Skip to main content

Homebrew Audio Signal Generator

Audio Signal Generator (or AF Signal Generator) is often used in RF and AF base designing and experiments. In this article we introduce less complex AF signal generator based on commonly available electronic components. The heart of this AF signal generator is Intersil ICL8038 precision waveform generator/voltage controlled oscillator IC. ICL8038 is a function generator capable of producing sine, square and sawtooth waveforms at same time. In this project we combine ICL8038 with inverting and non-inverting amplifiers to get above mentioned 3 waveforms with 0° and 180° phase differences at the same time. Those inverting and non-inverting outputs help to use this AF signal generator with balanced audio systems.

Final version of AF signal generator.

The given schematic and PCB design of this AF signal generator contains ICL8038 waveform generator, inverting and non-inverting amplifier stage, output buffer and 12V regulated power supply. All the above mentioned modules are integrated into 65mm × 110mm PCB with standard through-hole type components.

This AF signal generator is design to work with 18V 500mA AC input. To increase the stability, we recommended using "audio grade coaxial cables" for all external connections except to power indicator LED.

This given design is capable to generate 200Hz to 10kHz sine, square sawtooth waveforms. It is possible to have some slight frequency drifts due to temperature variations in the operating environment.

Generating 1.415kHz sawtooth waveform using AF signal generator.

As per our measurements and observations warm-up time of this AF signal generator is around 3 to 5minutes, but this can be varied based on the type of enclosure, component arrangements, external temperature, etc.

Schematic, PCB design and wiring diagrams of this AF signal generator is available to download at google drive. All these design files of this project are distributed under the terms of Creative Commons Attribution 4.0 International License (CC-BY-4.0). High resolutions photographs of this project are available at this flickr page.

Comments

Popular posts from this blog

CD2003 - yet another simple FM radio receiver

In the last few days, we are looking for some simple FM radio receiver to integrate into one of our ongoing projects. For that, we try several FM radio receiver ICs including TDA7000, CD2003/TA2003/TA8164, CXA1019, and KA22429. Out of all those chips we select CD2003 (or TA2003/TA8164) based receiver for our project because of its simplicity and outstanding performance. Except to CD2003, Sony CXA1019 also perform well but we drop it because of its higher component count. We design our receiver based on Toshiba TA2003 datasheet and later we try TA8164 and CD2003 with the same circuit. Either CD2003 or TA8164 can directly replace TA2003 IC, and as per our observations, TA8164 gives excellent results out of those 3 chips. A prototype version of CD2003 FM radio receiver The PCB design and schematic which we used in our prototype project are available to download at google drive (including pin-outs of crystal filters and inductors ). Except for CD2003 IC, this receiver consist

Arduino superheterodyne receiver

In this project, we extend the shortwave superheterodyne receiver we developed a few years ago . Like the previous design, this receiver operates on the traditional superheterodyne principle.  In this upgrade, we enhanced the local oscillator with Si5351 clock generator module and Arduino control circuit. Compared to the old design, this new receiver uses an improved version of an intermediate frequency amplifier with 3 I.F transformers. In this new design, we divide this receiver into several blocks, which include, mixer with a detector, a local oscillator, and an I.F amplifier. The I.F amplifier builds into one PCB. The filter stage, mixer, and detector stages place in another PCB. Prototype version of 455kHz I.F amplifier. In this prototype build, the Si5351 clock generator drives using an Arduino Uno board. With the given sketch, the user can tune and switch the shortwave meter bands using a rotary encoder. The supplied sketch support clock generation from 5205kHz (tuner frequ

Calculator for audio output transformers

Audio output transformers are heavily used in a vacuum tube and some (older) transistor base audio power amplifiers, but these days output transformer are quite hard to find and expensive item. For homebrew projects, the best option is to construct those transformers by ourselves and this script helps to calculate winding parameters for those transformers. This " AF output transformer calculator " script is written using Python and it works with most of the commonly available Python interpreters . The script is available to download at google drive under the terms of GNU General Public License version 3.0 . Homebrewed 25k: 4 output transformer Once supplied the input parameters this script provides a winding ratio, the number of turns required for primary and secondary winding and required copper wire gauges for both primary and secondary windings, etc. We construct several AF output transformers based on results of this script, which including transformers for M