Disclosed is an adaptive Finite Impulse Response ("FIR") filter speakerphone that provides improved echo cancelation by the inclusion of a tracking comb filter having nulls which change to track the voice portion of communications. The speakerphone also includes a pair of ambient noise recorders for recording both ambient background noise received from the telephone line and ambient background noise in the signal to be transmitted to the telephone line. During intervals of low signal level, pre-...

Low-nickel, low-molybdenum, air-meltable air-castable, fabricable, weldable, duplex stainless steel alloys of an austenitic-ferritic matrix that are essentially free of martensite and sigma phase. The alloys are not only substitutable for the various austenitic 18% chromium - 8% nickel grades of stainless steels but possess superior corrosion resistance properties to those prior art steels. The alloys consist essentially of between about 2% and about 5% of weight nickel, between about 23% and 28...

A duplex printer receives image data for both odd and even pages, prints the image data for odd pages on one side of each sheet of a stack of sheets, reverses and stores the stack of sheets, and prints the image data for the even pages on the other side of the sheets of the stack of sheets.

An improved quasi-duplex time division multiplexed (TDM) communication system provides for transmission by a talker until an interrupt command for role reversal is transmitted by a listener. Preferably, the time allocated for voice transmission is greater than the time allocated for command transmission. In this manner, the primary feature of full-duplex communications is provided simply while conserving spectrum.

A full duplex transponder system includes an interrogation apparatus and a transponder apparatus. The transponder apparatus includes a reception antenna for receiving an interrogation signal wave whose carrier wave is phase- or frequency-modulated with an interrogation signal, a demodulator for demodulating the interrogation signal from the interrogation signal wave received by the antenna, a rectifier for rectifying the carrier wave of the interrogation signal wave received by the antenna and o...

The duplex copying of two-sided originals onto two sides of a copy sheet is accomplished by interspersing images from two successive documents on a multi-image imaging member, specifically with the front-side image of a second document interspersed between the front and rear-side images of a first document. Copy sheet turnover can thus occur during the transfer of the front-side of the second document to achieve an increased "copy-output-rate to electrographic-procedure-speed" ratio.

A system of pre-collation copying a set of duplex document sheets by inhibiting the operation of a document inverting path during successions of contiguous plural document copying circulations to copy only one side of the documents during each succession, and actuating the document inverter path only during single document circulations at the end of a succession, after the document set has been circulated a number of times in that succession equal to the quotient of a constant number divided by ...

A duplex module for simultaneous bidirectional transmit-receive communication with the end of an optical fiber or fiber bundle. The end face of an optical fiber in optical coupling registry with one end of a common bidirectional transmit-receive optical path is tilted to divert any transmit signal back-reflected from such end out of such path. The other end of the transmit-receive path is affiliated with signal receiver and transmitter means via a beam splitter.

Apparatus for producing images on first and second sides of a copy sheet. Unfixed transferable images formed on an image transfer member are transferred to the opposite sides of a copy sheet brought into transferable relationship with the image transfer member. A copy sheet handling apparatus includes a vacuum member movable in opposite directions. The vacuum member is moved between first and second positions spaced from one another. At the first position, the vacuum member overlies the transfer...

A duplex printing arrangement is provided for printing on both sides of a plurality of rectangular sheets of paper, each of the sheets having a pair of parallel opposite edges which are shorter than the pair of edges perpendicular thereto. Each of the sheets is transported past a printer in a direction parallel to the longer pair of the edges of the sheet. The sheets are printed on a first side as they are moved past the printer with a first edge of the pair of shorter edges being the leading ed...