Today we are present in a digital world where almost all electronics are now digital i.e Digital clock,calculator etc. All the electronics depend on signals. Any thing which varies with respect to time is called signal or one axis must time. There are two types of signals
1)Continuous Time Signal: specified for every value of time
2)Discrete Time Signal:it is logic 1 for specified value else 0.
Digital signal have two specified value. When 1 is higher than 0 then it is +ve logic i.e 1V –> 5V.
It’s inverse is -ve logic i.e 1V –> -5V. Any method that produce 2 states (0,1) called digital method.
1–10 gates Small Scale Integration
10–100 gates Medium Scale Integration
100–10000 gates Large Scale Integration
10000–million gates Very Large Scale Integration
In electrical engineering power consumption refers to energy per unit time. Power consumption usually measures in Watts or kiloWatts.
number of inputs that can connected to specified output or maximum similar gates connected to each other. TTL gate has fan out of 10.
in electronics propagation delay means time consumed in transfer of signal from sender to receiver.
when signal exceeds the threshold a proper 0 or 1.
Continuous wave that changes Discrete wave that carry informat-
with time ion in binary form.
Sine wave Square wave
Described amplitude,frequency Described by bit rate,bit interval
No fix range Finite range
Prone to noise Less prone
human voice signals used for transmission in computer
Note:Decrease in amplitude of a signal is called attanuation.