INDUSTRIAL TRANNING

REPORT

BASIC TELEPHONY:-

DEMERITS OF FIXED LINE TELEPHONES

No mobility Security problem High call failure rate (line disconnection) Delay in getting new connections Limited value added services

CORDLESS TELEPHONY:-.

Cordless systems with enhanced functionality (DECT)have been developed that can support higher data rates and more application such use of multiple handsets with one home base station .

CELLULAR SYSTEMS:-

Analog cellular systems (AMPS, TACS and NMT) and digital cellular systems (GSM and CDMA IS-95).

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Analog cellular systems (AMPS, TACS and NMT) and digital cellular systems (GSM and CDMA IS-95).

WIRELESS SYSTEM EVOLUTION:-

Generation1 (analog wireless systems)

Generation 2 system(digital wireless system) :

Generation 3 systems:-

G.S.M Global system for mobile

communication. G.S.M was though first developed in

Europe In G.S.M. System, TDMA in a

combination with FDMA Is used. The usage of each radio channel is

portioned into multiple (8) time slots and each user is assigned a specific frequency\time slot combination.

SOME VERSION OF G.S.M:-

RANGE OF ONE CHANNEL:-

- Let’s take the case of G.S.M. Band frequency.

- 890 to 915 MHZ - Uplink Frequency

- 935 to 960 MHZ - Downlink Frequency

- Each Uplink band & Download band is of 25 MHZ duration. Now 25

MHZ is divided in 125 Parts. Each part is called Channels.

- 1 Channel=1 ARFCN=25 MHZ 125=200KHZ

- So, 1Channel=200 KHZ.

- Hence each channel becomes 200 KHZ .Each person is allocated

for 1 Channel. Hence in one band of frequency 125 Persons can talk at

a time.

HOW & HOW MUCH CAPACITY CAN BE EXTENDED BY INTRODUCING TDMA:-

- After FDMA each channel is of 200 KHZ. Now 200 KHZ is

again divided into same slots. 125 Channels=125*8=1000 time

slots. But out of 125,124 channels are used for speech

transmission. One channel in each frame is left for providing

gap to next frame. This one channel is used as a guard to avoid

overlapping between two frames. Hence from 125 channels

including TDMA no. of time slots used for

traffic=124*8=992 .Hence 992 persons can talk from one

frame. In this way it increases the capacity of traffic.

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CELL STRUCTURE:-

Each cell is hexagonal in shape. Each cell may be of different shape and size. In highly dense area, the size of cell will be small and in lesser dense area cell size will be larger. Size of cell on highways and on main roads, cell size is optimized to cover larger length along the road. This can be made possible by using highly directive antenna.

FREQUENCY REUSE CELLULAR TELEPHONY

GSM ELEMENT Consist of the mobile equipment and SIM card. MOBILE EQUIPMENT Uniquely identified by IMEI(international mobile

subscriber identity)  

SIM EQUIPMENT:- Uniquely identified by IMSI(international mobile

subscriber identity) Also contain secret key for authentication. Can be protected against unauthorized use by a

PIN(personal identity number) Can also store SMS message for later retrieval. IMSI & IMEI are independent personal mobility

.

BSS (BASE STATION SUBSYSTEM) BTS(BASE TRANS CEIVER STATION) BSC(BASE STATION CONTROLLER) HLR(HOME LOCATION REGISTER) VLR (VISITER LOCATION REGESTER) EIR (EQUIPMENT IDENTITY REGISTER) EIR (EQUIPMENT IDENTITY REGISTER) WHITE LIST, GREY LIST, BLACK LIST

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AUC (AUTHENTICATION CENTRE) OMC (OPERATION AND MAINTENANCE CENTRE) BASE MATERIAL CUTTING DRILLING ELECTROLESS PLATING

PCB MANUFACTURING A PCB is used to mechanically support

and electrically connect electronics component using conductive path –ways or tracks. Etched from copper sheets laminated into a non-conductive substrate.

STEPS FOR PCB PREPARATION BASE MATERIAL CUTTING DRILLING ELECTROLESS PLATING PUMICING LAMINATION EXPOSURE

DEVELOPMENT ELECTROPLATING STRIPPING ETCHING Sn-Pb STRIPPING (SOLDER STRIPPING) PISM (PHOTO IMAGE SOLDER MASK) HAL (HOT AIR LEVELLING) SCREEN MASKING/PRINTING ROUTING TESTING QUALITY CONTROL

The raw material used for the manufacturing of the PCB is “COPPER CLAD EPOXY LAMINATE”.

THROUGH HOLE TECHNOLOGY

In this technology electronics component are inserted into plated through whole (PTH) in the PCB & soldering is done at bottom side.

This technology involve following process:

Cutting of component

↓

Component forming

↓

PCB preparation

↓

1-stage component insertion

↓

Inspection of assembly

↓

Wave soldering

↓

2-nd stage insertion

↓

Final inspection

↓

Testing

SURFACE MOUNT TECHNOLOGY (SMT) Introduction Surface mount technology reduces PCB

size human work and give accuracy. ADVANTAGE OF SMT:- PCB size reduction DISADVANTAGE OF SMT:- Component identification is difficult

E1OB E10B is a digital switching system

which supports only voice communication and CIT ALKATEL of France develops this system. E10B is a telephone switching system based on electronics components and technique. this switching can be use to transmit a variety of signals telephone, telegraph Data.

E10B EXCHANGE STRUCTURE DIAGRAM