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Modulation

Modulation is the process of varying one or more properties of a periodic waveform (called the carrier signal) with a separate signal that typically contains information to be transmitted. In amateur radio, various modulation techniques are used to transmit voice, data, and other forms of communication.

Types of Modulation​

This section covers various modulation techniques commonly used in amateur radio:

  • Amplitude Modulation (AM) - Varying the amplitude of the carrier wave
  • Frequency Modulation (FM) - Varying the frequency of the carrier wave
  • Phase Modulation (PM) - Varying the phase of the carrier wave
  • Digital Modes - Various digital modulation schemes

Each modulation type has its own advantages and applications in amateur radio communications.

Key Concepts​

Understanding modulation requires familiarity with several fundamental concepts:

  • Carrier Wave - The base signal that carries the information
  • Modulating Signal - The information signal that modifies the carrier
  • Bandwidth - The range of frequencies occupied by the modulated signal
  • Signal-to-Noise Ratio - The measure of signal quality relative to background noise

Applications in Amateur Radio​

Different modulation techniques are suited for different applications:

  • Voice Communications - AM, FM, and SSB are commonly used
  • Digital Communications - PSK31, FT8, and other digital modes
  • Emergency Communications - Robust modes that work well in poor conditions
  • Experimental Communications - New and emerging modulation techniques