摘要
An RF transceiver composed of a zero-IF receiver and a direct up-conversion transmitter for cognitive radio applications is presented. The adjustable channel filter array in the receiver is used to suppress adjacent channel interference in televisions signal coexistence environments. The low noise amplifier （LNA） with wide dynamic range and high linearity is employed to enhance the anti-interference competence of the zero-IF receiver. Meanwhile, the high linearity power amplifier （PA） .is used to promote the adjacent channel power ratio （ACPR） characteristic of the direct up-conversion transmitter. The measured error vector magnitude （EVM） results show that the anti-interference competence of the zero-IF receiver is dramatically enhanced by employing a channel filter array. The measured ACPR of the direct up-conversion transmitter is -47. 98 dBc on the channel centered at 714 MHz when the output power is 27 dBm.
介绍了一种应用于感知无线电的射频收发机,该射频收发机包含一个零中频接收机和一个直接上变频发射机.在与电视信号共存的环境中,射频接收机采用可调信道滤波器组来抑制邻近信道干扰.采用了具有宽动态范围、高线性度的低噪声放大器来提升零中频接收机的抗干扰性能.同时,采用高线性功率放大器来提高直接上变频发射机的邻近信道功率比特性.测试得到的误差矢量幅度结果显示,通过采用信道滤波器组使零中频接收机的抗干扰性能得到了很大提高.当直接上变频发射机发射输出功率达27dBm时,在中心频率为714MHz的信道上,测得直接上变频射频发射机的邻近信道功率比为-47.98dBc.
基金
The National Natural Science Foundation of China(No.60621002)
the National High Technology Research and Development Program of China(863 Program)(No.2009AA011801)
