Exact streams.
Deterministic by theorem.

Flight-test and avionics telemetry: hundreds of sensors at mismatched rates merged deterministically, with byte-identical replay for post-flight and incident analysis.

Rates are declared once, in the query, as exact fractions; a 400 Hz inertial unit and a 1 Hz GPS fix meet on a common timeline with no resampling guesswork. The same recording replayed a year later yields the same bytes, so a finding from a flight review can be re-derived and audited.

ECU and vehicle-bus signals aligned without floating-point drift; reproducible traces for validation, fleet analytics, and homologation.

CAN, LIN and Ethernet frames arrive at unrelated periods. Streams are aligned by rational arithmetic instead of timestamps rounded to milliseconds, so a validation run and its replay agree record for record — across builds, machines and test campaigns.

Machine condition monitoring and predictive maintenance: vibration, current, and temperature reduced at the edge to exact, comparable features.

Windowed reductions such as averages, extremes and sums run next to the sensor, and only the features leave the device. Because every window boundary is exact, features from different machines and different days line up and can be compared directly.

Synchrophasors, substations, wind turbines: every rate is a rational multiple of line frequency, and post-fault analysis demands exact, replayable records.

Streams sampled at multiples of 50 or 60 Hz interleave without phase creep. Disturbance records keep every value in its slot, and missing samples are marked explicitly rather than silently interpolated, which matters when an event has to be reconstructed.

44.1 ↔ 48 kHz is exactly 147:160 — a rational conversion the algebra performs with zero accumulated drift, keeping long chains sample-accurate.

Rate conversion is a plan operator, not an approximation buried in a filter library. A chain of conversions can be inspected, and the plan shows exactly which samples feed which output, so long broadcast chains stay aligned without periodic correction.

Decimation and interpolation chains with rational factors are SDR’s daily bread; here they are exact, declarative, and inspectable query operators.

A decimation by 5 followed by an interpolation by 3 is written as a query, compiled into a plan and checked before it runs. The same declarative form documents the chain, so the pipeline a receiver runs is the pipeline its designer reviewed.

Encoder, IMU, and force signals fused across control-loop rates; hardware-in-the-loop runs replay bit-for-bit for regression testing and certification.

Control loops at 1 kHz, sensors at 200 Hz and supervisory logic at 10 Hz share one exact time base. Recorded bench sessions replay deterministically, so a regression test fails because the software changed, not because the timing did.

Vital-sign pipelines — the engine’s original domain and the paper’s worked example, a special case of the same algebra.

The engine grew out of ECG processing: detecting QRS complexes in signals recorded at different sampling rates. The worked example on this page — and in the paper — is that pipeline, expressed as a handful of continuous queries.