Martyn Smith wrote: > Hi, > > I need some help on using the HP3048A Phase Noise Test Set (11848A, 3561A, > 3585A, 3325A). > > My company makes a ultra low noise frequency standard with ten outputs. > Apart from very low phase noise (-112 dBc/Hz @ 1 Hz with a -170 dBc/Hz noise > floor) I also claim all spurious to be < -120 dBc. This includes the line > frequency spurious. > > I'm happy my test set is making accurate phase noise results as I agree with > other test results on sample oscillators to < 2 dB. > > But I seem to have an error on measuring spurs. > > As you all know, when the 3048A detects a big peak, it marks it in red and > shows the actual value, rather than normalizing it to a 1 Hz bandwidth. > > To test the 3048A accuracy I inject a spur at a known level using a > directional coupler (similar to the single-sided spur calibration method). > > I confirm the spur level on the spectrum analyzer. However the 3048A always > says the spur is 6 dB lower than it actually is (6 dB plus/minus 0.5 dB). > > Can anyone tell me why this is so. > > I wondered if it had something to do with phase noise and amplitude noise > not being the same thing. > > Any response would be appreciated. > > Best Regards > > Martyn > > This Email is from: > > Martyn Smith > Precision Test Systems LTD > Tel: +44 (0) 1245 329608 > Email: [EMAIL PROTECTED] > Web: www.ptsyst.com > > 3dB since AM and PM components are equal plus another 3dB to correct measurement from actual DSB to SSB??
Bruce _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
