ALGORITHM FOR DTMF DETECTION
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United States of America Patent
Stats
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N/A
Issued Date -
Nov 3, 2016
app pub date -
Apr 30, 2015
filing date -
Apr 30, 2015
priority date (Note) -
Abandoned
status (Latency Note)
Importance
Abstract
The calculation for DFT(Discrete Fourier Transform) is too much in prior art, so the present invention provides a new method DMFT(Discrete Multi-Frequency Transform) for calculation. For example, in prior art, to determine a DTMF signal “3”, the calculation must be performed for k=96˜92 (frequency 1477 Hz with tolerance ±2.5%) and k=45˜43 (frequency 697 Hz with tolerance ±2.5%), total 8 of X[k] value have to be calculated, but the present invention performs a single calculation of X[k] for each frequency. To determine a DTMF signal “3”, only a high frequency of X[k] and a low frequency of X[k] are required to calculate.
First Claim
Other Claims data not available