[Elecraft] FM Modulation

[David Toepfer]

> The choice is either lots of modes and modulations or good large signal
> properties - at least if the price is to be in the ham market. The K2
> designers have chosen to focus on the large signal properties.

And I thank them for this.

dt
.

--- Sverre Holm <svholm2 at broadpark.no> wrote:
> > I wonder why K2 and XV series have only CW and SSB modulation 
> > but not FM? Maybe, the answer of this question is very simple 
> > but any point of view would be appreciated.
> > 
> 
> If the K2 were to have FM it would need a wider filter after the
> post-mixer amplifier. This filter which is either a variable CW filter
> 0.1-1.5 kHz or an SSB filter 1.9-2.5 kHz, also determines the large
> signal properties of the rig along with the phase noise of the VCO and
> the mixer itself. This filter which is called the roofing filter, should
> shut out as much as possible of the undesired signals. 
> 
> In most other rigs, the roofing filter is much wider to accomodate the
> widest modulation of the rig (often FM), and consequently these rigs
> need to filter later, with DSP's etc. But by then the damage has already
> been done, and the large signal properties suffer. 
> 
> The choice is either lots of modes and modulations or good large signal
> properties - at least if the price is to be in the ham market. The K2
> designers have chosen to focus on the large signal properties.
> 
> --
> 73, 
> Sverre
> 
> ------------------
> Sverre Holm, LA3ZA
> www.qsl.net/la3za
> 
> 
> 
> 
> 
> 
> 
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