Data Transmission & Retrieval PPT Physics Class 12

 Page 1


DATA TRANSMISSION AND RETRIEVAL
This Chapter includes 
1. Demodulation
2. Data Transmission and Retrieval
3. FAX
4. Modem
Page 2


DATA TRANSMISSION AND RETRIEVAL
This Chapter includes 
1. Demodulation
2. Data Transmission and Retrieval
3. FAX
4. Modem
Demodulator
C’ offers low impedance to RF 
signal and high impedance to AF 
signal since  X
c 
= 1/2 ??C’
Amp. 
Modulated 
Signal
Output  
AF signal
L
1
L
2
R
L
C’ C
D
Page 3


DATA TRANSMISSION AND RETRIEVAL
This Chapter includes 
1. Demodulation
2. Data Transmission and Retrieval
3. FAX
4. Modem
Demodulator
C’ offers low impedance to RF 
signal and high impedance to AF 
signal since  X
c 
= 1/2 ??C’
Amp. 
Modulated 
Signal
Output  
AF signal
L
1
L
2
R
L
C’ C
D
Data Transmission
AF  Amplifier
AF Power 
Amplifier
Modulator
Power 
Amplifier
L
i
n
e
F
i 
l 
t
e
r
AF  Processor 
and  Filter
AF Data
HF  Amplifier
HF 
oscillator
Transmitting Antenna
Page 4


DATA TRANSMISSION AND RETRIEVAL
This Chapter includes 
1. Demodulation
2. Data Transmission and Retrieval
3. FAX
4. Modem
Demodulator
C’ offers low impedance to RF 
signal and high impedance to AF 
signal since  X
c 
= 1/2 ??C’
Amp. 
Modulated 
Signal
Output  
AF signal
L
1
L
2
R
L
C’ C
D
Data Transmission
AF  Amplifier
AF Power 
Amplifier
Modulator
Power 
Amplifier
L
i
n
e
F
i 
l 
t
e
r
AF  Processor 
and  Filter
AF Data
HF  Amplifier
HF 
oscillator
Transmitting Antenna
Data  Retrieval
Receiving 
Antenna
L
i
n
e
F
i 
l 
t
e
r
HF  Amplifier-I HF  Amplifier-II Demodulator
AF Power 
Amplifier
AF  Data 
Processor 
AF Data
Amp. 
Modulated 
Signal
AF  Pre-
Amplifier
Page 5


DATA TRANSMISSION AND RETRIEVAL
This Chapter includes 
1. Demodulation
2. Data Transmission and Retrieval
3. FAX
4. Modem
Demodulator
C’ offers low impedance to RF 
signal and high impedance to AF 
signal since  X
c 
= 1/2 ??C’
Amp. 
Modulated 
Signal
Output  
AF signal
L
1
L
2
R
L
C’ C
D
Data Transmission
AF  Amplifier
AF Power 
Amplifier
Modulator
Power 
Amplifier
L
i
n
e
F
i 
l 
t
e
r
AF  Processor 
and  Filter
AF Data
HF  Amplifier
HF 
oscillator
Transmitting Antenna
Data  Retrieval
Receiving 
Antenna
L
i
n
e
F
i 
l 
t
e
r
HF  Amplifier-I HF  Amplifier-II Demodulator
AF Power 
Amplifier
AF  Data 
Processor 
AF Data
Amp. 
Modulated 
Signal
AF  Pre-
Amplifier
FAX (Facsimile Telegraphy)
*  The electronic reproduction of a document at a 
distant place via Telephone line
Optical 
Scanner
Sensor Modem
Printer
Original 
Document
Light 
Signal
Digital 
Signal
Analog 
Signal
Telephone 
Line
FAX Copy
Functions Performed by FAX:
i) Optical Scanning     ii) Conversion of data for transmission   
and reception         iii) Printing a copy at the receiver’s end