Abstract: A scanning projector includes a mirror that scans in two dimensions, at least one of which is sinusoidal. A position sensor provides a position signal that represents an angular displacement of the mirror. The position signal is amplified by an amplifier with time variant characteristics. A beam position determination component compensates for the time variant characteristics of the amplifier.

Abstract: A scanning beam projection system includes a scanning mirror having a fast-scan axis and a slow-scan axis. Movement on the slow-scan axis is controlled by a slow-scan scanning mirror control system. The control system receives position information describing angular displacement of the mirror. An outer loop of the control system operates in the frequency domain and determines harmonic drive coefficients for a scanning mirror drive signal. An inner loop of the control system operates in the time domain and compensates for a scanning mirror resonant vibration mode at a frequency within the frequency band occupied by the harmonic drive coefficients.

Abstract: A scanning beam projection system includes a scanning mirror having a fast-scan axis and a slow-scan axis. Movement on the slow-scan axis is controlled by a slow-scan scanning mirror control system. The control system receives position information describing angular displacement of the mirror. An outer loop of the control system includes least mean square (LMS) tone adders that determine harmonically related signals that when combined produce a scanning mirror drive signal. An inner loop of the control system compensates for a scanning mirror resonant vibration mode at a frequency within the frequency band occupied by the harmonically related signals.

Abstract: A laser drive apparatus includes a plurality of transistors driven by different comparators. The different comparators receive an analog drive value and different ramp signals and produce pulse width modulated output signals. A calibration feedback circuit may be used to calibrate a power supply that provides a power supply voltage. A dither circuit may be used to reduce the number of bits received by the laser drive apparatus.

Abstract: A laser drive apparatus includes a plurality of transistors coupled to different power supply voltages. A control circuit selects one of the plurality of transistors to drive a light source. The control circuit also determines a pulse width to drive the selected transistor. A calibration feedback circuit may be used to calibrate power supplies that provide the different power supply voltages. A dither circuit may be used to reduce the number of bits received by the control circuit.

Abstract: A scanning projector includes a mirror that scans in two dimensions, at least one of which is sinusoidal. A position sensor provides a position signal that represents an angular displacement of the mirror. The position signal is amplified by an amplifier with time variant characteristics. A beam position determination component compensates for the time variant characteristics of the amplifier.

Abstract: A scanning projector includes a mirror that scans in two dimensions, at least one of which is sinusoidal. A digital phase lock loop locks to the sinusoidal movement of the mirror. A free-running pixel clock is provided. An interpolation component interpolates pixel intensity data from adjacent pixels based on the position of the mirror when a pixel clock arrives.

Abstract: Systems and methods are disclosed which provide wireless communication systems implementing subsystems adapted for flexible deployment configurations and to resist the introduction of interference. Preferred embodiments of the present invention provide a wireless communication system configuration in which an ODU subsystem is coupled to an IDU subsystem using a fiber optic link. According to a preferred embodiment of the present invention, an ODU subsystem is adapted to provide conversion between digital and analog to thereby facilitate the use of a digital link between the ODU subsystem and a corresponding IDU subsystem. Embodiments of the present invention utilize a plurality of ODU subsystems configured according to the present invention to provide wireless communication coverage of a service area, such as to provide a wireless application termination system (WATS) hub for use in providing wireless communication links with respect to a plurality of subscriber units.

Abstract: Systems and methods are disclosed which provide wireless communication systems implementing subsystems adapted for flexible deployment configurations and to resist the introduction of interference. Preferred embodiments of the present invention provide a wireless communication system configuration in which an ODU subsystem is coupled to an IDU subsystem using a fiber optic link. According to a preferred embodiment of the present invention, an ODU subsystem is adapted to provide conversion between digital and analog to thereby facilitate the use of a digital link between the ODU subsystem and a corresponding IDU subsystem. Embodiments of the present invention utilize a plurality of ODU subsystems configured according to the present invention to provide wireless communication coverage of a service area, such as to provide a wireless application termination system (WATS) hub for use in providing wireless communication links with respect to a plurality of subscriber units.

Abstract: A scanning beam projection system includes a scanning mirror having a fast-scan axis and a slow-scan axis. Movement on the slow-scan axis is controlled by a slow-scan scanning mirror control system. The control system receives position information describing angular displacement of the mirror. An outer loop of the control system includes least mean square (LMS) tone adders that determine harmonically related signals that when combined produce a scanning mirror drive signal. An inner loop of the control system compensates for a scanning mirror resonant vibration mode at a frequency within the frequency band occupied by the harmonically related signals.

Abstract: A scanning beam projection system includes a scanning mirror having a fast-scan axis and a slow-scan axis. Movement on the slow-scan axis is controlled by a slow-scan scanning mirror control system. The control system receives position information describing angular displacement of the mirror. An outer loop of the control system operates in the frequency domain and determines harmonic drive coefficients for a scanning mirror drive signal. An inner loop of the control system operates in the time domain and compensates for a scanning mirror resonant vibration mode at a frequency within the frequency band occupied by the harmonic drive coefficients.

Abstract: A radar, or other repetitive interference, detection and data flow control system and method for RF data transmissions uses an RF detector and an omni directional antenna to detect radar or similar signals. The information from the RF detector is communicated to a hub data transmission unit which processes the data about the signal provided by the detector. This information is used by the hub to schedule communications between the hub and subscriber units so that none of the communications between the hub and subscriber fall within the time period of the interfering pulses. Although there are no communications during the time periods of the pulses, the efficiency of communications is improved because collisions and retransmission of data are avoided.

Abstract: A radar, or other repetitive interference, detection and data flow control system and method for RF data transmissions uses an RF detector and an omni directional antenna to detect radar or similar signals. The information from the RF detector is communicated to a hub data transmission unit which processes the data about the signal provided by the detector. This information is used by the hub to schedule communications between the hub and subscriber units so that none of the communications between the hub and subscriber fall within the time period of the interfering pulses. Although there are no communications during the time periods of the pulses, the efficiency of communications is improved because collisions and retransmission of data are avoided.

Abstract: The present invention is directed to a system and method which statistically determines when regularly occurring interference events of a predictable duration will occur, for example radar pulses and dynamically adjusts an automatic gain control (AGC) for RF data transmissions accordingly. The repetition rate and width of radar pulses are regular. By averaging and watching for correlations, the present AGC identifies the pulse rate and pulse widths and over a fairly short period of time predicts when the next pulse is coming. When the next pulse occurs, the AGC is adjusted to react accordingly. The AGC can raise or lower gain levels for the duration of the pulse; or ignore the pulse, if it is of a very short duration, so that the AGC level will coast through the event.

Abstract: A system for mitigating the effects of interference in an unlicensed RF band for point to point data transmissions comprises a multibeam antenna locating interference with transmission to and from data transmission subscribers. A scanner determines the frequency, bandwidth and any periodicity of the interference. Separate scanners can be used for each antenna beam. Nulls are generated in the data transmission antenna pattern in the direction of the interference during periods of interference. Communications with subscribers in a direction of the interference is carried out using a different channel or is scheduled around the interference occurrences. Alternatively, such subscribers are directed to establish data transmissions with an alternate hub antenna.

Abstract: An unlicensed RF data delivery system uses interference characterization to adapt the RF transmission to accommodate the interferences. It uses at least one detection system to determine the type of interference present in an RF band. A channel per channel measurement of interference is made, usually in conjunction with a sweep of the total operating spectrum, generating a picture of the interference over the entire frequency spectrum. The system characterizes not only interference levels, but bandwidth of the interference. A profile is generated, the response to that interference profile is one of several methods, such as frequency change; changing modulation to higher or lower levels; changing the channel width; changing the code rate; changing antenna polarity; and using hub diversity. By first characterizing the type of interference, the system response is tailored to maximize the available interference free spectrum.

Abstract: The present invention includes an arrangement for averaging the content of first-in-first-out buffers of each track of a multi-channel digital tape recorder for controlling tape speed to enable a smooth over-dubbing of information recorded at different times on separate tracks.

Abstract: The synchronization circuitry can be described as operating in essentially four states and is particularly useful at startup, to locate synchronization codes and spacing there between in the data flows. In operation, the synchronization circuitry looks in a data flow at startup for any sync code and, when such sync code is found, counts ahead to where the next sync code should be. If a proper sync code is found, again the circuitry counts ahead to where the next sync code should be, continuing looking at points along the data flow until a certain number (n) of properly located sync codes are discovered whereat synchronization is declared and normal playback is ordered. However, if sync codes are not located where they should be in the data flow, then such failures are subtracted from success until either (n) successes are found or a total of successes less failures reaches zero whereat the circuitry returns to the first state of looking for any sync code.

Abstract: The present invention involves an apparatus and method for processing of digital information that includes duplication of information from each channel of a multi-channel recorder on main and backup tracks and provides a combination of error detection apparatus and procedures where data groupings or words on each track are individually subject to four separate tests for detecting errors and provides, from that analysis, for a selection of most likely correct data for further processing. Additionally, further system reliability is obtained by providing circuitry whereby a detected error activates a selection of data groupings coming before and after the detected error, providing where appropriate, for switching from main to backup track data over a certain number of data groupings.