Stanford Research Systems / SRS SR780

• DC to 102.4 kHz bandwidth
• 90 dB dynamic range
• Low-distortion synthesized source
• 145 dB dynamic range (swept-sine)
• Real-time octave analysis
• Up to 32 Mbyte memory
• GPIB and RS-232 interfaces

SR780 Dynamic Signal Analyzer

The SR780 Dynamic Signal Analyzer combines high performance and low cost in a full-featured package. It offers 102.4 kHz dual-channel FFTs with 90 dB dynamic range, swept-sine measurements, ANSI standard octave analysis, waterfall displays and transient capture for less than half the cost of other similarly equipped analyzers.

Spectrum Analysis

The SR780 delivers true two-channel, 102.4 kHz FFT performance. Its fast 32-bit floating-point DSP processor gives the SR780 a 102.4 kHz real-time rate with both channels selected. Two precision 16-bit ADCs provide a 90 dB dynamic range in FFT mode. Selectable 100 to 800 line analysis optimizes time and frequency resolution, and you can zoom in on any portion of the 102.4 kHz range with a frequency span down to 191 mHz.

Narrow Band FFT (top), Wide Band FFT (bottom)

The SR780’s unique architecture lets the two displays function independently. You can choose separate frequency spans, starting frequencies, number of FFT lines, or averaging modes for each display. So it’s easy look at a wideband display and zoom in on a specific feature simultaneously. The SR780 lets you select from two sampling rates: 256 kHz or 262 kHz, so frequency spans come out in either a binary (102.4 kHz, 51.2 kHz,...) or decimal (100 kHz, 50 kHz, 25 kHz,...) sequence depending on your requirements.

Flexible Averaging

Several averaging choices are provided. RMS averaging reduces signal fluctuations, while vector averaging minimizes noise from synchronous signals. You can choose linear averaging (stable averaging) for fixed signals, or exponential averaging to track drifting features. Because the SR780’s 102.4 kHz real-time bandwidth lets it take data seamlessly, vector averaging can be selected for any signal that’s repetitive within the time record—no trigger is necessary.

Transducer Units

Automatic unit conversion makes translating accelerometer data easy. You can enter accelerometer conversions directly in V/EU, EU/V or dB (1 V/EU). The SR780 will display results in units of meters, inches, mil, g, kg, lbs., N, dynes, pascals, bars, or dBSPL. Accelerometer data is automatically converted to velocity or displacement units. Built-in ICP power means you won’t need an external power supply for your accelerometer.

Octave Analysis

Octave Analysis

Real-time octave analysis at frequencies up to 40 kHz (single channel) or 20 kHz (two-channel), is standard in the SR780. Octave analysis is fully compliant with ANSI and IEC standards. Full octave, 1/3 octave and 1/12 octave analysis are all available. Switchable analog A-weighting filters as well as built-in user math weighting functions (A,B and C) are included. Octave averaging choices include exponential time averaging, linear time averaging, peak hold, and equal confidence averaging. IEC compliant peak hold, impulse, fast and slow sound level measurements are all calculated.

Swept Sine Bode Plot

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