双积分A/D转换器的量程自动转换

介绍了一种双积分式A/D转换器在宽范围量程测量中的自动量程转换技术.在测量仪表的输入通道中,用计数器对双积分型A/D转换器本身所固有的过量程/欠量程信号计数,计数器的输出作为量程编码去控制量程的选择,同时又是送到CPU的量程指示信号.该技术扩大了A/D转换量程,提高了精度,设计简单,工作可靠.     

Improved digital/analogue conversion technique using currentsplitting in lateral bipolar transistors

Describes the use of multiple collector lateral bipolar transistors as precision current splitting elements suitable for use in high resolution monolithic D/A convertor design. Multiple collector structures result in better overall linearity and smaller chip area than previously suggested techniques. A six-bit convertor implemented on a linear bipolar semicustom array is used to demonstrate the advantages of this technique     

Monotonic dual-ladder A/D conversion

The use of a monotonic ladder network in a two-stage n-bit flash A/D convertor is examined. The technique is verified by a 6-bit discrete ADC. High-speed and monotonic operation are theoretically impossible in a two-step flash converter with this technique. This method allows for a reduction in the required circuit die size, while maintaining the conversion speed of a flash A/D converter.     

基于A/D和DSP技术实现混频的实验方法

本文介绍采用A／D转换器和DSP技术实现混频的一种实验方法,文章从频域角度分析与研究A／D转换器的频率变换功能,并采用欠抽样技术（带通采样技术）对高频带通信号进行采样,然后通过DSP软件编程对采样信号进行实时处理与滤波,便得到低频带通信号。与常规电子线路组成的混频器比较,这种基于A／D和DSP技术实现混频的实验结果表明：对一些固定频率的带通信号是可以实现下混频的。     

HQC—2型红外器件测试台的设计与调试

本文讨论了HQC—2型红外器件测试台高输入阻抗、超低噪声交流阻抗变换器的设计技术和电磁屏蔽技术。     

ECL-CMOS and CMOS-ECL interface in 1.2-μm CMOS for 150-MHzdigital ECL data transmission systems

The design of a full-CMOS circuit that converts voltage signals from those used for emitter-coupled logic (ECL) to CMOS and vice versa, for use in digital data transmissions with clock frequencies up to 150 MHz, is described. Extremely high performances are obtained due to a novel circuit principle, in both the ECL-to-CMOS convertor and the CMOS-to-ECL convertor. A wideband CMOS amplifier used in the ECL-to-CMOS convertor, incorporating a current injection technique to increase the bandwidth of the circuit, is also presented. A circuit principle is presented to realize an extremely fast CMOS-to-ECL conversion, based on a current switching technique and charge injection to compensate the large output capacitance. Both circuits make use of replica biasing to ensure maximum switching speed in the ECL-to-CMOS convertor and correct ECL output levels in the CMOS-to-ECL convertor. An ECL-CMOS-ECL repeater has been designed in a 1.2-μm double-metal CMOS process     

Dual translinear voltage/current convertor

A new voltage/current convertor (VCCS) using a translinear loop and two current mirrors is described. This convertor has two bipolar outputs, and two different loads can be used. The properties of this convertor are presented for direct current and sinusoidal input signals.     

Controlling transformer saturation in the DC-isolated Cuk convertor

The problem of transformer saturation in the DC-isolated Cuk convertor is examined. A novel open-loop damping technique is developed to control transformer saturation. The new method is found to add significant damping without a noticeable degradation in convertor efficiency.     

2-bit 1-Gsample/s electro-optic guided-wave analogue-to-digital convertor system

An electro-optic analogue-to-digital convertor system has been demonstrated at 1 Gsample/s. This system has been tested with low-frequency waveforms and by means of a beat-frequency technique with a 499 MHz test signal. Digital outputs are slowed in time and then fed into 125 MHz digital-toanalogue convertors which accurately reconstruct the beat signal, proving the compatibility of electra-optic signal processing with digital circuits.     

基于AD650的VFC型A/D转换器

针对实际工程的技术要求，设计了一种新型高精度模数转换电路——VFC型A／D转换器。该电路作为计算机控制系统与受控设备之间的接口电路，在计算机控制下，所有的逻辑判断和校正网络均由计算机软件实现，此转换电路不仅调试方便、简单，而且增加了系统的可靠性。实践表明，设计的VFC型A／D转换电路完全满足系统设计要求。本文详细叙述了VFC型A／D转换电路的工作原理、设计思想和实现方法。     

Binary weighted D/A converters with mismatch-shaping

A D/A convertor suited to multibit sigma-delta modulators is described. This convertor is able to shape the spectrum of the error caused by the mismatch among its components. The hardware implementation is based on a simple, binary-weighted structure     

Noise-shaped multibit D/A convertor employing unit elements

By appropriately selecting the elements used to form each output sample of a multibit digital-to-analogue convertor, the spectrum of the error caused by element mismatch can be noise-shaped. Simulations indicate that first-order, second-order and bandpass noise-shaping are all possible. The technique enables the use of multibit feedback in delta-sigma A/D and D/A convertors     

High accuracy pipeline D/A convertor configuration

A new pipeline D/A convertor configuration is presented. This structure can be used as a module in a pipeline A/D convertor. The advantage of this D/A structure is that the accuracy is not influenced by any stray capacitor such as bottom plates or drain/source junction capacitors. As a result video frequency operation can be obtained with this structure     

Interpolative bandpass A/D conversion-experimental results

Experimental results for a second order interpolative bandpass A/D convertor are presented. The A/D convertor operating at 10 MHz sampling rate is able to process narrow-band bandpass signals centred at 2.5 MHz. The effective resolution in a 80 kHz bandwidth is between 9 and 10 bits.<>     

基于FPGA的高分辨率D／A转换器的实现

为增强FPGA（现场可编程门阵列）对模拟信号的处理能力,扩展FPGA的应用范围,介绍了一种基于FPGA实现高分辨率D／A转换器的技术。利用FPGA内部PLL（锁相环）,提高时钟信号的计数频率,从而提高PWM（脉宽调制）信号的基波频率,通过5阶巴特沃斯低通滤波器,实现14位高分辨率D／A转换器。阐述了PWM实现D／A转换器的理论基础和实际应用注意事项,该方法已用于实际D／A转换器系统,具有精度高、误差小的优点,对于FPGA的实际应用具有一定的指导意义。     

Wide-range temperature/frequency convertor

A novel wide range temperature/frequency convertor, based on comparing the current through a thermistor and the capacitor discharging current, is described. The input/output relationship is linear over a wide temperature range. The performance fitting has to be done only at the maximum temperature of the range. The convertor can be made multirange by simple modification of the circuit.     

一种可调精度的A/D转换器设计

现代测控系统对测量信号的处理基本由数字技术完成,A/D转换器的性能对系统具有重要的影响.采用SDM(∑-⊿调制器)实现A/D转换器,省略复杂的数字抽取滤波器,由DSP和CPLD对SDM输出的高速码流处理,实现A/D转换.DSP软件编程可以控制CPLD的计数器,实现可变精度(和速度)的A/D转换.通过对SDM特性分析,得到转换方法及计算公式,最后设计电路实现要求的功能.实验实现了最高16位A/D转换,很好地证明了设计分析的结论.     

5 GHz Josephson A/D converter

A four-bit A/D convertor using Nb/AlO_x/Nb Josephson junctions was fabricated. The circuit was designed to preserve the matching of characteristic impedances at all nodes. Four-bit A/D conversion was confirmed at a low frequency. The A/D convertor correctly operated at up to 5 GHz for two-bit conversion     

用ispPAC20和isp1032实现可编程逐次逼近式A/D转换器的研究

ispPAC20在系统可编程模拟器件集放大器、比较器、D／A转换器为一体、方便地完成放大器、有源滤波器、方波发生器等模拟电路单元的设计。还可将其与isp1032结合实现可编程的逐次逼近式A／D转换。本文给出了一个设计,它具有控制灵活,可8方便地嵌入到电子系统设计中的优点。     

New constant frequency PWM dual convertor with synchronous rectifier

A new constant frequency PWM dual convertor which has fully regulated dual outputs is proposed. The proposed convertor is the superposition of a forward convertor and a flyback convertor. The switches in the forward convertor for synchronous rectification provide another degree of freedom in controlling the flyback convertor. Thus, not only forward output but also flyback output can be fully regulated by constant frequency PWM control in continuous conduction mode (CCM).<>