Found in American documentation from the 1990s, this TTL circuit operates at frequencies typically up to 100 kHz. Input signals must be rectangular.
The circuit shown is from the Texas Instruments optoelectronics manual, applying to low power...
This circuit was found in a 1968 General Electric documentation. It has an input impedance of 2 M ohms...
This filter that rejects a frequency range determined by the double-T was found in the August 1993...