Using A Signal Generator; Tuning Requirements - Agilent Technologies E5500A User Manual

Using a Signal
Generator

Tuning Requirements

Table 6-1
Carrier
VCO Source
Agilent/HP 8662/3A
EFC
DCFM
Agilent/HP 8642A/B
Agilent/HP 8644B
Other Signal
Generator
DCFM Calibrated for
±1V
Other User VCO
Source
When using a signal generator as a reference source, it is important that the
generator's noise characteristics are adequate for measuring your device.
Often the reference source you select will also serve as the VCO source for
the PLL measurement. (The VCO source can be either the unit-under-test
(UUT) or the reference source.) To configure a PLL measurement, you will
need to know the following tuning information about the VCO source you
are using:
•
Tuning Constant (Hz/V) (within a factor of 2)
•
Tuning Voltage Range (V)
•
Center Voltage of Tuning Range (V)
•
Input Resistance of Tuning Port (ohms)
The primary consideration when evaluating a potential VCO source for your
measurement is whether it will provide the test system with sufficient
capture and drift tracking ranges to maintain lock throughout the
measurement. To make this determination, you must estimate what the drift
range of the sources you are using will be over the measurement period
(thirty minutes maximum). (Details on the relationship between the capture
and drift tracking ranges and the tuning range of the VCO source are
provided in Table
source based on the estimated drift of your sources.)
Table 6-1 lists the tuning parameters for several VCO options.
Tuning Characteristics of Various VCO Source Options
Tuning Constant
Freq. (Hz/V)
υ 5 E – 9 x υ
0 0
FM Deviation
FM Deviation
FM Deviation
FM Deviation
Estimated within a
factor of 2
Agilent Technologies E5500 Phase Noise Measurement System 6-9
Absolute Measurement Fundamentals
6-1. This information will help you evaluate your VCO
Center
Voltage Tuning
Voltage
±
Range ( V)
(V)
0 10
0 10
0 10
0 10
0 10
–10 to See Figure 6-7 on
+10 page 6-10
Selecting a Reference
Input Tuning
Resistance Calibration
Ω)
( Method
1E + 6 Measure
1 k (8662) Calculate
600 (8663) Calculate
600 Calculate
600 Calculate
R Calculate
in
1 E + 6 Measure