SignalPrep
Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-006-006

What audio shaping network is added at an FM transmitter to attenuate the lower audio frequencies?

  1. AAn audio prescaler
  2. BA heterodyne suppressor
  3. CA de-emphasis network
  4. DA pre-emphasis network

Correct answer: D — A pre-emphasis network. From the official ISED question bank, verified word for word.

Why

A pre-emphasis network boosts higher audio frequencies before transmission to make them stronger than lower ones, which helps overcome noise that naturally affects high pitches more. The full explanation — and one for every question — is in Pro.

Practise this section

Transmitters, modulation and processing is section A-005 of the Advanced exam: Transmitters, modulation and processing: AM, FM, SSB, keying, speech processing, and the numbers behind occupied bandwidth.

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