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Power Amplification

Question asked by dgeorgethomas in #Coffee Room on Jul 21, 2009
dgeorgethomas · Jul 21, 2009
I need to send a full wave signal over 10km of co-ax. I'm needing to transmit at 10 watts and it needs to be matched to the 50 ohm line. I'm having trouble figuring out what the best way to get both my power needs with 50 ohm matched. I'm wondering about a push-pull bjt network but i'm not very familiar with using such high power. Can anyone make a suggestion? Also do I need anything on the receiving end to accompany my demodulation of the signal. i.e. to ensure it is getting 10 watts. Posted in: #Coffee Room
dgeorgethomas · Jul 21, 2009
My post seems confusing since I am not very familiar with my problem. To simplify/clarify it I need the following:

10 watts out @ 50 ohms to an RG-58
w/ Full Wave @ around 32Khz or so.

I think the easiest way would be to use something like this Push-Pull Output Stage
or an audio amplifier, but I am unsure how to make it output 10 watts as well as matching to 50 ohms. This is a small problem in a big project but i can't seem to figure it out.

reachrkata · Jul 23, 2009
Rank C2 - EXPERT
I am not sure if Audio amps will help because 32kHz is out of the Audio range.😒

However a normal Class A/Class AB amplifier followed by an Emitter follower / Darlington with a 50 Ohm emitter resistance should do the trick. However choose the transistor device to match your power requirements.

- Karthik
Munguti · Jul 24, 2009
Rank C3 - EXPERT
My advice is to use to amplifiers, one will be a class A amp with very good linearity and the other will be a class AB push/pull. The preamplifier ensures that your signal is of such amplitude that it is not distorted by subsequent class AB push/pull amp.

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