Building an Audio Effects Processor and Karaoke

Overview

The project utilizes the Zilog Z8 Encore Evaluation Board to produce the Karaoke and Audio Processor device.

Explanation

Along with the Z8 Encore Evaluation Board is an analog processing board in which the input analog waveform is being conditioned and the PWM output from the evaluation board is being processed. The XTools ZDS II IDE is used to develop the software which consists of a set of signal processing routines wherein the desired features in a typical Karaoke environment is provided. These features include pitch transformation, voice reverb, and voice echo.

There is a small board containing a number of op-amps together with amplifier sections that comprise the analog hardware. The main purpose of the board is to amplify the microphone or guitar input while an anti-aliasing low-pass is provided. In order to maximize the dynamic range of the on-chip Z8 A/D, the gain and offset controls are also allowed. The PWM signal from the Z8 is being converted into an analog waveform y the presence of a filter, in addition to the front-end filter. A set of headphones or a small speaker can be driven by using a small audio amplifier.