🔍 Key Concepts

• RF (radio frequency) power stages in a transmitter • Difference between high-level and low-level modulation points in a transmitter • Where the plate circuit is located in vacuum-tube transmitter stages

💭 Think About

• Is the plate circuit of the last radio stage usually at a high RF power point or an early/low-power point in the transmitter chain? • In traditional AM transmitters, is the carrier modulated closer to the antenna (final amplifier) or earlier at low power? • How does the location of the modulation point (final plate circuit vs. earlier stage) affect whether it is called high- or low-level modulation?

✅ Before You Answer

• Identify whether the last radio stage plate circuit is the final RF power amplifier section • Recall the definition of high-level modulation versus low-level modulation in terms of power level at the modulation point • Verify that the modulation is applied where the RF carrier power is already at or near its maximum level before the antenna