*Heater Noise*
We measure the noise across a 10 kohm heater for different isolator slew rates. We've found a correlation between the heater pickup and the digital dataIN lines on the analog ADC isolators. On this page, we show the results of changing the slew rates on the isolators. If the noise is capacitive pickup on the PGND from the data lines, the signals should decrease with a slower slew rate. If it is from the isolators (the transformer signals which don't change with slew rate), the signals should stay the same.
In the noise plots below, the fast slew build with a drive of 24 has the largest noise peaks, but the other three are similar to each other (may a slight decrease in the peak amplitudes between the released build and the 6 ma drive build )
Slew Rates
The slew rates go from top to bottom, fastest to slowest. The top trace (yellow) is the fast slew with a drive of 24 ma, the second trace down is the released build (default drive 12 ma ). The trace below is set to slow slew with drive 12 ma ( the noise plots are not shown for this ). The second from the bottom is a slow slew build with a drive of 6 ma and the bottom trace is a slow slew build with a drive of 4 ma.
Fastest Slew Rate ( 24 ma drive )
Released Build ( 12 ma drive )
Slow Slew Rate ( 6 ma drive )
Slowest Slew Rate ( 4 ma )
This topic: CryoElectronics > WebHome > HeaterNoise Topic revision: r1 - 2011-05-26 - JamesKennedy
Slew Rates
The slew rates go from top to bottom, fastest to slowest. The top trace (yellow) is the fast slew with a drive of 24 ma, the second trace down is the released build (default drive 12 ma ). The trace below is set to slow slew with drive 12 ma ( the noise plots are not shown for this ). The second from the bottom is a slow slew build with a drive of 6 ma and the bottom trace is a slow slew build with a drive of 4 ma.
Fastest Slew Rate ( 24 ma drive )
Released Build ( 12 ma drive )
Slow Slew Rate ( 6 ma drive )
Slowest Slew Rate ( 4 ma )
| I | Attachment | Action | Size | Date | Who | Comment |
|---|---|---|---|---|---|---|
 png |
heater_fast_slew_24ma.png | manage | 39.9 K | 2011-05-26 - 18:43 | JamesKennedy | |
| png |
heater_fast_slew_24ma_zoom.png | manage | 50.0 K | 2011-05-26 - 18:43 | JamesKennedy | |
| png |
heater_nofilter.png | manage | 41.2 K | 2011-05-26 - 18:43 | JamesKennedy | |
| png |
heater_released_build_zoom.png | manage | 46.4 K | 2011-05-26 - 18:43 | JamesKennedy | |
| png |
heater_slow_slew_4ma.png | manage | 36.0 K | 2011-05-26 - 18:43 | JamesKennedy | |
| png |
heater_slow_slew_4ma_zoom.png | manage | 46.0 K | 2011-05-26 - 18:43 | JamesKennedy | |
| png |
heater_slow_slew_6ma.png | manage | 41.5 K | 2011-05-26 - 18:43 | JamesKennedy | |
| png |
heater_slow_slew_6ma_zoom.png | manage | 47.7 K | 2011-05-26 - 18:43 | JamesKennedy | |
| png |
isolator_slew_rates.png | manage | 22.7 K | 2011-05-26 - 18:43 | JamesKennedy |
This topic: CryoElectronics > WebHome > HeaterNoise Topic revision: r1 - 2011-05-26 - JamesKennedy
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