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An Introduction to Modular Design#

Moog synthesizer

The Moog synthesizer showcases modular design with its interconnected sound-producing and altering modules connected via Jack-to-Jack leads.

Modular Design: A Comprehensive Approach#

Using tried-and-true circuit blocks paves the way for a systematic approach to design, grounded on established principles.

The Six Tenets of ARMUST#

  • Abstraction: Enables focus on broad functionality without being bogged down by intricate details. Block diagrams often reveal potential solutions overlooked by conventional methods.

  • Replaceable: Ensures that modules can be exchanged without jeopardizing the entire system's functionality.

  • Modular: Promotes a tiered approach, encouraging iterative development and enhancements.

  • Upgradable: Allows for prompt or future module enhancements.

  • Substitutable: Enables module replacement, especially useful during diagnostics.

  • Testable: Ensures thorough evaluation at both the system level and the module level.

Challenges and Decisions in Modular Design#

When faced with faulty modules, such as in Design 2, designers are confronted with a critical decision:

graph LR Design1[Block Diagram 1] Design2[Block Diagram 2] Solution((Choose Best Design)) Decision{Which Design?} Design1-->|Without Defective Module|Decision Design2-->|With Defective Module|Decision Decision-->|Opt for Design 1|Solution

The "Black Box" Approach#

Block diagrams, often termed 'black boxes,' emphasize overarching functionality. These diagrams succinctly represent system components, focusing on their interactions rather than the intricate details within.

The following diagram depicts four interconnected audio blocks:

graph LR Microphone-->| millivolts |Preamp Preamp-->| 1V line signal level |Compressor Compressor-->|reduced dynamics |Headphones

Similarly, a direct conversion receiver can be represented as:

graph LR Antenna-->|all radio frequencies|BandPassFilter BandPassFilter-->|frequencies in band|RFMixer LocalOscillator-->|chosen frequency|RFMixer RFMixer-->|sum & difference|AudioAmplifier AudioAmplifier-->|only audio|Loudspeaker


In both software and hardware realms, block diagrams provide a cohesive, easily comprehensible overview, streamlining design and troubleshooting processes.