In this work, a board based on a Spartan-3 field-programmable gate array was designed as a hardware prototyping platform for development of a multichannel digital gamma spectrometer. The device is compatible with various detectors like high-purity germanium, NaI, and CsI detectors. Before implementing the hardware, the method for digital signal processing for gamma spectroscopy was developed. The aim of this paper is to introduce a robust tool suitable for optimizing the design of complicated systems. The characteristics of this method, such as its ability to implement adaptive shaping, are investigated. The optimum conditions for digital filtering were determined using MATLAB/Simulink. This scheme can be useful for commercial production. Simulation was used to examine each processing unit in the whole signal processing procedure including cusplike shaping. The proposed method can be used as a computer design tool for optimizing digital multichannel analyzers or digital nuclear spectrometers.