[Premium-Rx] HP 8649B?

[John Perlick]

Alberto

I've had both the SMD (two of them, just the 1 Ghz version of the SMDU) and
several 8640's.  The 8640 definitely has the edge on phase noise,
particularly in the HF region (cavity oscillator versus the LC oscillator in
the SMD/U).  But both are very good sig gens.  They are both extremely well
shielded.  I've worked on both and they are both extremely well built.

The only reason I would like the SMD/U over the 8640 is the nicer
flexibility with the microprocessor control, nice sweep functions, and mine
both had the AF modulation synthesizer also so that gave me 0-100 KHz
modulation AM/FM capabilities.  By the way, I was able to get one of hte
last SMD service manuals out of Rohde Schwarz, so let me know if you need a
copy of something.  If it's a few pages, I will do it for free.

Overall, if you need a very good, low noise gen, the SMD/U is great.  For
the best possible phase noise at inexpensive costs, I think the 8640B is
still tough to beat.  I think the HP 8662 or 8664 are better, but very, very
expensive.

----- Original Message -----
From: "Alberto di Bene" <dibene at usa.net>
To: <premium-rx at ml.skirrow.org>
Sent: Wednesday, August 20, 2003 12:44 PM
Subject: Re: [Premium-Rx] HP 8649B?


> Has anybody ever compared the HP 8640B with the Rohde  & Schwarz SMDU ?
> I have just bought the latter on eBay for a good price, but I don't have
> an 8640B
> to compare it with.  Functionally they are similar, though with a very
> different look,
> but how do they compare as far as phase noise or shielding are concerned ?
> Thanks.
>
> 73  Alberto  I2PHD
>
>
>
>
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