This simple circuit found in a 1968 EEE was intended for data transmission over the telephone line. The components are from that time, some are uncommon today.
The circuit presented uses Linear Technology Operationals, having been found in a 1993 manual. The...
The circuit presented with low drift is from the Motrorola LinearDatabook of 1990. The circuit...
120 degree lagged signals can be obtained with the simple configuration shown in the figure....