Communications: electrical – Continuously variable indicating – With meter reading
Patent
1985-04-03
1987-09-01
Weldon, Ulysses
Communications: electrical
Continuously variable indicating
With meter reading
3408255, 34082534, 235382, H04Q 700, G07D 700, G06K 500
Patent
active
046912029
ABSTRACT:
An identification system comprises an interrogator which transmits an interrogation signal to a plurality of transponders, each of which is arranged automatically to reply by means of a first coded identification signal stored in the transponder and modulated onto a carrier wave transmitted by the transponder. The interrogator receives and checks the reply signal. In the event of there being a plurality of transponders within range and broadcasting reply signals simultaneously, the interrogator receives corrupted reply signals. The interrogator therefore retransmits the reply signals to the transponders and each transponder checks the retransmitted reply signal with its first coded identification signal. In the event of correspondence the transponder discontinues transmission and in the event of non-correspondence the transponder continues transmission. In a polling mode of operation, the interrogator initially transmits a second coded identification signal corresponding to a selected transponder, and each transponder within the range compares the second signal with the first signal stored therein. If correspondence is established, the transponder is adjusted to receive further instructions which may comprise replacement of data stored therein. Each transponder includes a demodulator 34 comprising a phase locked loop which provides data, clock and carrier detect signals to a CPU 50 which includes ROM, RAM and an ALU. The carrier detect signal enables the CPU to switch the transponder from a power down condition to a power up condition.
REFERENCES:
patent: 3772668 (1973-11-01), Smith
patent: 3944928 (1976-03-01), Augenblick et al.
patent: 4063173 (1977-12-01), Nelson et al.
patent: 4399437 (1983-08-01), Falck et al.
patent: 4459474 (1984-07-01), Walton
patent: 4471356 (1984-09-01), Gidl
patent: 4546322 (1985-10-01), Crutcher
Denne Phillip R. M.
Hook Christopher D.
Smith Ralph E.
Weldon Ulysses
LandOfFree
Identification systems does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Identification systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Identification systems will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1267361