Abstract: The present disclosure describes circuit variants for reducing electromagnetic interference from saturable core keyboards to acceptable levels. The invention finds particular application in conjunction with capacitive-discharge scan techniques used in such keyboards. In order to attenuate the external field resulting from such techniques, a circuit is taught which effectively disconnects the scan line array from the capacitor charging circuit during the time between scans. A second variant, when added to the first, further reduces interference by disconnecting the entire scan circuit from the supply potential during the scan time thereby eliminating steady-state currents and turnoff oscillatory transients.

Abstract: Data processing information storage and retrieval system having a memory. A number of modules are interconnected with the memory. Encode and decode modules operate in conjunction with the memory for compacting and expanding data. A revolve module in association with a delta module and a memory enable coded signals to be transferred into a number of unique but equivalent and related signals. A seed module enables the shortest of the equivalent signals to be located. A change module enables any one of the equivalent signals to be updated. An output module causes an equivalent signal to be converted back to the original signal representation. Pipe and brightness modules perform a discrimination function on stored information. The data processor includes programs which by unique means and methods structure and retrieve data from the data base. The retrieval may be based on an inexact match between events and entries of a request and the structured data base.