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                                 ONE TO MANY COMM. RF SYNOPSIS

CONTENTS

S.N

TOPIC

PAGENO.

1.

INTRODUCTION TO BHARTI GROUP

2

2

THE GROUP STRUCTURE OF BHARTI

6

3

COMPANY SYNOPSIS

9

4

ABOUT THE LUDHIANA UNIT

11

5

THE PROFILE OF BHARTI SYSTEL LTD.

13

6

THE ORGANISATION CHART OF BSL

14

7

DIFFERENT TELEPHONE SETS

15

8

MAIN STORE

16

9

MOULDING SECTION

16

10

PRODUCTION ELECTRONICS     

22

11

PCB ASSEMBLY

25

12

WAVE SOLDERING

27

13

PCB TESTING

30

14

FINAL TESTING

31

15

FINAL REWORK

31

16

BASIC TELEPHONY

39

17

FINAL REWORK OF Bt2002

57

18

QUALITY CONTROL SYSTEM

69

19

CALLIBRATION ENSURES

88

20

RECEIPT AND ISSUING SECTION OF MATERIAL STORE

95

21

 

 

 

 

 

22

PROJECT REPORT

RF  Communication

INTRODUACTION TO OPTICA .

OVERALL WORKING

BLOCK DIAGRAM

BIBILIOGRAPHY

97

 

98

112

130

168

     

 

 

 

 

 

MATERIAL REQUREMENT :-

 

1.      RF 

2.      SOLDERING IRON-1

3.      SOLDERING WIRE FLUX-1

4.      DESOLDERING WICK- 1 Meter

5.      BREAD BOARD- 1

6.      CONNECTING WIRES- ACC. TO REQUIREMENT

7.      IC 741(2)

8.      L.E.D’S-1

9.      TRANSISTOR

10.  CONDENSER MIC-2

11.  SPEAKER( 8 OHM)-2

12.  RESISTANCES(10 K,4.7K,220K,110K,1K)

13.  P.C.B

14.  PHOTO DIODE-2

15.  LASER

16.  SUPPLY- 9V

17.  CAPACITORS

18.  IC 91214

19.  IC 8870

20.  IC 74154

21.  ZENER 3.3V

22.  IC 7805

23.  DIODES(4007)

 

 

 

Objective:-

 

One to Many communication using RF

 

 

 

 

 

 

 

 

 

 

Software Required:-

Window os

OrCAD

MS word

 

Introduction:-

In this project we will make the one to many communication using RF . Main features of this project is advantages of RF . We are using RF   which will keep your conversation and data secure from others. In this sytem we will make master slave system . In which master can send data and voice message to any slave . he has the full control on the system. In this project we are taking the example of office system. In this project officer can select the user with keyboard and can talk to any one by selecting from keyboard.

In this project we will learn about how to use RF  for communication purpose. RF  need not to introduce. Everybody although he/she may be from any field know about RF. RF  as we know a reliable, low cost, flexible, large bandwidth communication medium.  IN one to many communication we will control many speakers from our system and can send data on any particular  speaker.

In this project we can control any electrical appliances like speakers through DTMF dialing circuit for remote purpose .  When we want to control any electrical appliances through DTMF dialing circuit. Now again we press the switch on/off code to on/off any electrical appliances. With the help of this code unit is on and base unit give a acknowledge pulse for on and off separately.

DTMF Encoder Circuit:- in this circuit we will use IC91214 for no of devices. We will add keyboard with this IC. Ethis IC have option to generate 16 different pulses with different frequencies. These dual tone multi frequencies can be decoded at receiver side with IC8870 . these IC are esily available in market. We will use LASER for data transmission.

1.                 DTMF DECODER

In dtmf decoder circuit we use ic 8870 ic. IC 8870 is a dtmf decoder ic. IC 8870  converts the dual tones to corresponding binary outputs.

 

DTMF SIGNALLING. Ac register signaling is used in dtmf telephones, here tones rather than make/break pulse are used fro dialing, each dialed digit is uniquely represented by a pair of sine waves tones. These tones ( one from low group for row and another from high group fro column) are sent to the exchange when a digit is dialed by pushing the key, these tone lies within the speech band of 300 to 3400 hz, and are chosen so as to minimize the possibility of any valid frequency pair existing in normal speech simultaneously. Actually, this minimisator is made possible by forming pairs with one tone from the higher group and the other from the lower of frequencies. A valid dtmf signal is the sum of two tones, one from a lower  group ( 697-940 Hz) and the other from a a higher group ( 1209-1663 Hz). Each group contains four individual tones.  This scheme allows 10 unique combinations. Ten of these code represent digits 1  through 9 and 0. . tones in DTMF dialing  are so chose that none of the tones is harmonic of  are other tone. Therefore  is no change of distortion caused by harmonics. Each tone is sent as along as the key remains pressed. The dtmf signal contains only one component from each  of the high and low group. This significaly simplifies decoding because the composite dtmf signal may be separated with band pass filters into single frequency components, each of which may be handled individually.

 

First ic of this section is ic 74154. IC 74154 is  bcd to decimal decoder. 74154 is active low ic. Pin no 20,21,22,23 is connected to dtmf decoder ic.

Pin no 18 and 19 of this ic is connected to the collector of one npn transistor Base of the npn transistor is connected to the pin no 15 of the ic 8870. When dtmf decoder decode the signal at that time pin no 15 is on for a time and acknowledge the signal. This signal is fed to the  base of NPN transistor through 1 kohm resistor. When this signal is coming then 74154 is on and gives a output.

 

Then output of 74154 is active low. We will use IC 74ls 74  or transistors to invert the active low output. After that we will use flip flop & SCRs or relays to control & to give 220v Ac to devices for switching purposes.

 

 

 

 

 

COMPONENT DESCRIPTION

 

TRANSFORMER

 

 

Transformer works on the principle of mutual inductance. We know that if two coils or windings are placed on the core of iron, and if we pass alternating current in one winding, back emf or induced voltage is produced in the second winding. We know that alternating current always changes with the time. So if we apply AC voltage across one winding, a voltage will be induced in the other winding. Transformer works on this same principle. It is made of two windings wound around the same core of iron. The winding to which AC voltage is applied is called primary winding. The other winding is called as secondary winding.

                

Voltage and current relationship:

 

Let V1 volts be input alternating voltage applied to primary winding. I1 Amp is input alternating current through primary winding. V2 volt is output alternating voltage produced in the secondary. I2 amp be the current flowing through the secondary.

 

Then relationship between input and output voltages is given by

V1/V2 = N1/N2

 

Relationship between input and output currents is

I1/I2 = N2/N1

(Where N1 is no. of  turns of coil in primary and N2 is number of turns in secondary )

 

We know that Power = Current X Voltage. It is to be noted that input power is equal to output power. Power is not changed. If V2 is greater than V1, then I2 will be less than I1. This type of transformer is called as step up transformer. If V1 is

 

greater than V2, then I1 will be less than I2. This type of transformer is called as step down transformer.

For step up transformer, N2>N1, i.e., number of turns of secondary winding is more than those in primary.

For step down transformer, N1>N2, i.e., numbers of turns of primary winding is more than those in secondary.

 

 

 

 

 

RESISTORS

 

 

The flow of charge (or current) through any material, encounters an opposing force similar in many respect to mechanical friction. This opposing force is called resistance of the material. It is measured in ohms.  In some electric circuits resistance is deliberately introduced in the form of the resistor.

Resistors are of following types:

1.      Wire wound resistors.

2.      Carbon resistors.

3.      Metal film resistors.

 

Wire Wound Resistors:

 

Wire wound resistors are made from a long (usually Ni-Chromium) wound on a ceramic core. Longer the length of the wire, higher is the resistance. So depending on the value of resistor required in a circuit, the wire is cut and wound on a ceramic core. This entire assembly is coated with a ceramic metal. Such resistors are generally available in power of 2 watts to several hundred watts and resistance values from 1ohm to 100k ohms. Thus wire wound resistors are used for high currents.

 

Carbon Resistors:

 

Carbon resistors are divided into three types:

a.      Carbon composition resistors are made by mixing carbon grains with  

      binding material (glue) and moduled in the form of rods. Wire leads

      are inserted at the two ends. After this an insulating material seals the

      resistor. Resistors are available in power ratings of 1/10, 1/8, 1/4 ,

      1/2 , 1.2 watts and values from 1 ohm to 20 ohms.

b.      Carbon film resistors are made by deposition carbon film on a ceramic         

rod. They are cheaper than carbon composition resistors.

c.      Cement film resistors are made of thin carbon coating fired onto a

      solid ceramic substrate. The main purpose is to have more precise

      resistance values and greater stability with heat. They are made in a

      small square with leads.

 

Metal Film Resistors:

 

They are also called thin film resistors. They are made of a thin metal   coating deposited on a cylindrical insulating support. The high resistance values are not precise in value; however, such resistors are free of inductance effect that is common in wire wound resistors at high frequency.

 

Variable Resistors:

 

Potentiometer is a resistor where values can be set depending on the requirement. Potentiometer is widely used in electronics systems. Examples are volume control, tons control, brightness and contrast control of radio or T.V. sets.

 

Fusible Resistors:

 

These resistors are wire wound type and are used in T.V. circuits for protection. They have resistance of less than 15 ohms. Their function is similar to a fuse made to blow off whenever current in the circuit exceeds the limit.

 

Resistance of a wire is directly proportional to its length and inversely proportional to its thickness.

 

             R     L   

             R     1/A 

 

COLOUR CODES 

 

COLOUR

NUMBER

MULTIPLIER

COLOUR

TOLERANCE

Black                                 

Brown

Red

Orange

Yellow

Green

Blue

Violet

Grey

White

Gold

Silver

      0

      1

      2

      3

      4

      5

      6

      7

      8

      9

 

       100

        101

        102    

        103

        104

        105

        106

        107

        108

        109

        10-1

        10-2

    

Gold

Silver

No colour

      5%

       10%

       20%

 

 

CAPACITORS

 

A capacitor can store charge, and its capacity to store charge is called capacitance. Capacitors consist of two conducting plates, separated by an insulating material (known as dielectric). The two plates are joined with two leads. The dielectric could be air, mica, paper, ceramic, polyester, polystyrene, etc.  This dielectric gives name to the capacitor. Like paper capacitor, mica capacitor etc.

 

 

Types of capacitors:

 

 

Text Box: Capacitor

 

 

 


 

                                       

 

 

 

Capacitors can be broadly classified in two categories, i.e., Electrolytic capacitors and Non-Electrolytic capacitors as shown if the figure above.

 

 

 

Electrolytic Capacitor:

 

Electrolytic capacitors have an electrolyte as a dielectric. When such an electrolyte is charged, chemical changes takes place in the electrolyte. If its one plate is charged positively, same plate must be charged positively in future. We call such capacitors as polarized. Normally we see electrolytic capacitor as polarized capacitors and the leads are marked with positive or negative on the can. Non-electrolyte capacitors have dielectric material such as paper, mica or ceramic. Therefore, depending upon the dielectric, these capacitors are classified.

 

Mica Capacitor:

 

It is sandwich of several thin metal plates separated by thin sheets of mica. Alternate plates are connected together and leads attached for outside connections. The total assembly is encased in a plastic capsule or Bakelite case. Such capacitors have small capacitance value (50 to 500pf) and high working voltage (500V and above). The mica capacitors have excellent characteristics under stress of temperature variation and high voltage application. These capacitors are now replaced by ceramic capacitors.

 

Ceramic Capacitor:

 

Such capacitors have disc or hollow tabular shaped dielectric made of ceramic material such as titanium dioxide and barium titanate. Thin coating of silver compounds is deposited on both sides of dielectric disc, which acts as capacitor plates. Leads are attached to each sides of the  dielectric disc and whole unit is encapsulated in a moisture proof coating. Disc type capacitors have very high value up to 0.001uf. Their working voltages range from 3V to 60000V. These capacitors have very low leakage current. Breakdown voltage is very high.

 

 

Paper Capacitor:

 

It consists of thin foils, which are separated by thin paper or waxed paper. The sandwich of foil and paper is then rolled into a cylindrical shape and enclosed in a paper tube or encased in a plastic capsules. The lead at each end of the capacitor is internally attached to the metal foil. Paper capacitors have capacitance ranging from 0.0001uf to 2.0uf and working voltage rating as high as 2000V.

 

 

 

THE DIODE

 

Diodes are polarized, which means that they must be inserted into the PCB the correct way round. This is because an electric current will only flow through them in one direction (like air will only flow one way trough a tyre valve). Diodes have two connections, an anode and a cathode. The cathode is always identified by a dot, ring or some other mark.

 

The PCB is often marked with a +sign for the cathode end. Diodes come in all shapes and sizes. They are often marked with a type number. Detailed characteristics of a diode can be found by looking up the type number in a data book. If you know how to measure resistance with a meter then test some diodes. A good one has low resistance in one direction and high in other. They are specialized types of diode available such as the zener and light emitting diode (LED).

 

 

 

 

 

 

IC (Integrated Circuit) means that all the components of the circuit are fabricated on same chip. Digital ICs are a collection of resistors, diodes, and transistors fabricated on a single piece of semiconductor, usually silicon called a substrate, which is commonly referred to as ‘wafer’. The chip is enclosed in a protective plastic or ceramic package from which pins extend out connecting the IC to other device. Suffix N or P stands for dual-in-line (plastic package (DIP)) while suffix J or I stands for dual-in-lime ceramic package. Also the suffix for W stands for flat ceramic package.

 

The pins are numbered counter clockwise when viewed from the top of the package with respect to an identity notch or dot at one end of the chip.The manufacturer’s name can usually be guessed from its logo that is printed on the IC. The IC type number also indicates the manufacturer’s code. For e.g. DM 408 N SN 7404 indicates National Semiconductor and Texas Instruments.

 

Other examples are:

            Fair Child                               : UA, UAF

            National Semiconductor       : DM, LM, LH, LF, and TA.

            Motorola                                : MC, MFC.

            Sprague                                   : UKN, ULS, ULX.

            Signetic                                  : N/s, NE/SE, and SU.

            Burr-Brown                            : BB.

            Texas Instruments                 : SN.

 

The middle portion i.e. the IC type number tells about the IC function and also the family, which the particular IC belongs to.IC’s that belongs to standard TTL series have an identification number that starts with 74; for e.g. 7402, 74LS04, 74S04 etc. IC’s that belongs to standard CMOS family their number starts with 4, like 4000, 451B, 4724B, 1400. The 74C, 74HC, 74AC & 74ACT series are newer CMOS series.

 

Various series with TTL logic family are:-

 

            Standard TTL 74.

            Schottky TTL 74s.

            Low power Schottky 74LS.

            Advance Schottky 74AS.

            Advanced Low Power Schottky 74ALs.

 

Also there are various series with CMOS logic family as metal state CMOS 40 or

 

 

PIN DESCRIPTION

 

 

IC 74154 is a BCD to Decimal converter. This IC is a 24 pin IC. Pin no.20,21, 22,23 are the BCD input pins of this IC,pin no. 2,3,4,5,6,7,8,9,10,11, are the output pins, pin no.24 is connected to the positive 5 volt supply  and pin no.12 is the negative supply pin. Pin no. 18 and pin no. 19 of this IC is enable pin. If the data available on the pin no. 19 is negative then output is negative for a time. The negative pulse is given by the NPN transistor collector point. IC 74154 is a special package may be used to provide a 1 low output out of 16 outputs or may be used to send input data to one selected output of 16, the remaining 15 staying high.

 

Substitute IC: No other substitute easily available

 

 

               

 

                                                                                                                      

 

 

 

   IC 40499

 

 

 


 

PIN DESCRIPTION

 

 

IC 4049 is a hex inverter IC. Pin no. is connected to the positive supply. Pin no. 7 is connected to negative supply. Pin no. 3,5,7,9,11 are the inputs of the IC and pin no. 2,4,6,10,12 are the input pins of this IC. Since the output of IC 74154 are low hence IC 4049 is used to invert the output of IC 74154, ie ,  to convert the low output of the decoder IC into high output

 

Substitute IC:  7404

 

By using this portion with RF commnication, we can control different electrical or electronics equipments with the help of the  control signal. In communication circuit we use one dtmf decoder circuit. In that dtmf decoder circuit we use ic 8870 as a dtmf decoder circuit and one ic 7447 as a bcd to seven segment decoder.

 

We use one another dtmf decoder circuit, ic 8870 decoder and sense the output in the form of the bcd signal from the  dtmf decoder circuit.

 

 

 

Bibliography

For study material

www.projectidea.com

 

www.rfcom.com

 

www.atmel.com

For components:

www.ludhianaprojects.com