发明授权
US4853958A LPC-based DTMF receiver for secondary signalling 失效
基于LPC的DTMF接收机用于二次信令

LPC-based DTMF receiver for secondary signalling
摘要:
A dual tone multi-frequency (DTMF) receiver for use in detecting digitally transmitted signals in the telephone industry. The receiver derives linear predictive coefficients for the digital signals in the data frame. This information is used to compute frequency response magnitudes at the DTMF frequencies. A plurality of magnitude comparisons are then performed to verify the presence of true DTMF signals and concurrently the frequency of these signals is obtained.
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