Agilent Technologies HP 8642A/B Specifiche Scaricare il pdf (Pagina 117)

insufficient power at the

input port on the HP 11848A can cause excessive

conversion loss through the phase detector. In addition, the beatnote

may be compressed causing an incorrect calibration of the Phase Detector

Constant.

The input level at the R input port of the HP 11848A determines the

system's sensitivity. Amplification of the input signal to the R port will

increase the Phase Detector Constant thereby decreasing the system's

noise floor.

The Phase Detector Constant cannot be measured if the system cannot

generate a beatnote of less than 50 kHz (20 MHz for systems with an

RF Analyzer), or if the sources are injection locking. Also, the system

cannot measure the Phase Detector Constant if the beatnote deviates too

much from a sine wave, or is excessively noisy. In these cases, you may

need to enter the Phase Detector Constant using a power level estimate

or from examination of the beatnote.

If the beatnote is less than 1 kHz, and the system cannot locate three

zero-crossings within the time record of the HP 3561A Dynamic Signal

Analyzer, the system cannot measure the Phase Detector Constant. In

this case, you should abort the measurement, verify all of the entered

parameters and initiate a New Measurement.

The recommended range for the Phase Detector Constant when making

a phase lock loop measurement using the 5 MHz to 1.6 GHz Phase

Detector is 20 mV to IV. The recommended range when making a phase

lock loop measurement using the 1.2 GHz to 18 GHz Phase Detector is

100 mV to 0.3V. Detector Constants down to 20 mV may work but, proper

operation may be inhibited by dc offsets up to 50 mV.

Adequate isolation must be provided to insure that the injection locking

range is much less than the Phase Lock Loop Bandwidth. Injection Locking

removes or distorts the beatnote from which the Phase Detector Constant

is measured.

2-48 Calibr Process: $N w/PLL

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Agilent Technologies HP 8642A/B Specifiche Pagina 117