Ac Frequency Counter

8/10/2019 Ac Frequency Counter

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Abstract

So many electronic circuits use one form of oscillator or the other each characterized by their

frequencies of oscillation. Hence the need for a portable device which can count the number

of oscillations for any waveform and output the corresponding value on a display. This device

is always referred to as a frequency counter or meter. The main process of this research is

to display the frequency ranges of input frequency. Any desired input frequency from 10Hz to

0 !Hz can be counted and displayed using "eripheral #nterfacing $ontroller %"#$& 1'f()A

and seven digits of Seven Segment *ight emitting diodes %*+,& display. The input frequency

is counted by "#$1'-()A and the output from this "#$ pins are decoded by analog

multipleer/ )01 #ntegrated $ircuit %#$&. Seven digits are displayed by passing seven "

2ipolar 3unction transistors %23T&/ 2$)4.The main desired output is the high resolution

display in !Hz range of frequency. Studying the "#$ !icrocontroller/ seven segments *+,

display and the decoders are included in this research. "#$ Assembler Software Techniques

are also implemented with this research. #n this research/ the complete design of the advanced

frequency $ounter is provided. 2y the help of components/ such as/ transistors/ diodes/ the

hardware and software technology are combined and developed in this pro5ect. This

frequency counter has to count the number of cycles per second of an incoming signal. Hence

we need a device to count. #n electronics circuits/ counter #$s are available for counting.

These #$6s can count the input pulses. The count is given as coded output from the #$ %in

binary form or 2$, form&. The count must be converted into decimal digit to be understood

by human beings. !ore number of #$6s can be cascaded to increase the number of digits. The

number of digits required for the counter to display the count value depends on the

application and the accuracy needed. #n our design we use a single ) bit 2$, high7speed

$!8S counter chips. 8ne chip is used for one digit and we use 4 similar #$s to get seven

digit counter. Also we use $!8S decoder #$ to decode the 2$, output of the counter to

drive 4 segment displays.

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CHAPTER ONE

1.0 INTRODUCTION

A frequency counter is a measuring equipment used to measure the frequency or number of

cycles per unit time of an input signal. -requency counter can be of analogue type or digital

type. #n analogue type/ the frequency is indicated on calibrated a needle type meter. 9hereas/

a digital frequency counter shows the frequency reading on a digital display. ,igital

frequency counter are easy to read and reading error is minimum. There are so many other

advantages for a digital frequency counter. owadays analogue frequency counter are used to

measure *ow frequencies only.

The frequency measurement is one of the most important things in radio construction.

9ithout it you will be unable to set desired frequency in your receiver %and in transmitter

too&/ without it you will be unable to monitor frequency drift etc sometimes/ frequency

counter can be used to verify whether the oscillator wor:s and ensures the stability of the

generator.

This pro5ect consist of a power supply section which power the A,$ %Analog to digital

converter& and the A,$ sends out the decoded signals to seven segment display. ,igital

frequency counter is being used for wide range of application. ,igital frequency counter

etensively uses digital circuits and hence a fairly good :nowledge of digital circuits is

required to understand the operation of the frequency counter.

However/ this pro5ect has being written in such a way that a person who is not familiar with

electronic circuit :nowledge can assemble eperimental digital frequency counter that counts

from %10Hz ;


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CHAPTER T"O

#.0 $ITERATURE RE%IE"

-requency measurement is an indispensable practice in the field of +lectrical +lectronics

+ngineering. 9ithout it/ it will be difficult to :now the frequency by which your equipment is

operating on.

,igital frequency counters by "rof. T.> !ani %?@=11&. The counter circuit is designed

using discrete digital #$S. The number of #$S is more in the design. The circuit is capable of

counting up/ counting down and also capable of programming initial value. This feature is

often required if you want to :now the frequency of a station tuned by using your heterodyne

receiver. The counter chip used is 4)H$T1


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CHAPTER THREE

DE&INITION AND IDENTI&ICATION O& CO'PONENT(

)THEOR* O& CO'PONENT( U(ED+

,.0 RE(EARCH 'ETHODO$O-*

2asically/ the research on this pro5ect was done both on the internet and on various computer

and +lectricalE+lectronics tet boo:s. #ncluding some other electronics circuits design boo:s.

9e then constructed it on pro5ect board and tested itFs wor:ability. 9e then transferred it on a

printed circuit board for proper construction.

CO'PONENT


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,.# (TEP( TAEN TO PRO-RA' THE 'ICRO/PROCE((OR

1. 9e got a computer system with a micro7chip. *aboratory environment %popularly

:nown as !"*A2&

=. 9e began to write the soft ware

. After writing the software/ we transferred it to wind "#$ programmer environment.

). The wind pc programmer programmed the written micro processor

. 9e test run the program for error chec:.

,., CO'PONENT( IDENTI&ICATION AND %A$UE(

,$ 7 2attery


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'. The entire circuit was coupled properly in a plastic white casing hence the result gave

positive outcome.

,.2 DE&INITION O& TER'(

'cro Contro33er4A micro controller unit %!$@& is a small computer on a single integrated

circuit consisting a relatively simple $"@ combined with support functions such as a crystal

oscillator/ timers/ watch dog/ serial and analog etc.

either program memory in terms of 8C flash or 8T" C8! is also often included on

chips/ as well as a typically small redEwhite memory. The first simple chip microprocessor

was the ) bit #ntel )00) released in 1


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translates the analog data to binary code requires for data processing and transmission in the

control system. The micro controller processes the data received from the A,$ and sends

it to the decoder. The decoder decodes the processed signal from the micro processor and

displays it on the seven segment display unit as an output frequently.

DIODE

This is a two terminal device consisting of a " 5unction forward either in Be or Si crystal.

#ts circuit symbols are shown below.

4

Anode $athode

$ircuit symbol of a ,iode


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The " and type regions are referred to as anode and cathode respectively. #n the fig %.4&

the arrow head indicates the conventional direction of current flow when forward based. #t is

in the same direction in which hole flow ta:es place. $ommercial available diode usually

have some means to indicate which lead is " and which lead is . standard notation consist of

type numbers proceeded by KL such as #=)0 and #1=0. #n this pro5ect wor:/ the diode

used is #)004.

CAPACITOR

#t is an electronic device constructed by two parallel conductive plates/ separated by an

insulated material called dielectric. A charged capacitor is called temporary battery. The

amount if charge of a capacitor can store per unit frequency across its plate and its

capacitance denoted by $. #ts capacitance is a measure of a capacitor ability to store charge. #t

is epressed by the formula $ M N#?/ where KcL is the capacitance and its unit is -arad %-&

while the coulomb is the unit of electrical charge represented by KqL. !ost capacitors value

used in electronics are rated in micro7farad %Of& or in "ico farad %pf&. #t can be seen that a

capacitor is more complicated than that of a resistor. The current is not simply proportional to

the frequency but rather to the rate of shapes and sizes. The basic construction is simply two

conductors near each other but not touching. #n fact the simplest capacitors are 5ust that for

greater capacitance/ more area and greater spacing is needed. The usual approach is to place

some conductor into a tin insulated material called dielectric. 8ther popular types of

capacitor/ are thin ceramic/ waters/ metal coils with oide insulator %i.e. electrolytic and

materialized mica& each of those types of capacitors has unique properties.

RE(I(TOR

Cesistors are one of the most common components in an electronic current. The basic

operation is to limit the flow of current in the circuit.

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Ac Frequency Counter