Method and apparatus for detecting line card threshold
View Patent ↗A method and apparatus is provided. The method includes transmitting a signal having an AC component to a subscriber line and receiving at least a portion of the transmitted signal from the subscriber line. The method includes determining at least a portion of a period of the AC component of the received signal, and performing a function of a line card in response to determining at least the portion of the period of the AC component. The apparatus includes circuitry that is capable of transmitting a signal having at least one of an AC component and a DC component to a subscriber line, and receiving at least a portion of the transmitted signal from the subscriber line. The apparatus includes a filter and computation logic. The filter is capable of filtering the DC component from the received signal. The computation logic is capable of determining a value proportional to a power of the AC component of the received signal over at least a portion of a period of the AC component. The apparatus further includes logic capable of performing a function of a line card in response to determining the value proportional to the power of the AC component.
1. A method, comprising:
transmitting a signal having an AC component to a subscriber line;
receiving at least a portion of the transmitted signal from the subscriber line;
determining at least a portion of a period of the AC component based on the received signal and further calculating a squared value of the AC component over the determined portion of the period; and
performing a function of a line card in response to determining at least the portion of the period of the AC component.
2. The method of claim 1 , wherein the signal is a ringing signal and wherein performing the function includes at least one of performing ring-trip detection and performing AC-fault detection.
3. The method of claim 1 , wherein determining at least the portion of the period includes utilizing the zero crossing technique to determine the period of the AC component.
4. The method of claim 1 wherein the AC component represents AC current, and wherein calculating the squared value comprises calculating the squared value of AC the current.
5. A method, comprising:
transmitting a signal having at least one of an AC component and a DC component to a subscriber line;
receiving at least a portion of the transmitted signal from the subscriber line;
filtering the DC component from the received signal;
determining a value proportional to a power of the AC component of the received signal over at least a portion of a period of the AC component; and
performing a function of a line card in response to determining the value proportional to the power of the AC component.
6. The method of claim 5 , wherein determining the value proportional to the power of the AC component includes calculating a squared value of the AC component for at least the portion of the period.
7. The method of claim 6 , wherein determining at least a portion of a period includes determining at least the portion of the period using zero crossing.
8. The method of claim 6 , wherein the squared value of the AC component is calculated until the squared value is at least equal to a threshold value.
9. The method of claim 5 , wherein the signal is a ringing signal and wherein performing the function includes performing ring-trip detection.
10. The method of claim 5 , wherein the signal is a fault detection signal and wherein performing the function includes performing AC-fault detection.
11. The method of claim 5 , wherein the AC component represents AC current, wherein determining the value proportional to the power comprises determining a squared value of the AC current.
12. An apparatus, comprising: circuitry capable of:
transmitting a signal having an AC component to a subscriber line; and
receiving at least a portion of the transmitted signal from the subscriber line;
a digital signal processor capable of determining at least a portion of a period of the AC component based on the received signal and of calculating a squared value of the AC component over the determined portion of the period; and
the circuitry further capable of performing a function of a line card in response to determining at least the portion of the period of the AC component.
13. The apparatus of claim 12 , wherein the signal is a ringing signal and wherein the circuitry capable of performing the function includes the fault detection circuitry capable of performing ring-trip detection.
14. The apparatus of claim 12 , wherein the signal is a fault detection signal and wherein the circuitry capable of performing the function includes the fault detection circuitry capable of performing AC-fault detection.
15. The apparatus of claim 12 , wherein the digital signal processor capable of determining at least a portion of a period includes the digital signal processor capable of determining the period using zero crossing.
16. An apparatus, comprising: circuitry capable of:
transmitting a signal having at least one of an AC component and a DC component to a subscriber line; and
receiving at least a portion of the transmitted signal from the subscriber line;
a filter capable of filtering the DC component from the received signal;
a digital signal processor capable of determining a value proportional to a power of the AC component of the received signal over at least a portion of a period of the AC component; and
the circuitry further capable of performing a function of a line card in response to determining the value proportional to the power of the AC component.
17. The apparatus of claim 16 , wherein the digital signal processor capable of determining the value proportional to the power of the AC component includes the digital signal processor capable of calculating a squared value of the AC component for at least the portion of the period.
18. The method of claim 17 , wherein the AC component represents AC current, wherein calculating the squared value comprises calculating the squared value of the AC current.
19. The apparatus of claim 17 , wherein determining at least the portion of the period includes determining at least the portion of the period using zero crossing.
20. The apparatus of claim 16 , wherein the squared value is computed until it is at least equal to a threshold value.
21. The apparatus of claim 16 , wherein the signal is a ringing signal and wherein performing the function includes performing ring-trip detection.
22. The apparatus of claim 16 , wherein the signal is a fault detection signal and wherein performing the function includes performing AC-fault detection.
23. A line card, comprising:
a subscriber line interface circuit capable of:
transmitting a signal having at least one of an AC component and a DC component to a subscriber line; and
receiving at least a portion of the transmitted signal from the subscriber line;
a filter capable of filtering the DC component from the received signal;
a digital signal processor capable of determining a value proportional to a power of the AC component of the received signal over at least a portion of a period of the AC component; and
the subscriber line interface circuit further capable of performing a function of a line card in response to determining the value proportional to the power of the AC component.
24. The line card of claim 23 , wherein the subscriber line interface circuit is a voltage subscriber line interface circuit.
25. The line card of claim 23 , wherein the digital signal processor capable of determining the value proportional to the power of the AC component includes the digital signal processor capable of calculating a squared value of the AC component for at least the portion of the period.
26. The apparatus of claim 23 , wherein the signal is a ringing signal and wherein performing the function includes performing ring-trip detection.
27. The apparatus of claim 23 , wherein the signal is a fault detection signal and wherein performing the function includes performing AC-fault detection.
28. An apparatus, comprising:
means for transmitting a signal having an AC component to a subscriber line;
means for receiving at least a portion of the transmitted signal from the subscriber line;
means for determining at least a portion of a period of the AC component based on the received signal and for calculating a squared value of the AC component over the determined ponion of the period; and
means for performing a function of a line card in response to determining at least the portion of the period of the AC component.