SpeedandAccuracy

The speed and accuracy of a power meter calibration vary depending on the test setup and the measurement parameters. For example, number of points, number of readings, if the power is less than -20 dBm, continuous versus sample and sweep mode. Accuracy is improved if you set the source power such that it is approximately correct at the measurement port. Power meter calibration should then be turned on. With number of readings = 2, very accurate measurements are achieved.

‘lhble 6-7 shows typical sweep speed and power accuracy. The times given apply only to the test setup for continuous correction or for the first sweep of sample-and-sweep correction.

The typical values given in l’hble 6-7 were derived under the following conditions:

‘I&t Equipment Used

a HP 8753E network analyzer

nHP 436A power meter

nHP 8485A power sensor

Stimulus Parameters

The time required to perform a power meter calibration depends on the source power and number of points tested. The parameters used to derive the typical values in ‘lhble 6-7 are as follows:

m number of points: 51, 300kHz to 3 GHz

ntest port power: equal to calibration power

‘able 6-7.

Characteristic Power Meter Calibration Sweep Speed and Accuracy

 

Power Desired

Number of Beadings

Sweep Time

Characteristic

 

at lkst Port (dBm)

 

 

(secomls)l

Accuracy (dB)2

 

 

1

 

33

 

f0.7

 

 

 

 

 

+6

2

1

04

I

f0.2

 

 

 

 

 

I

I

3

I

96

1

fO.l

 

 

1

 

43

 

0.7

 

-16

2

 

92

 

f0.2

 

 

3

 

123

 

fO.l

 

 

 

 

 

 

 

 

 

1

 

194

 

f0.7

 

-30

2

 

360

 

f0.2

 

 

3

 

447

 

fO.l

 

 

 

 

 

 

 

1 Sweep speed applies to every sweep in continuous correction mode, and to the fkst sweep in sample-and-sweep made. subsequent sweeps in sample-and-sweep mode will be much faster.

2 The atxunwy values were derived by combining the accuracy of the power meter and lineariw of the analyzer’s internal source, as well as the mismatch uncertainty associated with the power sensor.

6-106 Application and Operation Concepts

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Image 387
HP 8753E manual SpeedandAccuracy, Number of Beadings Sweep Time Characteristic