  We report on the study of the impact of the finite resolution of the chirp
rate applied on the frequency difference between the Raman lasers beamsplitters
onto the phase of a free fall atom gravimeter. This chirp induces a phase shift
that compensates the one due to gravity acceleration, allowing for its precise
determination in terms of frequencies. In practice, it is most often generated
by a direct digital synthesizer (DDS). Besides the effect of eventual
truncation errors, we evaluate here the bias on the g measurement due to the
finite time and frequency resolution of the chirp generated by the DDS, and
show that it can compromise the measurement accuracy. However, this effect can
be mitigated by an adequate choice of the DDS chirp parameters resulting from a
trade-off between interferometer phase resolution and induced bias.
