Difference Equation Analyzer (DEA) - Architecture & Functionality

Overview

DEA is a specialized tool for designing, visualizing, and validating discrete-time filters. It bridges the gap between theoretical filter design (floating-point) and hardware implementation (fixed-point/MCU).

🏗 System Architecture

1. Backend (Python 3.12 + FastAPI)

The backend is responsible for heavy mathematical computations and data processing.

API Entry (dea_api.py): Routes requests to appropriate modules and serves the Vue.js frontend from static/.
Computation Engine (dea/):
- filter_design.py: Uses scipy.signal to calculate coefficients for various filter topologies.
- bode.py: Computes magnitude and phase response. Supports comparing "Ideal" (float) vs "Fixed" (quantized) responses.
- csv_processing.py: Processes time-domain CSV data. It applies the current filter to the signal and downsamples the result for efficient visualization.
- validation.py: Protects against unstable filter designs and invalid inputs.

2. Frontend (Vue 3 + Vite + Tailwind)

A reactive "Single Page Application" (SPA) approach.

Reactive Logic (src/app-options.js):
- Manages the state of all coefficients.
- Implements "Fine-tuning" sliders that allow real-time adjustment of poles/zeros.
- Handles Fixed-Point conversion logic (Q-format shifting).
UI Components (src/App.vue):
- Control Sidebar: Interactive inputs for all filter parameters.
- Visualization: Dual-plot system using Plotly.js for Bode plots and Time-domain waveforms.
Hardware Bridge: Uses the Web Serial API to send commands directly to connected MCUs (requires HTTPS).

🚀 Execution Flow

Design: User selects a filter type or enters coefficients manually.
Quantize: User adjusts Q-format bits to see how quantization affects the frequency response.
Verify: User uploads a CSV to see how the filter behaves with real-world signals.
Deploy: User clicks "Write to MCU" to send the coefficients to their hardware.

🛠 Tech Stack

Backend: FastAPI, NumPy, SciPy, Pandas, Uvicorn.
Frontend: Vue 3, Vite, Tailwind CSS, Plotly.js.
Security: Restricted to LAN/Loopback; implemented security headers and HTTPS support.

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