The monitor can also be switched in the hardware to measure the sampling levels of the A/D converters for test purposes
The correlator hardware starts with 20-bits and integrates in a buffer up to 24bits; these are then read out by the 32-bit multiplexer, so the least significant 8 bits are zeros.
The nominal value is "15K"
actually it is closer to 160.0047MHz
actally it is nearer to 160.0047MHz
The accuracy needed scales with the beam width, so that a 1 second accuracy is needed at 6cm
Divide by the wavelength of the line (in mm) to go from km/s to MHz, a positive velocity is lower frequency. The difference between LSR and barycentric is about 20km/s.
These observations were made in 1988 and 1989.