Frequency correction of a radio module. An estimate is made of the amount
of frequency correction needed while applying an original reference
frequency. If the frequency correction needed is greater than a
pre-determined amount, a large shift frequency correction is performed,
including applying a new reference frequency and verifying that the large
shift frequency correction is satisfactory. If the large shift frequency
correction is unsatisfactory, the original reference frequency is
restored. If the frequency correction needed is smaller than a
pre-determined amount, a small shift frequency correction is performed,
including applying a new reference frequency and updating a total of all
frequency corrections made since a stored reference frequency was
updated.