Squelch

In telecommunications, squelch is a circuit function that acts to suppress the audio (or video) output of a receiver in the absence of a sufficiently strong desired input signal. Squelch is widely used in two-way radios and radio scanners to suppress the sound of channel noise when the radio is not receiving a transmission.

Carrier squelch

A carrier squelch or noise squelch is the most simple variant of all. It operates strictly on the signal strength, such as when a television mutes the audio or blanks the video on "empty" channels, or when a walkie talkie mutes the audio when no signal is present. In some designs, the squelch threshold is preset. For example, television squelch settings are usually preset. Receivers in base stations or repeaters at remote mountain top sites are usually not adjustable remotely from the control point.

In devices such as two-way radios (also known as radiotelephones), the squelch on a local receiver can be adjusted with a knob, others have push buttons or a sequence of button presses. This setting adjusts the threshold at which signals will open (un-mute) the audio channel. Backing off the control will turn on the audio, and the operator will hear white noise (also called "static" or squelch noise) when there is no signal present. The usual operation is to adjust the control until the channel just shuts off - then only a small threshold signal is needed to turn on the speaker. However, if a weak signal is annoying, the operator can set the control a little higher thereby adjusting the squelch to open only when stronger signals are received.

Tone

Tone may refer to:

Sound

Music and artists

Musical tone

A musical tone is a steady periodic sound. A musical tone is characterized by its duration, pitch, intensity (or loudness), and timbre (or quality). The notes used in music can be more complex than musical tones, as they may include aperiodic aspects, such as attack transients, vibrato, and envelope modulation.

A simple tone, or pure tone, has a sinusoidal waveform. A complex tone is any musical tone that is not sinusoidal, but is periodic, such that it can be described as a sum of simple tones with harmonically related frequencies.

See also

References

Tone (Jeff Ament album)

Tone is the debut solo album of American rock bassist and Pearl Jam-member Jeff Ament, released September 16, 2008 on Monkeywrench Records. 3,000 copies of the album were pressed and distributed through independent record stores across the United States, as well as through Pearl Jam's official website. The album has also been made available as a digital download via Pearl Jam's official website for US$4.99.

Background

The album contains ten songs written over a span of 12 years. It features a raw, experimental sound and was recorded by Ament over an eight-year period at Horseback Court in Blue Mountain, Montana, which is Ament's home studio, and completed in 2008.Tone was mixed by Brett Eliason, who had previously worked with Ament as Pearl Jam's sound engineer. Its cover art was created by Ament.

Former Three Fish drummer and frequent Ament collaborator Richard Stuverud contributed his drumming to seven songs on the album, and King's X frontman Doug Pinnick contributed lead vocals to the song "Doubting Thomasina". Pinnick would later in 2010 feature as the lead singer of another Ament/Stuverud project, "Tres Mts". "The Forest" was recorded by Pearl Jam; however, vocalist Eddie Vedder never got around to adding vocals to the track. The instrumental version by Pearl Jam is featured in the 2007 Pearl Jam concert film, Immagine in Cornice. The version of the song on Tone features vocals by Ament and music taken from the original demo version of the song.