Help on building an AM transceiver

[orphefs]

Hi all!

I want to design a schematic for an AM transceiver, starting from the transmitter...I am keeping in mind that the transmitter consists of 5 parts (correct me if I'm wrong!):

1) Mic/Line Input (should I include a mic-preamplifier?)
2) Oscillator (what kind should I use for this application?)
3) Mixer (can anyone advise me on something more specific?)
4) RF amplifier
5) Antenna

How would I go about starting the design process? How should I pick the circuits that are good for this application? Is there any help you could give me on this, any good resources to read?

Thanks for taking the time!

 

[Hero999]

1) You have several options, an op-amp is probably best.

2) LC oscillator is the simplist but if you want more accuracy then go for PLL and a crystal oscillator.

3) Can be incorperated into the oscillator.

4) This will need to be a linear amplifier so don't expect it to be very efficient. Another more efficient option is to build a class C amplifier and modulate the switched mode power supply (which is powering it) with the audio.

 

[audioguru]

Of course the very small signal from a microphone needs a preamp.
A transmitter has a modulator, not a mixer.

 

[k7elp60]

Since you are talking about a tranceiver, you should add an IF amplifier, a modulator, and TR switching just to name some more blocks.

 

[audioguru]

The receiver has not been mentioned.
It might be a crystal 'radio", a super-regen, a tuned RF or a super-heterodyne.

 

[orphefs]

hey, I would like to ask a question: what's the difference between a single and a double balanced mixer?

excuse me for my ignorance :S

 

[orphefs]

also, i found these designs on the net:

https://www.radio-electronics.com/info/circuits/diode_single_balanced_mixer/diode_single_balanced_mixer.php

will that do the job??

 

[stevez]

Amateur radio publications, 1960s vintage, might be a good place to look as AM was still quite popular.