Browse Prior Art Database

Noise Free Remote Analog Data Transmission Scheme

IP.com Disclosure Number: IPCOM000045297D
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 3 page(s) / 59K

Publishing Venue

IBM

Related People

Pillera, TJ: AUTHOR

Abstract

Lab automation systems and remote central processing systems are receiving increasingly more emphasis than ever before and should continue to do so throughout the 80's. With integrated module prices coming down and with new design and manufacturing techniques, the price of such systems will be more affordable for many small businesses and consumers. One (technical and cost) problem which remains is the sensing of remote analog signals from one central point.

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Noise Free Remote Analog Data Transmission Scheme

Lab automation systems and remote central processing systems are receiving increasingly more emphasis than ever before and should continue to do so throughout the 80's. With integrated module prices coming down and with new design and manufacturing techniques, the price of such systems will be more affordable for many small businesses and consumers. One (technical and cost) problem which remains is the sensing of remote analog signals from one central point.

A typical distribution system (Fig. 1) may require sensing and/or control of events (e.g. , temperature, flow, pressure, voltage, etc.) up to several hundred meters distant from the operator's interface station at a central processor 1. These analog processes may be open-loop (monitor-only as at 2 or local control as at 3), or they may be closed-loop as at 4, in which case the central processor could actually control the signal set points. In any case, the analog signal must be received with good integrity in any (electrical) environment at the central processing point.

The design of a transmitter 6 (Fig. 2) and a receiver 7 (Fig. 3) accomplishes this goal. It provides an excellent and unique cost-effective solution. The stages of transmitter 6 are an input voltage converter 8, voltage-controlled oscillator (VCO) 9, buffer 10, driver 11, and optical transducer 12. The transmitter 6, would reside at the point where the analog process is located, and data is transmitted through a fiber-optic link 13.

Voltage converter 8 is a single-ended input which converts the transducer output voltage into an acceptable input to VCO 9. The voltage input range may be adjusted. Diode clamping on the input may be required for circuit-protection purposes.

VCO 9 converts the input voltage level into a frequency modulated output signal. Beyond this point the signal is no longer sensitive to amplitude variations and noise (FM broadcasting technique). A phase-locked loop is used as a modulating device due to its excellent linear performance.

Buffer 10 and driver 11 interface VCO to a...