[Elecraft] Kx3 receiver

[Wayne Burdick]

J. Fielden <gijoe1644 at gmail.com> wrote:

> is the kx3 receiver RF direct sampling or ?

Hi Jim,

The KX3's architecture is pretty unique. First, we use a quadrature downconverter to get I and Q signals at a baseband (zero Hz) I.F. Using a zero I.F. allows us to insert optional high-performance analog roofing filters into the path, protecting the A-to-D converter and DSP from out-of-band signals. The roofing filter module includes a narrow filter for CW and a medium filter for SSB/DATA.

When the filters are installed, the KX3 has blocking dynamic range of nearly 140 dB, higher than that of even the most advanced direct-sampling radios. (But not quite as high as the K3S, which uses a superhet architecture with crystal filters to obtain off-the-charts dynamic range in the 150 dB range.) 

With the filter module, the KX3 places 5th on Sherwood's receiver performance chart:

   http://www.sherweng.com/table.html

Even without this module, the KX3 receiver would still be in the top ten. 

That's the long answer :)

73,
Wayne
N6KR