SRS Labs manual SR785 Two Channel Dynamic Signal Analyzer, FFT Spectrum Analysis, Averaging

SR785 Two Channel Dynamic Signal Analyzer

FFT Spectrum Analysis

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. Whether your measurements involve modal analysis, machinery diagnostics, vibration testing, servo systems, control systems, or acoustics, the SR785 has the features and specifications to get the job done. Standard measurement groups include FFT, order tracking, octave, swept-sine, correlation, time capture and time/histogram. The SR785 brings the power of several instruments to your application – a spectrum analyzer, network analyzer, vibration analyzer, octave analyzer and oscilloscope.

A unique measurement architecture allows the SR785 to function as a typical dual channel analyzer with measure- ments like cross spectrum, frequency response, coherence, etc. Alternatively, the instrument can be configured so that each input channel functions as a single channel analyzer with its own span, center frequency, resolution, and averaging.

This allows you to view a wideband spectrum and simultaneously zoom in on spectral details.

The same advanced architecture provides storage of all measurement building blocks and averaging modes. Vector averaged, RMS averaged, unaveraged and peak hold versions of all measurements are simultaneously acquired and can be displayed without re-taking data.

Use the SR785 to monitor the fundamental and harmonics of your signal. Total harmonic power and THD are calculated in real-time for fast, accurate analysis.

Bottom display shows a wideband FFT, while the top display shows a narrowband FFT of the same signal. The sideband marker has been selected for calculation of the total sideband power.

Averaging

The SR785 comes equipped with a wide selection of averaging techniques to improve your signal to noise ratio. Choose RMS averaging to reduce signal fluctuations, vector averaging to actually eliminate noise from synchronous signals, or peak hold averaging. In the order-tracking measurement group, time averaging is available. Both linear and exponential averaging are provided for each mode.

The SR785 is so fast, there's no need for a separate "fast averaging" mode. Averaging is always fast, and the display update rate is never sacrificed to increase the averaging rate. For instance, in a full span FFT measurement with a 4 ms