Module 5 Β· Foundation

Information Theory β€” signal, noise, and loss

More data β‰  more information. Entropy measures surprise, noisy channels flip bits, and redundancy vs compression are engineering levers for recovery and trade-offs.

The single idea

Information removes uncertainty

Predictable outcomes carry little information; surprises carry more. In systems: flat metrics are dashboard noise; lossy summaries drop distribution tails.

Entropy

Surprise is measurable

H = βˆ’Ξ£ p logβ‚‚ p. Uniform sources maximize H; skewed sources carry fewer bits per symbol.

Channel noise

Transmission distorts

Each bit flips with probability p. Without coding BER β‰ˆ p; redundancy enables recovery.

Capacity

Speed limit

For a binary symmetric channel C β‰ˆ 1 βˆ’ H(p). You cannot beat that error-free.

Compression

Lossy vs lossless

LLM summaries and Grafana rollups are lossy. What did you drop? Does it matter for decisions?

Interactive

Channel Lab β€” noise and redundancy

Generate a 16-bit message, run it through a channel with flip probability p, compare BER before and after majority decoding.

Channel quality βœ“

Decoder recovers the message β€” redundancy pays off.

Source H 1.000
Channel C (β‰ˆ) 0.597
Raw BER 8.0%
Correct bits after decode 100%

What you should see

Information in engineering

Same laws show up in monitoring, logs, ML pipelines, and token limits.

Metrics & alerts

Ten KPIs correlated at 0.99 β€” low mutual information. One signal, noise elsewhere.

Logs & traces

Sampling and rollups are lossy compression. Drop rare tails β€” drop the incident.

Token budget

Context window = bandwidth. RAG routes signal; prompt injection injects noise.

Embeddings

Vectors compress meaning with loss. Similarity keeps signal; rare facts may vanish.

Cross-domain transfer

Same law β€” different context

After the lab, map the model to your stack.

EE / HW

ECC & channel

Memory bus BER.

Physics

SNR & ADC

Quantization and frontend noise.

FW

CRC / protocol

Corrupted frame = lost symbol.

SW

Metrics & logs

Aggregation = lossy compression.

Self-check

Did I get it?

βœ“

I can explain why a predictable source has low entropy.

βœ“

I connect noise p, BER, and capacity C β‰ˆ 1 βˆ’ H(p).

βœ“

I see why redundancy/error coding beats Β«just send it againΒ» blindly.

βœ“

I can name a lossy compression example in AI/observability and what gets lost.