project defending.docx

7/27/2019 project defending.docx

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DAR-ES-SALAAM INSTITUTE OF TECHNOLOGY

DEPARTMENT OF ELCTRONICS AND TELECOMMUNICATION ENGENEERING

NTA LEVEL 8

PROJECT TITLE: DESIGNING OF FREQUENCY COUNTER USING MICROCONTROLLER FOR DIT

TELECOMS LABORATORY

PROJECT TYPE: DESIGNING / PROBLEM SOLVING

STUDENT NAMES

KIFARU J. MALALE-100602G8393

MICHAEL J. MJATA-100602G8419


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INTRODUCTION:A frequency counter is anelectronicinstrument,or device, that is used for measuring

frequency.Currently, Electronics laboratory for Students uses analogue oscilloscope as an

instrument for measuring frequency, duty cycle and phase angle. This is not an easy task

especially to the students, since the OSCILOSCOPE needs to be recalibrated before measuring.

To get frequency and duty cycle of the signal, there are some mathematical procedures to be

done prior before getting to the final results. These are the tedious tasks to the students or

Technicians

Background Information

Frequency counter is a measurement system that is designed to measure frequency in audioranges (1Hz to 20 KHz, with a resolution of 0.1Hz). Besides, it can measure Duty cycle for pulse

waveform, phase angle for the sinusoidal waveform. There are four different types of

waveform, whose frequency is to be measured, sinusoidal, triangular, rectangular and saw-

tooth waveform.

The basic idea behind measuring frequency, is to transform the incoming waveform to pulses,

then pulses will be counted by the processing block in predefined time interval, and the

frequency will be displayed on the output

Currently, Electronics laboratory for Students uses analogue oscilloscope as an instrument for

measuring frequency, duty cycle and phase angle. This is not an easy task especially to the

students, since the OSCILOSCOPE needs to be recalibrated before measuring. This calls upon

the need for the designing of the alternative instrument that could display the result directly on

the LCD
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PROBLEM STATEMENT

Absence of electronic instrument that could measure audio frequency signal duty cycle phaseangle and be able to show the output directly on the LCD display has led to the use ofOSCILOSCOPE when measuring . This is not an easy task especially to the students, since theOSCILOSCOPE needs to be recalibrated before measuring. To get frequency and duty cycle of

the signal, there are some mathematical procedures to be done prior before getting to the final

results. These are the tedious tasks to the students or Technicians

Objectives of the projectThe objectives of this project are divided into general objective and specific

objectives.

General objectives.To design a measurement system that will save time for students and technicians

during their Laboratory demonstrations

Specific Objectivesi. To design a subsystem that will transform sinusoidal, square/ pulses, triangular, and

saw-tooth waveform to pulses before being sent to a processing block for pulse

counting.

ii. To design a subsystem that will condition the incoming square waves before being sentto processing block for duty cycle measurement

iii. To design a subsystem that will transform sinusoidal waves to pulses/square waves forphase angle measurement


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Significance of the Projecti. Once the system is ready, it will save time during measurement procedures. Since

procedures are few.

ii. It will completely eliminate mathematical procedures that are done prior beforeusing an OSCILOSCOPE

iii. No pre-calibrations that are needed before using the systemiv. Almost every students can use the instruments with just few instructions from

technicians

Existing System

Currently, DIT Students, teachers and Technicians, use Oscilloscopes to measure frequency ofthe signal under consideration. Usually, the process involves mathematical manipulations. This

sometimes becomes very tedious.

Measuring frequency with an OscilloscopeTo measure frequency of a certain electronic signal, the oscilloscope is setup to display a graph

of voltage versus time. The signal to be measured is applied to either the CH1 or the CH2

inputs. Triggering is set to show a trace on the screen. Then the vertical (VOLTS/DIV) and

horizontal (SEC/DIV) scaling controls are adjusted to show the signal to be measured

appropriately on the screen. With all the knobs in their calibrated position, the instantaneous

voltage at any time can be read directly from the y-axis and the period T (time for one cycle)

can be read from the x-axis.


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Measurements with the oscilloscope are made by reading the number of divisions on the screen

and multiplying by sweep-time per division over one complete circle.

Consider figure 1 below

Front screen of the Oscilloscope

To get Frequency, we have to calculate the period of the Waveform displayed above

Sweep-time per division =1 /ms div .

Total number of complete square in one cycle = 4 div.

Period (T) = 4 div *1 /ms div= 4ms .

Therefore, Frequency = 1/ T = 1/ 4ms = 250Hz

Therefore, frequency measured by an oscilloscope is not directly displayed on the front screen

of the oscilloscope; instead, it is obtained by calculations that lead to some errors, especially, for

those who will not be paying attention


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Disadvantages of the Existing system

Calibrations made prior to measurementsThere are more than one calibrations, this causes difficulties for the beginners

Frequency of the signal to be measured is not directly shown on the front panel It takes time for teachers or technicians to teach students on how to use the oscilloscope


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PROPOSED SYSTEM

The proposed system, will be able to measure frequency, phase angle and duty cycle directly,

and display the output as digits on the LCD, without having mathematical procedures that are

done personally prior before reaching to the final results. When measuring frequency The

system will be having a good resolution of about 0.1 Hz

Block diagram of a proposed system

Attenuator

Protectio

n

Block

A

mplifier

A

mplitude

limiter

W

ave

shaping

C

lamper

Amplifier

Amplim

iter

Clampe

r

Processingblock

LCD

display


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Z:\microcontrolle\Embedded System Design Using 8031 Microcontrollers.pdf

Amplitude

Limiter

Conversion

block

Processing BlockDis la in Block

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