Distributing Digital Signals to Multiple Destinations

Digital signal fanout is a very common requirement in testing, experimentation, and systems integration. Unlike radio frequency signals, high-speed digital signals cannot be simply split or "teed" off to multiple destinations. Even with a matched-impedance splitter, the resulting amplitude loss would render most clock and logic signals incompatible with the receiver. To preserve logic level compatibility, digital signals must be actively buffered when they are fanned out. Several factors must be controlled when building a fanout buffer for lab use, and each becomes more difficult at higher data rates and with longer cable lengths: