Fast comparators

Sure. I'm not normally trying to measure 100 uV in gigahertz bandwidths though....

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com

Wow, I've got to read most of that... (we're getting fiber at work and the internet is ~1/2 f'ed up. which is not such a bad thing!) So here are some nice pulses.

This the spad baised 5V above breakdown. ( At lower voltages it's not as snappy.) I'm triggering off a down stream comparator, chan 2. (3' of coax and 10ns delay.?) The threshold is ~100mV, (there's occasional fat pulses, which must be events during the recharge time. ~1us,) But most of the time they are amazingly consistent pulses. (for one more familiar with pmt's) About 1/2 the pulse in the picture are dark count and the other real. I've got tape and boxes and... I still have to close all doors and turn off lights to measure dark count, OH! I've got this pcb with heater on one face, I bet the light's leaking in through the edges, photons are tricky things, well I guess there's just a lot of 'em. :^)

George H.

If totally irrelevant to the universe of discourse.

Tim Williams, not being British, won't have been exposed to the "Just William" books, but he's playing the part to perfection.

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Bill Sloman, Sydney