[time-nuts] RF Mixers for oscillator comparison

[Ulrich Bangert]

Arnold,

as Bruce did already mention Minicircuits names MUNICOM as one of their
German distributors. The second source is Industrial Electronics Gmbh where
I buy Minicircuit parts from, just because they are located in the northern
part of Germany as me. They can supply a lot of parts right out of their own
stock and need only few parts to order themselves from the US. They deliver
also in small quantities like 1-5 but be prepared to pay a higher price per
part in small quantities.

Minicircuits have a BROAD range of mixers. Among other they built the RAY-3,
a 23 dBm high level mixer, that I have seen used in oscillator
characterization publications. My understanding about the benefits of high
level mixers for that purpose is that it allows you to work with higher RF
levels which in turn leads to a higher IF level which in turn may lead to a
better overall s/n of the system. 

On the other hand Minicircuits now supplies a class of "high output level"
mixers that may perhaps serve the same purpose.

Best regards
Ulrich Bangert   

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Arnold Tibus
> Gesendet: Montag, 20. April 2009 00:05
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] RF Mixers for oscillator comparison
> 
> 
> On Mon, 20 Apr 2009 09:03:36 +1200, Bruce Griffiths wrote:
> 
> >Corby Dawson wrote:
> >> Arnold,
> >>
> >> Look at the top of page 3 on the link below. Not sure how they 
> >> arrived at their conclusion but there is one opinion on the HP 
> >> mixers!
> >>
> >> http://www.unusualresearch.com/AppNotes/TimeNuts/OptDualMixer.pdf
> >>
> >> Corby Dawson 
> >> ____________________________________________________________
> >> Debt collectors calling your house?  Click here to 
> consolidate into 
> >> one payment. 
> >> 
> http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTIk3l9oQnolYGEY40TV
> >> wmsBD4opDDeVSRG36KHWHhZWexSiuRrXdm/
> >>
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> >>
> >>   
> >Statements about the low flicker noise of these mixers are sprinkled 
> >throughout the phase noise literature. Someone must have 
> measured the 
> >phase noise of these and other mixers at some time.
> 
> >Its relatively easy to measure mixer phase noise:
> >All one needs is a low noise preamp plus a sound card a 90 degree 
> >hybrid (or a suitable length of coax and a splitter) and a low noise 
> >source.
> 
> >However NIST papers often include a phase noise plot (attached) that 
> >illustrates that high level mixers can have a significantly 
> lower phase 
> >noise than low level mixers (like the HP10514A). When 
> choosing a mixer 
> >for this for phase noise measurement applications one may 
> actually need 
> >to measure the phase noise characteristics of candidate mixers.
> 
> >Bruce
> 
> 
> Wow, a good overview, Bruce! 
> 
> But remain the questions: 
> which are these high level mixers, are they readily available? 
> Are they affordable? 
> Perhaps not, why are they then not applied more often?
> 
> Arnold
> 
> 
> 
> 
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