Agilent Technologies HP 8642A/B Specifiche Scaricare il pdf (Pagina 405)

Table 8-1. Numbered Error Messages (9 of 17)

Measured beatnotes depict non-linear VCO Tuning Constant. (Error 7 only occurs

when the HP 3048A has been configured to Measure the VCO Tuniitg Constant.)

The values shown on the display represent the measured beatnote frequencies for four

tune voltage settings. The tune voltage settings are each derived as a percentage of the

entered Voltage Tuning Range of the VCO (-45%, -15%, +15%, +45%) relative to the

entered Center Voltage of the VCO Tuning Curve. For Example:

Voltage Tuning Range of VCO = +10V

Center Voltage of VCO Tuning Curve — OV

Tune Voltage Settings = -4.5V, -1.5V, +1.5V, +4.5V.

Refer to Instrument Parameters in Chapter 2, Measurement Definitions for system

requirements for VCO linearity.

Note that between the four measured frequency values shown on the display, three

frequency range intervals are created. (For example, the measured values 95 Hz, 98.2 Hz,

101.2 Hz, 105 Hz produce the following intervals: Interval 1 - 3.2 Hz, Interval 2 = 3 Hz

and Interval 3 = 3.8 Hz.)

Action:

This error will occur if a Tuning Voltage Range of ±10 volts has been defined for

a source with calibrated DC FM, and the HP 3048A is configured to Measure the

VCO Tuning Constant rather than to Compute it. Refer to "Enhanced Tuning" in the

Instrument Parameters section of Chapter 2, Measurement Definitions for details on

extending the Tuning Voltage Range of calibrated DC FM.

If Interval 2 (described above) >> 1, and Interval 2 >> 3,

then:

Reduce the value entered for the Voltage Tuning Range of the VCO and then initiate

a New Measurement.

3. If there appears to be too little or no change between the measured frequency

val-

ues (Intervals 1, 2, and 3^0) then :

• Check the Tune Voltage cable connections.

• Verify that the VCO's tuning is enabled.

• Perform the Estimating the Tuning Constant procedure provided in Chapter 3

of the Operating Manual to verify the tuning response of the VCO and check that

the entered VCO Tuning Constant is within a factor of 2 of the actual value.

• Refer to Instrument Parameters in Chapter 2, Measurement Definitions for

Tuning Constant linearity requirements.

• Verify that the beatnote is tuned to within the Capture Range for the

measurement.

8-10 Numbered Error Messages

1 2 ... 400 401 402 403 404 405 406 407 408 409 410 ... 452 453

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Agilent Technologies HP 8642A/B Specifiche Pagina 405