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VECTOR NETWORK ANALYZER
FUNDAMENTALS
WHAT ISA
VECTORNETWORK ANALYZER
?
SCALAR NETWORK ANALYZER
MICROWAVESIGNAL
MICROWAVEDETECTOR
DETECTOROUTPUT
VOLTAGE
DETECTOR OUTPUT VOLTAGE ISPROPORTIONAL TO SIGNAL AMPLITUDE.
VECTOR NETWORK ANALYZER
A VECTOR NETWORK ANALYZER IS A TUNED RECEIVER
MICROWAVESIGNAL
INTERMEDIATEFREQUENCY (IF)
TUNABLELOCALOSCILLATOR
GREATER DYNAMIC RANGELESS SENSITIVITY TO INTERFERING SIGNALS
VECTOR NETWORK ANALYZER
SOURCE
TEST SET/RECEIVER
DIGITAL SECTION
PHASE CAPABILITYMAKE POSSIBLE:
• Phase measurements• Smith chart• Time Domain• Group delay• Vector error correction
RECEIVER TECHNOLOGY
• Frequency conversion• Magnitude and Phase
Measurements• Wide dynamic range• Harmonic rejection• Low noise
VECTOR NETWORK ANALYZER
SPLITTER
MICROWAVESOURCE
DUT
SYNC.DET.
L. O.
SYNC.DET.
TAN-1 I/R
TAN-1 I/R
R2 + I2
R2 + I2
RE
IM
IM
RE
MAG.
TEST CHANNEL
PHASE
REFERENCECHANNEL
PHASE
MAG.
BASIC SYSTEM
SOURCE LOCK
MICROWAVESOURCE
1STLO.
ERRORAMP
PHASEDET.
1STI.F.
2NDLO.
2NDI.F.
3RDLO.
3RDI.F.
XTALREF
I.F. AND M'WAVE SOURCE PHASE LOCKEDTO CRYSTAL REFERENCE
SOURCE BECOMES SYNTHESIZED
FREQUENCY ACCURACYVERSUS
RESOLUTION
TEST SET
0-40SDM
P2 BIAS
P2P1
P1 BIAS
RA
TA
0-70
R F R F
RB
TB
RF IN
b1 In a1 In
FOUR CHANNELS
HARMONICGENERATOR
POWERAMP
CHANNELS
TB
TA
RA
RB
1ST IF89MHz
2ND IF2.5MHz
3RD IF80KHz IF OUTPUTS
TB
TA, RA
RA, RB
3RD LO
SOURCELOCK
2ND LOPHASE LOCK
1ST LOPHASE LOCK
FREQUENCY CONVERSIONEACH CHANNEL
A TRIPLE CONVERSION RECEIVER
MAGNITUDE & PHASE INFORMATION PRESERVEDTHROUGH LINEAR FREQUENCY CONVERSION
MICROWAVESOURCE
1STLO.
1STI.F.
2NDLO.
2NDI.F.
3RDLO.
3RDI.F. SYNC.
DET.DUT
DIGITAL SECTION
• Mathematical Operations• Human Interface• Display information• Data I/O
BASIC MEASUREMENT PRINCIPLES
INCIDENTENERGY
REFLECTEDENERGY
TRANSMITTEDENERGY
REFLECTION COEFFICIENT=
TRANSMISSION COEFFICIENT=
DUT
REFLECTED ENERGYINCIDENT ENERGY
TRANSMITTED ENERGY
INCIDENT ENERGY
S-PARAMETERS
S12 REVERSE TRANSMISSION
PORT 1 PORT 2
S11 FORWARDREFLECTION
S22 REVERSEREFLECTION
S21 FORWARD TRANSMISSION
DUT
PHASE MEASUREMENT
REFERENCE PLANE
• Defined at the test port measurement plane
Magnitude = 0 dBPhase = 0 degrees
• Established during calibration
ELECTRICAL DELAY
+180
+90
0
-90
-180
1.1 1.2 1.3 1.4 FREQUENCY,GHz
MEA
SUR
ED P
HA
SE
PATH LENGTH COMPENSATION
01.1
1.2
1.3 1.4FREQUENCY,GHz
+2
+1
-1
-2
RES
ULT
AN
T PH
ASE
DISPLAY PARAMETERS
• Magnitude(Log Magnitude, dB)
• Phase(Linear Phase, degrees)
POLAR DISPLAY
-90
180
90
0
SMITH CHART
50
INDUCTIVE
CAPACITIVE
Ω
FOUR CHANNEL DISPLAY
• Independent channels• Up to 8 traces• S-parameters• User-definable parameters
CAN CORRECT FOR THE FOLLOWING SIX ERROR SIGNALS IN BOTH THE FORWARD AND
REVERSE DIRECTION
• Transmission Frequency Response• Reflection Frequency Response• Directivity• Source Match• Load Match• Isolation between ports
THIS ADDS UP TO 12 TERMS
VECTOR ERROR CORRECTION
MAGNITUDE AND PHASE OFEACH ERROR SIGNAL IS DERIVED
THE RESULTANT ERROR VECTOR IS REMOVEDMATHEMATICALLY, HENCE 12-TERM ERRORCORRECTION
MAG
PHASE