Computational Laboratory Work Report

The assignment requires students to develop a C program to calculate components of matching attenuators, which are used to reduce signal levels and match them to their source and load. The program should allow users to input parameters such as the type of network (Tee or Pi), input impedance, output impedance, and loss, and then calculate the resistor values needed to achieve the desired attenuation and matching.

Coursework Title: Computational Laboratory work report
Module Information
Module Title: Computer Programming
Module Code: KD4008
Module Tutor: Dr Gary Wells
Academic Year: 2016-17
Dates and Mechanisms for Assessment Submission and Feedback
Date of hand out to students: WC 7-11-2016
Mechanism to be used to disseminate to students: via e-learning portal
Date and Time of Submission by Student: 23/1/2017
Mechanism for Submission of Work by Student: Faculty Office
Date by which Work, Feedback and Marks will be returned to Students: 3-4-2017
Mechanism(s) for return of assignment work, feedback and marks to students: via email
Assignment Brief
Objective: To develop a C Program to calculate components of matching attenuators.
Introduction: You are to develop a C program to help design resistive attenuation and matching pads
for a telephone line. Generally, telephone lines and electronic equipment need to be matched to their
source and loads to avoid reflection of the signals. Attenuators are used to reduce the level of large
signals that need to be fed to a more sensitive circuit.
Theory:
The two types of attenuator are Tee and Pi. Both are used extensively.
There are two types of each, balanced and unbalanced. Unbalanced type use a common earthed
return, while Balanced type do not.
The Tee arrangement can be used in its unbalanced form, or its balanced form (sometimes known as
a balanced H network).
Figure 1 illustrates the arrangement for the Tee Network.

Figure 1: Tee Networks with equations.
Figure 2 shows the arrangement for the Pi Network.
Figure 2: Pi Network with equations.
And Figure 3 shows the arrangement for the Minimum loss Network.

Figure 3: Minimum Loss Pad.
Z1 is the impedance seen looking into the network, while Z2 is the impedance seen looking into the
output. So if the source (generator) has an output impedance of 600
And the load has an impedance of 75 then the network will be arranged to have Z1=600, and
Z2=75.
Since the networks are all designed to introduce a loss (expressed in dB or Decibels) then this is
used, with the Z1, Z2 values to calculate the resistor values.
Task: What you have to do is develop a program to ask the user what kind of network she/he wants,
what the input and output impedance's are to be, and what the loss is. The program should then
calculate the value of the resistance values and display them, along with the other network
parameters. You might like to start by designing the program for the Tee network first. Then go on to
develop the Pi network. Test each as you develop it to avoid having a lot of error to deal with at one
time. You should also save the resistor values calculated by the program to a file.
The complete program can be developed as a menu program with an option to terminate the program,
or perform another calculation.
Test Case example:
Test Case 1: If Z1=600 ohms, Z2=900 ohms, an unbalanced Tee with a loss of 15db would have the
following resistor values. R1=369.29 ohms, R2=688.89 ohms, R3=269.88 ohms.
For other test cases, check your results by comparing with hand calculations.
Additional Instructions to students:
Marks will be awarded for good program structure and use of the user screen (within the constraints
of the Quincy output screen). See assessment criteria above.
The program should contain comments to indicate to the Lecturer that you understand what you have
done. If the lecturer thinks you have committed plagiarism you may be asked to explain your work to
him. If this is not satisfactory you may receive zero marks for the assignment.
The program should be tested with suitable test data and compared with theoretical calculations to
prove that it is correct.
The program listing, evidence of testing, and screen shots of user screen output should be included in
a report that is in Word Format and stapled down the left hand side (as a book). Just the program
listing on it's own or hand written report will not be acceptable. The complete report should be
submitted electronically as well.

Further Information
Learning Outcomes assessed in this assessment:
• Develop a program from a specification and provide suitable documentation.
• Develop a C program for a given task and prove that the program will work correctly through
the use of the Debug tool.
• Make effective use of the C built in software libraries.
Assessment Criteria/Mark Scheme:
No Item Marks (%)
1. Correct use of C mathematical functions for equations 20
2. Menu Program 20
3. Program Structure 20
4. User Screen 10
5. Save The resistor values to a file 10
6. Evidence of a working program with theoretical calculations 20
Total 100
(50% weighting)
Expected size of the submission:
There is no limit on the submission size but you should submit a report containing your program listing
complete with program documentation so that the lecturer can determine that you understand the
program that you have developed. The report should also contain documentation proving that the
program has been tested and found to work under all conditions.
Assignment weighting:
This assignment is worth 50% of the module marks
Referencing Style:
If you need to use any references please do so and reference them using an appropriate style
(Harvard or APA or British standards)
Academic Integrity Statement:
You must adhere to the university regulations on academic conduct. Formal inquiry proceedings will
be instigated if there is any suspicion of plagiarism or any other form of misconduct in your work.
Refer to the University’s Assessment Regulations for Northumbria Awards if you are unclear as to the
meaning of these terms. The latest copy is available on the University website.
Failure to submit:
Note that failure to submit work or submission of work after the required deadline without an
authorised late approval will result in a record of incomplete (IC) for the assessment component.
Referral in that component will then be required even when the module is passed overall.