Fft Analysis Software Specifications (Option 831C-Fft); Fft Analysis Software Specifications (Option 831C-Fft - Larson Davis SoundAdvisor 831C Reference Manual

A.7 FFT Analysis Software Specifications (Option 831C-FFT)
Specifications for FFT analysis are given for the SoundAdvisor 831C with firmware option 831C-FFT installed.
A.7.1 FFT Analysis
A.7.2 FFT Measurement Control
A.7.3 FFT History
A.7.4 Display Spectra
SoundAdvisor Model 831C
Sampling Frequency: Down sampling from 51.2 kHz
Frequency Span: 100 Hz, 200 Hz, 500 Hz, 1 kHz, 5 kHz, 10 kHz, 20 kHz
Lines of Resolution: 400, 800, 1600, 3200, 6400
Weighting: A, C, and Z
FFT Windowing Options: Hanning, Flat Top, Rectangular. All options have 33%
overlap.
Tonality: Selectable according to ISO 1996-2 and ISO/PAS 20065.
High-Pass Filter: the low-frequency cutoff is 1 Hz (-3 dB)
Manual: Start and stop measurements manually by using G4 software, LD Atlas
(for mobile iOS/Android), key press on the 831C, or via an external signal.
Exceedance: Measurements can also be started by an exceedance on one of three
configurable, time-based, broadband trigger sources.
Logic Input: Measurements can also be started by configuring the Logic-In port to
Run/Stop by using the included I/O interface cable (CBL170).
This setting enables measurement history records for any of the following
available run modes:
Manual Run/Stop: Measurements run and stop manual from any of the input
methods.
Count Stop: Measurements run for a given number of spectra up to 99,999
averages per FFT History. Repeatable up to 99,999 times.
Timed Stop: Measurements run for a certain amount of time per FFT History.
Repeatable up to 99,999 times.
Continuous: Measurements run continuously until a manual stop or until the
battery cannot power the meter. Data automatically stores in the selected
interval. Numerous intervals range from 1 minute to 24 hours.
Single Block Timer: Measurement is set to automatically start and end at the
selected time (Max: up to 10 years in the future).
Daily Timer: Daily measurements automatically start and stop and selected
times, including up to 3 daily selected blocks.
Latest (Live), Linear Average, and Maximum Spectra
X-axis display: Full frequency range, with the ability to zoom to 1:1 line to pixel
ratio (with 215 lines possible) in Hz or CPM.
Y-axis display: Linear, or Logarithmic with a user-selectable scale feature
(selectable from -60 dB to 340 dB).
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