This 1967 Philips circuit recognizes a light signal (visible or infrared) modulated by tone. The circuit makes use of components of the time that are equivalent to the current BCs.
The circuit shown in Figure bellow generates frequencies of 50 Hz, 100 Hz, and 200 Hz. The circuit uses a...
This circuit rejects frequencies around 1 kHz and can be adjusted using C1. Equivalent operational...
From stereo inputs, this circuit generates a modulated and multiplexed signal to be transmitted in the FM...