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E8361c, Test port input, Group delay – Atec Agilent-E8364C User Manual

Page 42: Group delay (typical)

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42

E8361C

Test port input

continued

Group delay

1

Description

Specification

Supplemental

information (typical)

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.

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)/[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.

Group delay (typical)

0.001

0.01

0.1

1

10

100

0.01

0.1

1

10

100

Aperture (MHz)

Accuracy (nsec)

E8361C fully optioned, full two port calibration using 85058B (Exp Math)

Frequency = 1 GHz

S11 = 0; S21 = 1; S12 = 0; S22 = 0

IF Bandwidth = 10 Hz; Average factor = 1

Cal power = -15 dBm; Meas power = -15 dBm; electrical length = 10 m