🔍 Key Concepts

• A2 emissions in radio communications and how they differ from A1 and A3 • What a chopper does in a radio transmitter circuit • How double-keying systems work in tone-modulated radiotelegraphy

💭 Think About

• Think about what physical action a "chopper" performs on a steady carrier wave—does it affect the carrier, the audio tone, or both? • Consider whether an A2 emission system with a chopper would typically include both an automatic keying element and a manual key, and how they might work together. • Ask yourself: if a system is described in multiple ways (double-keying, automatic on/off, normal hand key), are these mutually exclusive, or can they all describe parts of one arrangement?

✅ Before You Answer

• Review the definition of A2 emission (modulated continuous wave / tone-modulated telegraphy). • Clarify whether a chopper in this context is an automatic keying device that rapidly interrupts the carrier or the audio tone. • Verify if a typical A2 chopper system has both an automatic key and a manual hand-operated key, and whether that combination is known as a double-keying arrangement.