Signal Level of Transistor-Transistor/Low-power Schottky

Consider the signal-to-noise ratio results from the difference between the transmitting and the receiving level. Using the binary information representation, the signal-to-noise ratio can be adjusted to the environmental conditions within broad limits .

Signal level of a TTL-LS circuit
LOW level
Guaranteed transmitter level	max. 0.5 volt
Guaranteed receiver level	max. 0.8 volt
Static signal-to-noise ratio	0.3 volt
HIGH level
Guaranteed transmitter level	min. 2.7 volt
Guaranteed receiver level	min. 2.0 volt
Static signal-to-noise ratio	0.7 volt