apache-labs.com

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

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

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.

That's a great article, Dan. I'm going to post that up separately in the sub-forum.