Transfer functions of the injection locking servo electronics were taken.
The previous measurements from when the PSL underwent acceptance testing
are posted in the DCC under
  https://dcc.ligo.org/DocDB/0100/E1300129/001/tf.pdf
That result listed the unity gain and phase margin as being 2.8 kHz and
57 degrees respectively.

With the previous setting of gain = -1.50V, the unity gain is ~8.5 kHz
with about 40 degrees of phase margin.  Setting the gain to -1.70V, upped
the unity gain to ~10 kHz.  This is consistent with the acceptance test
result from L1, which is in the DCC under
  https://dcc.ligo.org/DocDB/0068/E1100716/006/injection_locking_tf.pdf

Also attached is the oscilloscope image of the injection locking error
signal.



Jason, Peter