L-band Sweep Frequency Source And S-band Frequency Channel Design

Sweep source is short for the sweep signal source, a signal generating device, providing various frequency and power signal output. In the sweep measurement system, the sweep source is in a very important position, is the heart of the sweep measurement system. In addition, sweep source are widely used in modern defence and civil areas, for example, electronic countermeasure, precision-guided, ranging radar, navigation, and spread spectrum communication.With the rapid development of the communications industry, the use of low-band frequency appear crowded. With improvement of the communication transfer rate, bandwith will be wider and the signal interference will be greater. The microwave and millimeter wave communication equipment just to make up for this shortfall. In the modern micowave and milimeter wave circuit system, low frequency signal often needed to be transferred into microwave and milimeter wave frequency signal. The up-frequency circuit achieves this function.Based on the principle of phase-locked loop, DDS, mixer, this paper complete the design of L band sweep source and S band up-conversion channel. Sweep source test result show that:In the1MHz～1GHz frequency range, the spurious signal inhibit are more than30dBc, the harmonic inhibit is greater than40dBc. The output power range can reach-110dBm～+7dBm. The up-conversion channel test result show that:In the2.8GHz～3.2GHz frequency range, the output power is21dBm. The power flatness is less than3dB. The signal off isolation is more than50dB.The paper also introduces and analyzes the key and difficult points in the circuit design and debugging, and proposed improvements.