Specifications
The VCO Tuning Constant
Introduction
The VCO Tuning Constant is the frequency sensitivity of the VCO source
to voltage changes at its control voltage input. This constant is measured
in Hz/V. The HP 3048A uses the VCO Tuning Constant along with the
defined Voltage Tuning Range and the VCO's Tuning Port Input Resistance
to determine the Peak Tuning Range for the measurement. The Bandwidth
of the Phase Lock Loop, the Lock Capture Range, and the Drift Tracking
Range for the measurement are all derived from the Peak Tuning Range.
Three calibration methods are available for determining the VCO Tuning
Constant for the measurement; Measure the VCO Tuning Constant, Use
the Current Tuning Constant, and Compute from the expected Tuning
Constant. The system uses the method displayed in inverse video on the
softkey. The
Tuning Const
computer screen. To change the method, press the
following table lists tuning characteristics of various VCO source options.
VCO Source
HP 8E62/3A
EFC
DCFM
HP 8642A/B
HP 8640B
HP BS56B
Other Signal Generator
DCFM Calibrated
for ±1V
10 MHz Source A
Direct
Multiplied
As a Timebase:
To HP 8662/3A
To other synthesized
signal generators
10 MHz Source B
Direct
Multiplied
As a Timebase:
To HP 8662/3A
To other synthesized
signal generators
350-500 MHz Source
Other User VCO Source
C airier
Freq.
Ilr,
I'll
I'.-l
i-'tJ
Tuning
Constant
(Hz/V)
5
E
- 9 x t!„
FM Deviation
FM Deviation
FM Deviation
FM Deviation
FM Deviation
10
1
E
- 6 x v
0
1 E 6 x i;„
1 E - 6 X T>„
100
10
E
- 6 x
v,-,
10
E
- 6 x v
0
10
E
- 6 X v
0
12E + 6
Estimated
within a
factor of 2
Center
Voltage
(V)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-10
to
+10
Voltage
Tuning
Range (±V)
10
10
10
10
10
10
10
10
10E + 9
-7-
v.,,
1 E-i- 6 x PTR" -r- v„
10
10
1
E
-i-
9
-7-
r„ ,
(up
to 2.5V max.)
100 E -r-3 x PTR* -r v„
2
See Graph 8
Input
Resistance
(ohms)
1
E
+ 6
1M8662)
600 (8663)
600
600
600
Rm
1 E
+ 6
1 E + 6
1 E + 6
1
E
+ 6
1
E
+ 6
1
E
+ 6
1
E
+ 6
1
E
+ 6
tE + 6
1 E t 6
Tuning
Calibration
Method
Measure
Compute
Compute
Compute
Compute
Compute
Compute
Measure
Measure
Measure
Measure
Limited PTR due to PLL BW limitations
2-50 Calibr Process: $N w/PLL