The difference between ASK/FSK receivers

[microlab]

ask/fsk receivers

hai all
i am trying to interface the rf transmiter/receiver module to the 89c51 microcontroller
where i found there are two types of them.FSK and ASK
what's the difference and advantage over another?
can we connect the rf modules directly to the serial port of the system?
is it necessary to add any encoder/decoder to the circuit
how can we impliment the antena on PCB?
i also would like to know what should i take care at the timr of design and writing softwares.
i am located in india,is there any place from where i can purchase the modules?
persons having prior experiance,please help me with your valuable advices

thanking you all


ml

 

[microlab]

Re: ask/fsk receivers

hai all
pls help me
i tried to interface an ASK receiver
but i'm receiving some junk charectors
what could be the reason and how can i solve it:

thanking you

ml

 

[hamdard]

Re: ask/fsk receivers

pL. be specific in the question. Upload the circuit diagram, you are using. Then I may help you.

 

[biff44]

Re: ask/fsk receivers

ASK circuits are normally used in very low cost applications where there is little interference, such as in a key fob for opening your car doors.

FSK circuits require much more circuitry, and are therefore more expensive. However, the nature of FSK is such that it can tolerate more interefence noise. So you can get longer range, and higher data rates in FSK.

 

[Mad2Max]

Re: ask/fsk receivers

Yes, as biff44 said reliability of FSK is higher.
Moreover there are lot of applications in which the distance between Tx and Rx is changing rapidly and you can't use Ask but just FSK.
In my experience, I would choose FSK anyway.
Max

 

[actinio]

Re: ask/fsk receivers

the antenna is embeded inside the RF modules, remember to take care about the interference as other members said.. It's important to establish some adjustaments in function the Tx-Rx you want to establish..distance..data rate.. Be specificall about the circuit and want do you want to do..