Lesson plan
ring modulation
, showing ring of diodes In electronics, ring modulation is a signal processing function, an implementation of frequency mixing, in which two signals are combined to yield an output signal. One signal, called the carrier, is typically a sine wave or another simple waveform; the other signal is typically more complicated and is called the input or the modulator signal. The ring modulator takes its name from the original implementation in which the analog circuit of diodes takes the shape of a ring: a diode ring. The circuit is similar to a bridge rectifier, except that all four diodes are polarized in the same direction. Ring modulation is similar to amplitude modulation, with the difference that in the latter the modulator is shifted to be positive before being multiplied with the carrier, while in the former the unshifted modulator signal is multiplied with the carrier. This has the effect that ring modulation of two sine waves having frequencies of 1,500 and 400 Hz produces an output signal that is the sum of a sine wave with frequency 1,900 Hz and one with frequency 1,100 Hz. These two output frequencies are known as sidebands. If one of the input signals has significant overtones (which is the case for square waves), the output sounds quite different, since each harmonic generates its own pair of sidebands that is not harmonically related.
Article summary
, showing ring of diodes In electronics, ring modulation is a signal processing function, an implementation of frequency mixing, in which two signals are combined to yield an output signal. One signal, called the carrier, is typically a sine wave or another simple waveform; the other signal is typically more complicated and is called the input or the modulator signal. The ring modulator takes its name from the original implementation in which the analog circuit of diodes takes the shape of a ring: a diode ring. The circuit is similar to a bridge rectifier, except that all four diodes are polarized in the same direction. Ring modulation is similar to amplitude modulation, with the difference that in the latter the modulator is shifted to be positive before being multiplied with the carrier, while in the former the unshifted modulator signal is multiplied with the carrier. This has the effect that ring modulation of two sine waves having frequencies of 1,500 and 400 Hz produces an output signal that is the sum of a sine wave with frequency 1,900 Hz and one with frequency 1,100 Hz. These two output frequencies are known as sidebands. If one of the input signals has significant overtones (which is the case for square waves), the output sounds quite different, since each harmonic generates its own pair of sidebands that is not harmonically related.
Key claims
No claims recorded.
Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
No sources recorded.
Key claims and bibliography are generated from the same tracked claims and sources as the article page.