Telegraphy – Systems – Printing
Patent
1977-09-02
1978-08-22
Robinson, Thomas A.
Telegraphy
Systems
Printing
178 68, 179 15AL, 324 585B, 343178, H04B 158, H04J 308, G01V 122, H04Q 900
Patent
active
041091175
ABSTRACT:
An apparatus is capable of recovering signals from N sites, N.gtoreq.2, distributed along a single coaxial cable. This multiplexing technique allows the separation of signals from many transducers on one line. Time domain reflectometry (TDR) is used, with variable resistive elements distributed along the cable. TDR is used to detect discontinuities in the impedance of the cable as well as their specific location along the cable. The magnitude of these discontinuities is modulated by an impedance that is proportional to the applied signal. An excellent way of obtaining this kind of variable impendance along the line is to bias a field effect transistor (FET) so that it functions as a variable resistor. For a large number of signals to be multiplexed onto a coaxial cable, an FET is placed at each of the N signal sources. The coaxial cable has a characteristic impedance of Z.sub.o and the FET's are evenly spaced at a distance l. Each of the FET's produces a discontinuity on the cable that can be detected by using time domain reflectometry. Microphones may also be used instead of the FET's.
REFERENCES:
patent: 3214734 (1965-10-01), Whitehead
patent: 3518628 (1970-06-01), Giel et al.
patent: 3609533 (1971-09-01), Pardis
patent: 3619504 (1971-11-01), DeVeer et al.
patent: 3909712 (1975-09-01), Rietz et al.
patent: 3911226 (1975-10-01), Angelle et al.
patent: 3924077 (1975-12-01), Blakeslee
patent: 3990036 (1976-02-01), Savit
"Pulse Testing of Coaxial Cables," by Lebert, Bell Laboratories Record, A 1951, pp. 153-157.
"Wire Line Fault Finder," by Flanagan, Radio and TV News, Jun. 1949, pp. 9 and 29.
Hicks Jay C.
McCartney Joseph F.
Wrench, Jr. Edwin H.
Johnston Ervin F.
Robinson Thomas A.
Sciascia Richard S.
Stan John
The United States of America as represented by the Secretary of
LandOfFree
Range division multiplexing does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Range division multiplexing, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Range division multiplexing will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1560269