Bruce, tks for your reply. > The latest spectrum analyser offerings from Agilent have similar phase > noise floors for both the millimeter wave and low frequency spectrum > analysers.
Yes, but kind of puzzles me a bit since I would be expecting phase noises more than 10x worst on a SA covering DC to 1GHz (+/-) (since the LO for this is an YIG oscillator circa 3GHz locked to a reference) comparing with an FFT analyzer that uses a few tens MHz sample rate. Assuming similar 10MHz reference oscillator the SA gets it multiplied by 300 while a low freq SA (preferably FFT) gets it multiplied by 10 maximum. How can they claim similar performance ?! --- Ok on the rest, tks. Luis Cupido. Bruce Griffiths wrote: > Luis > > The latest spectrum analyser offerings from Agilent have similar phase > noise floors for both the millimeter wave and low frequency spectrum > analysers. > However the low frequency analysers have a lower "flicker" noise corner. > > The noise floor of a good double balanced mixer is still 30-40dB lower > than that a spectrum analyser. > > Thus you are stuck with using a low bandwidth phase lock loop to get > down to the mixer noise floor. > > Alternatively a dual (first conversion uses analog mixers, 2nd > conversion uses DSP techniques) conversion Costas receiver using 4 > mixers and 4 ADCs should go down to -170dBc @ offsets of 100Hz or so > when correlation techniques are employed. Its a pity the TSC5120A doesnt > allow independent access to all 4 of its ADC inputs so a quad of > external mixers can be employed to extend the technique to the > millimeter wave region. > > All you need is 4 high resolution ADCs and an offset generator or 2. > A couple of high end sound cards may be suitable at least for testing > the concepts. > > Bruce > > _______________________________________________ > 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.