Abstract: A video display system such as a liquid crystal display television receiver projection system typically uses a high-intensity discharge lamp of the type that should not be re-started or turned on immediately after being turned off. An improved system protecting the lamp from restarts during a cooling off period. The system maintains the lamp, once energized to produce an image, in an off condition during a predetermined cool-down period following receipt of a power-off. Advantageously, the system automatically powers the lamp on at the end of the cool-down period upon receipt a power-on command during the cool-down period.

Abstract: A variable intensity light device is provided to illuminate front panel user buttons in a television apparatus. The television apparatus allows user control of the level of light intensity preferably via an on-screen menu. Automatic detection circuitry/logic is also provided that detects whether a light such as an LED is present upon initial user set-up. This allows the inclusion of the light device in televisions whose controllers are already designed. Moreover, the light device preferably utilizes a single wire for light presence detection and intensity control. Detection of the light causes the television apparatus to include a light control on-screen menu in the main television on-screen menu. Preferably, the light control menu allows the user selection of at least six different brightness or intensity levels for the light. In one form, the light is a diode that provides blue light though a light pipe.

Abstract: A method and apparatus for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a process variable for a material in a vessel. The method includes the steps of determining a reference signal along a probe in the vessel, establishing a first fiducial reference point, a reference end of probe location, a measuring length and a maximum probe length. The method also includes the steps of periodically detecting a TDR signal along the probe, establishing a second fiducial reference point, a detected end of probe location, an end of probe peak to peak amplitude, and attempting to determine a process variable reflection on the TDR signal. The method indicates a broken cable condition, a loss of high frequency connection, a low amplitude reflection condition, an empty vessel condition.

Abstract: A method and apparatus for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a process variable for a material in a vessel. The method includes the steps of determining an initial reference signal along a probe, storing the initial reference signal as an active reference signal, periodically detecting a TDR signal along the probe in the vessel, and computing the output result using the TDR signal and the active reference signal. The method also includes the steps of determining an appropriate time for updating the active reference signal, automatically computing an updated reference signal at the appropriate time, and overwriting the active reference signal with the updated reference signal for use in subsequent computations of the output result.

Abstract: A method for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a process variable for a material in a vessel. The method includes the steps of determining a background signal for a probe and detecting a sample TDR signal for the probe in the vessel. At least one transition point is established on the sample TDR signal and the background signal. A portion of the sample TDR signal on one side of the at least one transition point is combined with a portion of the background signal on the other side of the at least one transition point to establish an initial boundary signal, and the initial boundary signal is stored. The method also includes the steps of detecting the TDR signal and calculating the output result using the initial boundary signal.