CPE alert signal detector and caller identification detector using peak detection

A CAS (Customer premise equipment Alert Signal) detection apparatus for detecting a CAS from an input signal, comprising:

• a mixing unit that extracts and mixes two or more frequency components of the input signal to generate an amplitude modulated signal including a carrier and an envelope;
• an amplitude modulation detection unit that measures a frequency of the envelop;
• a signal detection unit that compares the frequency of the envelope to the predetermined range and compares a voltage level of the envelope to a reference voltage level;
• and
• a CAS discriminating unit that receives results of frequency and voltage level comparisons from the signal detection unit and from the results determines whether the CAS is present.

A method for detecting a CAS (Customer premise equipment Alert Signal) from an input signal, the method comprising:

• filtering the input signal to extract two or more frequency components;
• mixing filtering results to generate an amplitude modulated signal;
• measuring a frequency and a level of an envelope of the amplitude modulated signal;
• and
• determining whether the frequency and the level of the envelope indicate that the CAS is present.

A CAS (Customer premise equipment Alert Signal) detection apparatus for detecting a CAS from an input signal, comprising:

• a mixing unit for filtering the input signal into two or more frequency components and mixing filtering results to generate an amplitude modulated signal including a carrier and an envelope;
• a signal conversion unit for automatically controlling a gain of an output signal from the mixing unit so that the output signal is in a first range between a first threshold voltage and a second threshold voltage;
• an amplitude modulation detection unit for detecting the envelope in the output signal of the signal conversion unit;
• a signal detection unit for determining whether a frequency of the envelope is in a second range corresponding to the CAS and for detecting a maximum/minimum level difference of the envelope to determine whether the level of the envelope corresponds to the CAS;
• and
• a CAS discrimination unit coupled to the signal detection unit to determine whether the CAS is present.

A method for detecting a CAS (Customer premise equipment Alert Signal) from an input signal, comprising:

• (a) filtering the input signal and mixing filtering results to generate an amplitude modulated signal;
• (b) measuring an envelope and a carrier of the amplitude modulated signal;
• (c) predicting that the CAS is present if peaks in the carrier remain higher than a predetermined level for a predetermined period;
• and
• (d) if it is predicted that the CAS is present, determining that the CAS is present if a frequency and a voltage level of the envelope indicate that the CAS is present.

A CAS (Customer premise equipment Alert Signal) detection apparatus for detecting a CAS from an input signal, comprising:

• a mixing unit for filtering the input signal into two or more frequency components, and mixing filtering results to generate an amplitude modulated signal including a carrier and an envelope;
• a signal conversion unit for automatically controlling a gain of an output signal of the mixing unit so that the output signal is in a first range between a first threshold voltage and a second threshold voltage, and converting the gain adjusted signal into a digital signal;
• an amplitude modulation detection unit for detecting the peaks of the carrier and envelope from an output signal of the signal conversion unit;
• a signal prediction unit for detecting a level of the amplitude modulated signal and occurrence periods and the number of peaks in the carrier and envelope to predict the presence of the CAS in the input signal, and outputting the prediction result as a CAS prediction signal;
• a signal detection unit for determining whether a frequency of the envelope detected by the amplitude modulation detection unit is in a second range corresponding to the CAS, and for detecting a maximum/minimum level difference of the envelope to determine whether the maximum/minimum level corresponding to the CAS;
• and
• a CAS discrimination unit for determining whether the detection results from the signal detection unit maintains for a predetermined period to determine whether the CAS is present.

A method for detecting a CAS (Customer premise equipment Alert Signal) from an input signal, the method comprising:

• (a) filtering the input signal into two or more frequency components and mixing filtering results to generate an amplitude modulated signal;
• (b) measuring a carrier and an envelope of the amplitude modulated signal;
• (c) removing error peaks from peaks of the carrier and envelope, and predicting that the CAS is present if peaks in the carrier and envelope remain higher than a predetermined level for a predetermined period;
• (d) if it is predicted that the CAS is present, determining whether a frequency and a voltage level of the envelope is in a predetermined range using the peaks of envelope from which the error peaks have been removed;
• and
• (e) if it is determined that the frequency and the voltage level of the envelop is in the predetermined level, detecting a duration of the CAS to determine whether the CAS is present.

A caller information detection apparatus comprising:

• a signal conversion unit for filtering an input signal into predetermined frequency components and converting the filtering results into a digital signal, and automatically controlling a gain of the digital signal so that the digital signal is in a first range between a first threshold voltage and a second threshold voltage;
• a peak detector for detecting peaks of the digital signal and outputting maximum/minimum peak detection signals upon detecting the maximums and minimums of the digital signal;
• and
• a frequency shift keying (FSK) demodulation unit that determines a number of and an interval between the maximums and minimums of the digitals signal to discriminate between a MARK signal and a SPACE signal and generate an FSK data and a data clock signal, the FSK demodulation unit detecting an edge in the FSK data and generating the data clock signal for transfer of FSK data according to the detected edge.

A method for detecting caller information, comprising:

• (a) filtering an input signal and converting filtering results into a digital signal;
• (b) detecting extremes of the digital signal to detect frequencies corresponding to a MARK signal and a SPACE signal indicating bit values in FSK data;
• (c) detecting the edge of the FSK data to generate an FSK clock signal;
• (d) generating a data clock signal in response to the FSK clock signal and the FSK data, the data clock signal being enabled in only an actual data interval of the FSK data;
• and
• (e) transferring the FSK data in response to the data clock signal.