Abstract: A system for transmitting an analog signal comprises converting the input analog signal to a binary signal by detecting the change in sign of the slope of the analog signal and generating a binary signal whose transition occurs at each change of sign of slope of the analog signal. In a preferred embodiment of the invention, the binary signal is transmitted as an amplitude modulation on a carrier frequency over a fiberoptic line to a receiver. The receiver converts the detected binary signal into an analog signal by binary signal gating of a clock signal into an up/down counter whose digital output is converted to an analog signal which is filtered to remove the clock frequency and harmonics of the highest desired input signal frequency thereby providing a replica of the input analog signal. Multiple input signals may be multiplexed and their digital outputs processed in a computer to extract information as in seismographic exploration.