1. A signal processor, installed in a communication device which simultaneously plays a far-end signal sent from a far-end and converts sounds at a near-end to a near-end signal for transmission to the far-end, comprising:
a first voice activity detector, detecting a power of the far-end signal to generate a first control signal indicating whether a far-end talker at the far end is speaking;
a second voice activity detector, generating a second control signal indicating whether both the far-end talker and a near-end talker at the near end are speaking or only the far-end talker is speaking according to power of the near-end signal and the first control signal;
a nonlinear echo processor, controlled by the second control signal, canceling more nonlinear echo from the near-end signal in time domain while only the far-end talker is speaking, and canceling less nonlinear echo from the near-end signal in time domain while both the far-end talker and the near-end talker are speaking; and
a speaker attenuation module, controlled by the second control signal, attenuating the far-end signal while both the far-end talker and the near-end talker are speaking.
2. The signal processor as claimed in claim 1, wherein the signal processor further comprises a linear echo canceller, controlled by the first control signal, canceling linear echo linearly correlated with the far-end signal from the near-end signal.
3. The signal processor as claimed in claim 2, wherein the signal processor further comprises:
a third voice activity detector, detecting a power of the near-end signal to generate a third control signal indicating whether the near-end talker is speaking; and
a nonlinear echo cancellation module, controlled by the third control signal, canceling nonlinear echo from the near-end signal in frequency domain.
4. The signal processor as claimed in claim 3, wherein the signal processor further comprises a channel decoupling module, controlled by the first control signal, deriving a main channel signal and a reference channel signal as inputs of the nonlinear echo cancellation module from the near-end signal, wherein the main channel signal comprises more voices of the near-end talker and less echo, and the reference channel signal comprises less voices of the near-end talker and more echo.
5. The signal processor as claimed in claim 4, wherein the near-end signal is duplicated to generate a duplicated near-end signal, and the near-end signal and the duplicated near-end signal are sent to the channel coupling module as inputs.
6. The signal processor as claimed in claim 5, wherein the channel decoupling module directly outputs the near-end signal as the main channel signal and subtracts the near-end signal from the duplicated near-end signal to obtain the reference channel signal when only the near-end talker is speaking, the channel decoupling module subtracts the duplicated near-end signal from the near-end signal to obtain the main channel signal and directly outputs the duplicated near-end signal as the reference channel signal when only the far-end talker is speaking, and the channel decoupling module directly outputs the near-end signal as the main-channel signal and multiplies the duplicated near-end signal by a reference gain value less than 1 to generate the reference channel signal when both the near-end talker and the far-end talker are speaking.
7. The signal processor as claimed in claim 5, wherein the duplicated near-end signal is generated outside the signal processor.
8. The signal processor as claimed in claim 5, wherein the signal processor further comprises a gain controller, multiplying the near-end signal with a gain value to obtain the duplicated near-end signal.
9. A method for canceling echo in a communication device, wherein the communication device simultaneously plays a far-end signal sent from a far-end and converts sounds at a near-end to a near-end signal for transmission to the far-end, the method comprising:
determining whether both a far-end talker at the far end and a near-end talker at the near end are speaking or only the far-end talker is speaking;
canceling more nonlinear echo from the near-end signal in time domain while only the far-end talker is speaking;
canceling less nonlinear echo from the near-end signal in time domain while both the far-end talker and the near-end talker are speaking; and
attenuating the far-end signal while both the far-end talker and the near-end talker are speaking.
10. The method as claimed in claim 9, wherein the determining step comprises:
detecting a power of the far-end signal to detect whether the far-end talker is speaking; and
detecting a power of the near-end signal to detect whether the near-end talker is speaking.
11. The method as claimed in claim 9, wherein the method further comprises canceling linear echo linearly correlated with the far-end signal from the near-end signal.
12. The method as claimed in claim 11, wherein the method further comprises canceling nonlinear echo from the near-end signal in frequency domain.
13. The method as claimed in claim 12, wherein the cancellation of nonlinear echo in frequency domain is according to a main-channel signal and a reference channel signal, and the method further comprises:
duplicating the near-end signal to generate a duplicated near-end signal; and
deriving the main channel signal comprising more voices of the near-end talker and less echo, and the reference channel signal comprising less voices of the near-end talker and more echo from the near-end signal and the duplicated near-end signal.
14. The method as claimed in claim 13, wherein the separating step further comprises:
when only the near-end talker is speaking, directly outputting the near-end signal as the main channel signal and subtracting the near-end signal from the duplicated near-end signal to obtain the reference channel signal;
when only the far-end talker is speaking, subtracting the duplicated near-end signal from the near-end signal to obtain the main channel signal and directly outputting the duplicated near-end signal as the reference channel signal; and
when both the near-end talker and the far-end talker are speaking, directly outputting the near-end signal as the main-channel signal and multiplying the duplicated near-end signal by a reference gain value less than 1 to generate the reference channel signal.
15. The method as claimed in claim 13, wherein the duplicated near-end signal is obtained by multiplying the near-end signal with a gain value.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for authorizing payment upon delivery of an item comprising:
registering each one of a plurality of receiving parties with a transaction module;
registering each one of a plurality of sending parties with the transaction module;
generating an identifier;
associating the identifier with a particular sending party and a particular item;
storing data relating to the identifier and the particular sending party in the transaction module;
obtaining identifier data at a destination location;
correlating the identifier data to a sending party; and
authorizing a debit from a selected receiving party’s account.
2. The method as claimed in claim 1, wherein the identifier is generated from a closed system postage meter.
3. The method as claimed in claim 1, wherein the identifier is generated from an open system postage meter.
4. The method as claimed in claim 1, further comprising:
notifying the receiving party that the debit has occurred.
5. The method as claimed in claim 1, further comprising:
notifying the sending party that the debit has occurred.
6. The method as claimed in claim 1, wherein the transaction module is maintained by the receiving party.
7. The method as claimed in claim 1, wherein the transaction module is maintained by the sending party.
8. The method as claimed in claim 1, wherein the transaction module is maintained by a third party.
9. The method as claimed in claim 1, further comprising selecting a particular carrier from a plurality of carriers for transporting the item.
10. The method as claimed in claim 1, further comprising:
receiving confirmation information, at the transaction module, confirming satisfactory delivery, prior to the authorization step.
11. The method as claimed in claim 1, wherein the identifier is stored as a bar code representation and the obtaining step includes scanning the bar code.
12. An apparatus for authorizing payment for an article comprising:
a transaction facility adapted to store data relating to a plurality of articles, first party information and second party information;
the transaction facility adapted to generate an identifier associated with a particular article; and
the transaction facility adapted to authorize a transaction between an account of the first party and an account of the second party.
13. The apparatus as claimed in claim 12, wherein the identifier is generated from a closed system postage meter.
14. The apparatus as claimed in claim 12, wherein the identifier is generated from an open system postage meter.
15. The apparatus as claimed in claim 12, wherein the transaction facility provides notification to the first party that the transaction has occurred.
16. The apparatus as claimed in claim 12, wherein the transaction facility provides notification to the second party that the transaction has occurred.
17. The apparatus as claimed in claim 12, wherein the transaction facility is maintained by the first party.
18. The apparatus as claimed in claim 12, wherein the transaction facility is maintained by the second party.
19. The apparatus as claimed in claim 12, wherein the transaction facility is maintained by a third party.
20. The apparatus as claimed in claim 12, further comprising a carrier module, adapted to provide a selection of carriers for transporting the article.
21. The apparatus as claimed in claim 12, further comprising:
a tracking module, adapted to track the article during transportation of the article.
22. The apparatus as claimed in claim 12, wherein the identifier is stored as a bar code representation and the bar code is scanned at a second party facility.
23. An apparatus for authorizing payment upon delivery of an item comprising:
means for registering each one of a plurality of receiving parties with a transaction database;
means for registering each one of a plurality of sending parties with the transaction database;
means for generating an identifier;
means for associating the identifier with a particular sending party and a particular item;
means for storing data relating to the identifier and the particular sending party in the transaction database;
means for obtaining identifier data at a destination location;
means for correlating the identifier data to a sending party; and
means for authorizing a debit from a selected receiving party’s account.
24. The apparatus as claimed in claim 23, wherein the identifier is generated from a closed system postage meter.
25. The apparatus as claimed in claim 23, wherein the identifier is generated from an open system postage meter.
26. The apparatus as claimed in claim 23, further comprising:
means for notifying the receiving party that the debit has occurred.
27. The apparatus as claimed in claim 23, further comprising:
means for notifying the sending party that the debit has occurred.
28. The apparatus as claimed in claim 23, wherein the transaction database is maintained by the receiving party.
29. The apparatus as claimed in claim 23, wherein the transaction database is maintained by the sending party.
30. The apparatus as claimed in claim 23, wherein the transaction database is maintained by a third party.
31. The apparatus as claimed in claim 23, further comprising means for selecting a particular carrier from a plurality of carriers for transporting the item.
32. The apparatus as claimed in claim 23, further comprising:
means for tracking the item during the transportation of the item from a first location to the destination location.
33. The apparatus as claimed in claim 23, wherein the identifier is stored as a bar code representation and the means for the obtaining step is a scanner device.