An SoC FPAA Based Programmable, Ladder-Filter Based, Linear-Phase Analog Filter

Abstract

This work demonstrates a Continuous-Time (CT) Ladder filter using transconductance amplifiers as an approximate delay stage implemented on a large-scale Field Programmable Analog Array (FPAA) and characterized on an SoC FPAA. We experimentally demonstrate a reprogrammable CT Analog linear-phase filter by utilizing the ladder filter delay element and Vector-Matrix Multiplication (VMM) both compiled on the SoC FPAA. Using the Ladder Filter as a programmable CT delay operation enables a traditionally difficult analog signal operation. This effort extensively models and characterizes the ladder filter delay stage in terms of its transfer function, delay tunability, power requirements, distortion, and SNR. The theoretical development is compared to experimental measurements on an SoC FPAA with programmable ladder filter delay of 2.9μs and 4.2μs for multiple input frequencies (e.g. 5kHz, 20kHz). In addition, we show that VMMs can compensate the non-idealities found in the ladder filter delay-line operation.