Annex A - Group Research Proposal

NOTE: This proposal was for the previous experiment as we have changed experiments.

Group Project Proposal (Science)


Names: Aryan VIkhe, Dylan Tan, Teng Tjin Yao

Class: S2-01

Group Reference: F

A.    Indicate the type of research that you are adopting:

X   ] Test a hypothesis: Hypothesis-driven research
e.g. Investigation of the anti-bacteria effect of chrysanthemum

[   ] Measure a value: Experimental research (I)
e.g. Determination of the mass of Jupiter using planetary photography

[    ] Measure a function or relationship: Experimental research (II)
e.g. Investigation of the effect of temperature on the growth of crystals

[    ] Construct a model: Theoretical sciences and applied mathematics
e.g. Modeling of the cooling curve of naphthalene 

[    ] Observational and exploratory research
e.g. Investigation of the soil quality in School of Science and Technology, Singapore  

  1. Type & Category

Type of research: 1  (Write down one number from 1 to 6)

Category  –  12 (Write down one number from 7 to 20)

Sub-category – A (Write down the sub-heading alphabet)

Application of project relevant to SST Community, Society or the World:
This project allows us to improve society by having better quality phone calls. The quality of phone calls can sometimes drop due to the frequencies of the sound waves being transmitted and by determining the optimal frequency for the best quality sound we can vastly improve the quality of calls.

C.    Write down your research title:

Investigation of how the frequency transmitted by handphones can be adjusted better.

D.   (a) Aim / question being addressed 

Essential Questions

Aim of project?
How will this project help others?
What are some of the key elements of the project?

Aim of project?

Our aim in doing this project is to research on how to improve the sound quality of hand phone sound waves by finding out useful information about frequencies transmitted. As phone calls sometimes drop in quality, we theorised that it might be because of frequency of the sound waves transmitted which could impact the sound received. This project is our answer to that hypothesis.

By doing this project we are able to improve society by providing better quality calls on mobile phones, decreasing reliance on landlines for confirmed quality calls.


The very basic concept of a phone call is that sound waves are transmitted from one person’s phone to another person’s phone. This is complicated however by there having to be specific frequency for the soundwave to be properly received and played.

In the 1980s, acoustic researchers demonstrated that in order to fully understand speech, people need to hear a wider range of wavelengths. For instance, for listeners to distinguish between some consonants, frequencies need to be above 3400 Hz. As a side note, the highest frequency transmittable is 4000 Hz. (Why Mobile Voice Quality Still Stinks—and How to Fix It, Jeff Hecht, 30 Sep 2014)

Technically VoLTE would be better for sound quality as LTE as LTE helps transmit the soundwaves better but since some companies (not in Singapore) are unwilling to replace the cables, we’re stuck with this for now and will have to find better ways to transmit through traditional cell phone call lines. (Why Mobile Voice Quality Still Stinks—and How to Fix It, Jeff Hecht, 30 Sep 2014)

Helpful Information

According to the Cisco Networking Academy Program, converting an analog sample to a digital sample involves having the sampling rate being twice the highest frequency to produce playback that is not too choppy or smooth. Sampling refers to retrieving the value of the sound waves multiple times to transmit sound properly.  (Introduction to Packet Voice Technologies > Analog-to-Digital Voice Encoding, Cisco System, Inc, 2005)

Measuring Frequency (Oscilloscope)

So how do we measure the frequency response of the phone? Isn’t this subjective? To solve this, we can use a special device called an oscilloscope. Oscilloscopes are used to observe the change of an electrical signal over time, such that voltage and time describe a shape which is continuously graphed against a calibrated scale. The observed waveform can be analyzed for such properties amplitude, frequency, rise time, time interval, distortion and others. (Kularatna, Nihal (2003), "Fundamentals of Oscilloscopes", Digital and Analogue Instrumentation: Testing and Measurement, Institution of Engineering and Technology, pp. 165–208, ISBN 978-0-85296-999-1)

(b) Independent variable

The independent variable is the frequency of the sound waves. We are going to be testing using the frequency range 0Hz - 5000 Hz

(c) Dependent variable
The dependent variable is the frequency response of the phone.

(d) Controlled variables

(a)  The type of phone used
(b)  The type of frequency counter used
(c)  The amplifier configuration
(d) The message being transmitted  

      (e) Hypotheses

There is a specific frequency range which would allow phone calls to be of better quality (i.e. as close to the frequency sent as possible).

E.    Method – Description in detail of method or procedures (The following are important and key items that should be included when formulating ANY AND ALL research plans.)

(a) Equipment list:
 -       smartphone x2 (first phone calls second phone)
-       audio cable with 3.5mm jack x2 (connecting the phones to the frequency generator and oscillosope)
-       oscilloscope x1 (analyse frequency)
-       frequency generator (to generate frequency)
-     resistor x1 (resists flow of current)

(b) Diagrams

(c) Procedures: Detail all procedures and experimental design to be used for data collection

Using a first mobile phone, a call is made

to a second mobile phone and a voice test is

performed. Then, the audio plug connector

is attached into the audio port of the first

phone. Using a function generator set up with

a sinusoidal signal 100 mV in amplitude and

400 Hz in frequency (audible tone) its output

is connected to electrodes 1 and 2 in the

audio plug of the first phone through a 15 kΩ

resistor as explained earlier. In the second

phone a 400 Hz tone must be heard. Then,

a frequency sweep is made -keeping the 100

mV amplitude in all the frequencies—from

50 Hz up to a frequency which the listener

in the second phone barely hears. The first

tone heard and the last one define the phones

bandwidth. These mobile phones can be

swapped in order to find out if there are any

changes. This is not a very accurate measure-
ment but, in return, it is the simplest. Figure 2

depicts this approach.

(d) Risk, Assessment and Management: Identify any potential risks and safety precautions to be taken.

Body may get cramped after working for a while
Take breaks every 15 minutes
Phones may cause radiation to our bodies
Do not stay too close to the phones
We get electrocuted when trying to configure the phones through our hands, which may cause injuries to our body.
All wires must be insulated and no metallic objects should be inserted into the ports.
Accidentally break the equipment which may cause us to get hurt by the broken pieces through scratches.
Handle the smartphones with care.
Table 3: Risk Assessment and Management table

(e) Data Analysis: Describe the procedures you will use to analyze the data/results that answer research questions or hypotheses

  1. Collect data from the oscilloscope
  2. Find optimal frequency for best quality sound by comparing the results

F. Bibliography: List at least five (5) major sources (e.g. science journal articles, books, internet sites) from your literature review. If you plan to use vertebrate animals, one of these references must be an animal care reference. Choose the APA format and use it consistently to reference the literature used in the research plan. List your entries in alphabetical order for each type of source.

(a) Books
Smith S W (ed) 1997 The Scientist and Engineer’s Guide to Digital Signal Processing 1st edn (San Diego, CA: California Technical)

(b) Journals
Sans J A et al 2013 Oscillations studied with the smartphone ambient light sensor Eur. J. Phys.

(c) Websites
Horacio Munguía Aguilar (2015)

Klein P et al 2014 Classical experiments revisited: smartphones and tablet PCs as experimental tools in acoustics and optics

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