These are voltage devices term in 75 Effect of 50 ohm, zip. Though this being time-nuts there will be a long discussion its not. But thats why there are gain pots on the front of the amp. You do not want the fancy stuff thats trouble. And yes these amps can have all kinds of stuff normally it can be turned off. You can definitely loop the inputs. I do for 10 & 5 MC since I need a few outs. But only 1 da for 1 and 100 kc. Regards Paul.
On Thu, Apr 21, 2011 at 1:21 PM, W2HX <w...@w2hx.com> wrote: > Hi all, > > > > I am close to closing in on a video distribution amp for a GPSDO for use in > 10 MHz reference signals for various test equipment and had a few > questions. > > > > 1. 50/75 ohm question. I know that putting 50 ohm source into a 75 > ohm device will cause SWR. I know that the total power delivered to the > device will be the difference between forward power and reflected power. > So > that doesn't seem bad, just might have a lower power input into the DA. > However, what about distortion? Will the sine wave be distorted somewhat? > And what if any adverse effect could a distorted sine wave have on various > instruments using the 10 MHz reference? > > 2. Many of these amps have LOOP through connections to expand the > number of outputs (in ->loop->in). I often see 75 ohm terminators at the > end of the loop. Since we are mostly using 50 ohm sources (GPSDO) would > there be any benefit in terminating these loops with 50 ohm terminators? I > realize that the output of the DA's are still 75 ohm, but I am thinking if > a > 50 ohm source terminated in 50 ohms might have less distortion (question > above) going into the amp. > > 3. Some of these video distribution amps can be loaded with different > cards. Some cards are straight VDA cards. Others have some form of "EQ." > According to one description the card comes ".with the addition of > equalization to compensate for attenuation and phase errors associated with > long cable runs." And I was wondering, could some form of this EQ > compensation be useful in a 10 MHz ref distribution system? What are the > effects of long cables runs around a lab when distributing the reference > signal? What is the effect of not maintaining the same phase across all > instruments in a lab? > > > > 73 Eugene W2HX > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
