FSK modulation of 1Mbps data on a PLL loop

[7rots51]

Hello

I want to use an analod device PLL (ADF4xxx) and a VCO from minicircuits (in range about 2GHZ, and modulate the 1mbps data on it ,my modulation type is FSK.


How can I modulate this high data rate signal? what is the value of frequency seperation?

 

[biff44]

You need a narrowband loop, probably around 3 KHz loop bandwidth. You need to divide down the VCO frequency to a very low reference frequency, to perhaps below 25 KHz, to keep the instantaneous phase deviation well below 2Π. It would help to Manchester encode your data, so the center frequency does not wander. It would help to randomize your data so that if there is a long string of zeroes, the frequency does not drift off 500 KHz.

 

[jason_tian]

the frequency deviation is subject to the bandwidth and BER you want to achieve,
plz refer to some communication books for such a diagram.

 

[7rots51]

I used manchester encoder ,please send a diagram or article on this topic?

how can I apply 1Mpbs signal ? Apply it to VCO tune voltage?