effect of flat cable to mppc signal s. uozumi (kobe) jun-6 2008 scecal meeting
TRANSCRIPT
Objective
• How the MPPC signal skewed by passing through industrial-standard FPC cables and connectors?
• Any reflection clearly seen?• This will determine (or give a feeling) specs of
our readout flat cable (inpedance, length…).• Electrocal cross-talk between adjacent lines
on the flat cables?
Setup• 20-lines FPC cables with 15cm length 1.25mm pitch and
FPC connectors are used.
FPC (15 cm)
FPC (15 cm) FPC (15 cm)
Relay board
MPPC
MPPC
Readout circuit
Signal connected toOscilloscopeThrough x63 amp
FPC cable FPC connector
Dark noise signal with different cable length
With two cablesAnd relay board(30 cm)
With one cable(15 cm)
Electrical cross-talk
Signal channel Adjacent channel
Amount of electrocal cross-talk on the flat cable is at leastbelow noise level.
Conclusion Of course those checks are not perfect, but we can somehow learn :– Better to set the cable inpedance to 50ohm, even if it makes production cost ~20% higher. (it was NOT considered at the DESY BT.)– Electrical cross-talk on flat cable is not significant
level.– I suppose to go ahead with idea-I, but with 50ohm
flat cable, not industrial standard FPC cable.– But, if the cable length can be short enough, taking idea-3 is also possible(but with 50ohm
cable).