engineering

Interruptible foldback

Interruptible foldback is a engineering 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 Interruptible foldback rather than just read about it. In short: Interruptible foldback (IFB), also known as interrupted foldback, interruptible feedback, or interrupt for broadcast, is a monitoring and cueing system used in television, filmmaking, video production, and radio broadcast for one-way communication from the director or assistant director to on-air talent or a remote location. The names are backronyms for the Telex IFB-XXX model line.

Key takeaways

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

Reference excerpt

Interruptible foldback (IFB), also known as interrupted foldback, interruptible feedback, or interrupt for broadcast, is a monitoring and cueing system used in television, filmmaking, video production, and radio broadcast for one-way communication from the director or assistant director to on-air talent or a remote location. The names are backronyms for the Telex IFB-XXX model line. Less common names for the system include program cue interrupt (PCI) and switched talkback. IFB is often facilitated using an earpiece that on-air persons wear to get cues, feedback or direction from their control rooms. The earpiece itself may also be referred to as an IFB. The IFB is a special intercom circuit that consists of a mix-minus program feed sent to an earpiece worn by talent via a wire, telephone, or radio receiver (audio that is being "fed back" to talent) that can be interrupted and replaced by a television producer's or director's intercom microphone. On a television news program for example, a producer can talk to the news anchors, to tell them when they are live on the air and when to begin reading off the script on the teleprompter or cue cards. In live television, some news anchors are seen listening to IFBs in order to report breaking news and announcements. In electronic news gathering (ENG), the IFB can be sent through a telephone hybrid, or some other return link in a broadcast auxiliary service. The physics and design of electronics cause time delays in signals as they travel through wire, fiber optics, or space and when they are converted back and forth from physical sound, electronic signals, radio waves, and from analogue to digital. The latter process and other audio processing can introduce unacceptable delays or echos into the sound. To achieve the mix-minus program to the IFB, certain audio elements that originate remotely from the mix point will be eliminated from the mix that is sent back to the IFB at the remote site to avoid those undesirable effects. Wired or wireless in-ear monitors (IEMs) may be used to carry the IFB audio to the on-air talent.

See also Talkback (television production)

References

Worked examples

Example 1 — a first encounter with Interruptible foldback

Start with the simplest possible case. Write down what Interruptible foldback claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, 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 Interruptible foldback 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 Interruptible foldback 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 Interruptible foldback

In research: Interruptible foldback appears in engineering 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 Interruptible foldback 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: Interruptible foldback is common in secondary-school and first-year university syllabi. It links to neighbouring topics Broadcast engineering, Filmmaking stubs, Television terminology, so understanding it makes those chapters shorter.
In everyday life: Look for Interruptible foldback 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.

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How to study Interruptible foldback in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Interruptible foldback 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 Interruptible foldback out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Interruptible foldback in simple terms?

Why does Interruptible foldback matter?

Because it connects several engineering 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 Interruptible foldback?

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 Interruptible foldback.