Design of a Digital Telemetry Unit using Dot Components

It has long been apparent that uniformity of the body geometry and of the lead geometry and material of electronic parts is highly desirable. Dot or pellet component parts provide such uniformity to a high degree and thus lend themselves to the design of equipment of considerable sophistication. To demonstrate the technique a digital telemetry unit, previously packaged in the form of welded cordwood modules, was designed using dot components. The unit consists of some 1200 parts disposed on six card-shaped modules measuring 3" x 6.7" x 0.03". Modules are made of molded epoxy and are color coded for assembly and trouble shooting purposes. Silkscreened conductive adhesive is used for intraconnections. All interconnections (i.e. external to modules) are brought out along one edge of the module in the form of flexible, multistranded wires. These wires are permanently soldered, book fashion, to an interconnection matrix consisting of an array of welded tubes. By treating the modules as pages in a book, all parts are accessible for inspection or replacement without disconnecting any section of the circuit. Foil-clad balsa wood spacers are provided for separation between adjacent modules. The modules and spacers are stacked and compressed by means of two rigid end plates and two screws, thus providing a compact, prestressed structure virtually immune to shock and vibration.