SR785 - Spectrum Analyzer FFT The SR785 Two Channel Dynamic Signal Analyzer is a precision, full-featured signal analyzer that offers state-of-the-art performance and a wide selection of features at a price that's less than half that of competitive analyzers. Building on its predecessor, the SR780, the SR785 incorporates new firmware and hardware that make it the ideal instrument for analyzing both mechanical and electrical systems. For measurements involving modal analysis, machinery diagnostics, vibration testing, servo systems, control systems, or acoustics, the SR785 has the features and specifications to get the job done.