Keywords: class-spectral-axis-v12

Next: The signal frequency axis Up: The MODIFY VELOCITY command Previous: The MODIFY VELOCITY command Contents

### Principle

Changing the source systemic velocity is a change of source reference frame. The signal and image frequency scales in the measurement frame must stay constant under this transform. However they change in the source reference frame. Indeed

| (54)

with

| (55)

Hence

| (56)