Performance Testing
LT51 User Manual
82
Transmitter Level Accuracy
a) Set the LT51 to TX-RX interface mode. Set the TX frequency to 10 kHz.
b) Set the LT51 Ztx impedance and TX level as indicated in Table 8.1 below.
c) Connect a suitable DMM to the LT51 using a short low capacitance cable to
the TXa-b terminals.
d) The DMM must be terminated with the indicated impedance at its input
terminals.
e) Step down the levels in Table 8.1 and check that the readings are within the
ranges specified.
LT51 Tx Level
LT51 Ztx
DMM reading
0 dBm
75
0 dBm ± 0.05 dB
0 dBm
50
0 dBm ± 0.05 dB
0 dBm
600
0 dBm ± 0.05 dB (ref.)
+10 dBm
600
+10 dBr
0.20 dB
-10 dBm
600
-10 dBr
0.20 dB
-20 dBm
600
-20 dBr
0.20 dB
-30 dBm
600
-30 dBr
0.30 dB
-40 dBm
600
-40 dBr
0.30 dB
-50 dBm
600
-50 dBr
0.30 dB
Table 8.1
Transmitter Level Response
a) Set the LT51 to TX-RX interface mode. Set the TX level to 0.0 dBm.
b) Set the LT51 Ztx impedance and TX frequency as indicated in Table 8.2
c) Connect a terminated DMM / Thermal Voltage Converter to the LT51 using
a short, low capacitance cable to the TXa-b terminals.
d) With the TX Frequency set to 10 kHz, set the reference on the DMM / TVC.
All subsequent readings will displayed relative to the reading at 10 kHz.
e) Step down the frequencies in Table 8.2 and check that the readings are
within the ranges specified.
LT51 Tx Freq
LT51 Ztx
DMM reading
10 kHz
75
0 dBm ± 0.05 dB (ref.)
2 kHz
75
0 dBr
0.25 dB
200 kHz
75
0 dBr
0.25 dB
1,000 kHz
75
0 dBr
0.5 dB
2,000 kHz
75
0 dBr
0.5 dB
10 kHz
600
0 dBm ± 0.05 dB (ref.)
200 Hz
600
0 dBr
0.25 dB
20 kHz
600
0 dBr
0.25 dB
Table 8.2
Summary of Contents for UMDT51A
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