多通道甚高频超外差式接收机的设计

Design of multi-channel VHF superheterodyne receiver

针对甚高频天线阵信号的同时接收中存在信噪比差异过大以及信号质量不好等问题,设计一种通道差异小、噪声低、灵敏度高、动态范围大的多通道甚高频超外差式接收机。该设计采用高灵敏度和大动态范围的超外差式接收机结构,前级放大器采用低噪声、高增益的放大器来降低整个接收机的噪声系数,并选择合理的预选滤波器和中频滤波器抑制镜像频率的干扰,链路中还采用匹配网络调节通道增益,使各个通道间的增益差异在合理的范围内,中频放大器选择合理的1 dB压缩点放大器以保证接收机的动态范围足够大。该设计在经过测试后,各项接收指标均满足要求,可广泛应用于雷达、通信领域。

Since the simultaneous reception of VHF antenna array signals has the problems of unsuitable signal-to-noise ratio and poor signal quality,a multi-channel VHF superheterodyne receiver with small channel difference,low noise,high sensitivity and wide dynamic range is designed. The superheterodyne receiver structure with high sensitivity and wide dynamic range is adopted in the design. The low.noise high.gain amplifier is used as the preamplifier to reduce the noise coefficient of the entire receiver, and the reasonable preselection filter and intermediate frequency (IF) filter are selected to suppress the interference of the image frequency. The matching network is used in the link to adjust the channel gain to make the gain difference among all the channels within the reasonable range. A reasonable 1 dB compression point amplifier is selected as the IF amplifier to ensure the enough dynamic range of the receiver. The test results show that the receiving indicators of the receiver can meet the requirements,and the receiver can be widely used in radar and communication fields.