[Premium-Rx] The new R&S EM510 Direct-Sampling HF Receiver

[John Miles]

> Let's do the numbers. Let's say you have a 2 bit radio and that you are
> sampling at 100 MHz. The S/N in the nyquist band is 2*6.02+1.76
> or roughly
> 14 dB. The nyquist band is 50 MHz wide so you get a per Hz improvement in
> C/N of 10*log (50MHz)= 77dB. that means that if I used a digital
> filter that
> is 100Hz wide (a 20 dB hit from 1Hz) you could still get 70dN of
> C/N. This I
> would say is more than sufficient to demodulate CW, FSK, PSK etc.

I imagine this is also how the original Collins HF-2050s worked with the
primitive 8-bit ADCs available at the time, didn't they?  What was the
acquisition bandwidth on those?

> This technology is right around the corner with better
> performance and lower
> cost. I hate to say it since I am a die hard RF guy, but the more I play
> with this technology the more potential I see.

The real implications of this trend come to light when you realize that
Rohde & Schwarz uses the same $50 ADC chip that you use.  All of the
hardware technology that matters is inside that one off-the-shelf chip.
"Exotic" receiver performance really is a commodity at this point, and the
players are all going to have to differentiate themselves on the software/UI
side of things.

That's not necessarily a bad thing, but it does take some of the romance out
of it!

-- john, KE5FX