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M17-Project / TR-9

TR-9 - M17 protocol compatible handheld - schematics, PCB design files, BOM.
https://m17project.org/
GNU General Public License v2.0
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Power output #3

Open sp5wwp opened 3 years ago

sp5wwp commented 3 years ago
  1. Power output is limited to 0.75W. At that power, the bias voltage is 2.9V.
  2. There's a high pitched sound audible when PA is active.

ALC circuitry works.

sp5wwp commented 3 years ago

Squeak was eliminated by adding a 10k resistor in parallel to C106.

sp5wwp commented 3 years ago

Maybe we should get rid of Q3 (BGA6589).

tkuester commented 3 years ago

Is this related to issue #8/9 in the errata, about R64 and C106?

sp5wwp commented 3 years ago

@tkuester yes, it is.

sp5wwp commented 3 years ago

The RF lowpass stage (around L9, L10) has to be redesigned.

My proposal: obraz