Dual Tone Multi Frequency
Dual Tone Multi Frequency - Related Videos
10:41
Method to Measure Tone of Axial and Proximal Muscle
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Cited by 5 •
2011
We have developed a device (Twister) to study the regulation of tonic muscle activity during active postural maintenance. Twister measures torsional resistance and muscular responses in standing subjects during twisting of the body axis. The device can be flexibly configured to study various aspects of tonic control across the neck, trunk, and/or hips.
01:12
Alterations in Muscle Tone ll
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2026
Alterations in muscle tone are common manifestations of neurological disorders and reflect dysfunction within different nervous system regions. Spasticity, paratonia, and dystonia represent distinct forms of hypertonia, each with unique mechanisms, clinical features, and diagnostic importance.CharacteristicsSpasticity happens from upper motor neuron lesions and is characterized by velocity-dependent resistance to passive movement. Clinical features include:Exaggerated deep tendon reflexesClonus...
06:51
Microparticle Manipulation by Standing Surface Acoustic Waves with Dual-frequency Excitations
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2018
A protocol for manipulating the microparticles in a microfluidic channel with a dual-frequency excitation is presented.
01:11
Alterations in Muscle Tone lll
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2026
Rigidity and myotonia are distinct abnormalities of muscle tone that affect resistance and relaxation during movement. Although both involve altered muscle contraction, they arise from different neurological and muscular mechanisms.CharacteristicsRigidity is characterized by uniform resistance to passive movement across the entire range, independent of speed, affecting flexors and extensors equally. It may appear as lead-pipe rigidity (smooth, constant resistance) or cogwheel rigidity...
08:08
Comparing the Frequency Effect Between the Lexical Decision and Naming Tasks in Chinese
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Cited by 8 •
2016
Researchers adopt both the lexical decision task and the naming task to investigate some important topics such as character/word recognition by comparing the frequency effect between these two tasks. This article introduces this approach through two exemplar experiments and elaborates on the underlying logic.
FAQs
A receiver examines the incoming voice-channel signal for the simultaneous presence of two tones: one from the low-frequency group and one from the high-frequency group. It then treats that frequency combination as a code and maps the recognized pair to a specific keypad key. This two-part decision distinguishes one command from another.
Using one tone from each of two frequency groups creates a distinctive pair for each key, rather than relying on a single frequency alone. The encoder therefore represents a key through the interaction of both groups, while the receiver can verify the corresponding pair before producing a digital command. This arrangement supports signaling across voice channels.
The receiver can use band-pass filtering to isolate the relevant frequency regions, or frequency analysis to determine which tones are present. It compares the detected components with the low- and high-frequency groups used by the encoding scheme. Once both components are identified, the receiver maps their pair to the associated key, producing a discrete control result from the audio input.
First, an encoder accepts a keypad selection and combines one low-group frequency with one high-group frequency. The resulting audio travels through a voice channel. At the receiving end, filtering or frequency analysis identifies the two components, and a mapping stage converts the recognized pair into the corresponding key or command. This separates signal generation, transmission, and interpretation.
The same signaling approach supports interactive voice response systems, automated call routing, and remote control interfaces. In an interactive voice response system, recognized keypad pairs can select menu actions; in call routing, they can convey a user's selection; and in remote control interfaces, they can carry discrete commands. These uses extend keypad signaling into automated system control.
It shows how an analog medium can transport discrete information when a system assigns defined signal features to symbols. Here, the relevant features are paired frequencies, and the receiver interprets them through detection and key mapping. This makes DTMF a useful engineering example of encoding, transmission, and decoding working together across a voice channel.