Magnus Danielson wrote: > From: "Robert Lutwak" <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] More on paralleling output gates > Date: Sun, 9 Apr 2006 16:04:49 -0400 > Message-ID: <[EMAIL PROTECTED]> > >> I suspect you're just measuring the bandwidth of your 400 MHz oscilloscope. > > He is close... tau of 1.1 ns should be expected from a 400 MHz. > > I am sitting here and thinking "Hey, isn't those 3 x 50 Ohm sources in > parallel > a impedance missmatch?". If you have a sufficiently long system (> 1/12 of the > risetime in cable-length which in this case would mean maybe 50 cm or so) we > must consider it as an impedance system and thus we should care less about the > bulk capacitance behaviour (which can be "cured" with a stronger source) but > rather with the source and load impedances relative the cable impedance. > > I'd like to view the exercise as only mildly interesting. Better to find a > better source for that signal. If you feel like toying around more on that '04 > then directly parallel the outputs into a single 47 Ohm resistor might be more > productive.
Which would be exactly the same as putting 150 ohm resistors in series with each of the three outputs, and tying them all together in parallel. Which will produce a pulse that is 1/2 height when terminated with 50 ohms... hardly TTL. -Chuck Harris _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
