PADI Test @ Tsinghua

Jingbo Wang for Zhi DengApril, 2010

1

Test Setup

Pulser (AFG3102)

FEET Board with 2 PADI chips

20dB Attenuator (DC-2GHz)

Oscilloscope (DPO7104 with P6247 diff. probe, 1GHz B.W.)

2

~250mV

~28mV

Analog Output Digital Output

3

Gain Estimation

• Assuming 5ns rise time with 1-order RC response of the test voltage pulse

~1pF 50ohm

tr= 5nsI in

Gain = 277mV/mA

Just a rough estimation, sensitive to the coupling capacitor, signal rise time

Input current with 1V 5ns-rise time step signal

4

1V

Spikes

Without discriminator fired With discriminator fired

5

Averaged picture

Caused by logic transition?

Without discriminator fired With discriminator fired

6

Output width vs. Input current

7

Test with MRPC

Digital output

Analog output

Telescope PMT coni. output

8

Digital output

Analog output

Telescope PMT coni. output

Output from FEE of STAR TOFr

9

10

PADI jitter Test

11

Test setup

Signal Generator

CH1

CH2

TTL

Oscilloscope

CH1

CH2

AUX (trigger)

PADIDiff. probe

CH2 CH1

2 2 2PADI signal_generatorT

T T T

12

Signal Generator Only

CH1CH2

signal_generator 18.6ps 13

With PADI

CH1CH2

T 55.38ps@ 2VinV 14

Test Results

15