Heterodyne Heterodyning No one knows Commentary

Reginald Fessenden electromagnetism

Heterodyne

• To broadcast Morse code signals, a radio wave
• is turned on for different intervals to signify dashes and dots.
• However, to broadcast voice or music
• the signal must modify a continuous radio wave.
• Amplitude modulation of a radio frequency
• requires shifting the message frequency and combining it
• with the frequency of the continuous radio wave.
• This process is called heterodyning.
• For transmitting, the message frequency
• is combined with the carrier frequency;
• for receiving, the carrier frequency is subtracted from the signal
• resulting in a message shifted to the audio range.

Heterodyning

• Theremins heterodyne
• the variable capacitance
• of the musician’s hand to produce
• a corresponding audible tone.
• Frequency division multiplexing
• heterodynes hundreds of channels
• into different frequencies
• to share the same optical fiber.
• Superheterodyne receivers heterodyne
• the radio frequency that you select
• into an intermediate frequency
• that is processed so you can hear it

No one knows

• No one else can tell
• what goes on in my head.
• All I know is that I call “red”
• whatever’s labeled by that adjective.
• In between, the color
• doesn’t persist,
• only something different
• that represents it.