Advanced communication Laboratory Manual VI SEM E&C
Department of Electronics & Communication En gineering
S.D.M Institute of Engineering & Technology ,Ujire
ADVANCED COMMUNICATION LAB Subject Code : 06ECL67 No. of Practical Hrs/Week : 03 Total no. of Practical Hrs : 42
IA Marks : 25 Exam Hours : 03 Exam Marks : 50
LIST OF EXPERIMENTS : 1. TDM of two band limited signals. 2. ASK and FSK generation and detection. 3. PSK generation and detection. 4. DPSK generation and detection. 5. QPSK generation and detection. 6. PCM generation and detection using a CODEC Chip. 7. Measurement of losses in a given optical fiber (propagation loss, bending loss) and Numerical aperture.
8. Analog and Digital (with TDM) communication link using optical fiber.
9. Measurement of frequency, guide wavelength, power, VSWR and attenuation in a Microwave test bench.
10. Measurement of directivity and gain of antennas: Standard dipole (or printed dipole), Microstrip patch antenna and Yagi antenna (printed).
11. Determination of coupling and isolation characteristics of a stripline (or microstrip) Directional coupler.
12.(a) Measurement of resonance characteristics of a microstrip ring resonator and determination of determination of dielectric constant of the substrate (b). Measurement of power division and isolation characteristics of a microstrip 3dB Power divider.
ADVANCED COMMUNICATION LAB Subject Code : 06ECL67 No. of Practical Hrs/Week : 03 Total no. of Practical Hrs : 42
IA Marks : 25 Exam Hours : 03 Exam Marks : 50
LIST OF EXPERIMENTS : 1. TDM of two band limited signals. 2. ASK and FSK generation and detection. 3. PSK generation and detection. 4. DPSK generation and detection. 5. QPSK generation and detection. 6. PCM generation and detection using a CODEC Chip. 7. Measurement of losses in a given optical fiber (propagation loss, bending loss) and Numerical aperture.
8. Analog and Digital (with TDM) communication link using optical fiber.
9. Measurement of frequency, guide wavelength, power, VSWR and attenuation in a Microwave test bench.
10. Measurement of directivity and gain of antennas: Standard dipole (or printed dipole), Microstrip patch antenna and Yagi antenna (printed).
11. Determination of coupling and isolation characteristics of a stripline (or microstrip) Directional coupler.
12.(a) Measurement of resonance characteristics of a microstrip ring resonator and determination of determination of dielectric constant of the substrate (b). Measurement of power division and isolation characteristics of a microstrip 3dB Power divider.
CONTENTS Sl no
Name of the Experiments
1.
ASK Generation and Detection
2.
FSK Generation and Detection
3.
PSK Generation and Detection
4.
TDM of two band limited signals
5.
DPSK Generation and Detection
6
QPSK Generation and Detection
7
PCM generation and detection using a CODEC Chip
8
Measure of Losses in a given optical fiber and numerical aperture
9
Analog and Digital (with TDM) communication link using optical fiber.
10
Measurement of frequency, guide wavelength, power, VSWR and attention in the microwave test bench Measurement of directivity and gain of antennas: Standard dipole (or printed dipole), Microstrip patch antenna and Yagi antenna (printed).
11
12 13
14
Determination of coupling and isolation characteristics of a Strip line and directional coupler. Measurement of resonance characteristics of a microstrip ring resonator and determination determination of determination of dielectric constant of the substrate Measurement of power division and isolation characteristics of a microstrip 3dB Power divider.
Page No
EXPERIMENT 1:
ASK Generation and Detection
Aim: To generate ASK modulated signal and to recover the modulating signal from modulated signal.
Components Required :Resistors, Capacitors, Transistor SL100, Signal generator, CRO, Connecting wires, Spring board etc.
Procedure:
Modulation: 1. Make the connections as shown in the figure. 2. Connect the two carrier signal namely namel y carrier1 and carrier 2 to the function generator and also the message signal to the function generator as input. 3. Connect channel A of the CRO to the modulating signal and channel B to the output of the modulator. 4. Switch ON both signal generator and set the frequency and the voltage of the carrier such that frequency of carrier 1 should be less than the frequency frequenc y of carrier2 or vice versa and also set the frequency frequenc y and voltage for message signal. Observe the modulated output . Then note down the frequency and amplitude of the output waveform.
Demodulation: 1.Connects the output to the anode terminal of the diode and observe the output waveform of the demodulator output on the the CRO and note down the frequency and amplitude of the demodulated output.
Circuit Diagram: ASK Modulation:
Demodulation circuit:
Waveforms:
Design: 1 Frequency, f= 2π RC Let R=5KHz C=0.1F 1 Frequency, f=
3
-6
2 π X 5X10 X0.1X10 F=318Hz Choose R 1=10K, R 2=1K Design Of R E
Let Ic=IE =5Ma R E=
C(t)-VCB(sat) IE
=
5 - 0.3 5m
=940Ώ R E=1K Design Of R B
R B=
Vin-VBE IB
=
5V - 0.7V 0.43m
=10K
Observations: Modulation:
Frequency f=500Hz Output Vo=2.5Vp-p Demodulation: 1 Frequency f =500Hz 1 Output Vo =24Vp-p Result:
ASK modulated signal is generated and modulating signal is recovered from modulated signal.
EXPERIMENT 2:
FSK Generation and Detection Aim: To generate FSK modulated signal and to recover the modulating signal from modulated signal.
Components Required :Resistors, Capacitors ,Transistor SL100,SK100,op-amp741, Signal generator, CRO, Connecting wires, Spring board etc.
Procedure: Modulation: 1. Make the connections as shown in the figure. 2. Connect the two carrier signal namely carrier1 and carrier 2 to the function generator and also the message signal to the function generator as input. 3. Connect channel A of the CRO to the modulating signal and channel B to the output of the modulator. 4. Switch ON both signal generator and set the frequency and the voltage of the carrier such that frequency of carrier 1 should be less than the frequency of carrier2 or vic e versa and also set the frequency and voltage for message signal. Observe the modulated output . Then note down the frequency and amplitude of the output waveform.
Demodulation: 1. Connects the output to the anode terminal of the diode and observe the output waveform of the demodulator output on the CRO and note down the frequency and amplitude of the demodulated output.
Circuit Diagram: FSK Modulation:
FSK DeModulation:
WAVEFORMS:
Design: R 1=10K 1 Frequency, f= 2π RC 1 318=
3
2 π x5x10 xc
C=0.1F
Result: FSK modulated signal is generated and modulated signal is successfully recovered.
EXPERIMENT 3:
PSK Generation and Detection [Phase Shift Keying]
Aim: To generate PSK modulated signal and to recover the modulating signal from modulated signal.
Components Required: IC-CD4051,Opamp-741,Resistors,Capacitors,Diode , signal generator (0-1MHz, 10vp-p)-2, Dual channel CRO and CRO probes, Regulated power supply.
Procedure: Modulation:
1. Make the connections as shown in the fig. 2. Connect Channel A of the CRO to the modulating signal and Channel B to the output of the modulator (i.e. Pin 3). 3. Switch ON both signal generator and record the input and Output waveforms one below the other with proper synchronization.
Demodulation:
1. Connect output of CD 4051 i.e. pin3 to one of the input terminal of the summer. 2. Connect the carrier signal to one of the input terminal of the inverter. 3. Record the output waveform of the demodulation.
Circuit Diagram: PSK Modulation and Demodulation:
WAVEFORMS:
Note:CD4051 is a 8 channel Multiplexer & Demultiplexer IC Result: PSK modulated signal is generated and modulated signal is successfully recovered.
EXPERIMENT 4:
TDM PULSE AMPLITUDE MODULATION & DEMODULATION Aim: Modulation and Demodulation of a signal using TDM technique and to verify the output.
Components Required :Resistors,Capacitors,Transistor SL100,SK100, op-amp741, Signal generator, CRO, Connecting wires, Spring board etc.
Procedure: 1. Connections and switch settings are made as shown in the figure. 2. Connect power supply in proper polarity to the kit DCL-02 and switch it ON 3. Connect 250HZ ,500HZ,1KHZ and 2khz Sine wave signal from the function generator to the multiplexer input channel CHO,CH1,CH2,CH3 by means of connecting chords provided. 4. Connect to the multiplexer output TXD of the transmitter section to the demultiplexer input RXD of the receiver section. 5. Connect the output of the receiver section CH0,CH1,CH2 & CH3 to 1N0,1N1,1N2,1N3 of the filter section. 6. Set the amplitude of the input sine wave as desired. 7. Observe the output.
Observation: Observe the following waveforms on CRO & pl ot it on the paper. a. Input channel CH0,CH1,CH2,CH3. b. Channel selection signal. c. TX CLK & RX CLK. d. Channel identification signal TX SYNC & R X SYNC. e. Multiplexer output TXD. f. Demultiplexer input RXD g. Demultiplexer output CH0,CH1,CH2,CH3 h. Reconstructed signal OUT0, OUT1, OUT2,OUT3.
Conclusion:
In this experiment the transmitter clock & the channel identification clock are directly linked to the receiver section. Hence transmitter & receiver are synchronized & proper reconstruction of t he signal is achieved.
Circuit Diagram: TDM-2:1 MUX:
TDM-1:2 DEMUX:
BLOCK DIAGRAM OF TDM KIT:
WAVEFORMS:
RESULT :
TDM Modulation and Demodulation has been performed and output is observed.
EXPERIMENT 5:
DIFFERENTIAL PHASE SHIFT KEYING MODULATION Aim: To Perform Differential Phase Shift Keying Modulation.
Component Required: DPSK Kit, Patch cords.
Block Diagram :
Procedure: 1. Connections are made as shown in the figure. 2. Connect power supply with proper polarity to the kit ADCL-01 and switch it ON. 3. Select Data pattern of simulated data using switch SW1. 4. Compare the data ie. DPSK decoded data at data out with respect to input data. 5. If recovered data mismatches with respect to the transmitter data then use RESET switch for clear observation of data output .
Procedure: 1. Refer to the block diagram & carry out the following connections & switch setting. 2. Connect power supply in proper polarity to the kits ADCL-01 & Switch it ON. 3. Select data pattern of simulated data using switch SW1. 4. Connect SDATA generated to DATA IN of the NRZ-L coder. 5. Connect NRZ-L DATA output to the DATA IN of the DIFFERENTIAL ENCODER. 6. Connect the clock generated SCLOCK to CLK IN of the DIFFERENTIAL ENCODER. 7. Connect differential encoded data to control input C1 of CARRIER MODULATOR. 8. Connect carrier component SIN1 to IN1 & SIN2 to IN2 of the carrier modulator logic. 9. Connect DPSK modulated signal MOD OUT to MOD IN of the BPSK DEMODULATOR. 10. Connect output of BPSK demodulator b(t) OUT to input of delay section b(t)IN & one input b(t) IN of decision device. 11. Connect the output of delay section b(t-Tb)OUT to the input b(t-Tb)IN of decision device. 12. Compare the DPSK decoded data at DATA OUT with respect to input SDATA. 13. Observe various waveforms as mentioned below . if recovered data mismatches with respect to the transmitter data ,then use RESET switch for clear observation of data output.
Observation: Observe the following waveforms on the CRO 7 plot it on the paper. ON KIT ADCL-01 1. Input NRZ-L data at DATA IN of DIFFERENTIAL ENCODER. 2. Differentially encoded data at DATA OUT of DIFFERENTIAL ENCODER . 3. Carrier frequency SIN1 & SIN2. 4. DPSK modulated data at MOD OUT. 5. DPSK DEMODULATED signal at b(t) OUT of BPSK DEMODULATOR. 6. Delayed data by one bit interval at b(t-Tb)OUT of DELAY SECTION. 7. DPSK decoded data at DATA OUT of DPSK DECODER.
WAVEFORMS:
RESULT: DPSK Modulation & Demodulation is studied and Observed .
Conclusion: The differential coding of data to be transmitted make the bit “1” to be transformed into carrier phase variation. In this way the receiver recognizes one bit “1” at a time which detects a phase shift of the modulated carrier, independently from its absolute phase. In this way the BPSK modulation, which can take to the inversion of the demodulated data, is overcome.
EXPERIMENT 6:
QPSK Generation and Detection Aim: Study of Carrier Modulation techniques by QPSK method.
Component Required: QPSK Kit (ADCL-02 &ADCL-03), Patch cords 20Mhz dual trace oscilloscope.
Block Diagram:
Procedure: 1. Refer to the block diagram & carry out the following connections & switch setting. 2. Connect power supply in proper polarity to the kits ADCL-02 & ADCL-03 &Switch it ON. 3. Select data pattern of simulated data using switch SW1. 4. Select SDATA generated to DATA IN of the NRZ-L coder.
5. Connect NRZ-L DATA to DATA IN of DIBIT CONVERSION. 6. Connect S-CLOCK to CLK IN of the DIBIT CONVERSION. 7. Connect the dibit data I &Q bit to control input C1 &C2, of CARRIER MODULATOR respectively. 8. Connect carrier component to input of carrier modulation as follows: a:SIN1 to IN1 b:SIN2 to IN2 c:SIN3 to IN3 d:SIN4 to IN4 9. Connect QPSK modulated signal mod out in ADCL-02 to the MOD IN of the QPSK demodulator on ADCL-03. 10. Connect I bit ,Q bit and clock out outputs of QPSK demodulator to I bit IN ,Q bit IN & CLK IN. Ports of data decorder respectively. 11. Observe various waveforms. Observation: ON kit ADCL-02 1. Input NRZ-L data at DATA INPUT 2. Carrier frequency SIN1 to SIN4 3. Dibit pair generated data I bit & Q bit at DIBIT CONVERSION. 4. QPSK Modulated signal at MOD OUT . ON kit ADCL-03 1. Output of first squarer to SQUARER-1 2. Output of second squarer at SQUARER-2 3. Four sampling clocks at the output of SAMPLING CLOCK GENERATOR 4. Two adder outputs at the output of ADDER. 5. Recovered data bits (I & Q bits) at the output of ENVELOPE DETECTORS. 6. Recovered NRZ-L code from I & Q at the output of DATA DECODER.
Conclusion: In BPSK, we deal individually with each bit of duration Tb. In QPSK, we lump two bits together from a symbol. The symbol can have any one of four possible values corresponding to two-bit sequence 00, 01, 10, & 11.We therefore average to make available for transmission four distinct signals. At the receiver, each signal represents one symbol & corresponding two bits when bits are transmitted as in BPSK, the signal changes occur at the bit rate. When the symbols are transmitted the changes occur at the symbol rate, which is one half of the bit rate. Thus symbol time is Ts=2Tb.
Input and Output Waveform:
EXPERIMENT 7: PCM generation and detection using a CODEC Chip
Aim: To generate & detect the PCM using CODEC chip Component Required: Optic fiber kit, Patch cords
Block Diagram:
Procedure: 1. Connections are made as shown in figure. 2. Switch setting and jumper connections are done. 3. Optical cable is placed in the optic cable transmitter & also at the receiver. 4. The detected signal is observed at the oscilloscope. 5. Effect of voice signal at various test points are noted. 6. Switch SW6 is kept towards SINE IN position. 7. A sine signal of 1khz & amplitude of 2Vp-p is fed to SIN1 &SINE2 input terminals 8. Observe the reconstructed signal at OUT post for CODEC1 RX & CODEC 11
RX . 9. Observe the signal changes at various test points from I/p & o/p signals on CRO. 10. Vary the input frequency in steps & simultaneously observe the output signal. Measure the amplitude of o/p signal for each I/p frequency. 11. Find the frequency reading after which the response of codec drops. This gives between of codec. 12. Since if works for audio range we should get between at around 3.4khz.
Result: PCM generation and detection using a CODEC Chip
EXPERIMENT 8:
Measure of Losses in a given optical fiber and numerical aperture Aim:
1. To set up an analog link using 1meter optic fiber cable. 2. To (find) measure the losses in optical fiber communication link. 3. To measure attenuation loss. Component Required: Optic fiber kit, Patch cords optic fiber cable.
Block Diagram:
Procedure: Analog Link : 1. Set the switch SW8 to analog position 2. Connect 1m optical fiber between LED1.ie 1x1 & pin detector (RX2). 3. SW6 4. Feed 2Vp-p. Sine signal at 1khz from the function generator. 5. Set up voltage amplitude 2Vp-p by adjusting intensity control. 6. Reapt the above steps with 3m fiber. 7. Note down output voltage and find attenuation constant ‘α’
ln(V1/V3) i.e α= l3-l1
Where V1
I/P voltage
1m cable
V3 I/P voltage 3m cable Set frequency f=10khz V1=1v Bending loss: 8. With 1m cable (10khz frequency,1vp-p input)setup the connection. 9. Note down the output waveform & its amplitude. 10. Bend the fiber in loop. Reduce diameter from 5m to 2cm & note down the output voltage.
Note: Do not reduce the diameter less than 1cm 11. Tabulate the readings.
Attenuation Loss:
Fiber Length 1m 3m
Input Output Voltage Frequency Voltage Frequency 1Vp-p 10KHz 1Vp-p 10KHz 1Vp-p 10KHz 0.65Vp-p 10KHz
V3
-
α(l3-l1)
=e V1
ln(V1/V3) α= l3-l1 ln(1/0.65) α= ( 3-1) α=0.2154Npm 1
α in DB = α =4.343. α =0.9348db Bending loss Measurement:
1m Fiber Sl.No. Diameter Voltage 1 3cm 0.9 2 4cm 0.91 3 6cm 0.94 4 8cm 0.96 5 10cm 1.00 1 diameter α Signal strength
Conclusion: i. Analog link using optical fiber is established. ii. Attenuation less α iii. Bending loss increases as the cable is bent more
ie 1 diameter α Signal strength Procedure:
1. Make connections as shown in fig connect the power supply cables with properly Polarity to Link –B kit. While connecting this ensure that the power supply is OFF. 2 .Keep switch sw8 towards TX position. 3. Keep switch SW9 towards TX1 position. 4. Keep switch jumper JF5 towards +12v position. 5. Keep jumper JP6, JP9,JP10 shorted. 6. Keep jumper JP8 towards sine position. 7. Keep intensity pot P2 towards minimum position. 8. Switch ON the power supply. 9. Feed about 2Vp-p sinusoidal signal of 1KHz from the function generator to the IN post of analog buffer. 10. Connect the output post OUT of analog buffer to the post TX IN of transmitter. to the port TX IN. 11. Slightly unscrew the cap of SFH756V (660nm).Do not remove the cap from the connection. Once the cap is loosened insert the 1m fiber into the cap. Now tighten the cap by screwing it back. 12.Connect the other end of the fiber to detector SFH350V very carefully as per the above step. 13. Observe the detected signal at port ANALOG OUT on oscilloscope. Adjust intensity control port P2 optical power control potentiometer so that a signal of 2Vp-pamplitude. 14. To measure the analog band width of the phototransistor, vary the input signal frequency & observe the detected signal at various frequencies. 15. Plot the detected signal against applied signal frequency & from the plot determine the 3db down frequency. 16. Repeat the procedure as above for second transmitter SFH450V by making the following changes. Analog Band width of SFH350 for TX1 SFH756 is about 300khz while for TX2 SFH450is below 300khz.. 17. Keep switch SW9 towards TX2 position. 18. Keep jumper JP7 towards +12v position.
Setting up a Digital Optic Link
Block Diagram:
Procedure:
1. Make connections as shown in fig connect the power supply cables with properly polarity. 2. Keep switch sw8 towards RX position. 3. Keep switch SW9 towards RX1 position. 4. Keep switch jumper JF5 towards 12v position. 5. Keep jumper JP5 towards JP9,JP10 shorted. 6. Keep jumper JP8 towards sine position. 7. Keep intensity pot P2 towards minimum position. 8. Switch on the power supply. 9.Feed 2Vp-p sine signal of 1KHz from the function generator to 10V port of analog buffer. 10. Connect the output port to the port TX IN. 11. Sligthly unscrew the cap of SFH756V.Do not remove the cap from the connection. Once the cap is loosened insert the 1m fiber into the cap. Now tighten the cap by screwing it back. 12.Connect the other end of the fiber to detector SFH350 very carefully as per the above step. 13. Observe the detected signal at port analog out on oscilloscope. Adjust intensity control port P2 optical so that a signal of 2Vp-p is received. 14. Repeat the procedure as above for second transmitter SFH450V by making the following changes. Analog bandwidth of SFH350 for TX1 SFH756 is 300khz. 15. Keep switch SW9 towards TX2 position. 16. Keep jumper JP7 towards +12v position.
Result:
Fiber digital link is situated and frequency response of ph oto detector is obtained.
Determining the Numerical Aperture
Numerical aperture refers to the maximum angle at which light incident on the fiber is totally internally internally reflected and transmitted analog the fiber. Procedure: 1.Connections are made as shown in the figure and power supply with proper polarity is connected. It is ensured that while connecting the power supply is OFF. 2.Switch ON the supply. 3.Feed TTL square wave signal of 1KHZ from the function generator to the IN port of digital buffer. 4.Connect the output port OUT of digital buffer to the TXIN of transmitter. 5.Slighty unscrew the cap of SFH756V 6.Measure the distance between the tip of the fiber illuminated .Calculate the N.A of the fiber by
-1
θ = sin (NA)
circuits:
DC+BE x=
0.01+0.01 =
4
4
=5mm D=10mm
Sinθmax =0.4472 o
θmax =Sin-1(0.4472)=26.56
Result: Numerical Aperture of the given fiber is calculated.
EXPERIMENT 9: Analog and Digital (with TDM) communication link using optical fiber . Aim: To study Analog and Digital (with TDM) communication link using optical fiber. Component Required: Optical fiber cable, OFC kit patch cords . Block Diagram:
Procedure: 1.Connections are made as shown in figure. 2.Jumper & switch settings are done 3.Optical cable is transmitted in the optic transmitter & also at the receiver. 4.The detected signal is observed at TTL out on the oscilloscope. 5.The output are observed on the oscilloscope. 6.TX1 marker & TX2 marker are set & output is observed. Procedure: 1.Make the connections as shown in the diagram. 2.Keep the jumper & switch settings as shown in fig. 3. Select the fiber optic transmitter TX1 SFH756 using jumper & switch setting as shown in fig 4.Slightly unscrew the cap of SFH756V(660nm).Do not remove the cap from the connector. Once the cap is
loosened ,insert the one-meter fiber into the cp now tighten the cap by screwing it back. 5.Slightly unscrew the cap of RX1 photo transistor with TTL logic output SFH551V.Do not remove the cap from the connector. Once the cap is loosened, insert the other end of fiber into the cap. Now tighten the cap by screwing it back. 6.Observe the detected signal at post TTLOUT on oscilloscope. 7.Connect the received signal post TTL OUT to post MCD RX IN. 8.Observe the integrated output at INT OUT, observe edge triggered output at ET OUT as shown in fig. 9.Observe the recovered clock as shown in fig at RX CLK post the duty cycles of the recovered clock is not the same as transmitter clock, but the are s ynchronized except for a slight transmission delay in the received clock. 10.Observe decoded data at RX DATA post as shown in fig 11.Select marker 1 or 2 for display using switch SW5. 12.Select TX2 SFH450 using switch SW9 & repeat the above procedure. (after inserting the fiber on both sides, adjust the fiber alignment prop erly inside both SFH devices if required to get proper indication of o/p LEDs) 13.Repeat the above procedure for marker 1& 2 as given in the marker settings table below.
Note: The students can from hundreds of other comb inations apart from the marker settings table.Few settings may not give proper TDM o/p. Avoid 4 consecutive 1’s or 0’s in single ma rker settings to get proper TDM data.
TX MARKER-1 10010001 11011001 11011001 01011101 10101101 10111001 10110001 10011101 10010101
TX MARKER-2 10110110 10110110 10001010 10001010 10001010 11001011 01101010 01100010 01011001
Result:
TDM multiplexing & demultiplexing is observed & outputs are recorded.
EXPERIMENT 10:
Measurement of frequency, guide wavelength, power, VSWR and attention in the microwave test bench
Aim: To Measurement of frequency, guide wavelen gth, power, VSWR and attention in the microwave test bench. Component Required:
Microwave source, Isolator, frequency meter (cavity wave meter) ,Variable attenuator, S lotted section, tunable probe, detector mount matched termination, VSWR meter, waveguide stands, short circuit tuner, oscilloscope, BNC-BNC cable.
Block diagram :
Graph: Standing Wave:
Calculation:
λ g =2(d2-d1) λ g ---Guide wavelength d1------First minima=7.9+0.08=7.98cm d2 ----Second minima=10.38cm λ g =2(10.38-7.98) λ g =4.8cm λ c=2a =2x2.3cm = 4.6cm : 1 2 λ o
= 1 2 λ g
+
1 2 λ c
: 1 2 λ o
= 1 + 1 2 2 (4.8) (4.6)
where λ o =free space wavelength
λ o =3.32cm
: f= =
c λ o 3x10 3 .32
10
=9.039Hz
Also Vmax=2.2v Vmin=0.4v
=2.34
Procedure: Energizing the klystron
1.Set up the system. Connect a matched termination at the end of the setup. 2.Switch ON the cooling tan. 3.Keep the beam voltage control knob in the minimum position & repeller voltage Knob in maximum position. 4.Switch ON the power supply, adjust the beam voltage to around 250v & keep it constant. 5.Check the beam current that should be less than 20Ma. 6.Turn the knob to repeller voltage position & check the repeller voltage in the meter. It may be noted that some meter is used to measure beam voltage, beam current & repeller voltage at the corresponding knob position. 7.Reduce the repeller voltage to get a square wave form with maximum amplitude in any mode through the tunable probe & observe if using an oscilloscope. 8.Continue with the following steps to find different parameters.
Measurement of Frequency:
Tune the frequency meter knob to observe a dip in the output & measure the frequency of frequency of operation. Retune the frequency meter after measuring the frequency. Measurement of Guide Wavelength:
1.Replace the matched termination with a tunable short & standing wave is produced inside the waveguide. 2.Move the tunable probe & observe the changes in the output. The amplitude will vary with respect to the movement of the tunable probe along the slotted line section. If may be noted that there will be several maxima & minima positions. 3.Keep the tunable probe to any minima position & note down the scale provided at the slotted line
section(d1). 4.Move the tunable probe (any direction)to get the next immediate minima & note down the scale(d2). 5.Calculate the guide wavelength using the formula λ g =2(d2-d1). 6.Calculate the frequency of operation using rela tion given below & compare it with frequency measured using the frequency meter. : 1 2 λ o
= 1 2 λ g
+
1 2 λ c
λ g ---Guide wavelength λ c---- is the cutoff wavelength of the waveguide λ o ----is the free space wavelength λ c=2a
where a=2.28cm
Measurement of VSWR : 1.Replace the tunable short with a matched transmission. 2.Move the tunable probe along slotted line section & measure the minimum & maximum amplitude of the signal.
Vmax : VSWR= Vmin 3.Alternatively a VSWR meter may be used to measure the VSWR of the component. select normal position & select suitable dB level to measure the output & clock the reading at the meter at meter in VSWR scale. Adjust the gain control knob to normalize the VSWR-1.now bring the tunable probe to a minima position & observe the pointer comes back .The Reading indicates the VSWR of the component. Measurement of power :
1.Connect an RF power meter at the output to measure the absolute power. 2.Altenatively a VSWR meter may be connected & observe relative power at the output. Measurement of Attenuation:
1.Change the attenuator knob from its maximum insertion position minimum insertion position to observe the variation at the output power level in the VSWR meter in the db scale.
Result:
The frequency f=9.03Ghz(Practical) The Guide wavelength λ g =4.8cm VSWR=2.34
EXPERIMENT 11: Measurement of directivity and gain of antennas: Standard dipole (or printed dipole), Microstrip patch antenna and Yagi antenna (printed).
Aim:
To measure the directivity & gain of anten na’s.
Component Required:
Standard dipole antenna, Patch antenna, Yagi antenna
Block Diagram Of Patch Antenna:
Formula: Gt=Gr
41253 Directivity D= θHP X ΦHPs
G= ŋ D
ŋ---- efficiency
Pradiated Efficiency ŋ= Paccepted
Microwave Patch Antenna: Φ(0) Db Φ(0) Db Φ(0) Db (v) (v) (v) 0 58 60 58 120 49 5 59 65 58 125 50 10 60 70 57 130 52 15 60 75 56 135 54 20 60 80 56 140 55 25 61 85 55 145 55 30 59 90 54 150 56 35 60 95 52 155 57 40 60 100 51 160 58 45 59 105 51 165 58 50 59 110 50 170 59 55 58 115 48 175 59 Block Diagram Of Dipole antenna:
Φ(0) Db (v) 180 69 185 60 190 60 195 60 200 60 205 60 210 59 215 59 220 59 225 59 230 58 235 58
Φ(0) Db (v) 240 58 245 56 250 55 255 53 260 52 265 51 270 48 275 48 280 47 285 46 290 47 295 50
Φ(0) Db (v) 300 52 305 52 310 54 315 55 320 56 325 56 330 57 335 58 340 59 345 60 350 60 355 61
Standard Dipole antenna:
Φ(0) Db Φ(0) Db Φ(0) Db (v) (v) (v) 0 65 60 69 120 65 5 65 65 69 125 65 10 68 70 71 130 64 15 69 75 71 135 65 20 70 80 70 140 63 25 67 85 70 145 63 30 70 90 68 150 64 35 72 95 69 155 66 40 73 100 67 160 67 45 69 105 67 165 68 50 70 110 68 170 68 55 69 115 67 175 68
Block Diagram Of Yagi –Uda Antenna:
Φ(0) Db (v) 180 68 185 68 190 71 195 71 200 71 205 71 210 71 215 73 220 71 225 73 230 73 235 70
Φ(0) Db (v) 240 72 245 72 250 70 255 70 260 70 265 70 270 70 275 67 280 68 285 69 290 68 295 66
Φ(0) Db (v) 300 66 305 64 310 63 315 64 320 63 325 67 330 63 335 62 340 63 345 65 350 65 355 65
Yagi –Uda Antenna:
Φ(0) Db Φ(0) Db Φ(0) Db (v) (v) (v) 0 64 60 69 120 62 5 60 65 70 125 60 10 58 70 68 130 63 15 60 75 68 135 64 20 59 80 69 140 62 25 67 85 68 145 62 30 68 90 67 150 61 35 68 95 69 155 62 40 66 100 65 160 62 45 67 105 65 165 61 50 65 110 67 170 63 55 69 115 66 175 64
Φ(0) Db (v) 180 66 185 67 190 69 195 70 200 71 205 71 210 71 215 72 220 70 225 72 230 72 235 72
Φ(0) Db (v) 240 72 245 71 250 73 255 73 260 72 265 71 270 74 275 70 280 72 285 68 290 65 295 65
Φ(0) Db (v) 300 65 305 61 310 65 315 59 320 60 325 56 330 58 335 60 340 61 345 62 350 64 355 64
Procedure: 1.Mount the transmitting antenna on the stand. C onnected it to the s-9990 transmitter output. 2.Mount the receiving antenna an the positioner & connect it to the s-9990 receiver input . connect the mains cable & connect it to the mains. 3.The printed & microstrip antenna are gripped i n an expected polythene sheet (EPS). The EPS is pressed to fit on to a u-holder which has a nylon mount attached to it to fix it on the plastic rod. 4.The u-holder is pushed on the EPS as shown & centralized over the slit in the EPS. 5.The printed antenna is slipped in the EPS & appropriately centralized as required. 6.A manual rotator capable of rotating the antenna by 5 degree is used to obtain the polar plot. 7.At every 5 degree position of the antenna the db v reading is stored in the 72 point memory array of the s-9990 receiver. 8.On completion the data can be displayed recalled from memory. 9.Puy the equipment ON & adjust the antenna positioner to reading no.1 on the disk & note down the value from s-9990 device. 10.Now align the positioner such that the indicator is pointing to reading number 2 (5 degree) on the disk. 11.Simillarly take the readings upto 355 degree. 12.Plot the polar plot. Result: The three antennas are studied & directivity & gain are calculated.
EXPERIMENT 12: Determination of coupling and isolation characteristics of a Strip line and directional coupler.
Aim:
Determination of coupling and isolation characteristics of a Strip line and directional coupler. Component required: Receiver transmitter generator,5db wideband attenuator 50 ohms 5mA termination 2PCs adapter cable. Block Diagram of Isolation:
Block Diagram of Coupling:
Directional Coupler:
Procedure: For coupling character:
1.Connect the cable to generate o/p & the other cable to receiver i/p via attenuator load. 2.Connect directional coupler as per block diagram ie 5mA cable. 3.Close the unused ports using 50 Ohm matched terminations. 4.Take reading from 900-1200HZ for every 10HZ. 5.Find the difference between reference gain & the gain for directional coupler. The difference provides the characteristic curve. 6.Plot a curve of db values wrt frequency.
For Isolation character:
1.The setup & procedure for isolation characters is same as that of coupling ch aracter 2.Connections are made from block diagram. 3.Close unused ports using 50 Ohm matched terminations. 4.Repeat the same procedure as above to take readings & plot the graph. Tabular Column:
Frequency Without (MHz) device gain 900 920 940 960 980 1000 1020 1040 1060 1080 1100 1120 1140 1160 1180 1200
106.6 106.6 106.6 106.4 106.1 105.7 105.4 105.4 105.4 105.4
Device gain(db) 104.8 104.8 104.8 104.3 104.0 103.8 103.1 102.7 102.8 102.8
104.7 104.5 104.3 104.5 103.9 103.2
102.7 102.0 101.8 101.9 101.6 100.7
With Device (3db power divider) Characteristic isolation Characteristic gain(db) 1.7 87.5 19 1.8 85.0 21.6 1.7 83.3 23.2 2.1 81.8 24.6 2.1 78.2 27.9 1.9 81.6 24.1 2.6 86.3 19.4 2.7 84.0 21.4 2.6 87.6 17.8 2.6 91.7 13.7 1.9 2.6 2.7 2.3 2.1 2.5
92.4 93.1 93.9 94.6 94.4 94.0
12.2 11.5 10.6 9.6 9.3 9.2
Result:
Coupling & Isolation characteristics of a microstrip directional coupler is determined.
EXPERIMENT 13: Measurement of resonance characteristics of a microstrip ring resonator and determination of determination of dielectric constant of the substrate Aim: To study the resonance characteristics of a mocrostrip ring resonator. Component Required: Attenuator pad, microstrip ring resonator, transmitter and receiver. Block Diagram:
Ring Resonator:
Procedure:
Setup & procedure for creating the reference is same as that of directional coup ler setup. Set up for determining resonance & diele ctric constant at a microstrip ring resonator. 1.Conect cable to generatr o/p & other is to be connected via the attenuator pad to the receiver port(ie in place of 5 mA adapter) 2.Connect ring resonator in between ( ie in place of 5mA adapter) 3.Take readings from 900MHz to 1200MHz at every 10MHz.Tabulate the readings. 4.Find the difference between reference gain & gain for the resonator. 5.The difference provides the characteristic curve for ring resonator . 6.Plot the db values (characteristic) vs with respect to frequency.
Tabular Column:
Frequency Without (MHz) device gain 900 106.5 920 106.6 940 106.5 960 106.4 980 106.1 1000 105.7 1020 105.7 1040 105.4 1060 105.4 1080 105.4 1100 104.6 1120 104.6 1140 104.5 1160 104.2 1180 103.7 1200 103.2
With device gain 95.7 98.3 101.3 102.5 102.3 101.3 101.0 102.3 102.3 99.4 98.0 98.8 99.0 98.3 96.6 93.9
Characteristic 10.8 8.3 5.2 3.9 3.8 4.4 4.7 3.1 3.1 6.0 6.6 5.8 5.5 5.9 7.9 9.3
Result:
The resonance characteristics of a mocrostrip ring resonator is studied.
EXPERIMENT 14: Measurement of power division and isolation characteristics of a microstrip 3dB Power divider. Aim:
To measure the power division and to study the isolation characteristics of a microstrip 3bd power
divider. Component Required: Receiver, transmitter generator 5db wideband attenuator,50 Oh m 5mA termination, power divider.
Block Diagram of Power Divsion:
Block Diagram of Isolation:
Power Divider:
Procedure:
To setup reference 1.Setup reference & get the readings for 900MHz-1200MHz ie take readings or normalizing.The readings obtained from microstrip component under test. 2.Connect one cable to the transmitter output (generator o/p) & the other is to be connected via attenuator pad to the input. 3.Directly connect the input & output via the 5Ma adapter provided. Setup for Determining power division characteristic of a microstrip 3db power divider. 1.Connections are made as shown in block diagram. 2.Connect one cable to generate o/p terminal & the other cable is connected via the attenuator pad to receiver input. 3.Connect 5mA connections of the cable to a 3db power divider & terminators. 4.Take readings with frequencies same as in reference. 5.Subtract the reading obtained from the reference & plot db values so obtained wrt frequency. 6.Repeat the experiment for other port. Experiment setup for determination of isolation characteristic of a microstrip 3db power divider. 1.Connections are made as shown in the figure. 2.Connect one cable to output & others connected via attenuator pad to the input of the receiver. 3.Connect 5Ma connections of the cable to the 3db power divider & terminator. 4.Now take readings with frequencies same as done in reference. 5.Subtract the reading obtained from the reference & plot the db values so obtained wrt frequency in the graph.
Tabular Column:
Frequency Without (MHz) device gain
Device gain(db)
With Device (3db power divider) Characteristic isolation Characteristic gain(db)
900 920 940 960 980 1000 1020 1040 1060 1080 1100 1120 1140 1160 1180 1200
106.5 106.6 106.5 106.4 106.1 105.7 105.7 105.4 105.4 105.4
82.2 82.8 83.0 82.9 82.5 82.0 81.9 82.5 82.7 82.9
24.3 23.8 23.5 23.5 23.6 23.7 23.8 22.8 22.7 22.5
96.0 96.2 96.3 96.0 95.8 95.3 95.2 95.0 94.8 94.7
10.2 10.4 10.2 10.4 10.3 10.4 10.5 10.4 10.6 10.7
104.6 104.6 104.5 104.2 103.7 103.2
83.3 83.5 83.7 84.0 84.2 84.5
21.3 21.1 20.8 20.2 19.5 18.7
94.9 94.5 94.3 94.1 94.7 93.5
9.7 10.1 10.2 10.1 10.0 9.7
Result:
Isolation & power division characteristics of a microstrip 3db power divider is studied.
