Abstract: Disclosed is a circuit for and method of testing a facsimile transceiver to determine whether it is operating properly. The method employed utilizes a document having a test pattern on a first portion thereof which is placed adjacent the read head of the transceiver. The reading means of the transceiver is energized and the test pattern is scanned. The output of the reading means, when the transceiver is being diagnosed, is directed to a digital memory and stored. Subsequently, the output of this memory is connected to the transmitter section and from there to the receiver section of the transceiver which is then energized to display the contents of the memory on a second portion of the document. In the preferred embodiment of the invention, the test pattern is located on a portion of a document which does not encompass the entire circumference of a rotating drum.

Abstract: A facsimile method and apparatus wherein the white level is set during prescanning in one direction from a first extremity to a second extremity of a document. Scanning then proceeds with the white level set in a second direction from the second extremity to the first extremity. The white level is set using variable gain amplifier means comprising a digital-to-analog converter and gain control means comprising a digital register which stores a binary word representing the whitest level sensed during prescanning in the first direction.

Abstract: A receiver for a facsimile system in which a local carrier is either derived from a modulated signal or is generated when the carrier component of that signal is not detectable which employs a first variable frequency oscillator and a second variable frequency oscillator responsive to the first variable frequency oscillator for reducing the frequency variation of the local carrier in response to the first variable frequency oscillator. In the preferred embodiment, the second variable frequency oscillator which is frequency controlled while the first variable frequency oscillator is voltage controlled. The frequency controlled variable frequency oscillator preferably includes a stable clock driving one counter and a second counter being driven by the output frequency of the first oscillator.

Abstract: A method and system for inducing and controlling nutation of a gyroscope momentum wheel (or member) so that such controlled nutation can be used for purposes such as target searching, acquisition and tracking, particularly in a guided missile system. A nutation command signal having a frequency integrally related to the natural nutation frequency of the gyroscope momentum member is generated, preferably is response to a momentum member position feedback signal. The generated nutation command signal is applied to a torquer to induce movement of the momentum member at the frequency of the nutation command signal. The amplitude of the nutation command signal is selectively controlled to control the amplitude of the induced movement and thereby control the movement of the momentum member through a desired pattern. In the disclosed embodiment, the momentum member controls the line-of-sight of a sensor such as a light or other electromagnetic wave energy detector.

Abstract: The scanning drum of a facsimile receiver carries a longitudinally extending stripe such that portions of the stripe at opposite extremities of a document carried by the drum are exposed. The width of the stripe at the exposed portion adjacent the leading edge of the document is sensed by an optical sensing head and stored in memory prior to transmitting dark/light variations in the document. The scanning of the document continues until the optical scanning head is juxtaposed to the exposed portion of the drum adjacent the trailing edge of the document. At this time, the width of the stripe is again detected and compared with the width in memory so as to verify that the scanning of the document is complete. The facsimile transmission is then terminated.