Abstract: A device is provided for measuring the clearance between a member and a surface over and relative to which the member moves. The device has a first reference element, and a second reference element which faces the first reference element, and is movable to alter the distance to the first reference element. The device further has a fastening system for fastening the device to the member so that, during the relative motion, the first reference element is held in a fixed position relative to the member and the second reference element slides over the surface. The device further has an urging arrangement which urges the second reference element into contact with the surface so that, as the second reference element slides over the surface and the clearance between the member and the surface varies, the second reference element moves relative to the first reference element. The device further has a sensor which measures the distance between the first and second reference elements.

Abstract: There are a number of sensors (2, 22) such as thermocouples which can provide a putative measurand signal which is within a predicted range for such signals whilst the sensor is incorrectly operating, such as as due to an open circuit. Techniques and processes are available to determine by interrogation sensor operational validity, but these can distort the measurand signal if correct. By time division multiplex techniques the present arrangement takes a putative measurand signal from a sensor (2, 22) in order that either within the same time division or more normally a separate time division, an interrogation of the sensor is performed in order to determine accuracy and therefore validity of the sensor 22.

Abstract: A device is provided for measuring the clearance between a member and a surface over and relative to which the member moves. The device has a first reference element, and a second reference element which faces the first reference element, and is movable to alter the distance to the first reference element. The device further has a fastening system for fastening the device to the member so that, during the relative motion, the first reference element is held in a fixed position relative to the member and the second reference element slides over the surface. The device further has an urging arrangement which urges the second reference element into contact with the surface so that, as the second reference element slides over the surface and the clearance between the member and the surface varies, the second reference element moves relative to the first reference element. The device further has a sensor which measures the distance between the first and second reference elements.

Abstract: A single link digital telemetry system transmits data in serial form from a sending station. The data clock signal is recovered at a receiving station for data synchronization purposes. To achieve recovery of the data clock signal the incoming data is synchronized with a high frequency clock of n times the original data clock frequency; the fast clock is utilized to drive a data latch so that on each positive incoming data edge the latch produces a synchronized data pulse for feeding to a recirculating shift register n bits long, which is also driven by the fast clock. The original data pulse can be recovered merely by tapping off from a chosen location on the register.