceling signal may be generated and added as a feedforward signal. A repetitive control scheme uses a filtered version of the residual errors on previous media rotations as a feedforward signal to cancel harmonic effects.

Abstract: Systems and methods process instrument data in a data representation that is widely accessible. By enabling such accessibility, the instrument data is retained in a form that is independent of the instrument that originated the data, the operating system associated with the retrieval of the data, the processing applications that post-process the instrument data, and/or the like. In one embodiment, a method for processing instrument data comprises: retrieving instrument data from an instrument; encoding the instrument data within an extensible mark-up language (XML) file; and translating the XML file into a file format of a selected one of a plurality of post-processing applications.

Abstract: A design methodology for an Alexander-type PLL may begin by defining a candidate Lyapunov function that is parameterized by design parameters of the Alexander-type PLL. Then, a set of design constraints may be derived from said candidate Lyapunov function and a first derivative of said candidate Lyapunov function. From the design constraints, values for the design parameters of an Alexander-type PLL may be selected. Specifically, when the phase detector gain, the VCO gain, the filter coefficients, and/or the like are selected to satisfy the derived design constraints, the implemented Alexander-type PLL is ensured to be stable.

Abstract: A system and method for automatically capturing processed instrument measurement data into web pages is disclosed. One or more routines are used to access the processed measurement data and generate one or more web pages that include information representing the processed measurement data. The web page(s) can be dynamically created or statically created with links to the processed measurement data, output of the processed measurement data and the one or more routines. The web page can further include links to measurement specific commentary.

Abstract: Correction for harmonic disturbances on rotating storage media in a phase-locked loop. The effects of harmonic disturbances in a phase-locked loop are reduced by employing harmonic correction. Harmonic correction may be present in the loop at all times, or may be switched in once the loop has achieved phase lock. Disturbance within the loop bandwidth is corrected using additional integrating pole or a bump (resonant) filter. Disturbance outside the loop bandwidth is corrected using low pass or a notch (anti-resonant) filter. Alternately, a canceling signal may be generated and added as a feedforward signal. A repetitive control scheme uses a filtered version of the residual errors on previous media rotations as a feedforward signal to cancel harmonic effects.

Abstract: Correction for harmonic disturbances on rotating storage media in a phase-locked loop. The effects of harmonic disturbances in a phase-locked loop are reduced by employing harmonic correction. Harmonic correction may be present in the loop at all times, or may be switched in once the loop has achieved phase lock. Disturbance within the loop bandwidth is corrected using additional integrating pole or a bump (resonant) filter. Disturbance outside the loop bandwidth is corrected using low pass or a notch (anti-resonant) filter. Alternately, a canceling signal may be generated and added as a feedforward signal. A repetitive control scheme uses a filtered version of the residual errors on previous media rotations as a feedforward signal to cancel harmonic effects.

Abstract: A test system that includes a generator and an analyzer acting cooperatively to test a device having a plurality of device communication channels. The device has a plurality of inputs and corresponding outputs, each input being connected to a corresponding one of the outputs. The correspondence between the input and output channels may change if the device is turned off and on or if the device is not actively sending data from the inputs to the outputs. The test system determines a mapping between the device inputs and outputs prior to performing bit error rate testing utilizing a mapping test pattern. The test system can then switch to a bit error rate test pattern without causing the device to drift such that the correspondence between the input and output channels is lost.

Abstract: Bit-error-rate (BER) testing includes a data pattern generator transmitting a known data pattern to a device under test (DUT), which processes the data pattern and outputs the processed data pattern to an error analyzer. BER testing of telecommunications systems often uses data patterns in the form of SONET or SDH frames, which have error-checking bytes known as B bytes. The B Bytes computed for a given SONET or SDH frame are inserted into a next SONET or SDH frame. In memory-based BER tests, a fixed number of SONET or SDH frames is input to the DUT by the pattern generator. The last frame of the data pattern is adjusted so that the B bytes calculated using the last frame match the B bytes present in the first frame, which approach avoids parity errors that can occur in response to B byte mismatches between the last and the first frame.

Abstract: A data decoder for decoding digital data in a high frequency signal in an optical storage device. A carrier signal derived from the high frequency passed through a zonal bandpass filter and a limiter is multiplied by the high frequency signal passed through a high pass filter. The resulting product is filtered and passed through a comparator forming a digital data stream.

Abstract: An optical disk structure and optical disk recorder which enables data to be rewritten onto the recording layer of the optical disk. A clock reference structure is permanently formed along servo tracks of the optical disk. An optical transducer is coupled to the clock reference structure and generates a clock reference signal simultaneously with writing new data onto the recording layer of the optical disk. The data is written as data marks along the servo tracks. Each of the data marks includes edges. The edges of the data marks are recorded in synchronization with a write clock. The write clock is phase-locked with the clock reference signal. Therefore, the edges of the data marks are aligned with the clock reference structure with sub-bit accuracy. Standard DVD-ROM disk readers are not able to detect the high spatial frequency of the clock reference structure.

Abstract: A process and apparatus is described to break down the Position Error Signal (PES) of a magnetic or optical disk or tape drive to its contributing components. (In the case of the optical disk drive, the method is actually two different PESs, Focus Error Signal (FES) and Tracking Error Signal (TES).) This method is based on three concepts: an understanding of how Bode's Integral Theorem ties into noise measurements, a measurement methodology that allows for the isolation of individual noise sources, and a system model that allows these sources to be recombined to form the drive's Position Error Signal. The method measures frequency response functions and output power spectra of each servo system element. Each input noise spectrum can then be inferred and applied to the closed loop model to determine its effect on the PES uncertainty. The method allows the user to identify and rank the most critical noise sources in the positioning mechanism of a drive.

Abstract: A disk recording and/or reproduction device subject to shock and vibration. The track following function of the transducer is augmented by an acceleration responsive sensor. The acceleration responsive sensor is sampled at a different frequency than the sampling frequency of the head disk assembly position error signal. The variations in the gain of the acceleration responsive sensors can be compensated for in real time.

Abstract: Method and apparatus for determining open-loop parameters for each of three general feedback configurations from measurements of the closed-loop error signals or other output signals produced in response to provision of predetermined input signals for the configuration. The feedback loop in one embodiment includes a sum or difference module, a controller module, a plant module and a sensor dynamics module, arranged serially, where the actions of the controller module, the plant module and the sensor dynamics module are represented by associated matrices C, P and H, respectively, when operating in the linear region. The feedback loop in a second embodiment includes a first sum or difference module, a controller module, a second sum or difference module and a plant module, arranged serially, where the actions of the controller module and the plant module are represented by associated matrices C and P, respectively, when operating in the linear region.