This circuit was found in an Electronic Design from 1964. The components are from that time and can be replaced by equivalents. The modulation ranges from 0.25 to 0.75 of the 20 kHz pulses.
This circuit, suggested by National Semiconductor, provides an output voltage proportional to the...
Found in 1980s documentation, this amplifier uses a symmetric source and the gain is given by the...
This modulated light transmitter was found in a 90s Popular Electronics. In place of the lamp with...