Abstract: A method includes providing two or more momentum wheels arranged for rotation on a spacecraft in a momentum-canceling set. The method further includes causing the two or more momentum wheels in the momentum-canceling set to rotate at momentum-canceling speeds. Additionally, the method includes reducing rotational speed of a momentum wheel in the momentum-canceling set to initiate a slew of the spacecraft.

Abstract: A disk memory device is provided that will maximize the storage capacity of a memory disk while at the same time maximize the record and playback data rate. Two recording disks are mounted upon a common shaft that is rotated at a fixed speed. Each disk has a recording area including a surface upon which data can be recorded/read in the form of tracks arranged either in concentric tracks or in a spiral. The recording area surfaces are divided into multiple concentric track groups. Two read/write heads and two head positioning servos (including electronic controls) are mounted such that each disk recording surface can be read out or written by the read/write heads. Each track of the multiple track groups of the first disk are given designated numbers beginning with the outer track of the outermost or edge track group and continuing in higher consecutive numbers until the inner track of the innermost track group is designated.

Abstract: A circuit and method for enabling the automatic testing of trunks leading to automatic call distributors from a remote testing location is disclosed. In accordance with the invention, when the remote testing location wishes to test a trunk leading to an automatic call distributor, tones are generated which enable the remote testing location to be connected to a test line of the automatic call distributor rather than to an operator position.

Abstract: Method and apparatus for measuring the number of layers of a web material of known thickness wound on a storage or take-up reel. The method and apparatus are based on the principle that, at a relatively large radius, the loci of layers of a thin web wound on the reel approximate a family of concentric circles having radii respectively successively increasing by a length equal to the web thickness, t, whereby the difference in circumferences between adjacent web layers is substantially constant and equal to 2.pi.t. Tachometer pulses are generated in response to linear movement of the web and reset pulses are generated in response to rotation of the reel. The tachometer pulses, either prerecorded on a track of the web or generated by a code wheel rotating with the moving web, are spaced apart from each other by 2.pi.t. With that spacing, each layer of the web contains one pulse more than an immediately preceding layer.