254 results about "Servo loop" patented technology

Semi-integrated external cavity diode laser (ECDL) designs including integrated structures comprising a gain section, phase control section, and optional modulator section. Each integrated structure includes a waveguide that passes through each of the sections. A mirror is defined in the structure to define one end of a laser cavity. A reflective element is disposed generally opposite a rear facet of the gain section, forming an external cavity therebetween. A tunable filter is disposed in the external cavity to effectuate tuning of the laser. During operation, a modulated drive signal is provided to the phase control section. This modulates an optical path length of the laser cavity, which produces an intensity (amplitude) modulation in the laser output. A detector is employed to produce a feedback signal indicative of the intensity modulation that is used for tuning the laser in accordance with a wavelength locking servo loop. Upon passing through the modulator section, an optical signal is modulated with data.

A method and apparatus for providing ventilatory assistance to a spontaneously breathing patient An error signal (56) is computed that is the difference between a function of respiratory airflow (54) over a period of time and a target value (52). Using a servo loop, air is delivered to the patient at a pressure that is a function of the error signal, the phase of the current breathing cycle, and a loop gain that varies depending on the magnitude of the error signal. The loop gain increases with the magnitude of the error signal, and the gain is greater for error signals below a ventilation target than for error signals above the ventilation target value. The target value (52) is an alveolar ventilation that takes into account the patient's physiologic dead space.

A quadrature tranceiver has a transmitter, a receiver, and a common local oscillator. With the transmitter switched off and the receiver switched on, a DC-error in the receiver is nulled in servo loops in in-phase and a quadrature receiver paths. After settling, the servo loops provide output values that are freed of the DC-error. DC-nulling output values are then sampled and stored. After sampling, the servo loops are opened. Thereafter, the transmitter is switched on while inputting a fixed signal to the transmitter, and DC-signals injected into in-phase and quadrature paths of the transmitter are adjusted until the opened servo loops provide the same output signal as obtained at the end of the DC-nulling. Corresponding values of the injected DC-signals are then stored as transmitter calibration values.

A disk drive includes recording media having one or more recording surfaces, one or more transducer heads positionable relative to the recording surfaces by an actuator operating within a head position servo loop, and a data transfer driver. A preamplifier in the data transfer driver includes one or more head interfaces, each head interface for controlling a transducer head for read and write operations, and a mode controller for controlling each head interface based on configuration information for selectively (i) reading data from at least one recording surface, (ii) writing data to at least one recording surface, and (iii) simultaneously reading data (such as a reference pattern) from at least one recording surface and writing data (such as servo patterns) to at least one recording surface.

An SEA architecture for controlling the torque applied by an SEA that has particular application for controlling the position of a robot link. The SEA architecture includes a motor coupled to one end of an elastic spring and a load coupled to an opposite end of the elastic spring, where the motor drives the load through the spring. The orientation of the shaft of the motor and the load are measured by position sensors. Position signals from the position sensors are sent to an embedded processor that determines the orientation of the load relative to the motor shaft to determine the torque on the spring. The embedded processor receives reference torque signals from a remote controller, and the embedded processor operates a high-speed servo loop about the desired joint torque. The remote controller determines the desired joint torque based on higher order objectives by their impedance or positioning objectives.

A system and method for remotely measuring the temperature of an object using microwave radiometry that may be used in hostile environments. A single pole-single throw reflective PIN diode switch is operable in a PASS mode and a BLOCK mode. In the PASS mode, the switch passes the power received from the object to a low-noise block converter (“LNB”) for amplification. In the BLOCK mode, the switch blocks the object power and reflects the load noise power of an ambient temperature load to the LNB. A detector diode detects the amplified power output during both the BLOCK and PASS mode and the AC signal from the detector is converted to an output signal proportional to the difference in the noise powers detected in the PASS and BLOCK modes. A servo loop uses the output signal to generate a feedback signal to a noise injection diode that causes the diode to inject sufficient power into the LNB to automatically maintain a balance between noise power measured in the PASS mode and the combined noise powers measured in the BLOCK mode. The output signal is then used to compute the temperature of the object.

A servo system for displacing a head relative to a disk of a hard disk drive. The servo system comprises a dual-stage actuator, a calibration signal generator, and a calibration factor generator. The calibration signal generator generates a calibration signal having a calibration portion. The calibration factor generator generates a calibration factor. The servo system operates in operating and calibration servo modes. In the operating mode, the system defines first and second servo loops. The calibration factor is used as one of the parameters of the second servo loop. In the calibration servo mode, the calibration signal forms the second control signal, and the calibration factor generator generates the calibration factor based on movement of the head before any substantial response of the third servo loop to the calibration portion.

An interferometric fiber optic gyroscope (IFOG) includes a fiber light source, a multi-function integrated optic chip (IOC) and corresponding fiber sensing coil, and a wavelength division multiplexor connected to each other via a coupler, along with servo loop closure processing electronics. In addition, an absolute wavelength reference, such as an atomic reference, that is not susceptible to drift or effects of radiation, is connected to the wavelength division multiplexor. Periodically and momentarily, and for purposes of calibrating the wavelength division multiplexor, gyro return light from the IOC, which is normally passed to the wavelength division multiplexor, is suppressed in favor of a signal supplied by the absolute wavelength reference.

Position error values are obtained from a transducer head while following a plurality of servo tracks with a servo loop that band-blocks a frequency range that includes F, a nominal rotation frequency. An estimated difference distribution is derived from the position error values, the difference distribution having a first frequency component at a positive frequency ≦2*F. A scalar track squeeze magnitude indicator is derived from the estimated difference distribution so that the indicator to be transmitted depends on the frequency component.

A hard disk device includes a servo control unit that constitutes a servo loop for a head seek for performing read/write of data from/to a recording medium, a correction signal generation unit for generating a correction signal for correcting a control by the servo control unit based on an output of a predetermined sensor, and a correction signal control unit for estimating an effect of supplying the correction signal to the servo loop and for controlling whether or not the correction signal is to be supplied to the servo loop in response to a result of the estimation. Moreover, the gain of the sensor is dynamically controlled in response to the above estimation result.

A system for supplying compressed air to a pneumatic network includes a load compressor, an air supply and a power shaft driving the load compressor. The system also includes in an air outlet of such load compressor, a connecting channel connected, on the one side, with a channel connected with the pneumatic network and, on the other side, with an air discharge conduct towards an exhaust nozzle. Air flow rate bleed valves are controlled by a processing unit via servo-loops as a function of the pressure sensors and the speed sensor.

A DC offset correction system for a direct-conversion receiver is disclosed that may include a DC feedback correction servo-loop in signal communication with a baseband section, where the DC feedback correction servo-loop is coupled to both the input and output of the baseband section and an attenuator within the DC feedback correction servo-loop.

An apparatus and method for improving servo loop performance in a disc drive storage system are provided. The servo loop includes a voice coil motor actuator that moves the head in response to a received servo control signal. A sensor, located in the head, senses servo information located on the disc and produces a servo signal therefrom. The servo signal is combined with a reference signal to produce a position error signal. A servo controller receives the position error signal and responsively produces the servo control signal. The servo controller includes a drive signal generator that receives the position error signal and responsively produces a driving energy signal. A vibration damping circuit receives the driving energy signal and responsively produces the servo control signal. A real-time adaptive loop shaping circuit, included in the servo loop, detects vibrations in the position error signal and responsively adjusts at least one parameter of a transfer function of the vibration damping circuit to reduce vibrations at different frequencies in the driving energy signal.

The invention discloses a loop response time measuring device and method used for an atomic frequency standard. The device comprises an oscillation module, an executing module and a signal detecting module, wherein the oscillation module is used for receiving an output signal of a servo loop of an atomic frequency standard and outputting the signal after reversing the phase of the output signal of the servo loop of the atomic frequency standard; the executing module is used for acting according to the output signal of the oscillation module to control the quantum system of the atomic frequency standard to finish the quantum frequency discrimination; and the signal detecting module is used for measuring the oscillation period of the oscillation loop according to the output signal of the oscillation module, and the oscillation loop consists of an oscillation module, an executing module and an atomic frequency standard. The method comprises the following steps of: obtaining the oscillation period of the oscillation module; measuring the oscillation period of the oscillation loop; and calculating the loop response time of the atomic frequency standard according to the oscillation period of the oscillation loop and the oscillation period of the oscillation module. By adopting the device and the method provided by the invention, the loop response time of the atomic frequency standard system can be measured accurately.

An apparatus and method for tracking radially-dependent repeatable run-out in a disc drive having a servo loop for positioning a head over a rotating disc is provided. The disc includes multiple tracks. Radially-dependent repeatable run-out control components for at least a subset of the multiple tracks are first determined. Data representative of the radially-dependent repeatable run-out control components for the subset of the multiple tracks is then stored. The stored data representative of the radially-dependent repeatable run-out control components is retrieved before settling on the target track, and subsequently used to follow the selected track.

A hard disk has a servo loop and a rotating storage medium. The rotating storage medium has one or more significant flutter modes at frequencies below a zero cross frequency of a rejection transfer function of the servo loop. The effect of the forgoing is to allow the servo loop to better track a rotating medium that is subject to significant flutter. Peak filters with frequency bands that substantially overlap frequency bands of the significant flutter modes can also be added to the servo loop to further improve tracking. Multiple narrow band filters with frequency bands overlap can be used to cover the spectrum of a single flutter mode. Two lag-lead filters, the frequency responses of which overlap can be used to cover two adjacent significant flutter modes. At frequencies intermediate to the two adjacent flutter, modes, the lead caused by one filter, will be cancelled by the lag caused by the second.