Atec Agilent-E8364A - Manual (Page 19)

19
Group delay 1
Description Specification Supplemental information
Aperture (selectable) (frequency span)/(number of points – 1)
Maximum aperture 20% of frequency span
Range 0.5 x (1/minimum aperture)
Maximum delay Limited to measuring no more than 180° of
phase change within the minimum aperture.
The following graph shows characteristic group delay accuracy with type-N full 2-port calibration and a
10-Hz IF bandwidth. Insertion loss is assumed to be less than 2 dB and electrical length to be 10 m.
In general, the following formula can be used to determine the accuracy, in seconds, of a specific group
delay measurement:
±Phase accuracy (deg)/[360 x Aperture (Hz)]
Depending on the aperture and device length, the phase accuracy used is either incremental phase
accuracy or worse case phase accuracy.
1. Group delay is computed by measuring the phase
change within a specified frequency step (determined
by the frequency span and the number of points per
sweep).
Group delay (typical)
0.001
0.01
0.1
1
10
100
0.01 0.1 1 10 100
Aperture (MHz)
Accuracy (nsec)
E8362/3/4A
Frequency = 1 GHz
S11 = 0; S21 = 1; S12 = 0; S22 = 0
IF bandwidth = 10 Hz; Average factor = 1
Cal power = -12 dBm; Meas power = -12 dBm; Electrical length = 10 m