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From: Cursitor Doom <cd@notformail.com>
Newsgroups: sci.electronics.design
Subject: Re: Chip for fast pulses
Date: Sat, 18 Jan 2025 00:00:38 +0000
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On Sat, 18 Jan 2025 00:23:18 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:

>On 1/17/25 23:43, Cursitor Doom wrote:
>> On Fri, 17 Jan 2025 14:26:46 -0800, john larkin <jl@glen--canyon.com>
>> wrote:
>> 
>>> On Fri, 17 Jan 2025 17:47:04 +0000, Cursitor Doom <cd@notformail.com>
>>> wrote:
>>>
>>>> Gentlemen,
>>>>
>>>> What's available these days for generating well-defined pulses with
>>>> really sharp rise times? I admit to being like 40 years behind when it
>>>> comes to what ICs can do (and proud of it!) Would 50pS cut the mustard
>>>> or is that dog-doo slow nowadays?
>>>>
>>>> Thanks,
>>>>
>>>> CD
>>>
>>> 50 ps edges are pretty fast. I tell people that 1 ns starts to be
>>> interesting and 100 ps starts to be hard.
>>>
>>> Some CMOS parts make 200 ps edges.
>>>
>>> Eclips Lite (EL series) and GigaComm (NB7) are fast ECL logic
>>> families. Some Giga parts have 35 ps rise and fall, but tiny swings.
>>>
>>> There are some interesting laser drivers around, like the SY88022.
>>>
>>> There were some really fast Russian parts but I don't know if they
>>> still can be had.
>>>
>>> Step-recovery diodes and NLTLs (shock lines) make the fastest
>>> all-electrical pulses. Laser stuff gets truly fast, fs and as optical
>>> pulses.
>> 
>> Interesting. I'm seeing a *lot* of adverts on Ebay currently for
>> "optical TDRs" which must be challenging to produce (to my VHF mindset
>> anyway). So yeah, I'm perfectly certain SRDs would be more than
>> adequate for anything I wanted to do. NLTLs I'm not familiar with so
>> gonna have to look 'em up.
>
>Optical TDRs have VHF bandwidths. It's the /modulation/ they show.
>They certainly don't have the 600-odd THz bandwidth you seem to imply.
>
>Jeroen Belleman
>not


Ah - well that would explain a great deal! Thanks.