Atec Agilent-35670A - Manual (Page 5)

5
Full span FFT noise floor (typical)
Flat top window, 64 RMS averages, 800 line display.
Harmonic distortion <-80 dBfs
Single Tone (in band), ≤ 0 dBfs
Intermodulation distortion
<-80 dBfs
Two tones (in-band), each ≤ -6.02 dBfs
Spurious and residual responses
<-80 dBfs
Source impedence = 50 Ω.
Frequency alias responses
Single tone (out of displayed range),
≤ 0 dBfs, ≤ 1 MHz
(≤ 200 kHz with IEPE transducer power
supply On)
2.5% to 97.5% of the frequency span
<-80 dBfs
Lower and upper 2.5% of frequency span <-65 dBfs
Input noise
Input noise level
Flat top window, -51 dBVrms range
Source impedance = 50 Ω
Above 1280 Hz <-140 dBVrms/√
2 Hz
160 Hz to 1280 Hz <-130 dBVrms/√ 2 Hz
Note: To calculate noise as dB below full scale:
Noise [dBfs] = Noise [dB/√
2 Hz] + 10LOG(NBW) - Range
[dBVrms]; where NBW is the noise equivalent BW of the
window (see below).
Window parameters Uniform Hann Flat top
-3 dB bandwidth* 0.125% of span 0.185% of span 0.450% of span
Noise equivalent bandwidth* 0.125% of span 0.1875% of span 0.4775% of span
Attenuation at ±½ bin 4.0 dB 1.5 dB 0.01 dB
Shape factor
(-60 dB BW/-3 dB BW) 716 9.1 2.6
* For 800 line displays. With 1600, 400, 200, or 100 line displays, multiply bandwidths by 0.5, 2, 4, and 8, respectively.
dB below
full scale
Typical noise floor vs. range for different frequency spans
-51 -41 -31 -21 -11 27
0.0028 0.0089 0.028 0.089 0.280 22.4
-100 dB/0.001%
Amplitude range (dBVrms / Vrms)
-90 dB/0.003%
-80 dB/0.01%
-70 dB/0.03%
51.2 kHz Span
6.4 kHz Span
800 Hz Span