HP 3457A Service Manual page 180

Slope Amplifier (U513)
In order to reduce the voltage sensitivity requirements and enhance the available input overdrive of the
comparator,
an amplifier (U5S13) is inserted between
the output
of the integrator amplifier and the
comparator input.
Its prim purpose
is to amplify the smaller slopes before the comparator input.
This offers improved resolution of slope zero crossing detection.
ce this i s its function, it's generally
referred to as the Slope Amplifier. This amplifier provides an inverting gain of 20.
DA Compensation (U514 and Q512)
A/D Analog Auto-Zero Loop
HP 3457A Multimeter
8-15