science

Varicode

Varicode is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Varicode rather than just read about it. In short: Varicode is a self-synchronizing code for use in PSK31. It supports all ASCII characters, but the characters used most frequently in English have shorter codes.

Key takeaways

Varicode belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Varicode to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Varicode from memory before moving on to harder problems.

Reference excerpt

Varicode is a self-synchronizing code for use in PSK31. It supports all ASCII characters, but the characters used most frequently in English have shorter codes. The space between characters is indicated by a 00 sequence, an implementation of Fibonacci coding. Originally created for speeding up real-time keyboard-to-keyboard exchanges over low bandwidth links, Varicode is freely available.

Limitations Varicode provides somewhat weaker compression in languages other than English that use same characters as in English.

Varicode table

Control characters

Printable characters

Character lengths Beginning with the single-bit code "1", valid varicode values may be formed by prefixing a "1" or "10" to a shorter code. Thus, the number of codes of length n is equal to the Fibonacci number Fn. Varicode uses the 88 values of lengths up to 9 bits, and 40 of the 55 codes of length 10. As transmitted, the codes are two bits longer due to the trailing delimiter 00.

References

Worked examples

Example 1 — a first encounter with Varicode

Start with the simplest possible case. Write down what Varicode claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Varicode before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Varicode ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Varicode

In research: Varicode appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Varicode in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Varicode is common in secondary-school and first-year university syllabi. It links to neighbouring topics Character encoding, Data compression, so understanding it makes those chapters shorter.
In everyday life: Look for Varicode outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Varicode in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Varicode means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Varicode out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Varicode in simple terms?

Varicode is a self-synchronizing code for use in PSK31. It supports all ASCII characters, but the characters used most frequently in English have shorter codes.

Why does Varicode matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Varicode?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Varicode.