DESIGN AND CONSTRUCTION OF A FREQUENCY COUNTER
- Format: Ms Word Document
- Pages: 73
- Price: N 3,000
- Chapters: 1-5
- Download Full and Complete Project
Digital frequency counter is an electronic instrument, or component of one, that is used for measuring frequency. Frequency counters usually measure the number of oscillations or pulses per second in a repetitive electronic signal.
It detects the frequency value and displays that value with the help of the LCD employed. Depending on the power supply the value of the frequency on the LCD changes. Most frequency counters work by using a [counter] which accumulates the number of events occurring within a specific period of time. After a preset period (1 second, for example), the value in the counter is transferred to a display and the counter is reset to zero. If the event being measured repeats itself with sufficient stability and the frequency is considerably lower than that of the clock oscillator being used, the resolution of the measurement can be greatly improved by measuring the time required for an entire number of cycles, rather than counting the number of entire cycles observed for a pre-set duration. Frequency counters are commonly used in laboratories, factories, and field environments to provide direct frequency measurements of various devices.
TABLE OF CONTENTS
TABLE OF CONTENT
- AIM/OBJECTIVE OF THE PROJECT
- SIGNIFICANCE OF THE PROJECT
- SCOPE OF THE PROJECT
- LIMITATION OF THE PROJECT
- APPLICATION OF THE PROJECT
- PROBLEM OF THE PROJECT
2.0 LITERATURE REVIEW
2.1 BASICS OF DIGITAL FREQUENCY COUNTER
2.2 DESCRIPTION OF HERTZ
2.3 TYPES FREQUENCY COUNTING
2.4 HISTORICAL BACKGROUND OF HERTZ
2.5 TYPES FREQUENCY COUNTING
3.0 CONSTRUCTION METHODOLOGY
3.1 BLOCK DIAGRAM OF THE SYSTEM
3.2 CIRCUIT DIAGRAM
3.3 CIRCUIT DESCRIPTION
3.4 SYSTEM OPERATION
3.6 POWER SUPPLY UNIT
4.0 RESULT ANALYSIS
4.1 CONSTRUCTION PROCEDURE AND TESTING
4.2 ASSEMBLING OF SECTIONS
4.3 CONSRUCTION OF THE CASING
4.5 INSTALLATION OF THE COMPLETED DESIGN
Frequency measurement is the number of rising edges that occur within onesecond. Digital frequency counter is a frequency measuring device. Frequency is defined as the number of events of a particular sort occurring in a set period of time. Digital Frequency counters usually measure the number of oscillations or pulses per second in a repetitive electronic signal.
Most frequency counters work by using a counter which accumulates the number of events occurring within a specific period of time. After a preset period known as the gate time (1 second, for example), the value in the counter is transferred to a display and the counter is reset to zero. If the event being measured repeats itself with sufficient stability and the frequency is considerably lower than that of the clock oscillator being used, the resolution of the measurement can be greatly improved by measuring the time required for an entire number of cycles, rather than counting the number of entire cycles observed for a pre-set duration. The internal oscillator which provides the time signals is called the timebase, and must be calibrated very accurately.
The frequency counter has 6 digits and will work from 25MHz up to 200MHz.The best with this counter is that you don’t need to connect it with any wires to your equipment. Wires=interference and drift in the oscillation frequency. This counter use a small pick up coil to probe the oscillation. Just hold the pickup coil a few cm from the main oscillator coil and read the LED.
The LED has 6 digits and the resolution is set to 1kHz.This counter is perfect to check that oscillators are working and at which frequency.
1.2 OBJECTIVE OF THE PROJECT
The objective of this work is to design an electronic instrument that does the function of measuring frequency. It usually measures the number of oscillations or pulses per second in a repetitive electronic signal.
1.3 SIGNIFICANCE OF THE PROJECT
Frequency counters are test instruments used in many applications associated with radio frequency engineering to measure the frequency of signals very.
This frequency counter widely used within a variety of areas to measure the frequency of repetitive signals, and also for measuring the time between edges on digital signals.
1.4 SCOPE OF THE PROJECT
This device measures frequency. In scientific terms, frequency is the number of cycles per second in the signal. In terms of a layman, frequency of a signal denotes the rate of occurrence of the signal in certain time. Digital Frequency Counter is basically simple counter systems with a limited time period for counting.
In this work, we design simple frequency counter system using timers and two counters. While one of the Timer IC is used to produce clock signals, the other is used to produce the time limited signal of one second.
1.5 PROBLEM OF THE PROJECT
The accuracy of a frequency counter is strongly dependent on the stability of its timebase. A timebase is very delicate like the hands of a watch, and can be changed by movement, interference, or even drift due to age, meaning it might not “tick” correctly. This can make a frequency reading, when referenced to the timebase, seem higher or lower than the actual value. Highly accurate circuits are used to generate timebases for instrumentation purposes, usually using a quartz crystal oscillator within a sealed temperature-controlled chamber, known as an oven controlled crystal oscillator or crystal oven.
For higher accuracy measurements, an external frequency reference tied to a very high stability oscillator such as a GPS disciplined rubidium oscillator may be used. Where the frequency does not need to be known to such a high degree of accuracy, simpler oscillators can be used. It is also possible to measure frequency using the same techniques in software in an embedded system. A central processing unit (CPU) for example, can be arranged to measure its own frequency of operation provided it has some reference timebase to compare with.
Accuracy is often limited by the available resolution of the measurement. Resolution of a single count is generally proportional to the timebase oscillator frequency and the gate time. Improved resolution can be obtained by several techniques such as oversampling/averaging.
Additionally, accuracy can be significantly degraded by jitter on the signal being measured. It is possible to reduce this error by oversampling/averaging techniques.
1.6 LIMITATION OF THE PROJECT
- This circuit takes into account the signals with high duty cycle such that timing value of negative pulse is quite low compared to that of the positive pulse. This in turn can be erroneous.
- This circuit uses CMOS devices which are quite static and cannot be used with bare hands.
- This circuit is not accurate
1.7 APPLICATION OF THE PROJECT
An electronic instrument used to precisely measure the frequency of an input signal. Digital Frequency counters are commonly used in laboratories, factories, and field environments to provide direct frequency measurements of various devices. A good use of the frequency meter is to calibrate other equipment. For example a signal generator that doesn’t have its own digital display. The meter will show the exact frequency being produced by the signal generator. The most common applications for frequency counters are measurement and characterization of oscillator and transmitter frequencies. Various frequency counters have found application as an electronic tachometer to obtain accurate measurements of high-speed rotating machinery. A tachometer pickup may be used to produce signals that are fed directly to the frequency counter.