Hi The TI ADS1271/4/8 might make a nice alternative to a sound card. They have a bit better DC performance than a lot of the sound card chip sets. There's an EVM available for them, but I haven't really looked much at it. The nice thing is that you could get 4/8 channels of simultaneous samples. Nice for doing three (or 4 or 8) corner hat sort of stuff.
Bob On Jun 1, 2012, at 5:02 PM, Bruce Griffiths wrote: > The AP192 exhibits an input noise floor of around 100nv/rtHz ( for a low > impedance source) or so (IFIRC - when I measured it.) so with an HP 10534A/B > or 10514A/B a post mixer amplifier gain of 60db or so is required to ensure > that mixer/phase detector noise dominates. The equivalent input noise tends > to be somewhat higher in the vicinity of 10Hz. > > Other high performance sound cards should have similar input noise. > > Bruce > > shali...@gmail.com wrote: >> If you can offset one enough to have the output from the dbm in the audio >> band, you could use a sound card based spectrum analyzer to evaluate phase >> noise. Some sound cards may work down to 10 Hz, but their performance there >> is usually not specified. Bruce Griffiths has information on some high >> performance audio cards and maybe he can chime here. >> >> Using the 3 corner hat method, you could identify the relative phase noise >> performance of three oscillators. >> >> It will not help with longer term variations though. >> >> Didier KO4BB >> >> Sent from my BlackBerry Wireless thingy while I do other things... >> >> -----Original Message----- >> From: Attila Kinali<att...@kinali.ch> >> Sender: time-nuts-boun...@febo.com >> Date: Wed, 30 May 2012 16:59:39 >> To: Discussion of precise time and frequency measurement<time-nuts@febo.com> >> Reply-To: Discussion of precise time and frequency measurement >> <time-nuts@febo.com> >> Subject: Re: [time-nuts] is there a cheap and simple way to measure OCXOs? >> >> On Wed, 30 May 2012 07:18:12 -0700 >> Jim Lux<jim...@earthlink.net> wrote: >> >> >>> Got a mixer around, so you can beat them against each other (or against >>> your 5680)? >>> >> Not yet. I'm currently thinking about geting an mixer from minicircuits >> for the ZX05-1L[1] and a low pass filter BLP-1.9[2]. >> >> But what then? The frequency offset is low enough that it is still >> problematic to measure with standard measurements instruments. >> And the phase noise.. out of question. >> >> Attila Kinali >> >> >> >> [1] http://217.34.103.131/pdfs/ZX05-1L+.pdf >> [2] http://217.34.103.131/pdfs/BLP-1.9+.pdf >> > > > _______________________________________________ > 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.
