Hi Vlad, Before we get to your phase noise question...
Your plots ALTINEX-DA-F.png ALTINEX-DA-T.png look odd and the plot ALTINEX-DA.png shows massive amount of glitches. You must make sure that the frequency and the phase plots look "nice" before doing an ADEV plot. In this case there's probably something wrong with your setup. You should NOT be seeing all those jumps, spikes, wiggles, and noise in a frequency plot. Hundreds of outlier data points are destroying the validity of the ADEV calculations. Something is very wrong. Check wires, connectors, power supplies, groundings, vibration, air flow, mains voltage, etc. Try a 3rd oscillator in case it's a problem with one of your two oscillators. But you have to get rid of those spikes in the ALTINEX-DA-F.png plot. The way we usually test a distribution amp is to use a single oscillator and a splitter; one leg goes through the DA and the other does not. The phase difference plot then reveals the stability of the DA. But regardless of how you measure a DA, the frequency plot should not have so many erratic glitches. The kind of plot you should expect is the smooth portion between the 8700 second and 11600 second grid lines. /tvb ----- Original Message ----- From: "Vlad" <t...@patoka.org> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Wednesday, May 27, 2015 7:04 PM Subject: [time-nuts] Distributiuon Amlifier Altinex DA1804NT > > Hello, > > Recently, I acquired video distribution amplifier (model Altinex > DA1804NT). It says it could handle 350Mhz. I am planing to use it to > split 10Mhz Ref signal from my OCXO. This OCXO I bought on auction site. > It has Oscilloquarz model 8663-SX plus some components which give me 4 > outputs - 2 sines and two squares. After few days of "warm up" I did > measurement of ADV from one of the sine outputs and then measurement of > the same sine signal from OCXO, but this time through the Altinex DA. > Each test took 8 hours. Attached is the results. > > NOTE: on the ALTINEX* charts I forgot to change the label for OCXO. So, > its not DATUM. It is Oscilloquarz 8663-SX > I was using Trimble TB as a ref signal for HP 5386 > > Since I have no instruments which measuring phase noise, I am > interesting, what will be the quick method to measure the phase noise > for that DA ? > > > -- > WBW, > > V.P. _______________________________________________ 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.
