Commonly used Amplifier Topologies for RF circuit for FM Band

Thread Starter

philm01

Joined Mar 22, 2014
37
Hello all,

I was wondering if I could get some help. I am looking into designing some RF circuits for a project and I was wondering if there are any commonly used topologies for amplifing the signal? I found this pdf which I have been using as a reference:
http://www.qsl.net/v/va3iul/RF Power Amplifiers/RF_Power_Amplifiers.pdf

But the document presents all of the topologies that are available. Which is fine but again, I am wondering if there are any that are used alot in RF FM design.

Also, for one of my projects, I will be using RDS to control a device. Again, I was wondering if there are any commonly used amplifiers for FM sideband (the sideband is what the RDS works in).
 

Motanache

Joined Mar 2, 2015
481


Look so most common RF power stage.
Voltage divider of 2 capacitors and 1 coil. Minimum structure between two working common emitter bipolar transistors.
The structure (voltage divider of 2 capacitors and 1 coil) acts as a filter and and impedance adaptive.

Impedance adaptation should be done exit between the first stage outout and second stage input and so on.

How RF transistor parameters differ for the same type of transistor, there are many elements of this adjustment (variable capacitor).

Well filtered power for each stage.
RFC stops low frequencies, including constant current.

EDIT: I added a variation in witch voltage B-E it is performed using a diode.
 
Last edited:

bertus

Joined Apr 5, 2008
20,537
Hello,

The shown schematic is a class C amplifier as there is no bias.
It can only be used for FM as AM and SSB will require a linear amplifier.

Bertus
 
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