Efficient FPGA-based FIR – architecture and its significance in ultrasonic signal processing

The presented work demonstrates the most suitable architecture for the FPGA-based signal processing which makes available various real-time filtering algorithms, such as band pass, high pass, low pass, and band-reject for FIR filters. The processor was implemented with the fixed-point arithmetic using VHDL, which can be downloadable on FPGA device. The FPGA device can be interfaced with an analog-to-digital converter (ADC), digital-to-analog converter (DAC) and a personal computer with MATLAB for the user interface and feeding coefficients and order of the filter. The core part of this paper was to find the reconfigurable and efficient architecture of the processor with only one multiplier which can work for Finite Impulse response (FIR) filter with the best- suited structure. The system will be used for automatic generation of fixed-point FIR filters. The model was also implemented in MATLAB script and the verification of results in the case of low-pass filtering confirmed that both models in MATLAB and VHDL matched to each other. All components of architecture in VHDL were designed using generics which allow changing its structure and behavior by generic values. Therefore, it is a universal filter platform where user can process the data while changing the filter parameters as per the requirement of applications. The complete design was verified by taking the example of audio signal frequency, but parameterized components of system architecture can also facilitate its applicability at ultrasonic frequencies by changing the algorithm. The significance and applicability of FPGAs in ultrasonic signal processing were also studied and reviewed

Application-Specific FPGA using heterogeneous logic blocks

International audienceThis work presents a new automatic mechanism to explore the solution space between Field Programmable Gate Arrays (FPGAs) and Application-Specific Integrated Circuits (ASICs). This new solution is termed as an Application-Specific Inflexible FPGA (ASIF) [Parvez et al. 2009]. An ASIF can be considered as an FPGA with reduced flexibility, or as a reconfigurable ASIC that can implement a set of application circuits which will operate at mutually exclusive times. Execution of different application circuits can be switched by loading their respective bitstream on an ASIF. An ASIF that is reduced from a heterogeneous FPGA is termed as a heterogeneous ASIF. It is shown that a standard-cell-based heterogeneous ASIF for a set of 10 opencore application circuits is 9.6 times smaller than a single-driver mesh-based heterogeneous FPGA. The area gap between ASIC and ASIF is not too significant; however, it can be reduced by designing repeatedly used components of ASIF in full-custom. Unlike an ASIC, an ASIF is a reprogrammable device that can be used to reprogram new or modified circuits at a limited scale

Application Specific FPGA Using Heterogeneous Logic Blocks

International audienceAn Application Specific Inflexible FPGA (ASIF) [12] is an FPGA with reduced flexibility that can implement a set of application circuits which will operate at different times. Application circuits are efficiently placed and routed on an FPGA in such a way that total routing switches used in the FPGA architecture are minimized. Later all unused routing resources are removed from the FPGA to generate an ASIF. An ASIF which is reduced from a heterogeneous FPGA (i.e. containing hard-blocks such as Multipliers, Adders and RAMS etc) is called as a Heterogeneous-ASIF. This work shows that a standard-cell based Heterogeneous-ASIF using Multipliers, Adders and Look-Up-Tables for a set of 10 opencores application circuits is 85% smaller in area than a single driver FPGA using the same blocks, and only 24% larger than the sum of areas of their standard-cell based ASIC version. If the Look-Up-Tables are replaced with a set of repeatedly used hard logic gates (such as AND gate, OR gate, flip-flops etc), the ASIF becomes 89% smaller than the Look-Up-Table based FPGA and 3% smaller than the sum of ASICs. The area gap between ASIF and sum of ASICs can be further reduced if repeatedly used groups of standard-cell logic gates in an ASIF are designed in full-custom. One of the major advantages of an ASIF is that just like an FPGA, an ASIF can also be reprogrammed to execute new or modified circuits, but at a very limited scale. A new CAD flow is presented to map application circuits on an ASIF