一种基于软件无线电的频谱扫描技术

A spectrum scanning scheme based on software-defined radio

在无线电综合测试仪的设计中,频谱扫描是一项基础技术.将需要扫描的频谱划分成子带,进而提出了一种通过在模拟前端采用可变频率本振的混频器和低通滤波器实现子带信号分离,然后对子带信号进行采样并且变换到频域,最后将所有子带频谱拼接获得完整频谱的技术.为了实现该技术,设计了一个由软件无线电(Software-defined Radio,SDR)接收机和数字信号处理片上系统(System on Chip,SOC)组成的软件无线电平台.随后,在基于该平台实现的综测仪原型上对频谱分析技术进行了验证.仿真和实验表明,该方法和原型样机能够对0~6 GHz范围的频谱进行扫描,同时具有较低的噪声水平和较好的动态范围,且能够提供相位谱,因而适用于嵌入式频谱仪和无线电综测仪的应用场合.

Spectrum scanning is one of the basic techniques employed in the design of radio test instruments. In this paper, a mixer with variable local oscillator frequency followed by a low pass filter was adopted to acquire data to calculate the sub-bands of the entire spectrum. The sub-band signals are sampled and converted to the frequency domain. The entire spectrum was reconstructed by splicing the sub-bands spectrum. To implement this scheme, we proposed a software-defined radio platform, which was composed of a software-defined radio （SDR） receiver and a digital signal processing system on chip （SOC）. Finally, a radio test set prototype was implemented based on the platform, which verified the proposed spectrum analysis scheme. Simulations and experiments show that the proposed scheme and the prototype are able to analyze the spectrum within 6GHz span, with low noise and high dynamic range, and can also provide the phase spectrum. The proposed scheme and the prototype are suitable for applications in built-in spectrum analyzers and radio test instruments.