TY  - BOOK
AU  - Halliday David and others 
TI  - Electronic communications systems 
SN  - 0-07-463682-0 
U1  - 621.382 KEN  
PY  - 1998///
CY  - Tata mcgraw hill 
PB  - New Delhi 
KW  - COMMUNICATION SYSTEM
ER  -