Dear Graham, LF Group,
Try searching under "envelope elimination restoration" or "Kahn modulation
transmitter" - should get you several hundred thousand hits, but I haven't
yet found a good general reference. I think a large proportion of modern big
broadcast TXs use this technique to get high efficiency, and there is much
current intrest for on-chip PAs in personal wireless digi-widgets of various
kinds, but there is relatively little amateur-type material about this type
of technique - amateurs generally seem to have rather fallen behind the
times in TX hardware.
There is a lot made of the intricacies of getting good linearity in this
type of system, but with quite low carrier frequencies, and narrow
modulation bandwidths, most of the difficulties are greatly reduced. I used
a similar but bigger system on 136k a few years ago to get 1.2kW of PSK31
and "Wolf" BPSK - the 500kHz rig is intended to be a test-bed for a more
versatile version.
DF6NM's chirped-hell mode has both amplitude and phase modulation, so it is
definitely a "linear" mode. As in Hartmut's screen shot (thanks, Hartmut !),
it produces intelligible characters directly on the spectrogram screen. As
such, it isn't really a keyboard to keyboard mode - operating is similar to
QRSS, at similar "slow" speed. But the EER rig should work with pretty much
any digital mode - so far I have only tried it with PSK31 because that's
what is on my PC at the moment. I was wondering what modes people were
trying / thinking of trying, so that I could get hold of the neccessary
software and figure out how to work it!
Cheers, Jim Moritz
73 de M0BMU
----- Original Message -----
From: "Graham" <[email protected]>
To: <[email protected]>
Sent: Tuesday, October 30, 2007 11:55 AM
Subject: Re: LF: EER Transverter and Linear Modes testing
> ? Is this a keyboard-keyboard mode ? is it linea or 'fsk'
>
> EER Transverter , not seeing anything on google, is there a link for it ?
>
> Tnx
>
> G ..
>
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