Re: Software Defined Superhet
- --- In firstname.lastname@example.org, "Bob Hillard" <rhillard@a...>
> The first device in the received signal's path determines the
> noise figure. If it's a DBM, then the noise figure can't be anybetter
> than 6 dB. Putting a low noise preamp in front of the DBM fixesthis.
>I seem to remember reading some place the QSD mixer had a noise
in the area of 12 db ? Would this not be acceptable except maybe
above 28 mhz since the terrestial noise figure would be >15 db?
It would be interesting to see a gain/noise chart by stages of the
better commerical receivers when compared to the SDR-1000
Does anyone know the maximum usable gain of a receiver(?) aren't we
getting very close to that number in current HF technology?
Are we not close to the point where the LO phase noise and front end
IMD are the current limiting factors in a receiver design?
I would be interested in reading others response in these area. It
is an area in which I know very little.