What sort of TTL are you going to use with a 3 ns pulse????
One that stays solidly at either a high or low level?
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I'm looking to use the TTL as a trigger pulse for an NI scope
application. So the pulse can be stretched longer than the 3nS pulse.
The 3-5nS pulse is coming from a photodiode circuit on a Cobolt Tango
It does not have to stay high or low, except sufficiently to be used
as a trigger for NI scope input.
>"Phil Hobbs" <pcdhSpamM...@electrooptical.net> wrote in message
>> jamie_...@yahoo.com wrote:
>>> I'm trying to convert an analog signal, 150mV, 3-5nS pulse width to a
>>> TTL signal.
>> What sort of TTL are you going to use with a 3 ns pulse????
>> Phil Hobbs
>One that stays solidly at either a high or low level?
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I love to cook with wine Sometimes I even put it in the food
LVDS receivers make nice comparators with "CMOS"/"TTL" outputs at
these input voltage levels.
e.g. DS90C032 et al for few hundred mV swing inputs.
If the input isn't actually differential then appropriately biasing
the inactive input does the trick.
Sometimes the same parts used to be known as LVPECL receivers.
>I'm trying to convert an analog signal, 150mV, 3-5nS pulse width to a
That's a bit on the fast side for a TTL-level output, but you can try
looking at fast comparators. LVDS (or PECL or CML) will be easier.
You should probably think in terms that the pulse _must be_ stretched,
not "could be". Check the documentation on your hardware.
I assume that you're looking for a circuit? Your question didn't make
Perhaps you should start over again and tell the _whole_ story: "I am
trying to trigger a NI scope board (which one?) with a Cobolt Tango
laser which has a photodiode output. The NI board needs a TTL-level
input, but the laser pulse is 3-5ns long and only 150mV high".
Something like that.
Then you'll have provided a much nicer framework for folks to answer
You may want to make clear your requirements for jitter and maximum
pulse width -- if you have to slow it down for TTL you can pretty much
guarantee that you'll introduce jitter in the process, or the receiving
Wescott Design Services
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html
Uh, really, really, really fast TTL?
I assume the scope has an analog trigger input, with programmable
trigger level. So maybe all you need is a linear amplifier.
Like this, maybe:
This is likly a single MMIC in a can, so probably inverts the signal.
If the scope really needs TTL, of course we could sell you one of
> I'm trying to convert an analog signal, 150mV, 3-5nS pulse width to a
> TTL signal.
You have not specified if there is a DC component in this signal?
It would make a world of difference in design to know this.
From what I can gather in your info, it's 0..150v but it may
actually be a 10 to 10.150V PK, for example.
Googlies don't know how to do that. If they did, they'd get their own
answers. This is just copied out of the exam.
Upside-down ECL? ;-)
I like the left handed one's my self!
Maybe he should go back and use gold enhanced RTL logic??
I worked up a pulse-stretcher for pretty much exactly this application
Ghiggino, K.P., Phillips, D., and Sloman, A.W. "Nanosecond pulse
stretcher",Journal of Physics E: Scientific Instruments, 12, 686-687
It used a pair of 5GHZ wideband transistors to make a Schmitt trigger
- these days I'd probably use BFR92 npn parts rather than the pnp
parts we used back then.
It worked. It could have been improved, but since it did the job
nobody was interested in going to the trouble of designing something
Bill Sloman, Nijmegen
Hey, it works!
That's a 3 ns, 100 mV input and 4 volts out. It even works with an 80
mV, 1 ns input, still 4 volts out. I'm sort of impressed!
I just built one of those amps into a 6 GHz microwave setup yesterday.
16 dB gain at 1 GHz, 12 dB at 6 GHz, $50 with nice gold-plated SMA
connectors. Not bad.
BTW John, could you set up your FTP server to accept PASV? I have to
download those pictures using command-line FTP and look at them in a
photo editor, because Mozilla browsers always want to use passive-mode FTP.
Sorry, I have no idea what those words mean. My little ISP, a few guys
in a storefront in Berkeley, host it for me for free, and I've had
plenty enough trouble getting it to work at all. Firefox seems happy
opening the pics as-is. I assume it has a name, and not just an IP
address, but I can't figure out what it is.
>>BTW John, could you set up your FTP server to accept PASV? I have to
>>download those pictures using command-line FTP and look at them in a
>>photo editor, because Mozilla browsers always want to use passive-mode FTP.
> Sorry, I have no idea what those words mean.
FTP uses two TCP connections: a control channel and a data channel. The
control channel is used for sending commands and receiving status
responses. The data channel is used for sending and receiving data (files,
and directory listings).
The control channel is established by the client connecting to the server.
In the original FTP implementation, the data channel was established by
the server connecting back to the client (i.e. the client is the "server"
end of the data connection).
This doesn't work with some firewalls, which block inbound connections
unless specifically told otherwise. Passive (PASV) mode is an extension to
the FTP protocol which allows the data channel to be established by the
client connecting to the server.
> My little ISP, a few guys
> in a storefront in Berkeley, host it for me for free, and I've had
> plenty enough trouble getting it to work at all. Firefox seems happy
> opening the pics as-is.
It works for me, but that may just be that my firewall is more lenient
than Phil's. Some firewalls have explicit support for (non-passive) FTP.
They recognise FTP control channels (port 21), and monitor the traffic.
When the client tells the server to connect back to it on a specific port,
they add a temporary "exemption" to allow the FTP server to connect to
> I assume it has a name, and not just an IP
> address, but I can't figure out what it is.
> I assume it has a name, and not just an IP
>address, but I can't figure out what it is.
That is very simple:
grml: ~ # host 126.96.36.199
188.8.131.52.in-addr.arpa domain name pointer jjlarkin.lmi.net.
So, in your browser type:
Hmm. Maybe it's a firewall issue then. In any case, I can help with
the second problem:
"Name Server Lookup" in NetScanTools v4.02
Neat. I don't consider all this protcol/path/port sort of stuff to be
"electronics", and I haven't bothered to understand much of it... just
enough to get my Ethernet instruments to talk. There's plenty of real
stuff to keep up with.
I'll ping my guys at LMI and see if they can turn on the PASV thing
without breaking something else. Which they usually do.
$ whois 184.108.40.206
OrgName: LanMinds, Inc.
Address: 1700 Martin Luther King Jr. Way
NetRange: 220.127.116.11 - 18.104.22.168
NetType: Direct Allocation
# ARIN WHOIS database, last updated 2008-12-17 19:10
# Enter ? for additional hints on searching ARIN's WHOIS database.
I asked my ISP guys to enable PASV, and they replied that PASV is the
responsibility of the client, not the server, and they demonstrated
that they could access my site in PASV mode. They say...
"PASV or passive mode is a setting in the ftp client not on the
server. Some web browser's ftp clients are severely broken -cough-
Internet Exploder -cough. They might need to use a stand alone ftp
Hey, I tried.
Thanks. My FTP server has settings to enable/disable both active and
passive FTP. If it's switched on at their end, it's probably a firewall
PASV seems to be enabled now.
jasen@gonzo:~$ ftp 22.214.171.124
Connected to 126.96.36.199.
220 jjlarkin.lmi.net FTP server (Version wu-2.6.2(1) Wed Dec 5
16:35:31 PST 2001) ready.
Name (188.8.131.52:jasen): ftp
331 Guest login ok, send your complete e-mail address as password.
230 Guest login ok, access restrictions apply.
Remote system type is UNIX.
Using binary mode to transfer files.
Passive mode on.
Also I don't recall ever having a problem using seamonkey to view his files.
OTOH I can't get to jamie6" 's web site, my ISP is blocking traffic to
that ip-address block and gives me some line of bullshit when I ask them