High-speed high-accuracy multiplexing of analog signals for use in digital systems

The past few years have seen rapid strides in the understanding and use of digital systems. In the field of telemetry, pulse code modulation systems have been developed and tested with excellent results. An airborne PCM system is made up of the analog pickup devices, a switch or multiplexer for sampling more than one channel, an analog-to-digital converter, and an rf transmitter. The objective of this paper is to describe the multiplexing function. First, some of the necessary characteristics unique to PCM are described, followed by a description of a multiplexer that meets these requirements, and finally, a transistorized multiplexer that includes further refinements.