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2 pictures first (9/10/2009)

2 pictures first (9/10/2009). 2 pictures first (9/10/2009). First data from ADC125 module 8/24/2009. Input. Mainboard only. Output. Peaking here is designed/desired (cable response equalization). Keep in mind there is no cable installed in this measurement.

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2 pictures first (9/10/2009)

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  1. 2 pictures first (9/10/2009)

  2. 2 pictures first (9/10/2009)

  3. First data from ADC125 module 8/24/2009 Input Mainboard only

  4. Output Peaking here is designed/desired (cable response equalization). Keep in mind there is no cable installed in this measurement. Note: Range is 0-16384 (14 bits), two LSB are zero here (a 12 bit assembly)

  5. Output noise level (open input) σ=2.20 (as 12-bit: σ=0.55)

  6. Connector assembly problem corrected; first data from preamp & ADC125 together 9/10/2009 • Don’t worry about the tail: • ADC125 component values to be adjusted, when • final preamp • final cable length • also we can cancel the tail digitally in the FPGA Combined response of GAS-1/GPC-01, cable, and ADC125 to 94 electron x 5x104 signal with t0=1.38 ns Input pulse through capacitor to GAS-1 (top is detail) See GlueX-doc-931-v2 for details (same setup used here) About 20% of full scale range

  7. Combined response of GAS-1/GPC-01, cable, and ADC125 Single 4096-point acquisition noise spectrum (no averaging) • The overall structure is as expected from the preceeding pulse plot… 3 points on the leading edge implies that the bandwidth is ≈1/3 Nyquist. • But here you can see that there really is insignificant noise above the cutoff frequency ≈25 MHz • So all the waveform information is present in the digital data – the algorithms have a chance • My opinion is that this is a bit too conservative: want to raise the bandwidth by 20-30% here, will improve timing resolution w/o any noticeable compromise to charge resolution • Or we can drop the sample rate and hence the raw data volume • Also: hard to draw conclusions yet w/o averaging, but no anomalous peaks are seen here – no EMI issues (on lab bench)

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