Sunday, June 8, 2014

Digital audio amplifier with PLL synthesized FM radio

This is high quality stereo digital audio amplifier with PLL synthesized FM radio receiver. Some of the high level specifications of this receiver are listed in below:

  • Audio output power: 4W + 4W (with 8ohm speakers)
  • Input sources: FM and 3 external stereo line inputs
  • FM frequency range: 88.00MHz – 108.9MHz
  • Supply voltage: 12V – 15V (2A current source is recommended)
  • Tone control options: Bass, Treble and Loudness control
  • Bass / Treble boost: 14dB
  • Bass / Treble cut: 14dB
  • Station memory: Preset 10 FM radio stations
  • FM tune options: Auto and Manual with 25 kHz steps
Key components of this audio system are ATmega32A - 8bit microcontroller, TT502 (TEA5767) stereo FM radio module, PT2314 audio processor and μPC2002 audio power amplifier. This system is design to work with 12V - 15V (2A) DC power source and KA7632 multi-output regulator is used to manage power requirements to the above mentioned components.

Prototype version of digital audio amplifier

User interface of this system consist with 10 push buttons and 16 × 2 character LCD module. All the analog components of this receiver (including power supply) are controlled by ATmega32A microcontroller.

To get the best audio experience we recommend to couple this system with 8Ω - 8 inches (or higher) full range speaker system. In our prototyping stages we try this system on breadboards and hand-made PCB, and get equivalent results.

This project is an open source hardware project and all the contents are available to download at All the source codes and designs in this project are release under the terms of MIT license.
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