🔍 Key Concepts

• Parasitic oscillations in RF (radio frequency) amplifiers and transmitter stages • How unintended oscillations can affect bias, efficiency, and distortion • Relationship between stable operation of an amplifier and the quality of the modulated signal

💭 Think About

• If an amplifier starts oscillating at an unintended frequency, what happens to the DC operating point (bias) of the active device? • How would wasted power in unwanted oscillations affect the overall efficiency of the amplifier tube? • How can an unwanted RF signal mixing with the desired signal change the shape (and therefore the quality) of the modulated wave?

✅ Before You Answer

• Consider whether parasitic oscillations can cause a shift in bias by drawing unexpected current. • Think about whether they consume power without contributing to useful output, thus changing efficiency. • Evaluate whether they can distort the intended waveform of the signal being transmitted.