FSK OR BPSK, which one is better

[ahsan]

hi

I want to do RF communication. Basically i want to sent the data at 9.8kbps to a PC (RS-232 interface). I have two options, either to do FSK or BPSK (digital modulation). I want to know that which one is better and why ??. Which one has better signal to noise ratio.

thanks in advance

 

[flatulent]

The PSK will have 3 dB better performance at the cost of more complex receivers. The reason for the 3 dB is that FSK is orthogonal and PSK is antipodal. This may not mean much to you but the distance between the two signal points is 1.414 times larger for PSK.

 

[kleinesmurf69]

FSK IC's are readily available for designated frequency bands and are easy to interface with a microcontroller, e.g. hxxp://www.melexis.com.

Best regards.

 

[CMOS]

Use FSK for making your system power effecient.
If bandwidth effeciency is the main criteria of consideration, use BPSK.