IPC-TM-650 EN 2022 试验方法1.pdf - 第477页
Figure 5-3 Determination of M easurement Zone TIME 1,TL 2,TL SPD TRANSFER STANDARD TDR INSTRUMENT TRANSMISSION LINE UNDER TEST MEASUREMENT ZONE for TRANSMISSION LINE UNDER TEST PRECISION RF CABLE IPC-TM-650 Page 9 of 23
Figure 5-1 Determination of instant in the TDR waveform corresponding to the beginning of the transmission line. A is
the amplitude of the signal reflected from the open end of the probe. SPD is the static protection device (see 4.3.5).
PROBE
SPD
TDR
INSTRUMENT
PRECISION
RF CABLE
TRANSFER
STANDARD
TIME
0.5A
R,1
t
1,TL
A
R,1
Figure 5-2 Determination of instant in TDR waveform corresponding to the end of the transmission line. is the
amplitude of the signal reflected from the open end of the transmission line under test.
SPD
TRANSFER
STANDARD
TDR
INSTRUMENT
TRANSMISSION LINE UNDER TEST
0.5
R2
TIME
t
1,TL
t
2,TL
R2
PRECISION
RF CABLE
IPC-TM-650
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Figure 5-3 Determination of Measurement Zone
TIME
1,TL
2,TL
SPD
TRANSFER
STANDARD
TDR
INSTRUMENT
TRANSMISSION LINE UNDER TEST
MEASUREMENT ZONE
for TRANSMISSION LINE UNDER TEST
PRECISION
RF CABLE
IPC-TM-650
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Figure 5-4 Determination of instant in the TDR waveform corresponding to the beginning of the reference line. A is the
amplitude of the signal reflected from the open end of rf cable.
SPD
TDR
INSTRUMENT
PRECISION
RF CABLE
t
1,Ref
TIME
0.5
R.0
R,0
Figure 5-5 Determination of instant in TDR waveform corresponding to the end of the reference line (transfer standard or
air line reference).
is the amplitude of the signal reflected from the open end of the reference line.
SPD
TDR
INSTRUMENT
PRECISION
RF CABLE
t
1,Ref
TIME
0.5
R,0
R,0
REFERENCE LINE
t
2,Ref
IPC-TM-650
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