Question
What is the modulation envelope of an AM signal?
Answer Options
- A) The waveform created by connecting the peak values of the modulated signal
- B) The carrier frequency that contains the signal
- C) Spurious signals that envelop nearby frequencies
- D) The bandwidth of the modulated signal
Correct Answer: A
Explanation
The modulation envelope is a concept used to visualize the amplitude of a modulated signal over time, particularly in Amplitude Modulation (AM) and Single Sideband (SSB). It represents the shape of the modulating information.
The modulation envelope is literally the waveform created by connecting the peak values of the modulated signal. In a perfectly modulated AM signal, this envelope looks exactly like the audio waveform that was fed into the transmitter. Observing the envelope on an oscilloscope is the most effective way to detect distortion like ‘flat-topping.’
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