Specifications

Consideration for the VCO Tuning Constant
The VCO's tuning curve must be within the parameters shown in the
following graph.
-45%
FREQUENCY
CHANGE of VCO
■15% f r
Frequency Scole is dependent
on the tuning constant of VCO.
+ 15%
J
DRIFT TRACKING RANGE
1.5f-
1
+ 45%
% of TUNE
VOLTAGE
Figure 2-15. VCO Tuning Response Linearity Requirements of the HP 3048A
When the VCO Tuning Linearity does not meet the requirements of
Figure 2-15, an ERROR message is generated to inform you that the system
cannot continue. If this happens, you must do one of the following:
• Inspect the 4 points to determine the source of the non-linearity
(disconnected tune line, drift, wrong DC FM sensitivity, wrong voltage
tune range).
• Restrict the Tuning Range to a portion of the Tuning Curve which is
linear.
• Replace the VCO with one having a linear Tuning Constant, or
• Instruct the system not to measure the Tuning Constant.
rev.05SEP89
Calibr Process: $N w/PLL 2-53