Research On Automatic Level Control Technology Of Wideband Microwave

Automatic level control(ALC)is commonly used in precision RF measuring instruments such as annunciators and network analyzers and is also widely used in high-power amplifier equipment.The function of ALC is to stabilize the signal power.Even if the input signal power level fluctuates within a large range,ALC can maintain the stability of the output signal power level.ALC is an automatic power control system based on the principle of negative feedback.It belongs to AGC(Automatic Gain Control).)category.The ALC system couples part of the actual output signal energy to the feedback loop and completes the comparison of the actual power and the target power in the loop.Based on the comparison results,the system's internal control parameters are continuously modified,and the iteration is repeated to keep the output signal power level in a stable state.According to the accuracy requirements of the transmitter on the output signal power level,this thesis designs and demonstrates an ALC scheme for stabilizing the power level of broadband signals based on dismantling and analyzing related technical indicators one by one.In the process of engineering implementation,the corresponding software program is written,and the functional unit circuits involved in the scheme are designed,debugged and tested.This thesis first briefly introduces the generation and evolution of ALC technology,then clarifies the theoretical basis and engineering implementation method of ALC system,and illustrates the typical application of ALC system.Then according to the project's requirements for the signal power,the plan formulation and demonstration of the ALC system are carried out.In the process of project realization,write the corresponding software program,design,debug and test the functional unit circuits involved in the scheme.After the debugging of the functional unit circuit in the ALC system is completed,functional unit cascading is performed on the entire ALC system,and the system is debugged and tested.Finally,the operating frequency band of ALC system is 30 MHz ~ 3000 MHz,the output power is-20 dBm ~ 0dBm,and the power flatness is ± 1 dB,which meets the expected design requirements.