The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 25, 1976
Filed:
Jun. 17, 1975
Yutaka Wakasa, Musashino, JA;
Hisayuki Uchiike, Musashino, JA;
Koju Kataoka, Musashino, JA;
Yasuro Takiura, Musashino, JA;
Yokogawa Electric Works, Ltd., Tokyo, JA;
Abstract
A signal transmission system of the type used in process control systems for conveying a signal between a field telemetering instrument and a central controller, or between a central controller and a process control device. The signal transmission system is arranged with a transmitter accepting an input signal, a transmission line for carrying a transmission signal, and a receiver receiving the transmission signal and developing an output signal. In accordance with the invention, converter means in the transmitter develop a pulse width signal with a duration corresponding in a predetermined manner to the value of the input signal, and means in the transmitter provide the transmission signal (e.g., a current signal) with two states (e.g., opposite polarities), one of which has a duration corresponding to the duration of the pulse width signal. Means in the receiver provide the output signal with a duration corresponding to the duration of the one transmission signal state, which corresponds in turn to the value of the input signal, and can be used for conversion to digital or analog form. Means in one of the transmitter or receiver supplies power for the transmission signal, and means in the other of the transmitter or receiver derives operational power, e.g., for the telemetering instrument, from the transmission signal. The signal transmission system thus is able to convey signals with less susceptibility to noise, while at the same time retaining the ability to convey operational power.