NF FRA5014, Instruction Manual

Page: 17 / 107

1.4 Operation Principles
FRA5014 1-5
1.4 Operation Principles
The
FRA5014
uses a built-in oscillator to provide a sine wave test signal V
0
to the system under test,
then measures the following in the vector ratios V
2
/ V
1
, V
3
/ V
1
, V
4
/ V
1
(i.e., frequencies) of the
response signals V
1
, V
2
, V
3
, and V
4
Gain G = | V
2
/ V
1
|, | V
3
/ V
1
|, | V
4
/ V
1
|
Phase differential P =

V
2
− 
V
1
,

V
3
− 
V
1
,

V
4
− 
V
1
A block diagram of the
FRA5014
’s operations is shown below.
Figure 1-1. Block Diagram
•
Main Processor
The main processor controls the oscillator or analyzer based on the user’s actions, calculates the
ratios of signal vectors obtained by the analyzer, and outputs the data. Employing a quartz
resonator as its reference clock, the main processor uses the direct digital frequency synthesis
method to generate digital sine wave signals (Sin, Cos) with precise frequencies for use by the
oscillator or analyzer.
V
4
GPIB
USB
Isolator Isolator
RS-232
V
0
V
1
V
4
Main Processor
Panel
DIP SW & Lamp
Isolator
System Under Test
Signal vector
Analyzer CH4
Sub Processor
Signal
Conditioner
A/D
Sin
Cos


Analyzer CH1
Sub Processor
Signal
Conditioner
A/D
Sin
Cos


Oscillator
DC Bias
D/A
Amplitude
V
0
V
1
V
3
V
2