Explanation: A self-excited oscillator (SEO) transmitter uses a single stage to generate the radio frequency (RF) signal and output it, often directly to the antenna. This design is inherently simpler, requiring fewer components because the oscillating circuit itself produces the power. In contrast, a master-oscillator power-amplifier (MOPA) transmitter separates these functions. A stable master oscillator generates a low-power RF signal, which is then fed into one or more subsequent power amplifier stages to boost it to the desired output level. This separation significantly improves frequency stability and allows for higher power output, but it requires multiple stages and thus more components, making it more complex to construct than a simple self-excited oscillator. Therefore, the self-excited oscillator transmitter is simpler and has fewer parts.