Martyn - It depends on what you want to know. If you mix 10 MHz with 10.0001 MHz to create 100 Hz, you will have + 100 Hz and -100 HZ. The spectrum analyzer will more than likely only show the + 100 Hz. That does not mean there is no energy at -100 Hz, in fact most of the DSP I/Q processing depends on it. I do not have a 3048A so cannot replicate your measurement, but, I bet the 3048A is measuring the energy in both sidebands and that is why you are reading twice the voltage. The only way to guarantee that you have a true single sideband spur is by filtering. And, even then you have to make sure that any amplifiers following the filtered signal is well below compression or you will experience spectral re-growth of the unwanted sideband. Regards - Mike
Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Martyn Smith Sent: Thursday, January 17, 2008 9:03 AM To: [email protected] Subject: [time-nuts] New Question on HP3048A Phase Noise Test Set Bruce, Thanks for your input. Sorry I still don't understand. Could you explain further. The spur I inject is single sided (I mix 10 MHz with 10.000100 MHz to produce 100 Hz) So who is right? The spectrum analyser or the HP3048A. Best Regards Martyn _______________________________________________ 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. _______________________________________________ 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.
