Modulation and Signal Types Flashcards
7 cards from real GROL practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Modulation and Signal Types flashcards as text
An AM carrier has a peak amplitude of 100V and is modulated at 80%. What is the peak amplitude of each individual sideband?
Answer: 40V
Each sideband amplitude equals (m/2) × carrier amplitude = (0.8/2) × 100 = 40V.
An AM transmitter produces 1000W of carrier power. What is the total output power at 100% modulation?
Answer: 1500W
Total AM power = Pc(1 + m²/2) = 1000(1 + 0.5) = 1500W at 100% modulation.
What is the RF bandwidth of an AM signal with an audio frequency range of 300Hz to 5kHz?
Answer: 10kHz
AM bandwidth = 2 × highest audio frequency = 2 × 5000Hz = 10kHz.
What occurs when an AM signal is overmodulated (modulation index exceeds 1.0)?
Answer: The carrier is cut off during negative peaks, causing distortion and adjacent-channel splatter
Overmodulation clips the carrier on negative audio peaks, producing flat-topping that generates harmonics and causes splatter interference on adjacent channels.
An AM transmitter operates on 1600kHz and is modulated by a 4kHz audio tone. Where are the two sidebands located?
Answer: 1596kHz and 1604kHz
The upper sideband is at 1600 + 4 = 1604kHz and the lower sideband is at 1600 − 4 = 1596kHz.
What percentage of total AM transmitter power is contained in both sidebands combined at 100% modulation?
Answer: 33.3%
Sideband power = Pc × m²/2 = 500W; total power = 1500W; 500/1500 = 33.3%.
Which ITU emission designator identifies a standard double-sideband full-carrier AM voice transmission?
Answer: A3E
A3E designates double-sideband full-carrier amplitude modulation used for analog voice telephony.