Overview

The LC83025E is a special-purpose karaoke DSP that implements the signal processing required by karaoke systems, including pitch shift, microphone echo, voice muting and simple surround, with only a single 256Kb external DRAM.

Features

• Applications

— Pitch shift

The LC83025E can shift the music pitch or the microphone pitch by ±15 steps in 1/4 interval steps, or ±1 octave in scale tone steps according to command data sent from the microcontroller.

Furthermore, the pitch can be changed up to ±1 octave in arbitrary steps by setting internal coefficients.

— Microphone echo

The LC83025E implements echo processing for the signal input from the microphone A/D converter.

The amount of echo, the delay time and other parameters can be changed by setting coefficients.

— Voice mute

The LC83025E implements processing that removes monaural signal components included in the music signal. This allows CDs with vocals to be used as karaoke CDs. Command data is used to turn the voice mute function on or off.

— Simple surround

The LC83025E implements a simple surround function by adding delayed components to the music signal. The LC83025E includes six sets of simple surround coefficients as built-in preset data. These values can be switched by sending command data. Applications can implement their own original surround effects by setting the coefficients. However, the algorithm itself is fixed.

— Flexible input mixing

The LC83025E supports hybrid mixing of digital and analog left and right channel song inputs, and thus can handle a wide range of disk processing configurations.

• Audio inputs and outputs

— Inputs: Digital - One system (stereo) A/D converter - Three channels

— Outputs: Digital - One system (stereo) D/A converter - Two channels

— A/D converter Second order ∆∑ modulation - Three channels

— D/A converter 4× oversampling digital filters plus second order noise shaper plus 5-bit PWM system - Two channels

• Master clock: 768 fs

• External memory: Up to two 256K (64K × 4-bit) DRAMs can be used

• Microcontroller input: Synchronous 8-bit serial data

• Supply voltage: 5 V single-voltage

• Package: QFP80E