Spirent DLS 6700, Operating Manual

Page: 43 / 48

Appendix A "MEASUREMENTS AND TEST RESULTS"
Spirent Communications
7104000557
Page A-1
Appendix A MEASUREMENTS AND TEST RESULTS
A.1 Measurement of the DLS 6700
When measuring the insertion loss of a balanced line or line simulator throughout the
frequency domain, the following method is recommended:
Figure A.1 Electrical characteristics measurements
In Figure A.1, Rg, R
L
and the coax cables match the unbalanced winding of the balun.
The balanced winding of the balun must be 100 Ω for 24AWG or 26AWG (North Hills
0301BB) or 135 Ohm for TP100 (North Hills 0312BB), in order to match the reference
impedance indicated in the standards. The center tap on the balanced side is usually
connected to the shielding of the balun through one of the mounting screws.
The transmitter and receiver could be the transmitting and receiving sections of a net-
work analyzer.
Transformers and cables introduce errors of attenuation and phase. For accurate
measurements, first perform calibration (normalization) by replacing the simulator
with a direct connection.
WARNING
The use of unbalanced signals through the DLS 6700 will usually yield
incorrect measurements.