Electronic Gain Control in Quartz-Stabilized Oscillator

This is a quartz-stabilized oscillator circuit with electronic gain control. Replacing the common filament lamp  for amplitude stabilization, this circuit use an electronic gain control inside the stabilization loop. A 50-Ω variable resistor should be trimmed until the output level show 2-Vpp magnitude oscillations op-amp A1 output. Here is  the schematic diagram of the circuit:

[Circuit’s schematic diagram source: Linear Technology]