FCC Exam Question: 3-55G2

To produce a single-sideband suppressed carrier transmission it is necessary to ____ the carrier and to ____ the unwanted sideband.

A. Filter, filter.
B. Cancel, filter.
C. Filter, cancel.
D. Cancel, cancel.
Correct Answer: B

Explanation: To produce a single-sideband (SSB) suppressed carrier transmission, two distinct processes are essential: First, the carrier wave must be **cancelled**. This is typically achieved using a balanced modulator. A balanced modulator takes the radio frequency (RF) carrier and the audio frequency (AF) modulating signal as inputs and produces an output containing only the upper and lower sidebands, with the carrier wave ideally suppressed or cancelled to a very high degree. Second, the unwanted sideband must be **filtered**. After the balanced modulator generates both the upper and lower sidebands, a highly selective filter (such as a crystal, ceramic, or mechanical filter) is used to pass only one of these sidebands (either the upper or lower) and reject the other. This ensures only a single sideband is transmitted, conserving bandwidth and power. Therefore, the carrier is cancelled, and the unwanted sideband is filtered.

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Includes Elements 1, 3, 6, 7R, 8, and 9.