James Lux, P.E. Task Manager, SOMD Software Defined Radios Flight Communications Systems Section Jet Propulsion Laboratory 4800 Oak Grove Drive, Mail Stop 161-213 Pasadena, CA, 91109 +1(818)354-2075 phone +1(818)393-6875 fax
> -----Original Message----- > From: time-nuts-boun...@febo.com > [mailto:time-nuts-boun...@febo.com] On Behalf Of John Ackermann N8UR > Sent: Thursday, January 08, 2009 10:30 AM > To: dan...@verizon.net; Discussion of precise time and > frequency measurement > Subject: Re: [time-nuts] 10 MHz Band-Pass Filter Needed > > Dan Rae wrote: > > Richard W. Solomon wrote: > >> The GPSDO I want to use has an output rich in harmonics. In some > >> cases that is good, but Murphy rules and in the application I have > >> today, it is not good. > >> > >> I need a 10 MHz Band-Pass Filter, Bandwidth is not critical, > >> something small with SMA connectors would be ideal, but I > can live with BNC. > >> > >> Anyone have such a beast or know where I can get one ? I checked > >> Mini-Circuits and choked on the price !! You mean the ever popular BBP-10.7 for $41? Hard to beat that price for something comparable. > >> > >> > > > > Dick, it is really easy to build one. The wonderful (free!) filter > > design program ELSIE will give you all the help you need. I would > > have thought an hour or so with a couple of toroids would do the > > trick. Even just a Low Pass filter would usually do to > turn a square wave into a sine... > > It's actually much better to use an LPF than a bandpass > filter if you don't have subharmonic energy to deal with. An > LPF with a cutoff midway between the fundamental and the 2nd > harmonic will show much less tempco (in the form of phase > shift over temperature) than a bandpass filter. You might even be able to use some wonky little filter feedthrough with a suitable cutoff frequency. _______________________________________________ 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.