satallite manual

8/2/2019 Satallite Manual

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SATALLITE COMMUNICATION LAB

DEPARTMENT OF ECE Page 2

Angular Velocity (w):This is an indirect way of expressing the frequency

W = 2f rad / sec

Instead of considering the no of complete cycles angular velocity is a measure of how fast the vector

angle is changing. The Voltage equation of sine wave which gives the instantaneous value (v) of asine wave at any point in the cycle is given by:

v = Vpsin

for a convenience and brevity, the 2F part is often lumped together and given the title of angular

velocity().Using this notation the equation of sine wave can be written as:

v =VP sint

Wavelength:Since E/M waves at a known velocity vary sinusoidal, it is possible to consider how far a wave of

given frequency (f) would travel during the execution of one cycle. Denoting the speed of light as c

the wavelength () is given by:

= c / fFrom this, it so as clear that the higher the frequency the shorter the wavelength Satellite

broadcasting employs waves in this order of 10GHz frequency so the order of wavelength can be

calculated as follows:

= (3 108) / (10 109)

= 3 10-2m = 3 cm.

In practice the frequencies used are not necessarily a nice round figure like 10 GHz Nevertheless; the

wavelength in present use invariably works out in terms of centimeters. The enormously high

frequencies are used in satellite broadcasting? Before this can be answered it is necessary to

understand some fundamentals laws to broadcasting of information, whether it be sound or picture

information.

Carrier frequency:For simplicity, assume that it is required to transmit through space a 1000Hz audio signal, in theory

an electrical oscillator and amplifier could be rigged up and tuned to 1000 cycles per sec. And the

output fed to a piece of wire acting as primitive aerial. It is an unfortunate fact of nature that of nature

that for reasonably efficient radiation a wire aerial should have a length somewhere in order of

wavelength of 1000 Hz using the equation given above:

= c / f = 3 108/ 103 = 3 105 meters.

= 300000 m which is about 188 miles.

Apart from the sheer impractically of such an aerial, waves at these low frequencies suffer severe

attenuation due to ground absorption. Another important reason for using high frequencies is due to

the considerations of bandwidth, which is treated later. This solution is to use a high frequency wave

to carry the signal but allow the Intelligence (the 1000 Hz in our example) to modify one or more of

its characteristics. The high frequency wave is referred to as the carrier (Fc) simply because it carriesthe information in some way the method of impressing this low frequency information on to carrier is

called modulation. There are two main types amplitude modulation (AM) and frequency modulation(FM)

Amplitude modulation:The low frequency modulating signal is made to alter the amplitude of carrier at the transmitter

before the composite waveform is sent to the aerial system. If the amplitude of the modulating signal

causes the carrier amplitude to vary between double its unmodulated height and zero, the modulation

is said to be 100 percent. terrible distortion results if the modulation amplitude is ever allowed to

exceed 100 percent.


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Modulation factor:This is the ratio of modulation amplitude (Vm) to carrier amplitude (Vc)

m = Vm/ VcWhen m = 1 the modulation is 100 percent, although 100 percent is an advantage it is too dangerous

in practice, due to the possibility of over modulation, so 80% (m = 0.8) is normally considered the

safe limit.Sidebands:Although the modulating signal is simple sinusoidal waveforms, in practice it will be more complex.

Thus the envelope of the waveform will be non-sinusoidal. The unmodulated carrier sine wave has

the instantaneous form:

v = Vp sinct

But the amplitude of this wave (Vp) is made to vary by the modulating frequency which causes Vp to

have the form:

Vp = Vm sint

Substituting this expression in the first equation gives:

v = Vmsinct. sinct

We know one of the trigonometric identitiesSin A Sin B= Cos (AB) Cos (A+B)

So it follows that the modulated carrier waveform splits up in space into three pure Sinusoidal

components:

a) The carrier frequency

b) The frequency equal to the sum of the carrier and modulating frequencies. This is called Upper

sideband.

c) The frequency equal to the difference of the carrier and modulating frequencies. This is called

lower sideband. If the carrier frequency is 1000000 Hz and the modulating frequency is 1000 Hz then


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the upper sideband is 1001000 Hz sine wave and lower sideband is 999000 Hz. In practice the

modulating frequency will seldom be anything as simple as a 1000 Hz sine wave but more probably,

may consists of speech or picture information which contains a complex mixture of frequencies. For

example, the music frequency extends from about 20 Hz to about 18 KHz so, to transmit high quality

sound the upper sidebands would have to contain spread of frequencies extending from 20 Hz to 18

KHz above the carrier and the lower sidebands frequencies extending 20 Hz to 18 KHz below the

carrier. Television transmission is more difficult because picture have a far greater informationcontent than sound. Wider the sidebands of transmission, greater space will occupy in the frequency

spectrum so broadcast stations geographically close together must operate on frequencies well away

from each other in order to prevent the interference from their respective sidebands. Since television

station occupy several MHz in the spectrum, carrier frequencies are forced into ever higher and

higher frequencies as the number of stations fight for space. there are several novel solutions to the

overcrowding problem for example it is not essential to transmit both sidebands since all the required

information is contained in one of then, providing of course the carrier is sent with it. Such

transmission is contained in one of them, providing of course the carrier is sent with it. Such

transmissions are called SSB (single sideband). An even more drastic curtailment is to reduce the

carrier at the transmitter to almost zero and use it to synchronize a locally generated carrier at the

receiving end a Technique known as single sideband vestigial carrier modulation.

Frequency Modulation:Where as amplitude modulation alters the envelope in the vertical plane, frequency modulation takes

place in the horizontal plane, the amplitude of the carrier is kept constant but the frequency is caused

to deviate proportional to the modulating amplitude.

Frequency Deviation:The maximum amount by which the carrier frequency is increased or decreased by the modulating

amplitude is called the frequency deviation. It depends up on the amplitude (peak value) of the

modulating voltage. In the case satellite broadcasting, the signal beamed down to earth has a typical


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frequency deviation of about 16 MHZ and the bandwidth occupied by the picture information is

commonly about 27 MHz.

Modulation index:

This is the ratio of the frequency deviation (f) to the highest modulating frequency (fm)

M =f / fm

In contrast with amplitude modulation, the modulation index is not necessarily restricted to

maximum of unity.

Pre-emphasis (de-emphasis) improvement:Since the noise power density of a receiver demodulator output increases with frequency, high

frequencies are boosted or pre-emphasized prior to transmission, when the signal is subsequently

demodulated in the receiver the signal and its acquired noise is deemphasized or reduced by an equal

amount the overall effect is to reduce the noise component and leads to typical improvement in S/N

of 2dB for PAL I signals or 2.5 dB for NTSC M signals.

Noise:An unwanted signal which interferes with reception of the desired information. Noise is often

expressed in degrees Kelvin or in decibels.

Decibel (dB):

The logarithmic ratio of power levels used to indicate gains or losses of signals. Decibels relative toone Watts, milliWatts and millivolt are abbreviated as dBW, dBM and dBmV, respectively. Zero

dBmV is used as the standard reference for all SMATV calculations.

dB =10 log P1/ P2The sign of result is positive if p1 is greater than p2 and negative if p1 is less than p2.

Voltage db:Although dbs are normally used in conjunction with power ratio, it is sometimes convenient to

express voltage ratio in db terms.

dB = 20 log v1/ v2The use of 20 instead of 10 is because power is proportional to the square of the voltage so the

constant is 20 instead of 10.

Ku-Band Satellite TV:

The microwave frequency band between approximately 11 and 13 GHz used in Satellite broadcastingin European nations.

Clarke Belt:The circular orbital belt at 22,247 miles above the equator, named after the writer Arthur C. Clarke,

in which Satellites travel at the same speed as the earth's rotation. Also called the geostationary orbit.

Antenna:An antenna may be defined in the following way. To radiate or receive electromagnetic waves an

antenna is required. Antenna or aerial is system of elevated conductors which couples or matches the

transmitter or receiver to free space. A transmitting antenna connected to a transmitter by

transmission line, forces electromagnetic waves into free space which travel in space with velocity of

light. Similarly, a receiving antenna connected to a radio receiver, receives or intercepts a portion of

electromagnetic waves through space. Thus radio antenna is defined as the structure associated withregion of transition between a guided wave and a free space wave or between a free space wave and

guided waves. The official definition of antenna according to the institution of electrical and

electronics engineers is the simply a "means for radiating or receiving radio waves".


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A Satellite antenna intercepts the extremely weak microwave transmission from a targeted Satellite

and reflects the signal to its focal point, where the feed horn is placed. This is the process that

concentrates the signal so that the necessary power is available for subsequent electronic

components. The quality of a Satellite antenna, often simply called a dish, is determined by how well

it targets a Satellite and concentrates the desired signal and by how well it ignores unwanted noise

and interference. Dishes must be durable and able to withstand winds as well as other natural and

manmade forces. In order to be able to compete in the marketplace, they also must be aesthetically

pleasing and affordably priced.

Dish Antenna:To receive signal from the Satellite dish antenna are used. They are parabolic in shape. A dish

antenna collects the signal coming from the Satellite & focuses it at a point known as Focal point.

Dish antenna is used to obtain VHF & UHF signals. For different frequency ranges different sizes of

dish antenna are used. The size of dish antenna depends on wave length of the signal. For UHF range

the size of the dish antenna is 3 to 5 m & for signal up to 12 GHz the size is 91 to 180 cm.

These are made of fiber glass. The reflector at the dish antenna is made up of aluminum or fiber

glass. For different frequency the depth of the dish antenna is also different.


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Feed Horn:A dish antenna receives the signal coming through a very large area, these get reflected to a point, at

that point a pipe type instrument is fitted. This pipe type instrument is known as Feed Horn. From the

feed horn the signals are given to LNB.

It is made in such a way that it can receive maximum signal on adjustment. It is adjusted on the basis

of picture & sound quality reception. It acts as impedance matching amplifier.

Low Noise Block (Down Converter):Most important part mounted on the disk antenna is LNB. The signal from the feed horn is fed to

LNB. These are of SHF range & contain unwanted frequencies. This high frequency cannot be fed

directly to TV. Theoretically LNB converts high frequency range to low frequency range & also

removes noise. In Satellite reception different LNB are used for different frequency ranges. There is

a high frequency amplifier in LNB to amplify the faded signals coming from the Satellite. Now this

signal is converted into low frequency of definite amount.

There is a high frequency local oscillator & mixer inside a LNB. The amplified signal from the

amplifier and the signal from the local oscillator come to the mixer sections just like that in the

normal tuner. The LNB used for C band reception gets the input of 3.7 to 4.2 GHz & the output is

950 to 1450 MHz. The output signals are then fed to Satellite receiver through coaxial cables.

Satellite Receiver:The purpose of Satellite receiver is the selection of channel for listening, viewing, or both and

transforming the signals in to a form suitable for input to domestic TV and stereo equipment. Various

subsections of Satellite Receiver.

1. Power supply

2. Down conversion and tuner circuit

3. Final IF stage

4. FM video demodulator

5. Video Processing Stages

6. Audio processing stages


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Effective isotropic radiated power (EIRP) and foot print maps it the calculation of the power received

by an earth station from a Satellite transmitters fundamental to the understanding of Satellite

communications. Consider a transmitting source, in free space, radiating a total power P t, Watts

uniformly in all directions called an isotropic source. At a distance R from the hypothetical isotropic

source, the flux density crossing the surface of a sphere, radius R, is given by

F = Pt/RWatts/m2

In practice we use directive antennas to constrain out transmitted power to be radiated primarily in

one direction. The antenna has a gain G (6) in a direction 6, defined as the ratio of power per unit

solid angle radiated in a given direction to the average power radiated per unit solid angle:

G () = P ()/ (P0/4)

Where P () is the power radiated per unit solid angle by the test antenna G () is the gain of the

antenna at an angle The reference for the angle is usually taken to be the direction in which

maximum power is radiated, often called the boresight of the antenna. Thus for a transmitter with

output Pt Watts driving a lossless antenna with gain G t, the flux density in the direction of the

antenna boresight at distance R meter is

F = Pt Gt/RWatts/m2The product PtGt is often called the effective isotropically radiated power or EIRP, and it describes

the combination of transmitter and antenna in terms of an equivalent isotropic source with power PtGtWatts, radiating uniformly in all directions.

Footprint:

The geographic area towards which a Satellite down link antenna directs its signal. The measure of

strength of this footprint is the EIRP.

Downlink frequency allocations:The ITU has split the world up into three regions. The approximate frequency allocations above 10

GHz are as follows:Region 1 : Europe, CIS, Africa and Middle East

Fixed satellite service (FSS) band 10.70 - 11.70 GHz

12.50 - 12.75 GHz

17.70 - 21.20 GHz

Direct broadcast service (DBS) 11.70 - 12.50 GHz

Broadcast Satellite service (BSS) 11.70 - 12.50 GHz (from 2007)

Region 2 : The America, and Greenland



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17.70 - 21.70 GHz

Direct broadcast service (DBS) 12.20 - 12.70 GHz

Broadcast Satellite service (BSS) 17.30 - 17.80 GHz (from 2007)

Region 3 : India, Asia, Australia and the pacific


17.70 - 21.20 GHz

Direct broadcast service (DBS) 11.70 - 12.75 GHzBroadcast Satellite service (DBS) 21.40 - 22.00 GHz (from 2007)


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Experiment 2

Objective:Establishing a direct communication link between Uplink Transmitter and DownlinkReceiver using

tone signal

Apparatus Required:Uplink Transmitter

Dish Antennas

Downlink Receiver

Connecting cables

Block diagram:

Procedure:1. Connect the Satellite Uplink transmitter to AC Mains.

2. Switch ON the transmitter and frequency display will come on.

3. The transmitting frequency can be selected by frequency select switch. The frequency can be

changed from 2450-2468 MHz

4. Connect Antenna to Uplink transmitter with BNC -BNC lead.

5. Place Downlink Receiver at a convenient distance of 5 - 7m. (It can go even up to 10m.).

6. Connect the Downlink Receiver to the AC Mains and switch it ON by mains switch.

7. The Downlink Receiver Frequency can also be changed from 2414-2432 MHz

8. Attach Antenna to the Downlink receiver with BNC - BNC lead.


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9. Align both the Transmitter and Receiver Antenna's in line.

10. Keep the Uplink transmitter and Downlink receiver frequency to the same frequency.

11. Now Select the Tone from Channel Select B, so as to transmit tone signal from UplinkTransmitter.

12. The Tone signal is switched to Audio II of transmitter and transmitted.

13. Make the Downlink Receiver in Speaker mode with the help of ChannelSelect B

14. To observe Tone Signal on CRO select Tone mode from the Channel SelectB.15. Connect CRO probes to received tone socket.

16. By changing the frequency and amplitude observe the received tone on CRO as well as on

speaker.

Note: This is a test link for direct communication between transmitter and receiver.

Result: A clear music indicates that the microwave link has been successfully setupbetween uplink

transmitter and down link receiver directly.


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Experiment 3

Objective:Setting up an Active satellite link and demonstrate Link Fail operations.

Apparatus Required:

Uplink TransmitterDish Antennas

Downlink Receiver

Connecting cables.

Satellite Transponder

Theory:The Uplink Transmitter sends signals at an Uplink frequency, which is higher than downlink

frequency to avoid the interference. The quality of signal is much improved with active satellite

especially when distances between transmitter and receiver are considerable.

Block diagram:


2. Switch ON the transmitter and frequency display will come on.3. The transmitting frequency can be selected by Frequency Select switch. The frequency can be

changed from 2450-2468 MHz.


5. Place Downlink Receiver at a convenient distance of 5-7m. (It can go even up to 10m.).

6. Place a Satellite Transponder between Transmitter and Receiver at a convenient distance;

preferably all three can be placed in equidistant triangle of distance 5- 7m.


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7. Connect the Satellite Transponder to the AC Mains and switch it ON by mains switch.


9. The Downlink Receiver Frequency can be changed from 2414-2432 MHz.



12. Adjust transmitter uplink frequency to 2468 MHz and Transponder receiver frequency also to

2468 MHz, from frequency select 1 and frequency select 2.Note:In actual satellite transponder the multiplexer and de-multiplexer are provided which continuously

keeps on receiving the input frequency's in the satellite and transmit different 'output frequency. Here

we do this procedure manually to understand the operations of change in frequencies in the satellite.

We have two uplink frequencies and two downlink frequencies and we can demonstrate manually

how an actual satellite works.

13. Keep Downlink frequency of Transponder at 2414 MHz.

14. Keep the Downlink Receiver at 2414 MHz.

15. Now Select Tone from Channel select B in Uplink Transmitter.

16. Set the Downlink Receiver at speaker mode by changing Channel Select B.

Note: This is a test link for Active Satellite communication.

Link Fail Operation:By switching Off the Power of Satellite Transponder, you can demonstrate a Link Fail operation.

Result: The above setup shows that a successful satellite communication link has been setup

between Transmitter and Receiver.The link failure operation can be understood from the procedure.


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Experiment 4

Objective:Establishing an Audio-Video satellite link between Transmitter and Receiver

Apparatus Required:

1) Uplink Transmitter2) Dish Antennas

3) Downlink Receiver

4) Connecting cables

5) Satellite Transponder

6) Audio/ Video input (VCD)

7) Monitor (TV monitor)

Block diagram:

Procedure:1. Connect the Uplink Transmitter to the AC Mains and switch it ON by mains switch.

2. The transmitting frequency can be selected by Frequency Select switch. The frequency can be


3. Connect dish Antenna to Uplink transmitter with BNC -BNC lead.




6. Connect the Satellite Transponder to the AC Mains and switch it On by mains switch.


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9. Attach dish Antenna to the Downlink receiver with BNC - BNC lead.


11. Adjust transmitter uplink frequency to 2468 MHz and transponder receiver frequency also to

2468 MHz.

12. Keep Downlink Frequency of Transponder to 2414 MHz.13. Keep the Downlink Receiver to 2414 MHz.

14. Connect the Audio/Video signal at the input socket provided on the Uplink Transmitter, Video at

video input and audio at either Audio-I or Audio-II input.

15. To watch Video signal toggle the switch provided at Transponder unit to the Video position.

16. Connect TV monitor to the Audio/Video output of Downlink receiver. (Video from Video

Output, audio from Audio-I or Audio-II output (as in transmitter)) Set TV in AV Mode.

17. The TV monitor will display video and audio signal that you have connected to Uplink

Transmitter input.

18. Try link fail by using Transponder OFF.

Result: The monitor display shows that a successful audio and video link has beenestablish between

Transmitter and Receiver through satellite.


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Experiment 5

Objective:Communicating VOICE signal through satellite link

Apparatus Required:

1. Uplink. Transmitter2. Dish Antennas

3. Downlink Receiver

4. Connecting cables.

5. Satellite Transponder

6. Microphone

Block diagram:





4. Connect dish Antenna to Uplink transmitter with BNC -BNC lead.

5. Place Downlink. Receiver at a convenient distance of 5-7m. (It can go even up to 10m.).

6. Place a Satellite Transponder between Transmitter and Receiver at a convenient distance;preferably all three can be placed in equidistant triangle of distance 5-7m.

7. Connect the Satellite Transponder to the AC Mains and switch it ON by mains switch.8. Connect the Downlink. Receiver to the AC Mains and switch it ON by mains switch.

9. The Downlink. Receiver Frequency can be changed from 2414-2432 MHz.

10. Attach dish Antenna to the Downlink receiver with BNC - BNC lead.



2468MHz.

13. Keep Downlink Frequency of Transponder to 2414MHz.

14. Keep the Downlink Receiver to 2414MHz.

15. Connect microphone input at the socket marked 'MIC' on the Uplink Transmitter.16. Select MIC mode from Channel Select B in Uplink transmitter.17. Select the Speaker mode from Channel Select B in Downlink Receiver.18. Speak in the mike and you will hear the same sound in the speaker of receiver.

Result: The above shows a successful establishment of voice link between transmitter andreceiver.


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Experiment 6

Objective:Changing different combinations of uplink and downlink frequencies and to check the

communication link

Apparatus Required:1. Uplink Transmitter

2. Dish Antennas




6. Audio/Video input (VCD)

7. Monitor (TV monitor)

Block diagram:





4. Connect Dish Antenna to Uplink transmitter with BNC -BNC lead.







10. Attach Dish Antenna to the Downlink receiver with BNC - BNC lead.



2468 MHz


15. Connect the Audio/Video signal at the input socket provided on the Uplink Transmitter, Video at

video input and audio at either Audio-I or Audio-II input.

16. Connect TV monitor to the Audio/Video output of Downlink receiver. (Video from Video

Output, audio from Audio-I or Audio-II output (as in transmitter)) Set TV in AV Mode.

17. To watch Video signal toggle the switch provided at Transponder unit to the Video position.

18. The TV monitor will display video and audio signal that you have connected to uplink

Transmitter input.

19. Now change uplink-transmitting frequency from 2468 to 2450 MHz and correspondingly the


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receiver frequency of transponder is to be changed to 2450 MHz you will receive the same

quality of signal at the output of the downlink receiver.

20. Now change the downlink frequency of transponder from 2414 to 2432 MHz and similarly

change downlink receiver tuning frequency to 2432 MHz you will be receiving the same quality \

of signal.

Result: The above experiment shows a successful establishment of satellite audio/video linkbetweenUplink transmitter and Downlink receiver at different up-link and down-linkfrequencies.


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Experiment 7Objective:Transmitting and receiving three separate signals (Audio, Video, Tone) simultaneously through

satellite link

Apparatus Required:

Uplink TransmitterDish Antennas

Downlink Receiver

Connecting cables


Block diagram:

Procedure:

Connect the Satellite Uplink transmitter to AC Mains.

Switch ON the transmitter and frequency display will come on.

The transmitting frequency can be selected by Frequency Select switch. The frequency can be


Connect Dish Antenna to Uplink transmitter with BNC -BNC lead.

Place Downlink Receiver at a convenient distance of 5-7m. (It can go even up to 10 m.).

Place a Satellite Transponder between Transmitter and Receiver at a convenient distance;preferably all three can be placed in equidistant triangle of distance 5- 7m.

Connect the Satellite Transponder to the AC Mains and switch it ON by mains switch.

Connect the Downlink Receiver to the AC Mains and switch it ON by mains switch.

The Downlink Receiver Frequency can be changed from 2414-2432 MHz.

Attach Dish Antenna to the Downlink receiver with BNC - BNC lead.

Align both the Transmitter and Receiver Antenna's in line.

Adjust transmitter uplink frequency to 2468 MHz and transponder receiver frequency also to

2468 MHz.

Keep Downlink Frequency of Transponder to 2414 MHz.

Keep the Downlink Receiver to 2414 MHz.

Connect the Audio/Video signal at the input socket provided on the Uplink Transmitter, Video atvideo input and audio at Audio-I input.

Now Select the Tone from Channel Select B, so as to transmit tone signal from Uplinktransmitter.

Connect TV monitor to the Audio/Video output of Downlink receiver. (Video from Video

Output, audio from Audio I output) Set TV in AV Mode. Keep Downlink receiver voice switch

in the On position.

To watch Video signal toggle the switch provided at Transponder unit to the Video position.

The TV monitor will display video and audio signal that you have connected to Uplink


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Transmitter input.

Make the Downlink Receiver in Speaker mode with the help of ChannelSelect B. You will

be able to hear tone in the speaker of receiver.

Result:Three separate signals (Audio, Video and Tone) are successfully received at downlink

receiver through satellite communication link.


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Experiment 8

Objective:Transmitting and receiving function generator waveforms through satellite link

Apparatus Required:

1. Uplink Transmitter2. Dish Antennas




6. Function generator

Block diagram:


2. Switch ON the transmitter and frequency display will come on.3. The transmitting frequency can be selected by Frequency Select switch. The frequency can be


4. Connect Antenna to Uplink transmitter with BNC-BNC lead.





8. Connect the Downlink Receiver to the AC Mains and switch it ON by mains switch.9. The Downlink Receiver Frequency can be changed from 2414-2432 MHz.

10. The Downlink receiver On-Off toggle switch will switch On-Off the receiver.




2468MHz.

14. Keep Downlink Frequency of Transponder to 2414MHz.

15. Keep the Downlink Receiver to 2414MHz.16. Connect function generator Triangular wave output to Audio-I socket provided on uplink

transmitter.

17. Connect Audio-I socket of downlink receiver to the Oscilloscope.

18. Feed the signal of 1 KHz Triangular wave and you will observe similar wave of same frequency

on Oscilloscope.

Result:Function generator waveforms are successfully received at downlink receiver through

satellite communication link.


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Experiment 9Objective:Transmitting and receiving PC data through satellite link

Apparatus Required:

Uplink Transmitter

Dish AntennasDownlink Receiver

Software


USB cables -2 Nos.

Preferably 2 sets of PC's

Block diagram:


2. Switch ON the transmitter by Mains switch and frequency display will light up.




5. Place Downlink Receiver at a convenient distance of 5-7m. (It can go even up to 10m.).6. Place a Satellite Transponder between Transmitter and Receiver at a convenient distance;

preferably all three can be placed in equidistant triangle of distance 5-7m.

7. Connect the Satellite Transponder to the AC Mains and switch it ON by mainsswitch.8. Connect the Downlink Receiver to the AC Mains and switch it ON by mains switch.9. The Downlink Receiver Frequency can be changed from 2414-2432 MHz.


11. Align both the Transmitter and Receiver Antenna's in line such that both are in parallel

alignment.



2468 MHz.


16. Switch ON the PC's and install software.17. Connect interfacing cable from USB port of uplink transmitter to first PC.

18. Connect the interfacing cable from USB port of Downlink receiver to 2nd PC.

19. Install the drivers so that USB device is detected.

20. Now Select appropriate communication port and Baud Rate (19200) on both PC's.

21. To watch PC Data toggle the switch provided at Transponder unit to the Video position.

22. Select 1st PC as transmitter and 2nd PC as a receiver on the software window.


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23. When the link is established, the typed matter on first PC will be received to second PC via

Satellite link.

Result: PC data transmitted from first PC is received in the second PC via Satellitelink.


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Experiment 10Objective:Study the delay between Uplink transmitter and Downlink receiver during data transmission.

Apparatus Required:1. Uplink Transmitter

2. Dish Antennas3. Downlink Receiver


5. Digital Storage Oscilloscope


Block diagram:


2. Switch ON the transmitter by Mains switch and frequency display will light up.3. The transmitting frequency can be selected by Frequency Select switch. The frequency can be




6. Place a Satellite Transponder between Transmitter and Receiver at a convenientdistance; preferably all three can be placed in equidistant triangle of distance

5-7m.

7. Connect the Satellite Transponder to the AC Mains and switch it ON by mainsswitch.

8. Connect the Downlink Receiver to the AC Mains and switch it ON by mainsswitch.



11. Align both the Transmitter and Receiver Antenna's in line such that both are in

parallel alignment.

12. Adjust transmitter uplink frequency to 2468 MHz and transponder receiver

frequency also to 2468 MHz.

13. Keep Downlink Frequency of Transponder to 2414 MHz.

14. Keep the Downlink Receiver to 2414 MHz.

15. Select Data mode in the uplink transmitter using Channel Select A.

16. Select Data mode in the downlink receiver using Channel select A.17. To observe data from data generator, toggle the switch provided at Transponder

unit to the Telemetry position.

18. Connect the DSO to Received Data section and observe the data.

19. The recommended DSO settings are as follows:


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Adjust the Time/Div knob at 50ms.

Adjust Volt/Div. Knob at 2V.

Set appropriate trigger level, so that the signal becomes stable on screen.

20. Now slightly move the Delay Adjust knob and observe the changes in the Data

stream on DSO.

Result:

The experiment can be useful to observe simulated delay in satellite


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Experiment 11

Objective:To send tele-command and receive intensity of light from satellite

Apparatus Required:




5. Connecting cables

Block diagram:

Procedure:

Connect the Satellite Uplink transmitter to AC Mains.

Switch ON the transmitter by Mains switch and frequency display will lightup.

The transmitting frequency can be selected by Frequency Select switch. The

frequency can be changed from 2450-2468 MHz.

Connect Antenna to Uplink transmitter with BNC -BNC lead.

Place Downlink Receiver at a convenient distance of 5-7m. (It can go even up to

10m.).Place a Satellite Transponder between Transmitter and Receiver at a convenient

distance; preferably all three can be placed in equidistant triangle of distance 5-

7m.

Connect the Satellite Transponder to the AC Mains and switch it ON by mainsswitch.

Connect the Downlink Receiver to the AC Mains and switch it ON by mains

switch.

The Downlink Receiver Frequency can be changed from 2414-2432 MHz.

Attach Antenna to the Downlink receiver with BNC - BNC lead.

Align both the Transmitter and Receiver Antenna's in line such that both are in

parallel alignment.

Adjust transmitter uplink frequency to 2468 MHz and transponder receiver

frequency also to 2468 MHz.

Keep Downlink Frequency of Transponder to 2414 MHz.

Keep the Downlink Receiver to 2414 MHz.

Select Tele mode in uplink transmitter and downlink receiver using Channel

select A

The telemetry section has three toggle switches indicated E for enable, A1& A0

for selecting Light intensity and Temperature respectively. The command for

light intensity is 6.


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In uplink Transmitter switch on the toggle E so that telemetry becomes enable.

Now toggle On A1 and toggle Off A0 for Light Intensity and do same setupfor downlink receiver.

To watch telemetry signal toggle the switch provided at Transponder unit to

the Telemetry position.

You will find that the intensity of light in percentage form is appearing on theLCD screen of downlink receiver.

Change the intensity of light manually by using any light source on transponder,

the same ratio of percentage will appear on the LCD screen.

Result:As you send tele-command for light intensity, the transponder starts sending status of

light intensity to the receiver.


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Experiment 12

Objective:To send tele-command and receive Temperature from satellite

Apparatus Required:




5. Connecting cables

Block diagram:


2. Switch ON the transmitter by Mains switch and frequency display will light up.






preferably all three can be placed in equidistant triangle of distance 5-7m.

7. Connect the Satellite Transponder to the AC Mains and switch it ON by mains switch.8. Connect the Downlink Receiver to the AC Mains and switch it ON by mains switch.9. The Downlink Receiver Frequency can be changed from 2414-2432 MHz.


11. Align both the Transmitter and Receiver Antenna's in line such that both are in parallel b

alignment.


2468 MHz.



15. Select Tele mode in uplink transmitter and downlink receiver using Channelselect A.

16. The telemetry section has three toggle switches indicated E for enable, A1 & A0 for selectingLight intensity and Temperature respectively.

17. In uplink Transmitter switch on the toggle E so that telemetry becomes enable.

18. Now toggle On A0 and toggle Off A1 for Temperature and do same set-up for downlink

receiver. The tele command for temperature is 5.

19. To watch telemetry data toggle the switch provided at Transponder unit to theTelemetryposition.

20. You will find that the Temperature of transponder is appearing on the LCD screen of receiver.

Result:As you send tele-command for temperature, the transponder starts sending status of

temperature to the receiver.


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Experiment 13

Objective:To calculate the carrier to noise ratio of established satellite link

Apparatus Required:




5. CRO Connecting cables

Block diagram:






6. Place a Satellite Transponder between Transmitter and Receiver at a convenient distance;preferably all three can be placed in equidistant triangle of distance 5-7m.




11. Align both the Transmitter and Receiver Antenna's in line such that both are in parallel

alignment.


2468 MHz.



15. Disable Tone mode for transmission. In this case only carrier will get transmitted from uplink

transmitter.

16. Observe the Carrier waveform on Spectrum Analyzer and measure its power (It is power of

Carrier and Noise without any input, say it C1).

17. Now switch OFF the uplink transmitter and measure the power again (It is power of Noise, sayit N).

18. Now subtract amplitude of noise from previously received signal (Carrier + noise), you can get

actual Carrier signal amplitude (say it C).

C = C1N


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19. Calculate Carrier to noise ratio from the formula.

Carrier to noise ratio = C /N

Carrier to noise ratio (in dB) = 20 log C / N

Result:Signal to noise ratio (in numeric) =_____

Signal to noise ratio (in dB) =_____dB


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Experiment 14

Objective:To calculate signal to noise ratio of established satellite link

Apparatus Required:




5. CRO Connecting cables.

Block diagram:




4. Connect Antenna to Uplink transmitter with BNC -BNC lead.5. Place Downlink Receiver at a convenient distance of 5-7m. (It can go even up to 10m.).






11. Align both the Transmitter and Receiver Antenna's in line, such that both are in parallel

alignment.


2468 MHz.



15. Now Select the Tone from Channel Select B, so as to transmit tone signal from Uplink

transmitter.

16. Make the Downlink Receiver in Tone mode with the help of Channel SelectB.17. Observe Tone Signal on CRO and measure its amplitude. (The received tone has original signal

and noise both, say it S1 ).

18. Now change Tone mode to any other mode with the help of Channel SelectB of the uplinktransmitter and again measure amplitude of received signal at downlink receiver (This signal


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SATALLITE COMMUNICATION LABhave only noise, say it N).

19. Now subtract amplitude of noise from previously received signal (Tone + noise), you can get

actual tone signal amplitude (say it S).S = S1N

20. Calculate signal to noise ratio from the formula.

Signal to noise ratio = S / N

Signal to noise ratio (in dB) = 20 log S / N

Result:Signal to noise ratio (in numeric) =_____

Signal to noise ratio (in dB) =_____dB

satallite manual

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