# Coupling constant in 1H NMR with phosphorus

I observed a doublet with peaks at 5.6336 and 5.5886 ppm with the NMR instrument running at 300 MHz, and got a $$J_\ce{PH}= \pu{13.5 Hz}$$. Is this correct for this molecule (ethoxycarbonylmethyl(triphenyl)phosphonium bromide)? This value is larger than the hydrogen coupling constants for the C-C bonds. Is this larger coupling constant a consequence of the phosphorous?