If we replace the potentiometer VR1 with an AC signal plus DC bias signal in any of the previous Figures 3 to 17, the voltage controlled attenuators can become an amplitude modulator circuit instead.

The AMMA-2, the new digital AM modulation monitor from Belar, may look like an ordinary piece of broadcast equipment. It’s one rack unit tall and has the typical buttons and LEDs on the front panel.

There was a time — not long ago — when radio and even wired communications depended solely upon Morse code with OOK (on off keying). Modulating RF signals led to practical commercial radio stations ...

Field tests are described which investigate the transmission of compatible-single-sideband signals from a typical high-power transmitter for high-frequency broadcasting and which compare reception of ...