Abstract: An ink transfer roll composed of a steel base covered by a ceramic-fluorocarbon outer layer into which are formed generally cylindrically shaped ink holes having a hemispherical bottom, a generally cylindrical intermediate portion and a rounded, beveled entryway. The ink holes are produced using a pulsed high energy source, such as a pulsed laser. An intermediate layer of corrosion resistant metal and fluorocarbon may be deposited between the steel base and the outer layer of ceramic-fluorocarbon material. Adhesion of the ceramic-fluorocarbon layer to the transfer roll is improved if corrosion resistant metal-fluorocarbon material is contained in the ceramic-fluorocarbon layer such that the quantity of corrosion resistant metal-fluorocarbon material in the ceramic-fluorocarbon layer gradually decreases in the direction away from the intermediate layer-outer layer interface, the quantity of corrosion resistant metal-fluorocarbon material in said outer layer being greatest at said interface.

Abstract: An echo canceller for use in a long-distance telephone network having a four-wire circuit and a two-wire circuit in which echoes are inherently produced at the junction of the four-wire circuit and the two-wire circuit. A sample interpolator converts the incoming digital signal into a digital signal having the same sampling rate as that of the outgoing digital signal on the basis of relative positions of sampling time for corresponding imaginary envelopes of the incoming and outgoing digital signals. An echo estimator produces an estimated echo signal responsive to the output of the sample interpolator for cancelling the echo signal. The estimated echo signal is substracted from the unprocessed digital signal to produce an echo-cancelled digital signal.

Abstract: A medical support board to inhibit movement of a patient's limb is provided. The support board is provided with an adherent strip applied to its reverse side. The adherent strip is a removably adherable to materials underlying the support board such as carpets, blankets or the clothing of the patient. The adherent strip adherring to an underlying material inhibits movement of the patient's limb relative to the body. Straps are provided to secure the limb to the support board and are fastened by means of adherent strips.

Abstract: A digital speech scrambler system allowing for the transmission of scrambled speech over a narrow bandwidth by sequency limiting the analog speech in a low-pass sequency filter and thereafter multiplying the sequency limited speech with periodically cycling sets of Walsh functions at the transmitter. At the receiver, the Walsh scrambled speech is unscrambled by multiplying it with the same Walsh functions previously used to scramble the speech. The unscrambling Walsh functions are synchronized to the received scrambled signal so that, at the receiver multiplier, the unscrambling Walsh signal is the same as and in phase with the Walsh function which multiplied the speech signal at the transmitter multiplier. Synchronization may be accomplished by time division multiplexing sync signals with the Walsh scrambled speech. The addition of the sync signals in this manner further masks the transmitted speech and thus helps to prevent unauthorized deciphering of the transmitted speech.