  FRB 20220912A is a repeating Fast Radio Burst (FRB) that was discovered in
Fall 2022 and remained highly active for several months. We report the
detection of 35 FRBs from 541 hours of follow-up observations of this source
using the recently refurbished Allen Telescope Array, covering 1344 MHz of
bandwidth primarily centered at 1572 MHz. All 35 FRBs were detected in the
lower half of the band with non-detections in the upper half and covered
fluences from 4-431 Jy-ms (median$=$48.27 Jy-ms). We find consistency with
previous repeater studies for a range of spectrotemporal features including:
bursts with downward frequency drifting over time; a positive correlation
between bandwidth and center frequency; and a decrease in sub-burst duration
over time. We report an apparent decrease in the center frequency of observed
bursts over the 2 months of the observing campaign (corresponding to a drop of
$6.21\pm 0.76$ MHz per day). We predict a cut-off fluence for FRB 20220912A of
$F_\textrm{max}\lesssim 10^4$ Jy-ms, for this source to be consistent with the
all-sky rate, and find that FRB 20220912A significantly contributed to the
all-sky FRB rate at a level of a few percent for fluences of $\sim$100 Jy-ms.
Finally, we investigate characteristic timescales and sub-burst periodicities
and find a) a median inter-subburst timescale of 5.82$\pm$1.16 ms in the
multi-component bursts and b) no evidence of strict periodicity even in the
most evenly-spaced multi-component burst in the sample. Our results demonstrate
the importance of wideband observations of FRBs, and provide an important set
of observational parameters against which to compare FRB progenitor and
emission mechanism models.
