L-3 / Vigra MMI-4211 VME Audio Processor Module

The L-3/Vigra MMI-4211 is a VME-based audio processor module delivering real-time digital mixing and CD/DAT quality audio reproduction for industrial and military systems. Built around four Motorola DSP56002 digital signal processors, the module provides programmable sample rates from 1500 Hz to 50,000 Hz and dynamic range up to 80 dB using Sigma-Delta conversion technology. Its modular I/O architecture supports custom daughter board configurations, enabling tailored input/output designs for specific system requirements.

Technical Specifications

Processing Core: Four Motorola DSP56002 DSPs

Memory: 16Kx24 data and program memory per DSP; Multi-Ported RAM; Private DSP Static Memory

Sample Rate: Programmable 1500 Hz to 50,000 Hz

Frequency Response: 20 Hz to 45.5% of sample rate

Dynamic Range: Up to 80 dB (Sigma-Delta A/D conversion)

Audio Quality: CD/DAT Quality specification

VME Interface: VMEbus integration

Key Features

Four-channel fully programmable matrix mixer with cross-channel mixing capability

Real-time digital mixing across four channels

Modular daughter board I/O configurations

Sigma-Delta analog-to-digital conversion for accurate reproduction

Flexible input coupling options via onboard DIP switches (DC, AC capacitor, 600Ω transformer, 150Ω transformer)

Software-controlled microphone preamplifiers (0 dB, 20 dB, 40 dB gain settings)

Line-level input attenuation via fixed gain buffers (-6 dB) supporting up to 2 Vrms without clipping

Typical I/O Configurations The module supports multiple I/O architectures: stereo line inputs/outputs with stereo microphone inputs, monophonic line inputs/outputs, or transformer-coupled audio circuits with independently selectable input coupling modes. Specific configurations accommodate four stereo channels or four monophonic channels depending on application requirements.

Compatibility & Integration Designed for VME-based system integration with modular architecture enabling custom I/O configurations through daughter board selection. The architecture supports demanding applications requiring real-time audio processing in constrained digital environments.