Design of RF amplifier based on direct digital synthesizer output

As a new RF generator, the direct digital synthesizer(DDS) has been widely used. In order to reduce the high cost of the signal generator comprising a high performance DDS device, the method of picking-up a desired aliased signal DDS output is adopted in the design. A device of AD9850 is used to generate RF signal in the system, and the amplitude modulation of the system is achieved by using a voltage variable attenuator.The amplifier based on tetrode is selected to get an output power of 10kW at (96±1) MHz. Amplifier operates in a grounded cathode configuration. A short-circuited coaxial transmission line is adopted in both input circuit and output circuit. The PID-control strategy has been used in control system ,and the relay method has been used for measurement. The controller has a b