sheng_james

hi guys i just a few question about designing a fm transmitter. what are the things that i should consider in designing it.

Torben

Some things to consider:

- Licensing. Are you in a region where transmissions are regulated? You may need a licence to operate; you should check that out.
- Construction techniques. You won't be able to breadboard it; wire lengths and connection quality are important.
- How much money do you have to spend on this? It'll probably be more expensive to build than to buy.

What exactly are you trying to do? What are your power requirements?

You could try looking up local ham radio clubs. If you find one, get in touch with them and chances are someone will be happy to give you advice.


Torben

RadioRon

-what frequency will it operate on?
- what output power will it deliver?
- what kind of antenna will be used with it?
- what kind of receiver will be used to receive it?
- what power supply will be used?

Based on the answers to those questions, others will then come up like:
- what bandwidth will my signal occupy, and therefore what frequency deviation will my modulator deliver?
- what type of modulator will be required...analog, digital, stereo, subcarrier?
- if digital, what protocol or standard will be supported?
- what frequency stability will be necessary?
- what modulation signal to noise ratio will be met?
- what spurious emissions are acceptable?

there are many other questions, but these are the basics. FM transmitters are commonly used in broadcasting and two-way communications radios, so it would be helpful if you specified which type you are thinking of as the two types are very different.

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RadioRon