A digital signal
1, the modem
analog signal to a digital signal
sampling interval -> Quantification -> encoding
2, why the digital signal is a trend
(1) the analog signals of noise: thermal fluctuation, digital signal noise: the quantization error noise
I think the reason is better save the analog signal digital signal most primitive state, do not worry about noise.
Second, the basic knowledge of digital signal
1, the binary representation of a number
2 on the physical, analog voltage range of the digital signal represents a 0
(1)
outputs 0 ~ Vol Voh ~ Vdd
input 0 ~ Vil Vih ~ Vdd
large range of inputs, to the noise point space, the output range of dots, precise dot
noise tolerance margins noise
. 3, the transmission delay
(1) transition between 0 and 1 is delayed in practice
(2) TPD
. 4, delay pollution
(1) Definition: the signal changes at the input -> output terminal have long signal change
(2) the TCD
(. 3) register design to design
summary:
input signal changes -> propagation delay -> signal stability -> delay pollution -> output end change
Third, the digital system
1 **, Digital System Application: remote mobile computer **
** 2, core: ** + interface processor
3, the processor Category: SCM processor plus a "program memory" is a computer processor i7
** 4 logic: ** Boolean, logic circuit implemented tube : Shannon
5, implemented with logic gates tube
two switches in series: the gate
two switches in parallel: an OR gate
