FPGA design of a Time-Variant Coefficient Filter

Resumen

Currently, a variety of solutions of Linear Time-Variant Filters (LTV) are reported to apply on Software Defined Radio, Radar and Sensor Networks systems. In contrast to Linear Time-Invariant Filters (LTI), LTV filters exhibit better performance regarding constraints on time domain such as risetime and overshoot parameters. Despite they have been used for a variety of applications, they are unable to reach certain processing speeds.  To achieve the processing of higher data rates binary signals, it is necessary to reduce risetime of output filters, which is accomplished by properly changing the characteristic frequency parameter just on the transient time period. This article is related to the implementation of an LTV digital lowpass filter, to process binary and multilevel signals. The LTV filter represents a novel proposal with considerably shorter risetime. Implementation on a Field-Programmable Gate Array (FPGA) is addressed and discussed by using Xilinx System Generator software on MatLab. Results exhibit proper performance when a lowpass Bessel LTV Filter is considered.