[R-390] HP 8640B Question

[2002tii]

Jerry wrote:

>I went through two 8640b's several years back and ended up with the same
>gear and output attenuator problems as everybody else before I threw up
>my hands and bought a clean used HP 8656B
>      *     *     *
>Even though it's relatively old technology, it's like
>stepping up from a Yugo to a Lexus for receiver work when compared to
>the 8640B. I especially like being able to quickly program sets of IF
>and RF alignment freqs and output levels for a bunch of different
>receiver bands, and recall any of them instantly with a couple of button
>punches during an alignment procedure.

The 8656A/B and 8657B are great generators, but like all synthesized 
generators, their phase noise and spectral purity are orders of 
magnitude worse than the 8640B (harmonics specified at only >30 dB 
down!).  That's why the 8640B is beloved by engineers the world over 
-- stability similar to a synthesizer but (still, today) world-class 
signal purity from that wonderful cavity resonator.

Best regards,

Don