The signal source is described here: Impedances of source, load and DUTs. where also the first section of the receiver is described.
The rest of the receiver is described here: Measurement system November 2012 An amplifier with a PSA4-5043 was inserted between the 3dB pad on the circulator and the measurement system.
The Linrad S-meter is set to show dBm and the different DUTs are inserted and removed a couple of times. The average of the RMS power is computed (Linrad-03.47 and later.) Figure 1 shows the resulting screen for DUT2.
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| Figure 1. The signal level with and without DUT2. The average levels are 41.7695 and 41.7098 for an insertion loss of 0.0597 dB. | |||||||||||||||||||
device Mismatch Insertion Dissipative
loss loss loss
(dB) (dB) (dB)
Tx port 0.00005 -
DUT1 0.16591 0.1753 0.0094
DUT2 0.00005 0.0597 0.0597
DUT3 0.00071 0.0290 0.0283
DUT4 0.00022 0.0590 0.0588
DUT13 0.16672 0.2041 0.0374
DUT31 0.17655 0.2294 0.0528
DUT123 0.16538 0.2696 0.1042
DUT132 0.16572 0.2631 0.0974
DUT312 0.17788 0.2930 0.1151
DUT213 0.16719 0.2815 0.1143
DUT231 0.17039 0.2802 0.1098
DUT42 0.00022 0.1188 0.1186
DUT24 0.00034 0.1195 0.1192
DUT34 0.00060 0.0874 0.0868
DUT43 0.00106 0.0889 0.0878
DUT32 0.00064 0.0897 0.0891
DUT23 0.00128 0.0903 0.0890
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Table 1 Mismatch, insertion and dissipative losses from direct measurements. | |||||||||||||
Dissipative losses are additive. Table 1 does not look good, the dissipative losses of e.g. DUT13 and DUT31 should be equal. Table 1 is computed under the assumption that a the female BNC to female BNC adapter does not change the impedance. Without a precision calibration kit for both genders of BNC connectors it is not so easy to know, but after a small adjustment of the impedance for the Rx port it looks better. See table 2. | |||||||||||
device Mismatch Insertion Dissipative Fitted Diff
loss loss loss loss
(dB) (dB) (dB) (dB) (dB)
Tx port 0.0004 0.0000 0.0000 0.0000
DUT1 0.1565 0.1753 0.0180 0.0196 0.0016
DUT2 0.0004 0.0597 0.0586 0.0600 0.0014
DUT3 0.0005 0.0290 0.0278 0.0288 0.0010
DUT4 0.0005 0.0590 0.0578 0.0581 0.0003
DUT13 0.1576 0.2041 0.0457 0.0484 0.0027
DUT31 0.1796 0.2294 0.0491 0.0484 -0.0007
DUT123 0.1558 0.2696 0.1131 0.1084 -0.0047
DUT132 0.1566 0.2631 0.1057 0.1084 0.0027
DUT312 0.1810 0.2930 0.1113 0.1084 -0.0029
DUT213 0.1766 0.2815 0.1041 0.1084 0.0043
DUT231 0.1680 0.2802 0.1115 0.1084 -0.0031
DUT42 0.0005 0.1188 0.1176 0.1181 0.0005
DUT24 0.0008 0.1195 0.1180 0.1181 0.0001
DUT34 0.0007 0.0874 0.0860 0.0869 0.0009
DUT43 0.0002 0.0897 0.0888 0.0869 -0.0019
DUT32 0.0004 0.0897 0.0885 0.0888 0.0003
DUT23 0.0022 0.0903 0.0874 0.0888 0.0014
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Table 2 Mismatch, insertion and dissipative losses from direct measurements after adjusting the Rx port impedance from (49.48,-j0.26) to (49.57,-j0.85). The column Fitted loss is computed from the assumption that the dissipative losses are additive and that the dissipative losses of DUT1 to DUT4 are as listed. | |||||||
The dissipative loss in one of the DUTs consists of cable losses and connector losses. The length of a BNC connector pair is about 20 mm. Table 3 lists the lengths of DUT1 to DUT4 and a guess for the losses of the connector pair that makes the loss per meter in the cable the same for DUT2 to DUT4 cables. | |||||
device Fitted Length Connector Cable Nominal
loss loss loss loss
(dB) (mm) (dB) (dB/m) (dB/m)
DUT1 0.0196 126 0.0019 0.1405 ?
DUT2 0.0600 328 0.0019 0.1771 0.1571
DUT3 0.0288 152 0.0019 0.1770 0.1571
DUT4 0.0581 318 0.0019 0.1767 0.1571
long 0.6738 4031 0.0019 0.1667 0.1571
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Table 3 Dissipative losses splitted in cable and connector losses. As a comparison a long cable is measured. The cables are about 20 years old. | |