https://hackaday.com/2021/08/06/sbitx-hackable-hf-sdr-for-the-raspberry-pi/
Month: August 2021
AFTIA! The Audio Frequency Termination Insensitive Amplifier from W7ZOI
It really pays to check Wes Hayward’s web site. I looked yesterday and found something that we really need: A termination insensitive amplifier for audio frequencies — an AFTIA. Just last week I was looking at the AF amplifier of my Mythbuster rig, wishing that it had TIA properties. Now, thanks to Wes, we have a circuit available: http://w7zoi.net/audio-fba.pdf
And let’s not forget that it was Wes Hayward W7ZOI and Bob Kopski K3NHI whose 2009 article alerted us to the RF variety of termination insensitive feedback amplifiers.
Mythbuster Video #12 — Bandpass Filters
The really cool part comes at the end when I put the scope probe on the output, then on the input of the bandpass filter. Exciting stuff my friends!
Mythbuster Video #11 — Block Diagram and Overview of the Transmitter Circuits
Much of the transmitter is now done. This video looks at the circuitry and how it all fits together.