The quadrature detector on your imager has a reference signal of 63.85 MHz coming into one of the channels.
The signal channel has a signal of 63.86 MHz coming into it.
What frequency or frequencies will be coming out of the detector?
The DBM within the quadrature detector produces frequencies at (ν - νo) and (ν + νo).
The filter within the quadrature detector removes (ν + νo).
ν = 63.86 MHz, and νo = 63.85 MHz.
Therefore, (ν - νo) = 10 kHz.