Yves,
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I double checked and filled the table like you did
| ? |
Log |
Lin |
| VLOG2 |
-7.990 |
10,092 |
| VLOG3 |
-8,015 |
10,089 |
| VLOG1 |
-8,07 |
10,087 |
| -8VT |
-8,236 |
-8,236 |
| VLIN |
3,672 |
-6,624 |
| VLOG/VLIN |
3,695 |
-8,005 |
Some differences but not directly issues i'd say.
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I checked but don't have a replacement LM339 on hand. I doubt that's the issue though, since at the output of the LM339 the full swing is measured, it's only after the resistor division in the "Gain Control Lines" part that the voltages are not reaching the expected levels anymore. So it seems the circuit after the Gain control lines division is loading it incorrectly.
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I also checked the REF Level Cal signal. It's the output of a DAC on the Analog interface board, U106 pin 16.?
Measured in factory default cal and after self cal. level changes so it seems to function, don't know if its correctly though.?
| ? |
Fact Def cal |
Self cal done |
| REF Level Cal |
8,85V |
6,864V |
| Mrkr freq |
300MHz |
300MHz |
| Mrkr level |
-14,1dBm |
-5,1dBm |
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Since my analyzer measures the cal signal in LIN mode at around -30dB~-35dB when in factory default cal it wouldn't surprise me if the additional gain is added because the signal is measured too low in LIN mode during selfcal.?
| ? |
Fact Def cal |
Self cal done |
| MKR Freq |
292,7MHz |
300,05MHz |
| MKR Level Log |
-14,3dBm |
-5,1dBm |
| MKR Level Lin |
-27,8dBm |
-20,2dBm |
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I'm starting to think the full Log amp adjustment might have to be done because the lin and log gaines are perhaps not what they should be.. Although maybe the G4/G5/G6 voltage levels should be fixed first??
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Marco?
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