Rion VA-12 User Manual

72
Measurement in FFT Mode
Frequency resolution ( f) and frame time (T
Frame
)
The frame time duration is determined by the number of analysis lines and
the frequency span. The values are shown in the table below.
Number of
analysis
lines
Frequency
span
200
lines 400 lines 800 lines 1600 lines 3200 lines
T
Frame
(sec)
f
(Hz)
T
Frame
(sec)
f
(Hz)
T
Frame
(sec)
f
(Hz)
T
Frame
(sec)
f
(Hz)
T
Frame
(sec)
f
(Hz)
100 Hz 2.00 0.5 4.00 0.25 8.00 0.125 16.00 0.0625 32.00 0.03125
200 Hz 1.00 1.0 2.00 0.50 4.00 0.250 8.00 0.1250 16.00 0.06250
500 Hz 0.40 2.5 0.80 1.25 1.60 0.625 3.20 0.3125 6.40 0.15625
1 kHz 0.20 5.0 0.40 2.50 0.80 1.250 1.60 0.6250 3.20 0.31250
2 kHz 0.10 10.0 0.20 5.00 0.40 2.500 0.80 1.2500 1.60 0.62500
5 kHz 0.04 25.0 0.08 12.50 0.16 6.250 0.32 3.1250 0.64 1.56250
10 kHz 0.02 50.0 0.04 25.00 0.08 12.500 0.16 6.2500 0.32 3.12500
20 kHz 0.01 100.0 0.02 50.00 0.04 25.000 0.08 12.5000 0.16 6.25000
FFT calculation interval: t (sec)
Number of
analysis
lines
Frequency
span
200 lines 400 lines 800 lines 1600 lines 3200 lines
Frame time
ratio
100 Hz 0.25 sec 0.5 sec 1.0 sec 2.0 sec 4.0 sec 1/8
200 Hz 0.125 sec 0.25 sec 0.5 sec 1.0 sec 2.0 sec 1/8
500 Hz 0.1 sec 0.2 sec 0.4 sec 0.8 sec 1.6 sec 1/4
1 kHz 0.1 sec 0.2 sec 0.4 sec 0.8 sec 1.6 sec 1/2
2 kHz 0.1 sec 0.2 sec 0.4 sec 0.8 sec 1.6 sec 1/1
5 kHz 0.04 sec 0.08 sec 0.16 sec 0.32 sec 0.64 sec 1/1
10 kHz 0.02 sec 0.04 sec 0.08 sec 0.16 sec 0.32 sec 1/1
20 kHz 0.01 sec 0.02 sec 0.04 sec 0.08 sec 0.16 sec 1/1
Note 1 The FFT calculation interval is a value speci c to the VA-12.
Note 2 The time required until the  rst FFT processing results is displayed is equal to the
frame time.

Rion VA-12 Specifications

General

Brand	Rion
Model	VA-12
Category	Measuring Instruments
Language	English