Agile ALC system with amplitude and pulse modulation function and control method thereof

Abstract

The invention relates to the technical field of microwave radio frequency, and provides an agile ALC system with an amplitude and pulse modulation function and a control method thereof. The system comprises a main link and a feedback loop, and the main link comprises an analog attenuation circuit, an amplification circuit, a switch and a coupler which are connected in sequence; the feedback loop comprises a detection circuit, a first voltage processing circuit, an ADC sampling circuit, an FPGA, a DAC conversion circuit, a second voltage processing circuit and a switch driving circuit. Through simple hardware circuit design and a digital control method, accurate and rapid power output with amplitude modulation and pulse modulation functions is realized. By means of FPGA + high-speed AD / DA and table look-up, the power agility time is in the ns level, the problem that the amplitude modulation rate is limited by ALC stabilization time is solved, meanwhile, the level accuracy when carrier output exists under pulse modulation is guaranteed, and complex hardware circuit design is avoided.

Description

technical field [0001] The invention belongs to the field of microwave radio frequency technology, and in particular relates to an agile ALC system with amplitude and pulse modulation functions and a control method thereof. Background technique [0002] Automatic level control (ALC) technology is used to precisely control the output power and is widely used in signal sources and transmitters of mobile communication systems. Usually, an amplitude modulation circuit and a pulse modulation circuit are added to the ALC link to achieve power stability control of the signal source , amplitude modulation and pulse modulation functions. [0003] Such as figure 1 As shown, it is an AM ALC loop of a radio frequency microwave signal source in the prior art. The reference level and the AM signal are superimposed to form a feedforward signal that first acts on the linear attenuator, and the radio frequency signal is amplified and linearly modulated on the main link. , After re-amplific...

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Problems solved by technology

However, this circuit can only work in a certain range of AM, and it will conflict with the control of ALC during deep AM. The response time of the ALC loop is very long, generally at the us level, which affects the power stabilization speed, and the AM bandwidth is limited by the ALC system. Hysteresis characteristics; at the same time, the hardware circuit is complex, the debugging workload is heavy, and it is not easy to realize

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