Design Of RF Frequency Sweeper Based On DSP

RF frequency sweeper is used to measure the frequency characteristic of RF radio communication devices. This paper presents the design of a high cost-effective RF frequency sweeper, which is mainly based on DSP technology, DDS technology and phase-locked loop technology.This paper analyses the trend of frequency synthesis technology, with focus on the working principle and characteristic of direct digital synthesizer (DDS) technology and phase-locked loop (PLL) technology. It compares the three methods of DDS-hybrid-PLL frequency synthesis technology, and then puts up a design of a new RF frequency sweeper system which is based on a structure of DSP and frequency synthesis technology.The system consistants of sweep signal source, amplitude detection circuit, A/D conversion circuit, data processing and control circuit. The sweep signal source makes use of DDS+PLL frequency synthesis technology, and the processing and control circuit is based on DSP. This paper presents design of the system software, which including system initialization procedures, control procedures, interrupt handlers and the chip driver. At last it tests the sweep signal source, amplitude detection and processing circuit. The results show that requirement of design has been reached.