The 16 - bit adcs inside the single - chip microcomputer are used in the instrument to measure the output signal of the high frequency tuner , two12 - bit dacs are used to give the control signal needed by programmable gain amplifier . the system has the characteristics such as light volume , light weight , and low cost , which make it more applicable 该标量网络分析仪能方便地测试一个系统的传输特性和反射特性,与pc机通过通用串行总线( usb )连接,实现被测网络频率特性的图形显示、保存、打印及参数设置功能。
Comparing with conventional nyquist converters , - converters greatly release the requirements for high performance of analog circuit and precisely matched components . additionally , these converters exploit the enhanced speed , circuit density and low cost of modern vlsi technologies . currentlly , - adcs have been widely used for audio a / d conversion - adc采用过采样噪声整形技术实现高精度模数转换,和传统的nyquist率模数转换器相比,避免了对模拟电路性能指标和元器件匹配精度的较高要求,并可充分利用现代vlsi的高速、高集成度、低成本的优点,已成为音频模数转换的主要技术。
In recent years , oversampling techniques based on sigma - delta modulation are widely used to implement the interfaces between analog and digital signals in vlsi systems . this kind of technique can offer numerous advantages for the realization of high - resolution analog - to - digital converters ( adcs ) , and be insensitive to process variations . in other ways , the architecture is power - efficient means of implementing adcs 近年来,基于sigma - delta调制器的过采样技术被广泛的应用于模拟和数字接口电路,这种技术对实现高精度模数转换器有较多优势,同时可以降低系统功耗,但对工艺要求不是很苛刻,而且采用合适的低电压,以保证电路在低电压下可靠的工作。
Frequency response , quantization noise , reconstruction error and its sensitivity to mismatch among adcs are studied at length in prqmf banks adc system , and the theoretic results include : ( 1 ) the distortion / aliasing functions of hybrid filter banks adc system is similar with that of switch capacitor filter banks adc system ; ( 2 ) for wide or narrow band input signal , the effective resolution of the two adc systems is 0 . 51og2m bits higher than their adc ; ( 3 ) reconstruction error ' s sensitivity to mismatch among adcs of the two adc systems is reduced effectively than time interleaved adc system 2对prqmf滤波器组adc系统的频响、量化噪声特性、重建误差特性以及重建误差对adc间的失配敏感性进行了理论分析研究，所得到的理论结果为： ( 1 )混合滤波器组adc系统与开关电容滤波器组adc系统的失真/混迭函数一致； ( 2 )无论输入宽带还是窄带信号，这两种adc系统的有效分辨率均比其adc提高了0 . 5log _ 2m比特； ( 3 )这两种adc系统的重建误差对其adc间的失配敏感性均明显低于时间交织adc系统。
