I got my Hermes 14-bit board a few weeks ago and am up and running with Thetis. But I still haven't received my 10w PA board.
In the meantime....I was thinking about trying out one of those cheap 70w PA kits from eBay, AliExpress, etc.
If I understand correctly, Pure Signal should improve the out-of-band spurious performance of a linear (i.e. second, third, etc harmonics) in the same way that it improves in-band splatter (signal width on the waterfall).
A question: is it reasonable to assume that Pure Signal can clean up the output spectrum of such an amplifier sufficiently that post-filtering is not needed at all?
Thanks and 73!
Dan
Pure Signal, out-of-band improvement question
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Re: Pure Signal, out-of-band improvement question
phaselocked wrote:If I understand correctly, Pure Signal should improve the out-of-band spurious performance of a linear (i.e. second, third, etc harmonics) in the same way that it improves in-band splatter (signal width on the waterfall). A question: is it reasonable to assume that Pure Signal can clean up the output spectrum of such an amplifier sufficiently that post-filtering is not needed at all?
PureSignal is not a substitute for an amplifier's low-pass filter. You'll need to ensure LP filtering is included with the amp you purchase, or build it on your own.
Paul, W9AC
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- Posts: 7
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Re: Pure Signal, out-of-band improvement question
w9ac wrote:PureSignal is not a substitute for an amplifier's low-pass filter. You'll need to ensure LP filtering is included with the amp you purchase, or build it on your own.
Paul, W9AC
Thanks, Paul. After your reply, I read https://www.analog.com/media/en/analog-dialogue/volume-56/number-2/digital-predistortion-for-rf-communication.pdf. Clearly, my mental model of how pre-distortion does its magic was too simplistic.
Re: Pure Signal, out-of-band improvement question
That's a great article, Dan. I'm going to post that up separately in the sub-forum.