Re: analog multiplier help


theJackal wrote:
> On 21 Dec 2005 04:36:13 -0800, bill.sloman@xxxxxxxx wrote:
>
> >The OP wants to generate a 5kHz output from his mixer, and he seems to
> >want to keep the harmonics 40dB down or lower. One would have thought
> >that a multipole 5kHz bandpass filter would deal with them, but maybe
> >he can't cope with the phase shifts through such a filter - I've had
> >that problem.
> >
> >> Did you read those articles? NO I guess because they mention use of
> >> the MOS at lower frequencies.
> >
> >No, I haven't read the articles, in part because I haven't got easy
> >access to the articles you cited, in part because I haven't had time,
> >and in part because I haven't yet had any real reason to take you
> >seriously. That you can find articles to cite moves you many notches up
> >the pecking order, but your log 1^6 /log 12 x 4 blooper moves you right
> >back down again.
> >
> >----------------
> >Bill Sloman, Nijmegen

<snipped crap>

> Let me take 1 example... above you claim that the output of the mixture has to be 5kHz
> according to the Op. ... Absolutely wrong The Op said his IF filter is centered on that
> frequency . The output of the mixer contains a mixture of the sums and differences of the
> LO , signal and carrier frequencies.

These are the "spurs" I was talking about. By multiplying clean sine
waves with a good analog multiplier, you can minimise most of the
irrelevant sum and difference products - obviously you are stuck with
the up-to-20MHz sum associated with the 5kHz difference.

> And i could go on but

You do go on.

> I must admit though that compared to some people in this newsgroup who have posted to me
> you show human traits that distinguish us from the lower beasts.

Whereas I'm afraid I've got to consign you to the lower beasts.

--
Bill Sloman, Nijmegen

.

Quantcast