On the power implications of floating point addition in IIR filters

Author(s):  
R.V.K. Pillai ◽  
D. Al-Khalili ◽  
A.J. Al-Khalili
Keyword(s):  

In real time Signal Processing applications, the analogue signal is over sampled as per the Nyquist criterion in order to avoid the aliasing effect. Floating Point (FP) adder is used in the floating point Multiplier Accumulator Content (MAC) for real time Digital Signal Processing(DSP) applications. The heart of any real time DSP processor is floating point MAC. Floating Point MAC is constructed by Finite Impulse Response (FIR) or Infinite Impulse Response (IIR) filters. FIR filters are stable than IIR filters because the impulse response is finite in FIR. Hence, for stable applications FIR filters are preferred. These FIR filters are intern constituted by FP adder, FP multiplier and shifter. In conventional floating point adder the two floating point numbers are added in series. Series means one after the other so the computation speed is less. In series fashion adding the floating point numbers means definitely it furnishes more delay[1] because in the addition of floating point numbers, along with the addition of mantissas; computation is required for both signs and exponents also. Hence, the processing speed is slow for computing the floating point numbers compared with fixed point numbers. Therefore, in order to increase the speed of operation for floating point addition in real time application i.e., to add 16- samples at a time which are in floating notation; a parallel and pipe line technique is going to be incorporated to the two bit floating point architecture. Before developing such novel architecture, a novel algorithm is developed and after, the novel architecture is developed. The total work is simulated by Modelsim 10.3c tool and synthesized by Xilinx 13.6 tool.


2020 ◽  
Vol 33 (109) ◽  
pp. 21-31
Author(s):  
І. Ya. Zeleneva ◽  
Т. V. Golub ◽  
T. S. Diachuk ◽  
А. Ye. Didenko

The purpose of these studies is to develop an effective structure and internal functional blocks of a digital computing device – an adder, that performs addition and subtraction operations on floating- point numbers presented in IEEE Std 754TM-2008 format. To improve the characteristics of the adder, the circuit uses conveying, that is, division into levels, each of which performs a specific action on numbers. This allows you to perform addition / subtraction operations on several numbers at the same time, which increas- es the performance of calculations, and also makes the adder suitable for use in modern synchronous cir- cuits. Each block of the conveyor structure of the adder on FPGA is synthesized as a separate project of a digital functional unit, and thus, the overall task is divided into separate subtasks, which facilitates experi- mental testing and phased debugging of the entire device. Experimental studies were performed using EDA Quartus II. The developed circuit was modeled on FPGAs of the Stratix III and Cyclone III family. An ana- logue of the developed circuit was a functionally similar device from Altera. A comparative analysis is made and reasoned conclusions are drawn that the performance improvement is achieved due to the conveyor structure of the adder. Implementation of arithmetic over the floating-point numbers on programmable logic integrated cir- cuits, in particular on FPGA, has such advantages as flexibility of use and low production costs, and also provides the opportunity to solve problems for which there are no ready-made solutions in the form of stand- ard devices presented on the market. The developed adder has a wide scope, since most modern computing devices need to process floating-point numbers. The proposed conveyor model of the adder is quite simple to implement on the FPGA and can be an alternative to using built-in multipliers and processor cores in cases where the complex functionality of these devices is redundant for a specific task.


2012 ◽  
Vol 1 (6) ◽  
pp. 67-68
Author(s):  
M. Somasekhar M. Somasekhar ◽  
Keyword(s):  

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