ok. i'm going to design a bpsk demodulator. then, for recovering the modulator signal, i need a frequency divider, because i do the square of the signal, and with a pll i obtain my wave signal but with a frequency two times the one i need. then, how can i divide this frequency? thanks.
You use a digital divider, as you commonly do in PLL circuits. However, you need to get one which will work at 100MHz - I think standard TTL is only 50MHz.