数字自动增益控制和模数转换数值抖动研究

摘要

In order to improve the blocking performance of receivers,a digital automatic gain control(AGC)circuit was designed. The gain control does not rely on the FPGA,DSP or micro⁃processor in the form of look⁃up table. It controls the digital step attenuator by digital output quantity of the ADC directly to decrease the response time and the circuit complexity of the system. A method to achieve high⁃precision AGC by means of low⁃precision device is proposed. A novel circuitry to deal with the numerical jitter during analog⁃to⁃digital conversion in the subelement. The circuit has better real⁃time performance than other methods.%　　为了提高接收机的阻塞性能，设计一种数字式的自动增益控制电路，增益控制无需 FPGA，DSP 或微处理器通过查表的方式来实现，它通过直接使用模数转换的数字输出量来控制数字步进衰减器，这样降低了系统的响应时间和电路的复杂度。提出了一种利用低精度器件实现高精度数字 AGC 的方法，并针对子单元中模数转换的数值抖动设计了一种抖动消除电路，与其他方法相比，该设计电路实时性能更好。