Multiply And Accumulate Research Articles

A DSP Architecture for High‐Speed FFT in OFDM Systems

This paper presents digital signal processor (DSP) instructions and their data processing unit (DPU) architecture for high-speed fast Fourier transforms (FFTs) in orthogonal frequency division multiplexing (OFDM) systems. The proposed instructions jointly perform new operation flows that are more efficient than the operation flow of the multiply and accumulate (MAC) instruction on which existing DSP chips heavily depend. We further propose a DPU architecture that fully supports the instructions and show that the architecture is two times faster than existing DSP chips for FFTs. We simulated the proposed model with a Verilog HDL, performed a logic synthesis using the 0.35 µm standard cell library, and then verified the functions thoroughly.

A 16-Bit by 16-Bit MAC Design Using Fast 5: 3 Compressor Cells

3:2 counters and 4:2 compressors have been widely used for multiplier implementations. In this paper, a fast 5:3 compressor is derived for high-speed multiplier implementations. The fast 5:3 compression is obtained by applying two rows of fast 2-bit adder cells to five rows in a partial product matrix. As a design example, a 16-bit by 16-bit MAC (Multiply and Accumulate) design is investigated both in a purely logical gate implementation and in a highly customized design. For the partial product reduction, the use of the new 5:3 compression leads to 14.3% speed improvement in terms of XOR gate delay. In a dynamic CMOS circuit implementation using 0.225 μm bulk CMOS technology, 11.7% speed improvement is observed with 8.1% less power consumption for the reduction tree.

A Compiler-Friendly RISC-Based Digital Signal Processor Synthesis and Performance Evaluation

As DSP (Digital Signal Processing) applications become more complex, there is also a growing need for new architectures supporting efficient high-level language compilers. We try to synthesize a new DSP processor architecture by adding several DSP processor specific features to a RISC core that has a compiler friendly structure, such as many general-purpose registers and orthogonal instructions. The synthesized digital signal processor supports single-cycle MAC (Multiply-and-ACcumulate), direct memory access, automatic address generation, and hardware looping capabilities in addition to ordinary RISC instructions. The compiler for the new architecture is quickly implemented by developing a code-converter that modifies the assembly codes that are generated by the RISC compiler. The performance effects of adding each of these as well as all the combined features are evaluated using seven DSP-kernel benchmarks, a QCELP vocoder, and an MPEG video decoder. The effects of CPU clock frequency change due to the addition of these features are also considered. Finally, we also compare the performances with several existing DSP processors, such as TMS320C3x, TMS320C54x, and TMS320C5x.

A CORDIC processor for FFT computation and its implementation using gallium arsenide technology

In this paper, the architecture and the implementation of a complex fast Fourier transform (CFFT) processor using 0.6 /spl mu/m gallium arsenide (GaAs) technology are presented. This processor computes a 1024-point FFT of 16 bit complex data in less than 8 /spl mu/s, working at a frequency beyond 700 MHz, with a power consumption of 12.5 W. The architecture of the processor is based on the COordinate Rotation DIgital Computer (CORDIC) algorithm, which avoids the use of conventional multiplication-and-accumulation (MAC) units, but evaluates the trigonometric functions using only add and shift operations, Improvements to the basic CORDIC architecture are introduced in order to reduce the area and power of the processor. This together with the use of pipelining and carry save adders produces a very regular and fast processor, The CORDIC units were fabricated and tested in order to anticipate the final performance of the processor. This work also demonstrates the maturity of GaAs technology for implementing ultrahigh-performance signal processors.

A high-performance CMOS redundant binary multiplication-and-accumulation (MAC) unit

This paper describes the design of a pipelined CMOS 16/spl times/16 redundant binary multiplication-and-accumulation (MAC) unit. The MAC unit uses a novel coding scheme for representing binary signed digits. The coding, integrated with the modified Booth algorithm, produces a factor of four reduction in the number of summands feeding the adder tree without preprocessing. The consequent chip layout is compact and small. Furthermore, the MAC's pipeline stages are balanced, resulting in a clock rate exceeding 200 MHz with 0.8-/spl mu/m two-level metal CMOS technology.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A 32/24 bit digital audio signal processor

A digital signal processor of novel architecture developed for high-performance audio applications and realizing a new level of parallelism and dynamic range is presented. The chip, featuring 32-b*24-b multiplier/accumulator and 80-ns cycle time, is fabricated using 1.2- mu m CMOS double-level metal technology. The performance of audio signal processing is efficiently increased by parallel operation of (calculations and data transfers) and by the configuration of the arithmetic logic unit and the MAC (multiplier and accumulator). The MAC gives sufficient dynamic range for high-precision audio signal processing. Two 24*256 words of data RAMs enable users to execute over 500 taps of FIR (finite impulse response) filtering with one processor. The cascade configuration of the processors enables users to execute very long taps of FIR filtering. >