Acs Lab Manual

Lab Manual – Advanced Communication Systems

Vishwakarma Institute of Information Technology, Pune 1

Table of contents

Sr.

No Contents Page No

1 1. To calculate look angles from ES listed below to each of

geosynchronous satellite listed

• Azimuth Angle

• Elevation Angle

2. To calculate distance between ES & satellite

3. Determine if satellite is visible from Es and indicate if not

2

2 1. To study the characteristics of Horn Antenna & Parabolic

Antenna

2. To plot its radiation pattern

3. To calculate its gain and beam-width

9

3 1. To Study the Satellite Communication System

2. To determine the Carrier to Noise ratio of Analogue

Satellite Receiving system at base band

12

4 Program for Simulation of Satellite link design using MATLAB 15

5 To Study of Wavelength Division Multiplexing 30

6 To prepare Optical Link Power Budget for Repeater less Optical

Fiber Link using MATLAB & Microsoft Excel 33

7 Displacement Measurement using Optical sensors 36

8 Case study 47

H.O.D – E&TC



EXPERIMENT NO: 01

TITLE OF EXPERIMENT :

4. To calculate look angles from ES listed below to each of

geosynchronous satellite listed

• Azimuth Angle

• Elevation Angle





1.1 Aim: 7. To calculate look angles from ES listed below to each of geosynchronous satellite

listed

• Azimuth Angle

• Elevation Angle



Earth Station

1. 44° 48' 59'' N

70° 42' 52'' W

2. 24° 52' 13'' S

113° 42' 13'' E

Satellites

1. 87° W

2. 127.5° W

3. 110° E

1.2 Theory: 1. Elevation Angle: It is the angle measured upward from the local horizontal plane

at ES to the Satellite path

Cos (EL) = __________Sin (r)_________

[1 + (re/rs) ² – 2(re/rs) Cos(r)] ½

Cos (r) = Cos (le) Cos (ls-le)

…… for geosynchronous

2. Azimuth Angle: It is the angle measured eastward(clockwise) from geographic

north to the projection of satellite path on a locally horizontal plane at ES

S = _a + c+ r_ a = ls-le

2 c = Le

Tan² (α / 2) = _Sin(s-r) Sin (s-c)_

Sin(s-a) Sin (s)

Case 1:-

• Satellite to SE of ES :- Az = 180 – α

• Satellite to SW of ES :- Az = 180 + α

Case 2:-

• Satellite to NE of ES :- Az = α

• Satellite to NW of ES :- Az = 360° - α

3. Distance between ES and satellite is given by-

d = [rs² + re² -2 (re)Cos(r)] ½

4. For a satellite to be visible from ES, its EI must be above some min value, which

is at least 0°. A positive or zero EI requires that-

rs ≥ __re__

Cos(r)

1.3 Result: Comparison of Matlab and Theoretical output



1. 44° 48' 59'' N

70° 42' 52'' W

Matlab Result-

Satellite 87° W 127.5° W 110° E

Visible YES YES YES

d

E1

Az

Theoretical Result-

Satellite 87° W 127.5° W 110° E

Visible YES YES YES

d

E1

Az

2. 24° 52' 13'' S

113° 42' 13'' E

Matlab Result-

Satellite 87° W 127.5° W 110° E

Visible YES YES YES

d

E1

Az

Theoretical Result-

Satellite 87° W 127.5° W 110° E

Visible YES YES YES

d

E1

Az

1.4 Conclusion: _____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________



Program: clc; clear all; close all; Le_arr = input(' enter ES latitude '); Ie_arr = input(' enter satellite longitude '); Is_arr = input(' enter satellite longitude '); % Ls = 0 for GEO Le_deg = Le_arr(1) + [Le_arr(2)/60] + [Le_arr(3)/3600]; Ie_deg = Ie_arr(1) + [Ie_arr(2)/60] + [Ie_arr(3)/3600]; Is_deg = Is_arr(1) + [Is_arr(2)/60] + [Is_arr(3)/3600]; Le = Le_deg * 3.142 / 180; Ie = Ie_deg * 3.142 / 180; Is = Is_deg * 3.142 / 180; re = 6370; rs = 42242; % caculate gamma gamma = acos (cos( Le ) * cos ( Ie - Is) ); if ( rs < [re/cos(gamma)] ) disp('Satellite is not visible from earth station '); else disp ('Satellite is visible from the earth station '); % calculate 'd' d = sqrt ( rs^2 + re^2 - 2*re*cos(gamma)) ; disp('Distance between ES and satellite is :- '); disp(d); % calculate elevation angle temp = sqrt ( 1 + (re/rs)^2 - 2*(re/rs)*cos(gamma) ) ; EI_rad = acos ( [sin(gamma)] / temp ) ; EI = 180 * EI_rad / 3.142; disp('Elevation Angle is :- '); disp(EI); % calculate 's' a = abs( Is - Ie ); c = abs(Le); temp = ( a + c + gamma )*180 / 3.142; s_deg = temp / 2; s = s_deg*3.142 / 180; % calculation of alpha p = sin(s-gamma); q = sin(s-c); r = sin(s-a); s = sin(s); alpha_rad = 2 * atan( sqrt([p*q]/[r*s])); alpha = alpha_rad*180 / 3.142; % calculation of azimuth angle if ( Le >= 0 ) if ( Is < Ie) AI = 180 + alpha;



else AI = 180 - alpha; end ; else if ( Is < Ie) AI = 360 - alpha; else AI = alpha; end ; end ; disp('Azimuth Angle is :- '); disp(AI); end;



Result: Enter ES latitude [44 48 59] Enter satellite longitude - [70 42 52] Enter satellite longitude - [87 0 0] Satellite is visible from the earth station Distance between ES and satellite is:-

4.2719e+004 Elevation Angle is:-

35.8868 Azimuth Angle is:-

202.5112 Enter ES latitude [44 48 59] Enter satellite longitude - [70 42 52] Enter satellite longitude - [127.5 0 0] Satellite is visible from the earth station Distance between ES and satellite is:-

4.2720e+004 Elevation Angle is:-

14.4604 Azimuth Angle is:-

245.2228 Enter ES latitude [44 48 59] Enter satellite longitude - [70 42 52] Enter satellite longitude [110 0 0] Satellite is visible from the earth station Distance between ES and satellite is:-

4.2720e+004 Elevation Angle is :-

50.6521 Azimuth Angle is :- 1.0699 enter ES lattitude -[24 52 13] enter satellite longitude [113 42 13] enter satellite longitude -[87 0 0] Satellite is visible from the earth station Distance between ES and satellite is :-


62.0882 Azimuth Angle is :-

221.9980 enter ES lattitude -[24 52 13] enter satellite longitude [113 42 13] enter satellite longitude >> -[127.5 0 0]



Satellite is visible from the earth station Distance between ES and satellite is :-



257.0115 enter ES lattitude -[24 52 13] enter satellite longitude [113 42 13] enter satellite longitude >> [110 0 0] Satellite is visible from the earth station Distance between ES and satellite is :-



351.2512



EXPERIMENT NO: 02

TITLE OF EXPERIMENT : 4. To study the characteristics of Horn Antenna & Parabolic Antenna

5. To plot its radiation pattern 6. To calculate its gain and beam-width



2.1 Aim:

1. To study the characteristics of Horn Antenna & Parabolic Antenna

2. To plot its radiation pattern

3. To calculate its gain and beam-width

2.2 Apparatus:

Gunn power supply, Gunn oscillator, Pin modulator, isolator variable attenuator, Detector mount,

VSWR meter, Radiation pattern, Transmitter horn, Matched loads, CRO, Horn Antenna & Turn

Table, Wave guide stands, Frequency meter, Cooling fan , BNC cable , Pick up horn , etc

2.3 Theory:

At microwaves, the power emitted from the transmitter must be radiated into the free space in

the form of electromagnetic waves, on the receiving end, electromagnetic waves must b intercepted and

fed into the transmission line running to the receiver. The component which radiates and intercepts is

course of the antenna. The antenna can be thought of as a matching network which couples the

transmission line to free space with minimum reflection am loss, in addition. The antenna can be shaped

to propagate the electromagnetic wave in a particular direction and to present, depending upon the

application a broad or narrow beam. Antennas are reciprocal. An antenna used with a transmitter has the

same characteristics am performance as it would have when used with a receiver. Thus the VSWR

looking into the terminals of an antenna is the same whether it is used as a transmitting antenna or as a

receive antenna. The gain, beam width and other characteristics are the same for both applications, an

antenna which radiates in all direction equally is called an isotropic radiator or source. HOW ever the

isotropic antenna is a convenient reference point , and thus the gain or directivity of ; real antenna is

expressed as the increase in power radiated in a given direction compared to the power radiated by the

fictitious isotropic antenna, assuming the same total power in both cases Obviously if an antenna has

directivity, the gain is a function of direction from the antenna .; matched transmitting antenna with a

gain of 20 db would put out a signal 20 db greater then signal from an isotropic source which is fed by

the same transmitter. The radiation pattern if two identical antennas are available, It is possible to

measure the gain of an antenna directly The two antennas are separated by a distance at least as great as one

meter, under these circumstances the gain of an individual antenna .assuming both antennas are identical, is

given by :

Gain (G) = 4ΠΠΠΠR PR/PT

λλλλo Where PR is the power received and PT is the power transmitted. R is of course the distance between the

two antennas indicated in figure 7 is sufficient accurate. In the above equation PR & PT can be measured

and gain can be computed. The quantities PR PT are not measured directly but instead their ratio is

determined, first the detection system i connected to the receiving antenna and a reference level is noted

on the output meter. Then the detection system is moved to the transmitter and connected at the output

of the calibrate attenuator. The attenuator is adjusted until the output meter reads the same reference

level the ratio PT to PR in decibels is the sum of the coupling of the directional coupler and the

attenuation of the calibrated attenuator.

2.4 Procedure:

• Adjust the repeller voltage to get maximum signal (power) voltage a the output

Feed this known (power) signal to the transmitting Horn antenna

• Keep the receiving Horn antenna at a distance of say about 1 mete and in the same

axis [say 0°]

• Now, measure the received (power) voltage at 0° or reference angle with the help

of a CRO



• Then, rotate the Horn antenna at 10°, 20°, ....... 90° in left and right hand side and

tabulate the reading from CRO

• Plot the graph on a polar sheet & find its beam-width

2.5 Observation table:

Signal Level (v)

Angle (°)

Left

Right

0

10

20

30

40

50

60

70

80

90

2.6 Calculation of Gain:

Gain (Theoretical) = 4ππππA/ππππλλλλo² Where,

A = a.b/2

a = width of horn

b = height of horn

λλλλo = free space wave length

Gain (Practical) = 4ππππR/λλλλo ⋅⋅⋅⋅ √√√√ Pr/ Pt Where,

R = distance between Transmitter & Receiver

Pt= Transmitted power

Pr= Received Power

2.7 Result:

• The characteristics of given Horn Antenna [E-H plane] is studied

• The radiation pattern is plotted

• The calculated beam-width= ______°

• The gain of Horn Antenna = ______ dB

2.8 Conclusion: _____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________



EXPERIMENT NO: 03

TITLE OF EXPERIMENT : 3. To Study the Satellite Communication System

4. To determine the Carrier to Noise ratio of Analogue Satellite Receiving

system at base band



3.1 Aim:

5. To Study the Satellite Communication System

6. To determine the Carrier to Noise ratio of Analogue Satellite Receiving system at

base band

3.2 Apparatus:

Satellite uplink transmitter, satellite downlink receiver and satellite link emulator,

Helix antennas Antenna stands with connecting cables, mic, video monitor, CCTV camera,

Function generator, CRO, spectrum analyzer, etc.

3.3 Procedure:

1. Setup the link as before. Press the frequency select switch of satellite emulator down link

channel several times so as to set the frequency display from 2.400, 2.427, 2.454, and

2.481 and then back to 2.400.

2. Now, switch off the carrier by switching of both Transmitter (TX) and satellite.

3. Receiver (Rx) will read only its noise floor at RSSI output which has a DC voltage output

in proportion to the received signal strength.

4. The chart at the back of the manual can be used to convert DC voltage to corresponding

RF signal level in dBm or dBuV.

5. Say, in absence of any carrier Rx reads 0.92 V which is equal to -96 dBm (refer chart).

6. Thus, -96 dBm is noise floor of Rx that means if carrier received by Rx is less than -96

dBm it will be unable to measure it.

7. Now, switch on Tx and satellite and say, the Rx reads 1.93 V which equals to -59 dBm of

carrier level being received.

8. Thus, C/N = carrier level / noise level. As both noise and carrier signal detected are

measured in dB, C/N can be calculated by taking the difference of two readings or C/N =

carrier level (in dB) - noise level (in dB).

9. Hence, C/N = -59-(-96) =37 dB.

10. Make sure the Rx is not saturated with carrier otherwise incorrect C/N will be read. This

can be done by increasing path loss at Rx and satellite and or taking Rx farther away from

satellite.

11. Measure the C/N readings for different levels of pathless.

12. Monitor the audio and video transmissions and correlate them to various levels of C/N.

Thus higher level of C/N results in better picture and sound quality.

13. If you are able to receive audio & video sent, clearly it means you are well above

threshold level of signal. Now, the effect of noise can be seen if you decrease the received

signal strength to a considerable level. This can be achieved by increasing the path loss.

14. This means the received signal is just above the noise floor of receiver. Although we are

using FM demodulator but because the received signal is barely above the noise floor you

can hardly receive any intelligent information. Thus, signal cannot be received below

noise floor of Rx.

3.4 Observations:

Noise Voltage [RSSI]= _____ (Volts)

From table, Noise power in dB = _______dBm ---- (1)

Carrier Voltage [RSSI]= _____ (Volts)



From table, Carrier power in dB = _______dBm ---- (2)

Therefore,

=dBmin power Noise

dBmin power Carrier

N

C = ( )dBm – ( )dBm = ______ dBm

3.5 Result: 1. Satellite Communication System have been studied

2. Measured Carrier to Noise ratio of the given Satellite Receiving

3. System at base band is ______dB

3.6 Conclusion:

1. The difference between two readings of receiver noise level and carrier level is the C/N ratio

in dB. Actual reading will depend on a number of factors and will differ from to case to case.

Increasing the path loss and distance between antennas shall result in lower C/N ratios due to

lower levels of received carrier. Amount of noise received/generated remains constant.

2. More power at transmitter shall result in better picture quality and more C/N ratio. Lower

noise at receiver is essential for better picture. Higher gain antenna could be used to capture

more signals. Hence a helix antenna could result in higher C/N.

3. When noise is increased, sparkles start appearing on black or white portions of picture.

Further increasing the noise will make the picture lose its sync resulting in complete loss of

information.



EXPERIMENT NO: 04

TITLE OF EXPERIMENT : Program for Simulation of Satellite link

design using MATLAB



Program No. 1

A regional Satellite Communication System using 4/6 GHz band has following

parameters.

Satellite

1. Transponder Gain variable between 85 to 100 dB

2. Transponder Bandwidth 36 MHz

3. Transponder peak output power 6.3 watt

4. Antenna Gain (Transmit) 20 dB

5. Antenna Gain (Receiver) 22 dB

6. Satellite Receiver noise temperature 100° K

Earth Station

1. Antenna Gain (Transmit) 61.3 dB

2. Antenna Gain (Receiver) 60.0 dB

3. Receiver Noise Temp 100° K

Four Identical earth stations share one transponder in an FDMA mode. The

allocated channel capacities and B.W are:

Station 1 and Station 2, 132 channels/ 10 MHz BW

Station 3 and station 4, 24 channels/ 5 MHz BW

Assume, in FDMA mode. Transponder is operated at 5 dB output back off to minimize

the IM noise.

Slant distance is such that

FSL Uplink 200 dB

FSL Downlink 196 dB

Determine the following:

• Assuming Earth Station to be located at center of beam coverage, determine the transmitter power required for E.S, if transponder gain setting is at 90dB.

• Determine C/N at receiving E.S. for station 1 and station 3, assuming that these station are located at 3 dB contour of satellite foot print.

• Assuming station 1 and station 3 at 3 dB contour and station 2 and station 4 of beam centre, determine transmitter power levels for E.S.1 and E.S. 4 , if we have

to get minimum weighted signal to noise ratio 47 dB in any worst channel for

station 1 to station 2 and station 4 and station 3

Assume - a) Standard pre-emphasis filters are used.

b) I.M. Noise to be negligible

c) Terrestrial interference noise 1000 pwpo

d) Satellite interference 2000 pwpo



Program No. 2

A Satellite provides direct television broadcast service in USA with beam width

1° wide at 3 dB points. The uplink frequency is 30 GHz and down rank frequency is 42

GHz. The Satellite supports two transponders, with each capable of relay one television

channel.

Receiving station uses antenna of 0.8 meter diameter (Assume η= 0.60), an

antenna random (to prevent build up of snow) with loss of 1 dB when the surface is wet.

A LNA is directly mounted on antenna feed with noise figure of 7.0 dB at ambient

temperature of 17° C

The TV signal with video BW of 4.2 MHz is frequency modulated on uplink freq

and occupies the R.F. Bandwidth of 30 MHz


1. G/T ratio of Receiving Station.

2. C/N for I.F. bandwidth of 30 MHz for receiver, if satellite transmitter has power

output of 1 watt (Assume No losses in Atmosphere, coupling etc.)

3. C/N for receiver located at the edge of the coverage zone(i.e.3 dB contour point),

Assuming (a) 1 dB clear air atmospheric loss, ( b) Attenuation due to Rain is 10

dB, (c) pointing error of 0.33° in receiving antenna.

4. Assuming FM threshold for domestic receivers is 13 dB; determine minimum

power output of transponder to provide satisfactory service of receivers located at

‘C’ above.



Program No. 3

A Ku - band Satellite carries a number of narrow bandwidth transponders to

permit communications between small earth stations. The major parameters of satellite

are given below.

Parameter Uplink Downlink

Frequency 14.9 GHz 11.30 GHz

3 dB contour zone of antenna 3.6° x 2.4° 3.6° x 2.4°

Antenna efficiency 65% 65%

Transponder output power (saturated) ----- 20 watt

Transponder I/P noise Temp 520° K -----

Transponder gain, B.W 125dB, 5MHz -----

Pointing Accuracy +1°

Assume the slant distance between E.S. and Satellite - 39000 Km

Determine following:

1. Assuming Satellite Antennas to be having rectangular shape, dimension of

transmitting and receiving antennas in meters and gains of antennas in dB.

2. Determine the power flux density at the center of the coverage area, when

transponders are fully saturated. What is the flux density at the edge of the

coverage zone?

3. Determine the G/T of E.S. located at the edge of the coverage zone to achieve C/N

of 22 dB in 5 MHz bandwidth when transponder in fully saturated by single

carrier.

4. Determine the G/T of E.S. located at edge of the coverage zone to achieve C/N of

10 dB in the bandwidth of 50 kHz, when 20 carriers access the transponders with

equal power, simultaneously and transponder is used at 5.0 dB backoff at the

output.

5. Determine E.S. ‘EIRP’ to fully load the transponder up to saturation with single

carrier.



Program No. 4

The Characteristics of a digital service transponder are as follows.

Frequencies Terminal A to Terminal B 14.9/11.3 GHz

Frequencies Terminal B to Terminal A 14.4/10.8 GHz

Antennae Beam width (3dB) 1.5° (both Uplink & Downlinks)

Transponder Saturated Power 20 Watts

Transponder input noise temperature 500° K

Transponder gain to saturation point 120dB

Transponder bandwidth 50MHz

Slant distance to E.S from Satellite 38000km


1. Assuming VSAT terminal (Terminal B) is with antenna of 3mt diameter and

located at edge of coverage zone, find the transmitter power required to saturate

the transponder

2. Ignoring the transponder noise, determine the G/T of the terminal B used in the

receive mode to get the C/N of 18 dB and the effective received noise temperature

of VSAT terminal. Assume all other losses (Atmospheric, coupling, polarization)

to be equal to 1.5dB

3. If the above satellite is used for transferring digital data in TDM/TDMA mode

with terminal A as ‘Hub’ transmitting at 256kbps (TDM format) and terminal –B

the VSAT transmitting at 48kbps. Hub station consists of antenna of 7.5 meter

diameter dish, effective Ts=100° K and transmitter power output as 500 Watts.

Assume the Hub to be located at the center of the coverage zone and VSAT to be

located at the edge of the coverage zone. Both Hub and VSAT use QPSK

modulation with (24, 12) Goley channel coding scheme, which requires Eb/ No of

10dB for getting 1x10-9

BER performance.

Determine the parameters of VSAT terminals (i.e.: G/T, Antenna Diameter,

Effective noise temperature, power amplifier of VSAT transmitter) to ensure BER of

1x10-9

for two way transfer of digital data (i.e.: both A—B @ 256kbps and B—A

@48kbps)

Assume:

• Fading due to rain in Ku-band to be 4.0dB in each satellite hop

• Satellite transponder power to be uniformly distributed as per bandwidth occupancy and 20 Watts maximum power for entire 50MHz bandwidth

occupancy

4. In the above network configuration as in ‘c’ above, determine maximum number

of VSAT terminals, a ‘Hub’ station can service at a time



Solution of Program 1:

clc;

clear all;

close all;

disp('SATELLITE--');

gain = input('transponder gain (85 to 100db) =');

BW = input('transponder BW (hz)= ');

po = input('transponder peak output power(W) = ');

tx_gain = input('antenna gain (transmit)(db) =');

rx_gain = input('antenna gain (receiver)(db) = ');

rx_nt = input('sat. receiver noise temperature(K) =');

disp('EARTH STATION--');

ant_txgain = input('antenna gain (transmit)(db) =');

ant_rxgain = input('antenna gain (RECEIVER)(db) =');

ES_nt = input('receiver noise temp (K)=');

fsl_up = input('enter FSL uplink in db=');

fsl_dn = input('enter FSL downlink in db=');

op_backoff = input('enter output back off (in db): ');

transponder_opdb = ( 10*log10(6.3) - op_backoff);

disp('transponder output power in db =');

disp(transponder_opdb);

transponder_opw = 10 ^ (transponder_opdb/10);

disp('transponder output power in Watts =');

disp(transponder_opw);

po1 = transponder_opw /3;




disp('transponder output power1 in db =');

p1 = 10*log10(po1);

disp(p1);


p2 = 10*log10(po2);

disp(p2);


p3 = 10*log10(po3);

disp(p3);


p4 = 10*log10(po4);

disp(p4);



disp('power received at Xponder i/p due to ES1 in db =');

pr1 = p1 - 90;

disp(pr1);


pr2 = p2 - 90;

disp(pr2);


pr3 = p3 - 90;

disp(pr3);


pr4 = p4 - 90;

disp(pr4);

pt1 = pr1 - ant_txgain - rx_gain - fsl_up;

pt1_w = 10^(pt1/10);

disp ('transmitter power required for ES1 and ES2 = ');

disp(pt1_w);

pt3 = pr3 - ant_txgain - rx_gain - fsl_up;

pt3_w = 10^(pt3/10);

disp ('transmitter power required for ES3 and ES4 = ');

disp(pt3_w);

ES12_BW = input('Station 1&2 bandwidth (Hz) =');

ES34_BW = input('Station 3&4 bandwidth (Hz) =');

t = 10*log10(ES_nt);

bw1 = 10*log10(ES12_BW);

CN_ES1 = p1 + tx_gain + ant_rxgain - fsl_dn -3 - (-228.6 + t+ bw1);

disp ('C/N at receiving for ES1 = ');

disp(CN_ES1);

bw3 = 10*log10(ES34_BW);

CN_ES3 = p3 + tx_gain + ant_rxgain - fsl_dn -3 - (-228.6 + t+ bw3);

disp ('C/N at receiving for ES3 = ');

disp(CN_ES1);



OUTPUT: SATELLITE--

transponder gain (85 to 100db) =90

transponder BW (hz)= 36000000

transponder peak output power(W) = 6.3

antenna gain (transmit)(db) =20

antenna gain (receiver)(db) = 22

sat. receiver noise temperature(K) =100

EARTH STATION--

antenna gain (transmit)(db) =61.3

antenna gain (RECEIVER)(db) =60

receiver noise temp (K)=100

enter FSL uplink in db=200

enter FSL downlink in db=196

enter output back off (in db): 5

transponder output power in db =

2.9934

transponder output power in Watts =

1.9922

transponder output power1 in db =

-1.7778


-1.7778


-4.7881


-4.7881

power received at Xponder i/p due to ES1 in db =

-91.7778


-91.7778


-94.7881


-94.7881

transmitter power required for ES1 and ES2 =

3.1061e-038

transmitter power required for ES3 and ES4 =

1.5531e-038



Station 1&2 bandwidth (Hz) =10000000

Station 3&4 bandwidth (Hz) =5000000

C/N at receiving for ES1 =

17.8222

C/N at receiving for ES3 =

17.8222




clc;

close all;

clear all;

uplinkfreq=30e9;

downlinkfreq=42e9;

diameter_rx_ant=0.8;

efficiency_rx_ant=0.6;

beamwidth=1;

NF=7;

To=290;

Latm=1;

Lrain=10;

L_ant_radome=1;

L_contour=3;

L_pointing_error=1.98;

wavelength_up=3e8/downlinkfreq;

ans=(pi*diameter_rx_ant)/wavelength_up;

ans=power(ans,2);

ans=efficiency_rx_ant*ans;

Gr=10*log10(ans);

ans=NF/10;

ans=power(10,ans);

T=To*(ans-1);

T=10*log10(T);

ans=Gr-T;

disp('G/T of receiving station is ');

disp(ans);

P_sat_tx=1;

P_sat_tx=10*log10(P_sat_tx);

IF_BW=30e6;

ans=33000/(beamwidth*beamwidth);

Gt=10*log10(ans);

ans=(4*pi*38000000)/wavelength_up;

ans=power(ans,2);

FSL=10*log10(ans);

k=-228.6;

IF_BW=10*log10(IF_BW);

ans=P_sat_tx+Gt+Gr-FSL-k-T-IF_BW;

disp('C/N of Rx without extra losses');

disp(ans);

ans=P_sat_tx+Gt+Gr-FSL-Latm-Lrain-L_ant_radome-L_contour-L_pointing_error-k-T-

IF_BW;

disp('C/N of Rx');

disp(ans);

ans=13-(Gt+Gr-FSL-Latm-Lrain-L_ant_radome-L_contour-L_pointing_error-k-T-

IF_BW);

ans=ans/10;



ans=power(10,ans);

disp('Minimum power output of transponder to provide satisfactory service of receiver');

disp(ans);

OUTPUT:

G/T of receiving station is

18.0514

C/N of Rx without extra losses

0.5629

C/N of Rx

-16.4171

Minimum power output of transponder to provide satisfactory service of receiver

874.3964




clc;

clear all;

close all;

freq_uplink=14.9*(10^9);

freq_downlink=11.3*(10^9);

zone_3db_d1=3.6;

zone_3db_d2=2.4;

ant_eff=0.65;

sat_pow=20;

trans_noise_temp=520;

trans_gain=125; %in db

trans_bw=5*(10^6);

R_km=39000; %in km

R_m=39000000;

pointing_acc_loss=0.5; %in db

%****************************************************

%**Dimensions of transmitting antenna**

wavelenght_down=[3*10^8]/freq_downlink;

dim_trans_1=75*wavelenght_down/zone_3db_d1

dim_trans_2=75*wavelenght_down/zone_3db_d2

%**Dimensions of receiving antenna**

wavelenght_up=[3*10^8]/freq_uplink;

dim_rec_1=75*wavelenght_up/zone_3db_d1

dim_rec_2=75*wavelenght_up/zone_3db_d2

%**Transmitting antenna gain

Gt=ant_eff*4*pi*dim_trans_1*dim_trans_2/(wavelenght_down)^2;

Gt_db=10*log10(Gt)

%**Receiving antenna gain

Gr=ant_eff*4*pi*dim_rec_1*dim_rec_2/(wavelenght_up)^2;

Gr_db=10*log10(Gr)

%*************************************************

%power flux density

flux_den=sat_pow*Gt/(4*pi*R_m^2); %in watts/m2

flux_den_db=10*log10(flux_den)

%flux density at the edge of coverage area

flux_edge=flux_den_db-3

%*************************************************

c_n1=22 ; %indb



bw1=5*(10^6);

bw1_db=10*log10(bw1);

path_loss=(4*pi*R_m/wavelenght_down)^2;

path_loss_db=10*log10(path_loss);

sat_pow_db=10*log10(sat_pow);

k=-228.6;

G_T1_db=c_n1-sat_pow_db-Gt_db+k+bw1_db+path_loss_db+3+0.5

G_T1_db=G_T1_db/10;

G_T1=10^G_T1_db

%**************************************************

c_n2=10 ; %indb

bw2=50*(10^3);

bw2_db=10*log10(bw2);

pt=sat_pow_db-5;

pt=pt/10;

pt=10^pt;

pt=pt/20;

pt_db=10*log10(pt);

k=-228.6;

G_T2_db=c_n2-pt_db-Gt_db+k+bw2_db+path_loss_db+3+0.5

G_T2_db=G_T2_db/10;

G_T2=10^G_T2_db

%*************************************************

i_p=sat_pow_db-trans_gain;

path_loss_up=(4*pi*R_m/wavelenght_up)^2;

path_loss_up_db=10*log10(path_loss_up);

EIRP=i_p-Gr_db+path_loss_up_db+0.5

Output:

dim_trans_1 = 0.5531

dim_trans_2 = 0.8296

dim_rec_1 = 0.4195

dim_rec_2 = 0.6292

Gt_db = 37.2573

Gr_db = 37.2573

flux_den_db = -112.5458

flux_edge = -115.5458

G_T1_db = 18.9467

G_T1 = 78.4642

G_T2_db = 4.9570

G_T2 = 3.1311

EIRP = 58.9798




clc;

close all;

clear all;

a2b_up=14.9e9;

a2b_down=11.3e9;

b2a_up=14.4e9;

b2a_down=10.8e9;

beamwidth=1.5;

ans=33000/2.25;

sat_ant_gain=10*log10(ans);

xponder_pow=10*log10(20);

xponder_noise_temp=10*log10(500);

lin_xponder_gain=120;

xponder_bw=50e6;

R=38000000;

wave=3e8/b2a_up;

FSLup=20*log10((4*pi*R)/wave);

ans=(pi*3)/wave;

ans=power(ans,2);

ans=0.6*ans;

Gt=10*log10(ans);

Pr=xponder_pow-120;

Pt=Pr-Gt-sat_ant_gain+FSLup+3+4;

Pt=Pt/10;

Pt=power(10,Pt);

disp('Transmiter power required to saturate the transponder.');

disp(Pt);

CbyN=18;

wave1=3e8/a2b_down;

FSLdown=20*log10((4*pi*R)/wave1);

ans=10*log10(50e6);

GbyT=CbyN-xponder_pow-sat_ant_gain+FSLdown+1.5+4-228.6+ans;

disp('G/T of terminal B to get C/N= 18dB');

disp(GbyT);

EbNo=10;

CbyN_ov=10*log10(2560000);

BW_VSAT=10*log10(96000);

wave2=3e8/a2b_up;

ans=(pi*7.5)/wave2;

ans=power(ans,2);

G=10*log10(ans);

CbyN_up=((10*log10(500))+G+sat_ant_gain-FSLup-4)-(-

228.6+(10*log10(500))+(10*log10(50e6)));

CbyNdown=CbyN_ov-CbyN_up;

ans=10*log10(96000);

G_T=CbyNdown-xponder_pow-sat_ant_gain+FSLdown+7-228.6+ans;

G_vsat=10*log10(500)+G_T;

G_vsat=G_vsat/10;



G_vsat=power (10,G_vsat);

ans=G_vsat*wave2*wave2;

p=power(pi,2);

ans=ans/p;

ans=ans/0.6;

ans=power(ans,0.5);

disp('Antenna Diameter...in meters');

disp(ans);

noise_bw=48000;

Brf=noise_bw*(1+0.5)+28000;

ans=xponder_bw/Brf;

disp('No. of Vsats that a hub can service at a time');

disp(ans);

OUTPUT:

Transmitter power required to saturate the transponder.

29.2410

G/T of terminal B to get C/N= 18dB

22.3151

Antenna Diameter...in meters

0.1706

No. of Vsats that a hub can service at a time

500



EXPERIMENT NO: 05

TITLE OF EXPERIMENT : To Study of Wavelength Division

Multiplexing



5.1 Aim: To Study of Wavelength Division Multiplexing.

5.2 Objective:

1. Study of the Multiplexing & De-multiplexing of two different signal using Laser Diode (At

1310 nm and 1550 nm) and Photo detector.

2. Observe the waveform at Multiplex output and DE- Multiplex output

5.3 Apparatus: NWS _1310nm_LTK board + NWS_1310nm_TX-RX board. (Box -1)

NWS_1550nm_LTK board + NWS_1550nm_TX-RX board. (Box - 2)

Optical Multiplexer, De-multiplexer, ST to ST Coupler, Connecting Cable with Spin connector on

either side, CRO/DSO, Power Supply, etc.

5.4 Procedure:

1. Make the all jumper settings of Analog link on the NWS_1310nm_LTK &

NWS_1310nm_TX-RX (Box -1)

2. Make the all jumper settings of Digital link on the NWS_1550nm_LTK &

NWS_1310nm_TX-RX (Box -2)

3. Optical Mux and De-Mux provided with the kits are interchangeable. Each of them

consists of two single mode fiber cables connected at one end carrying separate

wavelengths and one single mode fiber cable at other end carrying multiplexed

wavelengths. These cables are terminated at one end by ST connectors. Cable marked as

1310 carries 1310 nm wavelength and that marked as 1550 carries 1550 nm wavelength due

to the internal arrangements with the MUX or De-Mux

4. Insert the ST connector of the Mux cable marked as 1310 in to the ST housing of the

1310nm LASER and ST connector of MUX cable marked as 1550 in to the ST housing of

the 1550nm LASER and lock it properly

5. Connect the ST coupler provided with the kit between the single cables of Mux & De-mux.

This will couple the Mux and De-Mux to each other

6. Insert the ST connector of the De-Mux cable marked as 1310 in to the ST housing of the

Photo detector (D1) on NWS_1310nm_TX-RX board. Similarly Insert the ST connector of

the De-Mux cable marked as 1550 in to the ST housing of the Photo detector (D1) on

NWS_1550nm_TX-RX board

7. Switch ON the power supply & press the switch SW 1 on each of the Box to power the

Laser drivers & Lasers with delay

8. Note that since 1310 nm Laser is configured to transmit analog signal and 1550 nm Laser is

configured to transmit digital signal, optical MUX will multiplex these two different signals

and transmit them simultaneously through single fiber cable at the output. The De-MUX

will de-multiplex these two wavelengths (Thus signals) in to separate channels at its

output

9. You can observe the recovered signals at the receiver output. You will recover both analog

as well as digital signals



10. This proves that by optical multiplexing two different wavelengths carrying different

signals (Information) we can increase the signal carrying capacity of the fiber cable to a

large extent

5.5 Conclusion: _____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________



EXPERIMENT NO: 06

TITLE OF EXPERIMENT : To prepare Optical Link Power Budget

for Repeater less Optical Fiber Link using

MATLAB & Microsoft Excel



6.1 Aim: To prepare Optical Link Power Budget for Repeater less Optical

Fiber Link using MATLAB & Microsoft Excel

6.2 Given Data:

1. Optical Fiber Link operates at a wavelength of 1310nm at a data rate

of 512 Mbps

2. Link Length(L) = 25Km

3. Transmitter (Tx) Output Power = Pi

• 0.1 mW

• 0.5 mW

4. Receiver(Rx) Sensitivity =Po

• -25 dBm

• -30 dBm

• -35 dBm

5. Cable Attenuation (αƒ)

• 0.2 dB/Km

• 0.5 dB/Km

6. Splice Loss (αj) = 0.12 dB / splice Km

7. Dispersion Equalization Penalty (Dl) = 1.5 dB

8. Extinction Ratio Penalty (El) = 1.2 dB

9. Safety Margin (M) =7 dB

10. Connector Loss (αcr)= 1 dB / connector

11. Difference = Total System Margin – Total System Loss

6.3 Remark:

1. If difference is negative, reject Transmitter & Receiver combination

2. If difference is positive, then select,

• Largest difference configuration ( Tx, Rx, Cable)

• Find out ‘L’ for Zero or smallest non integer difference

6.4 Formulae:

Pi = Po + ααααƒƒƒƒ L + ααααj (L-1) + Dl + El + M + ααααcr



6.5 Calculations: 1. using MATLAB

2. using Microsoft Excel

Note: Attach Graphs using both the methods

6.6 Conclusion: _____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________



EXPERIMENT NO: 07

TITLE OF EXPERIMENT : Displacement Measurement using Optical

sensors



7.1 Aim: To study working and characteristics of fiber optic displacement transducer

7.2 Apparatus: Optical Transmitter and Receiver Box, fiber cable, micrometer, digital

multimeter, LVDT Kit, etc

7.3 Theory:

7.3.1 Fiber optic sensors Optical fibers can be used as sensors to measure strain, temperature, pressure,

displacement and other parameters. The small size and the fact that no electrical power is

needed at the remote location give the fiber optic sensor advantages to conventional

electrical sensor in certain applications.

7.3.2 Optical Sensor Technologies

7.3.2.1 Measurands and Sensor Categories

At this point in the evolution of optical sensing technology, one can measure

nearly all of the physical Measurands of interest and a very large number of chemical

quantities. The Measurands possible are listed in Table

Optical Sensor Measurands

Techniques by which the measurements are made can be broadly grouped in three

categories depending on (a) how the sensing is accomplished, (b) the physical extent of

the sensing, and (c) the role of the optical fiber in the sensing process.

7.3.2.2 Means of sensing

In this category, sensors are generally based either on measuring an intensity

change in one or more light beams or on looking at phase changes in the light beams by

causing them to interact or interfere with one another. Thus sensors in this category are termed either intensity sensors or interferometer sensors. Techniques used in the case of

intensity sensors include light scattering, spectral transmission changes (i.e., simple

attenuation of transmitted light due to absorption), micro bending or radioactive losses,

reflectance changes, and changes in the modal properties of the fiber. Interferometer

sensors have been demonstrated based upon the magneto-optic, the laser-Doppler.

7.3.2.3 Extent of sensing

This category is based on whether sensors operate only at a single point or over a

distribution of points. Thus, sensors in this category are termed either point sensors or



distributed sensors. In the case of a point sensor, the transducer may be at the end of a

fiber the sole purpose of which is to bring a light beam to and from the transducer.

7.3.2.4 Role of optical fiber

Further distinction is often made in the case of fiber sensors as to whether

Measurands act externally or internally to the fiber. Where the transducers are external to

the fiber and the fiber merely registers and transmits the sensed quantity, the sensors are

termed extrinsic sensors. Where the sensors are embedded in or are part of the fiber -- and

for this type there is often some modification to the fiber itself -- the sensors are termed

internal or intrinsic sensors. Examples of extrinsic sensors are moving gratings to sense

strain, fiber-to-fiber couplers to sense displacement, and absorption cells to sense

chemistry effects. Examples of intrinsic sensors are those that use micro bending losses in

the fiber to sense strain, modified fiber claddings to make spectroscopic measurements,

and counter-propagating beams within a fiber coil to measure rotation.

7.3.2.5 Displacement and position sensors

The simplest sensors rely on the change in retro reflectance of light into a fiber

because of movement of a proximal mirror surface. One of the first Photonics sensors was

of this type, in which a conical tip is applied to the end of a fiber. Light is totally reflected

back into the fiber if the surrounding medium is air; however, if the fiber is inserted into a

liquid matching the fiber index, light is extracted from the fiber and lost. Thus,

displacement of the liquid surface can be tracked.

7.3.3 Enabling Sensor Components

7.3.3.1 Specialty fibers for sensors

Since a large percentage of today's optical sensors involve optical fibers in some

form, it is important to discuss the status of fiber R&D. For much of the work, sensor

designers have made use of the all-glass fibers that are readily available commercially

due to high-volume use in telecommunications. Interferometer sensors need single-mode,

all-glass fibers; intensity type sensors typically utilize multimode fiber for greater light-

gathering capability. While high-NA (numerical aperture) plastic fibers are used for some

intensity type sensors, the transmission and fluorescence properties of the plastic

complicate the spectral response, so all-glass fibers are favored for many spectroscopic-

type sensors. Polarized light transmission is important for a number of sensors (e.g., the

fiber-optic gyroscope, FOG); many fiber devices are designed to retain this property

along the length of the fiber and in the presence of macro- and micro-bending. In the case

of the FOG, the requirements are for a small coil of fiber for which the bending loss must

be small, the polarization properties of the light must be maintained, and the physical

strength of the fiber must not be jeopardized. For many of the chemical sensors, it is

important for the light wave to interact with its surroundings. Therefore, fibers have been

made where the core is close to the cladding-outside interface. An example of this type of

fiber is the "D-fiber." Shown in Figure are the cross-section views of several types of

fiber manufactured and used today.



Fig. End view of specialty fibers.

7.3.3.2 Detectors

While not much change has taken place in the semiconductor devices actually

used to convert photons into electrons, progress continues to be made in readout

techniques for the sensor signals. Of particular note is the use of optical fiber

interferometers to monitor other interferometer sensors.

7.3.3.3 Light sources The majority of optical sensors still utilize semiconductor lasers and LEDs as light

sources. Increasingly, however, the low-cost semiconductor lasers have been used to

pump rare-earth-doped fibers to provide excellent, stable fluorescent sources for chemical

monitoring.

7.4 Procedure:

1. Connect power cord to the transmitter box and Receiver Box, and then switch ON

the power supply.

2. Insert the fiber optic cable from transmitter to LVDT kit

3. Insert other fiber optic cable from LVDT to Receiver Box.

4. Attach DVM at the output of the Receiver

5. Move the LVDT using micrometer; i.e. assembly attached with the LVDT kit

6. Measure the DC output voltage and plot the graph of displacement vs. DC output

voltage

7.5 Observation table:

Sr. No. Displacement

(mm)

Dc output voltage

(V)

1

2

3

7.6 Conclusion: _____________________________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________



Isolator

Klystron Oscillator

Attenuator

Klystron Power Supply

Frequency Meter

Fig. Horn Antenna Bench Setup

Detector

CRO



Block Diagram of WDM:

Laser (D1) 1310nm

Laser (D2) 1550nm

Multiplexer Power Supply

De- Multiplexer

1310nm Photo Detector

1550nm Photo Detector

CRO

Analog Signal

Digital Signal

ST to ST Coupler



• Connect Ammeter cable to J2 with White dot of connector on right while facing back side of it to you. Keep J3 (Digital_CON), J4 (ANALOG_CON), J7 (TDM_CON) open.

• Similarly, keep jumpers J2 (ANALOG/DIGITAL SEL), J3 (TDM_RX / RS 232 SEL), J8 (TDM_OUT_CON) open & connectors J4 (DIGITAL CON), J6 (PCI) & J7 (PC3) unconnected on NWS_131 Onm_TX_RX board.

Analog Jumper setting

1 2 3 4

1 2 3

A/D SEL

1 2

MOD_CON

LASER CON

J2

J5

J6

1 2 3 4

SW2

ON

EXT_IN W

J5

Signal I/P

Amp I/P

MIC M/P

On NWS_1310nm_Tx_Rx board

Analog Con



• Connect Ammeter cable to J6 with White dot of connector on left while facing it to you. Keep J4 (ANALOG_CON), J7 (TDM_CON) open.

• Similarly, keep jumpers J3 (TDM_RX / RS 232 SEL), J8 (TDM_OUT_CON) open & connectors J5 (ANALOG CON), J6 (PCI) & J7 (PC3) unconnected on NWS_1310nm_TX-RX board.

Digital Jumper setting

1 2 3

MOD_CON

J5

1 2 3 4

A/D SEL

J2

1 2

LASER CON

1 2 3 4

ON

EXT_IN

ANALOG/DIGITAL SET

J2

1 2 3

On NWS_1550nm_Tx_Rx board

J6

SW2

W



Block Diagram of Satellite System

Satellite

Uplink Transmitter

Satellite

downlink Receiver

Satellite

Link Emulator

CROVideo

Monitor

Spectrum

Analyzer

Function

GeneratorCRO



Block Diagram of Optical Sensor

Power

Supply

LVDT

Optical

Transmitter

Optical

Receiver

Fiber Optic



Power Supply

DVM

Optical Receiver

Optical Transmitte

r

Micrometer

Target

Micrometer Mount

Optical Fiber

Block Diagram of Optical Sensor

Documents

Acs Lab Manual