Atec Agilent-E8361A - Manual (Page 42)

E8361A
Test port input
continued
Group delay
1
Description Specification Supplemental information (typical)
Aperture (selectable) (frequency span)/(number of points – 1)
Maximum aperture 0% 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.
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).
The following graph shows characteristic group
delay accuracy with type-N full 2-port calibra-
tion 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)/[60 x Aperture (Hz)]
Depending on the aperture and device length, the
phase accuracy used is either incremental phase
accuracy or worse case phase accuracy.
Group delay (typical)
0.001
0.01
0.1
1
10
100
0.01 0.1 1 10 100
Aperture (MHz)
Accuracy (nsec)
E861A fully optioned, full two port calibration using 85058B (Exp Math)
Frequency = 1 GHz
S11 = 0; S1 = 1; S1 = 0; S = 0
IF Bandwidth = 10 Hz; Average factor = 1
Cal power = -15 dBm; Meas power = -15 dBm; electrical length = 10 m