RF Power Amplifier System
The RF Power amplifier is custom made solid state RF power amplifier operating at 200 MHz. The amplifier has a gain of about 75 dB and can transform 10mW (10dBm) of RF signal into 320 kW of RF power. The amplifier can operate a pulse length of 1.25mS at a pulse repetition rate of 40 Hz. The RF Power amplifier connected to the RFQ is shown in Figure 4.
The RF power amplifier requires two timing channels from the Timing system.
- Channel 2 for the RF Power Amp pulse gate
- Channel 3 for the RF Power Amp sample and hold
The RF power amplifier takes the low level signal generated from the RF source. The amplifier has a 75dB directional coupler mounted on its output and the forward and reflected RF signals are available on the front panel. These signals are fed into the RF power monitor.
The manufacturer of the RF power amplifier provides a Modbus TCP interface so the RF Power amplifier can be controlled and monitored. The manufacturer provides a detailed spreadsheet of the Modbus table as well. The tray code is written in the Node-RED programming environment as shown in Figure 1. The tray flow is a modified version of the standard Blinky-LiteTM tray for serial communications. A Node-RED Modbus TCP node was used handled communications to the amplifier.
To develop and test the interface to RF power amplifier without having to power on the amplifier, a simulation flow as shown in Figure 2 was also developed.
Figure 1. RF Power Amplifier tray flow with Modbus interface.
Figure 2. RF Power Amplifier simulation tray flow with Modbus interface.
