Browse Prior Art Database

Analog Storage Device

IP.com Disclosure Number: IPCOM000094052D
Original Publication Date: 1966-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Beck, JW: AUTHOR

Abstract

A field effect transistor FET and a charge holding capacitor are provided for storage of an analog signal level for a multiplexed control system.

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Analog Storage Device

A field effect transistor FET and a charge holding capacitor are provided for storage of an analog signal level for a multiplexed control system.

It is desirable in such storage devices for the means to supply the charge to the capacitor to have a long lifetime and a low leakage resistance. A substrate of thin film insulated gate FETs and all the interconnecting wiring is fabricated as an integrated assembly. This assembly comprises face plate 10 of cathode ray tube
12. Each gate surface 14 is coated with a suitable material to enhance the secondary emission properties of surface 14. The latter serves as the target for an electron beam in cathode ray tube 12. The beam position is determined by deriving suitable horizontal and vertical deflection voltages by decoder circuit 16 working directly from a computer address register 18.

The operation of one channel is shown in the lower drawing. Multiplexer 20 supplies a new analog voltage En to the gate of FET 22. Circuit 24 compares En to the previous analog voltage Eo which is stored in capacitor C1. If En is greater than Eo, the compare circuit raises the cathode ray tube acceleration voltage through control circuit 26 to a level such that the secondary emission yield of the gate surface exceeds unity. The beam is unblanked by a signal from multiplexer 20. The closed loop consists of FET 28, compare circuit 24, beam acceleration voltage control 26. The resultant analog voltage Eo adjusts itself ...