7 Standard Step Frequency from Frequency Generator

Overview

The circuit was designed to create a frequency generator that consists of 7 steps during the operation.

Terminology

• Crystal Oscillator – an electronic circuit made of one or more crystals or quartz located in the feedback loop circuit where its physical characteristics determine a particular designed frequency where electrical oscillations are produced
• 4584 – a 4-bit single-chip microcomputer designed with CMOS technology using a simple, high-speed instruction set, equipped with four 8-bit timers, a 10-bit A/D converter, interrupts, oscillation circuit switch function, and used in application with remote control transmitter
• 4017 – a decade counter where the count advances as the clock input becomes high that may be combined with diodes for some functions such as flash sequences
• BC337 – a small signal NPN Silicon AF medium power transistor used for general purpose switching and amplifying applications with features such as TO-18 manufactured package, suited for AF driver stages and low power output stages, and divided into three group types

Circuit Explanation

The standard frequencies produced by the circuit lies around the 10s and 1s digits. These 7 steps consist of 1 Hz, 10 Hz, 100 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. It can also produce waveforms such as TTL pulse wave, negative-going pulse wave, positive-going pulse wave, negative-going sawtooth wave, positive-going sawtooth wave, square wave, triangle wave, and sine wave.

A 1 MHz highly accurate crystal oscillator is being used to produce the basic frequency. The crystal oscillator is creating an electrical signal with a very precise frequency by using the mechanical resonance of a vibrating crystal of piezoelectric material. The fundamental frequency can be hundreds of megahertz since the quartz crystal is oscillating naturally at a particular frequency. The crystal functions as a stable mechanical vibrator due to the excellent piezoelectric characteristics of the crystal that the crystal oscillator utilizes. It provides various advantages since crystals have stable temperature characteristic, excellent processing ability, and high frequency stability.

By using a frequency divider, the standard step frequencies are made possible to be generated in multiples of 10 as the reference frequency.  It can be used for both analog and digital applications. Some frequencies are integral submultiples of the frequency of the input signal.

Part List

Application

The frequency generators are widely used in electronics laboratories in training centers, colleges, and universities. They are used to add waves like pulse and ramp in addition to triangle, square, and sine waves. Moreover, they can be utilized for internal sweep or internal & external AM-FM. Some multifunction generators are designed with frequency counter with accuracy. The use of a crystal oscillator does not only apply as a frequency generator, but also as a frequency converter and a frequency modulator. Electronic devices such as portable telephones are using surface mounting crystal oscillator as a frequency reference source because of its light weight and compact size.

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