Keywords: pdbi-freq-setup

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## Basic Equations

The LO2 frequency used to track a spectral line at a given frequency Frest centered in the IF band (350 ) is

| (6)

and, from eq. (5), the image rest frequency at the band center is

| (7)

A little algebra follows

cm and result in

| (8)

This result is not independent of the Doppler effect. Accordingly, it the doppler tracking is not exact for the image frequency. and for 2 different values, and , corresponding to different velocities and , we obtain (assuming no change of )

| (9)

or, assuming and , and with , , the frequency shift in MHz is

| (10)

or, in velocity (in km.s)

| (11)

Next: Consequences Up: Image Frequency Doppler Tracking Previous: Image Frequency Doppler Tracking Contents