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Chapter 8 Agilent 53181A Specifications
Measurement Specifications (Continued)
Measurement Specifications (Continued)
Frequency Measurement Example:
Given an Agilent 53181A with a High Stability Oven that was calibrated 3 days ago, measure a 15 MHz square wave signal (which has
negligible trigger error) with a 1 second gate time. Compute the measurement error to within 2-sigma confidence.
=
Measurement Error
Systematic Uncertainty 2
±
=
Time Base Error
=
Number of Samples
200,000 since Frequency is greater than 200kHz and gate time equals 1 second
=
Time Base Error
Temperature Stability
–
9
=
×
2.5
10
–
9
×
=
4.0
10
±
×
=
Measurement Error
4.0
10
=
(
±
×
4.1
10
=
(
±
×
4.1
10
=
±
63.1 mHz
Which is to say that the Agilent 53181A would display results in the range 15 MHz ±63.1 mHz. Note however that the dominant error is the
Time Base Error. If an even higher stability time base is available to the instrument or if the instrument can be source locked to the 15 MHz
signal, then this error term can be substantially reduced. The measurement resolution under these conditions is ±0.8 MHz (1 sigma) which
determines the number of digits displayed.
Assembly-Level Service Guide
±
×
RMS Resolution
t
4
2
±
--------------------------- -
ac c
±
×
------------------------------------------------------------------------------------------- -
Gate Time
Gate Time
×
+
3 Days
Daily Aging Rate
–
10
+
×
(
×
)
3
5
10
–
10
×
×
(
1
10
s
4
500
–
9
±
--------------------------- -
±
×
--------------------------------------------------------------------------------- -
2
1s
1s
–
–
–
9
12
12
±
×
(
×
+
×
2
4.47
10
50
10
–
–
9
10
±
×
)
×
1.09
10
15MHz
2
2
×
(
×
)
+
t
2
Trigger Error
r es
--------------------------- -
+
×
Gate Time
Number of Samples
2
–
–
12
12
×
)
(
×
)
×
+
10
s
2
0
50
10
------------------------------ -
+
×
,
1s
200 000
)
)
×
15MH z
t
jit ter
×
Frequency
s
×
15MHz
8-7
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