Project: TBASErdn021203 Roger Norrod Tried to use test tone (LO1B) thru the IF Rack noise source to measure linearity of the system, but insufficent level. Now attempt using noise source and ODM attenuators. Scan 1 - ignore. Using ODM 2, 6, 8 (4 out of service). Equipment Room connections: OR CM SF DCR CH 2 1 1 9 2 2 2 10 6 11 3 11 6 12 4 12 8 15 7 15 8 16 8 16 DCR mode TPnoCal, tau=1s, T=600s. Recording all 16 chans. Scans 2-3: Started near 1V, Added 10dB, then took out 1dB steps each ~30s until voltage reached 10V. Ch 6 only got to 5.86V at min attennuation. Rebalanced to 1V at 7:15 left in scan 3. At 4:00 left, began adding 1dB steps. At 2:00 left, rebalanced to 1V. Scan 4: Did not disturb system. fi at 14:51:57. Reconfigured for ODM 1, 3, 5 (ODM 7 out of service). Equipment Room connections: OR CM SF DCR CH 1 1 1 9 1 2 2 10 5 11 3 11 5 12 4 12 3 5 5 13 3 6 6 14 Scan 5 & 6: Same process as scans 2,3 described above. Scan 7-9: Undisturbed. Reconfigured for chans 2, 6, and 8. Scans 10-12 undisturbed. Conclusions: - The major observation is that ODM 1 (SN5), 2 (SN4), and 5 (SN1) indicate major saturation. The measurement technique used above is crude, but it's hard to understand why 3 of the 6 channels checked act so differently from the others. Hence, we need to schedule rotating all of the ODM units off the telescope for careful compression tests. - I wrote a couple of glish routines to use within the dcrAnalysis program for calculating and plotting the percent error from linear. It assumes the attenuator steps are exactly 1dB, so be aware. The routines are in the file ./AnalysisScripts/lin.g - Figures 1a, 2a, 3a, 4a, 5a, and 6a show the collected raw data for IF channels 1, 3, 5, 2, 6, and 8 respectively. Figures 1b, 2b, 3b, 4b, 5b, and 6b plot the linearity percent error for each case respectively. The errors toward the left side of the plots probably are due to detector video amp zero offsets.