STL-FG-000020-S1 is a portable, programmable, touchscreen-controlled Function Signal Generator designed and manufactured for standard test instrumentation, communication, and radar systems as a local function signal source. It is a sine/cosine wave generator optimized for driving single-sideband modulators. The generator provides two outputs, in-phase and quadrature (I/Q), with adjustable DC offset, relative phase, and gain. The generator's output spans up to 2.5 MHz, sufficient to simulate a Doppler shift of Mach 10 at 94 GHz. The output amplitude can drive I/Q mixers with an input requirement of ±4 Vp-p at over 20 mA. This instrument integrates an advanced embedded processor, which runs stably and responds quickly. It supports direct touchscreen control via an easy-to-access HMI or remote control via the USB and Ethernet ports from a computer. It can perfectly support Eravant's Radar Target Simulator, and when combined, they can achieve the best testing performance.