HP 54710A User's Reference Manual page 268

Flattop Use for amplitude accuracy.
Window Characteristics The window characteristics are shown below.
Window
Rectangular
Hanning
Flattop
Highest Side Lobe The minimum attenuation in the stop band. It indicates the level
of leakage present in the filter; that is, how high the skirts are in relation to the main
peak.
3 dB bandwidth The width of the peak at a level 3 dB down. A narrow 3 dB
bandwidth helps in separating frequency peaks that are close together.
6 dB Bandwidth The width of the peak at a level 6 dB down.
Bins The distance between frequency points. One bin equals the resolution.
Scallop Loss The attenuation of the peak half way between bins. The scallop loss
determines the amplitude accuracy of a window. It measures the attenuation of a
signal that falls between frequency bins versus one that is exactly on a frequency bin.
FFT Measurements
FFT Freq Frequency of a peak
FFT Mag Magnitude of a peak
FFT ∆Freq ∆ Magnitude between peaks
FFT ∆Frequency between peaks
∆Mag
TMax Frequency at maximum point
FFT Update Time
Points Update Time
64 10 ms
128 15 ms
256 20 ms
512 35 ms
1024 70 ms
The update time includes acquisition, window calculation, FFT calculation,
and the display of the FFT. The conditions are: 125 MHz span, real time,
triggered mode, channels off, measurements and markers off, other functions
off, and interpolation off.
Highest 3 dB
Side Lobe Bandwidth
(dB) (bins)
−13 0.89
−32 1.44
−70
3.38
TMin Frequency at minimum point
VMax Maximum amplitude
VMin Minimum amplitude
Vp-p ∆ Magnitude, Max–Min
Vtim Magnitude at a frequency (HP-IB only)
Points Update Time
2048 140 ms
4096 290 ms
8192 600 ms
16384 1.25 s
32768 2.60 s
Specifications and Characteristics
Characteristics
6 dB Scallop
Bandwidth Loss
(bins) (dB)
1.21 3.92
2.00 1.42
4.17 0.005
16–7