NF FRA5022, Instruction Manual

Page: 17 / 145

1.4 Principle of Operation
FRA5022
1-5
1.4 Principle of Operation
“
FRA5022 Frequency Response Analyzer
” obtains the vector ratio V
2
/V
1
of the response
signal V
1
and V
2
by supplying a sine wave test signal V
0
from its internal oscillator to the
system under test, more specifically, the gain G =
|
V
2
/V
1
|
and phase differential
P =
∠
V
2
- ∠
V
1
at a given frequency. Below are the block diagram and operation outline
of
FRA5022
.
Figure 1-1 Block Diagram
•
Main Processor
According to the user ’ s operation, the main processor controls the oscillator and
analyzer to calculate, output, and display the vector ratio of the signals obtained by the
analyzer. By using the direct digital frequency synthesis method based on the reference
quarts-crystal resonator, the main processor generates accurately pitched digital sine
wave signals (Sin, Cos) to be used by the oscillator or analyzer.
•
Oscillator
The
FRA5022
oscillator converts digital sine signals to analog signals with D/A (Digital
to Analog) converters and filters. It also adds DC bias before output.
Main Processor
LCD
Color Display
Panel
Key & Lamp
GPIB
USB
Isolator Isolator Isolator
System Under Test
V
0
V
1
V
2
Oscillator
DC Bias
D/A
Amplitude
V
0
V
1
V
2
Signal vector
X
Y
Analyzer CH1
Sub Processor
Signal
Conditioner
A/D
Sin
Cos
X
Y
∫
∫
Analyzer CH2
Sub Processor
Signal
Conditioner
A/D
Sin
Cos
X
Y
∫
∫