公开(公告)号：WO1989007874A1

公开(公告)日：1989-08-24

申请号：PCT/US1989000637

申请日：1989-02-16

Applicant: SPARTON CORPORATION

Inventor： SPARTON CORPORATION ,  VINES, Arthur, Dudley ,  SCHONFELD, Frederick, Andrew ,  ESPAT, Ricardo

IPC: H04Q09/00

CPC classification number: H04Q9/00 ,  G08C19/26

Abstract: A plurality of addressable transducers (20) at remote locations are connected to a home station (10) by a pair of transmission lines (12) which carry power as well as address signal to the transducers (20) and carry response signals from the transducers (20) when addressed, to the home station (10). Each transducer (20) carries a decoder (34) which is programmed to recognize a particular code, and a response circuit (36, 38) comprising a current sink oscillator (36) to modulate the transmission line current at a frequency corresponding to the measured parameter. The response circuit (36, 38) operates on an analog voltage representing the measured condition by an A/D converter (102) to generate a corresponding digital number, a clock (98) provides a fixed frequency, a divider (104) divides the fixed frequency by the digital number to provide a resultant frequency, which in turn is divided by a flip-flop (106) to yield a square wave output.