“Handling PCM on the ground — Some problems, some solutions”
Thomas G. Hagan · IRE Transactions on Telemetry and Remote Control · 1957
Pulse code modulation provides a highly accurate means of transmitting and recording multichannel instrumentation data. But in addition to accuracy and ease of entry into digital computers, PCM affords other advantages which have not yet been fully realized. Accurate analog outputs are easily obtained from PCM systems for real time recording or processing of data in analog form. Moreover, time scale change during tape playback may be achieved easily and with no loss of accuracy, thereby “matching” the data spectrum to the bandwidth of the analog computing and plotting equipment. Practical techniques for such data handling operations are discussed along with some of the consequences and limitations of these methods.