AM transmitter modulation circuit design question
AM transmitter modulation circuit design question
(OP)
I'm currently in the process of building an AM radio transmitter, and it's working, but not great. When modulating the signal, a section of the negative part of the wave is being cut off. Does anyone know what might cause this to happen? Here's an image pulled from the oscilloscope, with the input signal (yellow) and the modulation (blue):





RE: AM transmitter modulation circuit design question
https://en.wikipedia.org/wiki/Radio_transmitter_de...
The most straight-forward concept is 'Plate Modulation'. This is where the high power audio signal is imposed on the 'Plate' (or solid state equivalent) voltage in a final power amplifier stage.
You might simply be over-modulating, and it just so happens that you're running out on the negative side before the positive. In other words, if it's 'Plate Modulation', your plate voltage is going negative.
RE: AM transmitter modulation circuit design question
It would be very useful to show us the schematic. Use the picture with the circle in it.
Keith Cress
kcress - http://www.flaminsystems.com
RE: AM transmitter modulation circuit design question