Magnus Danielson wrote:
Bruce Griffiths wrote:
Magnus Danielson wrote:
Bruce Griffiths wrote:
Active mixers almost invariably have a higher noise floor than
passive mixers, particularly in the flicker noise region.
Consequently a DMTD system using active mixers will have a higher
system noise floor than one using active mixers.
... than one using passive mixers.
You still need driving amplifiers.
Cheers,
Magnus
Its much easier to ensure that the flicker phase noise of a buffer
amplifier is low than it is to achieve a low flicker phase noise for
an mixer using nonlinear active devices.
Even passive FET mixers have higher flicker noise than passive mixers
using schottky diodes.
True, but my comment was rather to say that it will most probably not
be all passive, but I completely agree (as you very well know) that
phase noise of amplifiers is much better contained than that of mixers.
Cheers,
Magnus
Hej Magnus
To confuse matters Minicircuits use the term active mixer for a
conventional diode mixer that uses amplifiers on the LO and/or RF ports
to boost signal levels.
Whereas I was referring to mixers like gilbert cell mixers as active mixers.
With the Minicircuits so called active mixers one needs to measure
their phase noise in order to make meaningful comparisons.
Bruce
Bruce
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