1. ODL: Status and Issues Mike Regan, Eddie Bergeron, Kevin Lindsay, & Doug Long

2. Outline Using warm reference pixels to test for EMI How to drop bits to improve data compression Current Issues and Testing

3. Raw reference pixels look significantly different on a warm detector RMS is 5 times higher Standard deviation of the RMS is 20 times higher. COLD WARM

4. Our selectable noise source, the fans in the readout electronics.

5. Filtering out the 1/f noise leads to an RMS that is only 10% higher when warm.

6. Webb generates a lot of data and has only one 8 hour contact a day. The assumption has always been that we could do lossless 2:1 compression in hardware. Using simulations with CRs and bad pixels -> 1.7:1 What if we drop low order bits? –1 bit = 1.9:1 –2 bits = 2.1:1 –3 bits = 2.5 :1 What is the noise effect?

7. You can drop up to three bits and have no effect on the noise. Drop 5 bits Drop 4 bits

8. The noise effect is larger for reference pixels. Drop 5 bits Drop 4 bits Drop 3 bits

9. We have many issues we are investigating that will not be dealt with in instrument testing.