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Mixer LO-RF isolation
For each mixer the isolation from LO to RF port has been measured as a function of the level of the first 10 LO harmonics visible at the RF port. These results have been compiled in to the following table for all investigated mixers:
15M LO harmonic isolation (-dBm) |
Mixer |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
Avg |
Avg |
2-10 |
spur |
ADT1-1WT |
FSA3157 |
AC04 |
47,2 |
66,4 |
47,2 |
59,6 |
45,6 |
61,6 |
41,2 |
46,8 |
40,4 |
49,2 |
50,9 |
-10,8 |
ADTT1-1 |
FSA3157 |
AC04 |
58,0 |
61,6 |
59,6 |
58,0 |
59,2 |
54,0 |
51,6 |
41,6 |
46,8 |
49,2 |
53,5 |
-9,3 |
BN43-2402 4+8 |
FSA3157 |
AC04 |
66,0 |
59,6 |
65,6 |
61,2 |
66,0 |
57,6 |
56,0 |
44,0 |
62,4 |
52,8 |
58,4 |
-8,8 |
BN43-2402 4+4 |
FSA3157 |
AC04 |
53,2 |
58,0 |
58,0 |
54,8 |
58,8 |
53,6 |
54,0 |
46,0 |
47,2 |
47,6 |
53,1 |
-7,0 |
ADT1-6T spur |
FSA3157 |
AC04 |
61,2 |
54,0 |
58,4 |
51,6 |
48,8 |
44,4 |
37,2 |
43,2 |
51,6 |
38,0 |
47,5 |
-6,9 |
TT4-1A spur |
FSA3157 |
AC04 |
75,2 |
61,2 |
64,8 |
52,8 |
62,4 |
42,4 |
55,6 |
42,8 |
52,0 |
44,4 |
53,2 |
-5,6 |
TT4-1A |
FSAV430 |
AC74 |
56,0 |
50,8 |
54,8 |
58,0 |
62,4 |
50,0 |
50,4 |
45,2 |
55,2 |
46,8 |
52,6 |
-4,8 |
T4-1 |
FSA3157 |
AC04 |
50,0 |
34,4 |
50,0 |
32,8 |
50,0 |
31,2 |
50,8 |
30,6 |
45,6 |
32,0 |
39,7 |
-3,3 |
ADTT1-6 spur |
FSA3157 |
AC04 |
47,2 |
55,2 |
45,2 |
50,0 |
39,2 |
45,6 |
41,2 |
39,2 |
42,4 |
32,4 |
43,4 |
-3,2 |
ADTT4-1 |
FSA3157 |
AC04 |
67,6 |
54,8 |
57,2 |
49,2 |
50,8 |
37,2 |
52,0 |
40,4 |
60,4 |
39,6 |
40,3 |
-3,1 |
TT4-1A |
FSA3157 |
AC74 |
54,4 |
56,0 |
50,8 |
56,4 |
48,0 |
51,6 |
43,6 |
47,6 |
54,4 |
42,8 |
50,1 |
-2,9 |
T1-1T |
FSA3157 |
AC04 |
55,6 |
51,2 |
56,0 |
49,2 |
53,6 |
46,0 |
47,6 |
39,2 |
40,0 |
37,6 |
46,7 |
-2,5 |
T1-6T spur |
FSA3157 |
AC04 |
45,2 |
52,8 |
40,8 |
47,6 |
34,8 |
39,6 |
38,0 |
39,6 |
51,6 |
33,2 |
42,0 |
-1,2 |
TT4-1A |
FSAV450 |
AC74 |
54,4 |
51,6 |
52,0 |
56,0 |
46,4 |
37,6 |
39,2 |
34,4 |
43,2 |
44,0 |
44,9 |
1,2 |
TT1-6 spur |
FSA3157 |
AC04 |
66,0 |
60,0 |
45,6 |
48,0 |
36,8 |
40,8 |
46,8 |
40,4 |
34,4 |
40,4 |
43,7 |
1,3 |
BN43-2402 8+8 |
PI5C3125 |
AC86 |
45,2 |
43,6 |
47,2 |
50,8 |
57,2 |
50,0 |
54,4 |
36,8 |
44,0 |
32,0 |
46,2 |
2,3 |
TT4-1A |
FSAV332 |
AC74 |
38,4 |
46,8 |
41,6 |
39,6 |
48,4 |
36,8 |
29,2 |
31,2 |
35,6 |
28,8 |
37,6 |
3,6 |
ADTT1-1 |
FSAV332 |
AC74 |
49,6 |
49,6 |
48,4 |
37,6 |
54,4 |
38,0 |
48,4 |
34,8 |
35,6 |
26,8 |
41,5 |
3,8 |
BN43-2402 4+8 |
PI5C3125 |
AC86 |
44,0 |
43,6 |
47,6 |
51,2 |
53,6 |
48,8 |
53,2 |
32,4 |
35,2 |
30,0 |
44,0 |
3,9 |
TT4-1A |
FST3125 |
AC74 |
38,4 |
46,0 |
41,6 |
38,0 |
45,2 |
34,0 |
25,2 |
28,4 |
33,2 |
24,8 |
35,2 |
4,2 |
TT4-1A |
FSA3157 |
AC04 |
80,8 |
58,8 |
69,6 |
53,6 |
66,0 |
42,0 |
53,6 |
42,8 |
75,6 |
43,6 |
56,2 |
4,5 |
BN43-2402 4+4 |
PI5C3125 |
AC86 |
39,2 |
43,6 |
52,4 |
52,8 |
51,2 |
48,4 |
46,4 |
32,8 |
44,8 |
27,6 |
44,4 |
6,2 |
TT4-1A |
NC7SZ384 |
AC74 |
54,4 |
28,4 |
50,4 |
36,0 |
40,8 |
39,2 |
30,4 |
36,0 |
40,4 |
34,4 |
37,3 |
7,7 |
TT4-1A |
FSAV330 |
AC74 |
53,2 |
36,4 |
52,4 |
40,4 |
45,2 |
31,2 |
31,6 |
27,6 |
31,6 |
39,2 |
37,3 |
9,3 |
The table is sorted in ascending order with respect to the measured average level of 132 spurs on 15M.
The level of suppression of the LO harmonics obviously plays an important role in the amount of spur reduction, because the average over the 2nd to 10th harmonics correlates more or less with the observed average spur level.
This confirms the idea that one kind of spurs is caused by transmission from LO-port to RF-port followed by heterodyning with anything available at the LO-port again.
The only big exception is the "TT4-1A/FSA3157/AC04" row with 5.6dB spur levels but also 56.2dB average on the LO harmonics. There is apparently something rather subtle to the LO-RF isolation when it comes to explaining or predicting the amount of spur rejection.
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