Gate Symbols - HP 5340A Operating And Service Manual

Model 5430A
Theory of Operation
4-6. INVERSION. AND and OR gates are shown in Figure 4-2(A,B). A circle on the output
logic symbol indicates a LOW when activated as shown in Figure 4-2(C and D). Thus, a circle
indicates inversion. An AND gate with a n inverted output is called a NAND gate; and OR gate
with a n inverted output is called a NOR gate. A unity-gain amplifier with a n inverted output is
called a n inverter, Figure 4-2(E).
Three types of digital signals are present in this instrument. They are:
Transistor Transistor Logic (WL).
1.
2. Emitter Coupled Logic (ECL).
3. Emitter Emitter Coupled Logic (EECL).
Digital signals have two logic states, referred to as High and Low. The voltage associated with
the High different for each logic
Low state is
or
High
When logic levels are stated i,n this manual, they will be prefaced by 'M'L, ECL, or EECL. When
no preface is given, assume tha the logic level under discussion is "L.
4-2
Figure 4-2. Gate Symbols
AND OR
D E
NOR INVERTER
NOTE
type.
TTL
0 to +0.4V
approximately
2.4 to 5V approximately
NAND
ECL EECL
approximately
approximately
ov
of a