A Floating-Point ADC with Variable Gain Pipeline Stages

Typically an automatic gain control (AGC) amplifier is needed in a receiver to control the amplitude of the signal at the input of the ADC. To get rid of the AGC, a floating-point pipelined analog-to-digital converter (FP-ADC), which consists of variable gain stages, is presented. The frontend pipeline stages of the ADC use a larger gain if the value of the signal is small. If the value of the signal is large, they act as typical pipeline stages. Thus, the small values of the signal are converted using higher resolution than larger values. The dynamic range of the ADC is increased and a separate AGC is not needed.     

基于快速舍入的双精度浮点乘法器的设计

文章设计了一个基于快速合入的双精度浮点乘法器。它通过预测和选择实现快速舍入。克服了传统合入方法舍入模式单一、舍入逻辑复杂、硬件开销大等不足，显著地提高了浮点乘法器的性能。该浮点乘法器采用四级流水线，在0．180μm CMOS工艺下综合实现，关键路径延迟为3．15ns。     

浮点加法器IP核的VHDL设计

浮点数加法运算是浮点运算中使用频率最高的运算。结合VHDL和FPGA可编程技术，完成具有5级流水线结构、符合IEEE754浮点数标准、可参数化为单／双精度的浮点数加法器IP核的VHDL设计。     

基于FPGA的高速双精度浮点乘法器设计

设计了一种基于FPGA的高速双精度浮点乘法器．采用了基4Booth算法产生部分积,然后用优化的Wal—lace树阵列结构完成对部分积的累加得到伪和和伪进位,进而对伪和和伪进位采用了部分和并行相加得到最后尾数结果．采用了优化的5级流水线结构的设计在CycloneIIEP2C35F672C6器件上经过综合后运行频率可达123．32MHz．在同等优化下,相比于AlteraIP核在调用DSP乘法资源情况下运行速度提高大约11％,相比于不调用DSP乘法资源情况下运行速度提高大约67％．     

嵌入式处理器的浮点乘法器设计

利用阵列乘法器中的压缩部分积的思想,通过对传统的串行执行乘法器的改造,提出了一种带压缩器的串行执行浮点乘法器,分析了具有不同压缩模块结构的乘法器的性能.实验表明,该乘法器可以有效地提高传统的串行乘法器的性能,而面积要小于阵列乘法器.     

一种新型的定点到浮点转换的全流水线FPGA实现

利用FPGA器件完全采用底层自主设计,实现定点数到浮点数的转换.提出了一种全新的实现方法,变对数为减法,通过占用1%的逻辑资源,实现3个时钟周期输出数据.避免了局限于使用IP core的束缚,为后续ASIC设计打下了基础.     

DSP中的浮点与定点比较

介绍目前常用的DSP定点数据格式和浮点数据格式,对比两种数据格式的优缺点,提出了对其适用场景和格式选型的相关建议。     

Double span floating point representation scheme for the powers-of-two filter

The area of signal processing has been experiencing silent revolution over the last few years. A number of promising algorithms are being developed in this regard. In connection to this, minimization of hardware complexity of digital filter has grown sufficient interest amongst the research community. Hardware cost of digital filter may be reduced by encoding the filter coefficient in the form of sum of signed powers-of-two (SPT). This article introduces a new encoding strategy of the non-uniform powers-of-two coefficients for the sake of exploiting minimum hardware units. Proposed scheme targets to minimize the highest powers-of-two terms in any coefficient by judiciously dividing the ‘span’ part into two segments. As a matter of fact, it necessitates the use of minimum number of full-adder blocks during implementation as compared to other existing coefficient representation schemes. Supremacy of the proposed double span floating point (DSFP) representation technique has been mathematically substantiated and supported with the help of few design examples.     

定制VLIW结构实现四精度浮点基本函数

本文针对科学应用中基本函数种类多、实现复杂、使用频率低的特点,提出一种定制VLIW结构四精度浮点基本函数协处理器(QPC-Processor).该结构通过显示并行技术挖掘基本函数实现算法的并行性,在同一硬件平台上通过元操作的不同组合来计算多种基本函数.同时,本文还提出基本函数元操作序列到定制VLIW指令的映射算法,指导基本函数的设计.最后,在FPGA平台上进行验证.实验结果表明,相对软件实现,单个QPC-Processor能够取得6倍以上的加速比,而且,QFC-Processor在同一硬件平台上实现多种类型的算法,弥补单一算法的不足,获得较高的硬件资源利用率.     

三数据通道浮点加法器的FPGA实现

浮点加减运算是现代数字信号处理中非常频繁的操作,浮点运算的快慢直接影响数字信号处理的速度.常用的硬件实现算法有双通道算法和三通道算法.文中介绍了浮点加法器电路设计的常用算法,重点介绍了一种低功耗的三数据通道结构,最后以MAXPLUSⅡ为工具,给出了该结构的现场可编程门阵列(FPGA)实现.仿真结果显示,该方法可以提高数据采集及运算速度,为实时数据处理提供了一种方法.