  Air-shower radio arrays operate in low signal-to-noise ratio conditions,
which complicates the autonomous measurement of air-shower signals without
using an external trigger from optical or scintillator detectors. A simple
threshold trigger for radio detector can be efficiently applied onlyin
radio-quiet conditions, because for other cases this trigger detects a high
fraction of noise pulses. In the present work, we study aspects of independent
air-shower detection by dense antenna clusters with a complex real-time trigger
system. For choosing the optimal procedures for the real-time analysis, we
study the dependence between trigger efficiency, count rate, detector hardware
and geometry. For this study, we develop a framework for testing various
methods of signal detection and noise filtration for arrays with various
specifications and the hardware implementation of these methods based on field
programmable gate arrays. The framework provides flexible settings for the
management of station-level and cluster-level steps of detecting the signal,
optimized for the hardware implementation for real-time processing. It includes
data-processing tools for the initialconfiguration and tests on pre-recorded
data, tools for configuring the trigger architecture andtools for preliminary
estimates of the trigger efficiency at given thresholds of cosmic-ray energyand
air-shower pulse amplitude. We show examples of the trigger pipeline developed
with this framework and discuss the results of tests on simulated data.

Instrumentation and Methods for Astrophysics