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McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


(1) (Fused Deposition Modeling) See 3D printing.

(2) (Frequency Division Multiplexing) Transmitting multiple data signals simultaneously over a single channel. Each data stream (text, voice, video, etc.) is modulated onto a carrier with a unique center frequency by the multiplexor and demodulated at the receving end (see modulation and carrier). FDM works in both wired and wireless applications (see FDMA).

It Started in the 1930s
In the 1930s, the telephone companies began to use FDM to combine multiple analog voice signals over one line to maximize efficiency of their long distance trunks. During the 1960s, FDM was replaced with TDM, its digital counterpart (see TDM and channel bank).

Cable TV companies use FDM to transmit hundreds of channels of analog and digital TV as well as Internet over a single coaxial cable. The set-top box or TV tuner locks onto a particular frequency (channel) and demodulates the carrier to derive the data for the TV screen. The cable modem both modulates and demodulates the appropriate carriers to provide bi-directional operation for Internet access. See FDMA, OFDM, circuit switching and WDM.

Analog FDM vs. Digital TDM
FDM separates signals by using different carrier frequencies, whereas TDM (time division multiplexing) interleaves signals as in the following illustrations.

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References in periodicals archive ?
These results were similar to those of other researchers in the study of FDM processing parameters.
Based on results given in Tables 3-12, it can be concluded that in the case of the posed problem the highest accuracy was achieved by applying the DQM, also in most cases the accuracy of the results obtained by the HWM is higher than that obtained by the FDM (there fundamental frequencies in Tables 3 and 7 are exceptions).
Reconstruction and Development of a 3D Printer Using FDM Technology.
Like many companies, Flowserve first used FDM and FFF for development of its parts made via the investment casting process.
Print process simulation provides further insights into the residual stresses and performance of the 3D printed FDM part.
As an application to the FEM and FDM, we consider the following test case with the values M = 1, m = 1, K = 0.1, [P.sub.0] = 1, T = 0.25 fixed, and Y [member of] [-1,1].
Like FDM, SLS theoretically can work with any thermoplastic, as well as metal and ceramic powders, although polyamide and TPU are the most widely used plastic materials.
Inserting (35) and (37) into PDE (10) and omitting the higher term O[([DELTA][tau]).sup.2-[alpha]]) and 0([([DELTA]S).sup.2]), we obtain the FDM scheme (with notation [V.sup.n.sub.j] [approximately equal to] V([S.sub.j], [[tau].sub.n])) as follows:
The RENUA Ireland President and his other half Mary shared [euro]559,068 from their financial services firm FDM in 2014 and [euro]652,144 in 2013.
Joe Castro, a 69th Aerial Port Squadron air transportation specialist, attended a senior program management course offered by the FDM Group at its headquarters in London, England.
The US Patent Trial and Appeal Board of the United States Patent and Trademark Office (USPTO) has denied US-based 3-D printer manufacturer Afinia's requests for inter partes review of three FDM technology patents held by US-based 3-D Printing company Stratasys Ltd.