http://www.aaroncake.net/circuits/slave.htm
TOTX176, TOTX173
http://www.sc-elec.demon.co.uk/totx.htm
http://www.epanorama.net/circuits/strobo.html
Display Binary and Hex data on this Hand Held device
http://www.webelectricmagazine.com/98/2/ddisplay.htm
http://www.rlocman.com.ru/am/a04001.htm
a visual display of the activity of a digital logic signal
http://www.edn.com/archives/1995/101295/21di2.htm
helps monitoring the quality of a mile long column of air for optical communications experiments.
http://www.imagineeringezine.com/PDF-FILES/airmon0.pdf
It has a bandwidth that extends beyond 50MHz.
http://www.imagineeringezine.com/PDF-FILES/fetamp0.pdf