In a single-sideband transmitter, what does the fixed RF oscillator do?

In a single-sideband (SSb) transmitter, the first step in creating the transmitted signal is generating a steady, constant radio frequency wave. This unmodulated wave is known as the RF carrier, and it is produced by the fixed RF oscillator (often called the carrier oscillator). Once this fixed RF carrier is generated, it is fed into a balanced modulator along with the amplified audio from the microphone. The balanced modulator combines them and suppresses the carrier to create a double-sideband (DSB) signal, which is then filtered to become SSB. Students sometimes confuse the fixed RF oscillator with the Variable Frequency Oscillator (VFO). The fixed oscillator provides the initial carrier for modulation, whereas the VFO is used later in a mixer stage to shift the SSB signal to the final desired transmitting frequency.