Signal Quality Engine

Real-time digital signal processing engine between RTU telemetry sources and downstream control logic. It filters signals, detects anomalies, and computes a composite Signal Quality Index (SQI) scored 0-100.

The engine is deterministic. It runs no background threads and no async, and timing is predictable at ~0.1-0.2ms per signal per scan. It includes a CLI, replay harness, integration adapters for the companion simulators, and an evaluation pipeline.

The diagrams use synthetic telemetry to trace one scan through the engine and into replayable quality evidence.

Pipeline

Each scan processes every registered signal through a fixed sequence of DSP stages:

1. Filter bank: EWMA, high-pass, and simple moving average run in parallel
2. Innovation model: Kalman-inspired residual tracking for drift detection
3. Drift classification: sustained, transient, and monotonic drift with configurable thresholds
4. Spike detection: sliding-window variance with configurable sigma thresholds
5. Frequency analysis: correlation-based and FFT oscillation detection
6. Staleness, step-change, and plausibility checks
7. SQI computation: weighted composite across noise, drift, spikes, oscillation, and missing samples

Signal Quality Index

SQI compresses multiple signal-health indicators into a single 0-100 score while preserving component-level evidence for troubleshooting.

Quality incidents

The incident engine consumes SQI scores and emits lifecycle events: started, updated, and resolved. Configurable persistence and hysteresis avoid flapping. Group incidents aggregate related signals, such as all points on one RTU, into a single event stream. Every incident ID is deterministic and reproducible across replay runs.

Integration layer

Three adapter modules connect SQE to the companion simulators:

• PointCore Adapter: ingests raw point signals from the Point Lifecycle Simulator and returns processed results with quality scores
• Scan Adapter: wraps the engine inside a PLC-style fixed-interval scan loop for deterministic simulation
• Comms Adapter: processes signals arriving through the SCADA Comms Front-End, including comms health aggregation

CLI and tools

# Analyze a signal from CSV with plots
sqe analyze --signal-file data.csv --plot

# Simulate synthetic signal processing
sqe simulate --duration 1000 --noise 1.5 --plot

# Generate incident events from a signal file
sqe incidents --signal-file data.csv --out incidents.jsonl

# Deterministic replay with config
sqe replay --in scans.jsonl --config cfg.yaml --out ./output

# Offline parameter tuning
python -m sqe.cli.sqe_cli offline-tuning \
  --replay-input replay.jsonl \
  --labels labels.yaml \
  --sweep-config tuning.yaml \
  --out-dir ./tuning-results

Performance

• ~0.1-0.2ms per signal per scan on consumer hardware
• Fixed memory allocation: ~15-20 KB per signal, no dynamic growth
• Typical scan utilization: 10-20% within a 100ms PLC window
• 146+ unit and integration tests, deterministic across runs

All visuals use synthetic telemetry and simulator-style point names. No production utility data, real station names, real HMI screens, or operational network details are represented.