HP 8920A, User Manual

Page: 579 / 658

579
Chapter 24, Connector, Key, and Knob Descriptions
Connector Descriptions
10 MHz REF INPUT
This connection allows you to input an external reference.
Operating Considerations
Input frequency = 1, 2, 5, or 10 MHz
Input level >0.15 V rms
Input impedance approximately 50
Ω
.
When a valid signal is applied to the 10 MHz REF INPUT, the Test Set
automatically switches from internal to external reference.
This signal is used as a reference for, and directly affects, these functions:
RF Generator Frequency (including the Tracking Generator)
RF Frequency Counter
AF Frequency Counter
RF Analyzer Tune Frequency
Spectrum Analyzer Center Frequency
AF Generators 1 and 2, and the decoder’s frequency counter, are not affected
using an external reference; they use their own reference.
NOTE: The reference output frequency is always 10 MHz, independent of the selected input reference
frequency.
Electrostatic discharges to the 10 MHz REF INPUT port of 0.5 kV or above may
cause degradation of performance requiring operator intervention.
10 MHz REF OUTPUT
This connector furnishes a 10 MHz reference for external instruments.
Operating Considerations
Waveform = sinewave
Output frequency = 10 MHz
Output level >0.5 V rms
Output impedance approximately 50
Ω
.
NOTE: The reference output frequency is always 10 MHz, independent of the selected input reference
frequency.