EECB351-Exp 1_Intro to EMONA Trainer

7/27/2019 EECB351-Exp 1_Intro to EMONA Trainer

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COMMUNICATION SYSTEM LABORATORY

EXPERIMENT 1: INTRODUCTION TO EMONA 101 TRAINER

A. OBJECTIVE OF EXPERIMENT

1. To investigate the function of the communication modules available in the EMONA 101 trainer

kit.

B. EQUIPMENT REQUIRED

1. Emona Telecoms – Trainer 101

2. Oscilloscope and Patch leads

3. Dual Channel Oscilloscope

C. SUMMARY OF THEORY

EMONA 101 trainer is used to help student learn about communications and telecommunications

principles. It lets the students brings to life the block diagrams that fill communications textbooks.

Block diagram are used to explain the principle operation of electronic systems without worrying

about how the actual circuit implementation. Among the block diagrams available in the EMONA 101

are master signals, buffer, adder, phase shifter and voltage controlled oscillator.

D. PROCEDURE

Part A. – Buffer Module

Amplifiers are used extensively in communications and telecommunications equipment. The buffer

module in Emona Trainer 101 is an amplifier that can make the signals bigger and also used as an

interface between devices and circuits that can’t normally be connected.

1. Locate the Buffer module and set its Gain control to about middle of its travel. Connect the set up

shown in Figure 1.

Figure 1

2. Adjust the timebase control to view two or so cycles of the Buffer module’s input and output.

Measure and record the peak to peak amplitude of both signals.

The measure of how much bigger an amplifier’s output compared to its input is called gain. Gain is

represented as;

Av = Vout/Vin (1)

3. Calculate and record the Buffer nodule’s gain.




The Buffer module’s gain is variable. Usefully, it can be set so that the output voltage is smaller than

the input voltage. This is called as attenuation or loss.

4. Turn the Buffer module’s gain contr ol fully anti clock wise. Repeat step A.2 and A.3.

Clipping usually occurs when the amplifier’s input signal is too big for the amplifier’s gain. When thishappens, the amplifier is said to be overdriven. It can also occur if the amplifier’s gain is too b ig for the

input signal.

5. Turn the Buffer module’s gain control fully clock wise. Repeat step A.2 and A.3.

Part B. – Adder

Adder is used to add two signals together.

1. Locate the Adder module and turn its g control (for Input B) fully anti clock wise.

2. Set the G control (for Input A) to about middle of its travel.

3. Connect the setup shown in Figure 2.

Figure 2

4. Adjust the timebase control to view two or so cycles of the Master Signals module’s 2 kHz sine

output.

5. Vary the Adder module’s G control left and right and observe the effect. Record your observation.

6. Measure the voltage on the Adder module’s input A.

7. Turn the Adder module’s G control to fully clock wise.

8. Measure and record the Adder module’s output voltage. Calculate and record the voltage gain. Record your measurement in Table 1.

9. Turn the Adder module’s G control to fully anti clock wise. Repeat steps B.8.

Table 1

Input A

Input Voltage Output Voltage Gain

Maximum

Minimum

10. Disconnect the Master signal module’s 2 kHz sine output from the Input A and connect it to Input B.

11. Turn the Adder module’s g control fully clockwise.

12. Measure the Adder module’s output voltage. Record your measurement in Table 3. Calculate andrecord the voltage gain of the Adder module’s Input B.

13. Turn the Adder module’s g control fully anti clockwise. Repeat step B.12.




Table 2

Input A

Input Voltage Output Voltage Gain

MaximumSee Table 1

Minimum

14. Compare the results in Table 1 and 2. What can you say about the Adder’s outputs in term of their

gain?

15. Turn both of the Adder module’s gain controls fully clock wise.

16. Connect the 2 kHz sine output to both Input A and Input B.

17. Measure and record the adder module’s new output voltage.

Part C. – Phase Shifter

Several communications and telecommunications systems require that the signal to be transmitted is

phase shifted.

1. Locate the Phase Shifter module and set its Phase Change control to the 00

position.

2. Set the Phase Adjust Control to about the middle of its travel.


4. Adjust the Timebase control to view two or so cycles of the master signal module’s 2 kHz sine

output and the phase sifiter’s output.

5. Vary the Phase Adjust control left and right and observe the effect on the two signals. Record your

observation.

6. Set the Phase Shifter module and set its Phase Change control to the 1800

position.

7.

Repeat step C.5.

Figure 3




Part D. – Voltage Controlled Oscillator

The VCO module is an oscillator with varying output frequency. The VCO has two outputs, namely

analog and digital.

1. Locate the VCO and set the Gain control to about middle of its travel.

2. Set the VCO module’s Frequency Adjust control to about middle of its travel. 3. Set the VCO module’s Range control to the LO position.


5. Adjust the scope’s Timebase control to view two or so cycles of the VCO module’s sine output.

6. Measure the peak to peak amplitude of the VCO module’s sine output.

7. Vary the Frequency Adjust control left to right. Measure and record the minimum and maximum

VCo output frequency.

8. Set the VCO module’s Range control to the HI position.

9. Repeat step D.7.

The output frequency of VCO module can also be varied by changing the voltage on the Variable DCV.

10. Connect the VDC to the VCO input. Set the VDC control to middle of its travel.

11. Set the input coupling of the scope that connected to the Variable DCV to DC position.12. Vary the Variable DCV module left to right. Observe the effect to the frequency of the VCO

module’s output. Record your measurement in Table 3.

Table 3

Minimum DCV voltage = Frequency of VCO output =

Maximum DCV voltage = Frequency of VCO output =

Figure 4




Part E. – Using the EMONA Trainer to Model Equations

1. Set up the connection shown in Figure 5. This set up is to implement the following equation:

Adder module output = 4Vpp (2 kHz sine) + 4Vpp (2 kHz sine with phase shift)

2. Set the Phase Change control to 1800. Set the Phase Adjust control until the two signals look like

they’re out of phase to each other.

3. Measure and record the amplitude of the Adder module’s output. Is the output waveform that you

obtained is perfect? If not, do necessary adjustments.

Figure 5




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EECB351-Exp 1_Intro to EMONA Trainer