Subelement G: Transmitters— Topic 55: SSB Transmitters
Question 3-55G5
Element 3 (GROL)What is the output peak envelope power from a transmitter as measured on an oscilloscope showing 200 volts peak-to-peak across a 50-ohm load resistor?
Explanation
To determine the Peak Envelope Power (PEP), we first need to convert the peak-to-peak voltage (Vpp) to the peak voltage (Vp).
1. **Calculate Peak Voltage (Vp):**
Vp = Vpp / 2 = 200 V / 2 = 100 V
2. **Calculate PEP:**
For sinusoidal RF power, the power is calculated using the peak voltage and the load resistance. The formula for power in watts, given peak voltage and resistance, is:
PEP = Vp² / (2 * R)
This formula accounts for the relationship between peak voltage and RMS voltage (Vrms = Vp / √2), as power is typically defined using RMS values (P = Vrms² / R).
Substitute the values:
PEP = (100 V)² / (2 * 50 ohms)
PEP = 10000 / 100
PEP = 100 watts
Therefore, the output peak envelope power is 100 watts. Option B is correct. Options A, C, and D would result from using the peak-to-peak voltage directly or incorrectly applying the power formula for peak voltage.
Related Questions
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