Splitter and combiner for multiple data rate communication system
View Patent ↗Complementary band-splitter and band-combiner devices and methods of operation of both are disclosed. Embodiments of the invention may allow wideband and narrowband functions and services to operate seamlessly by band-splitting wideband data into low-band data and high-band data. Narrowband data may include only low-band data. Wideband services may operate on both low-band and high-band data, while narrowband services may operate only on low-band data. Another embodiment may include computer-readable storage having stored thereon a computer program having a plurality of code sections executable by a processor for causing the processor to perform the foregoing.
1. A split band signal processing system, comprising:
a first filter for modifying wideband data to produce low-band data representing spectral components occupying a first band width with non-linear phase;
a second filter for modifying the low-band data to produce reconstructed low-band data with a linear phase with respect to the wideband data;
a delay element for delaying the wideband data; and
a device for removing the low-band data from the delayed wideband data to produce high-band data representing spectral components occupying a second band width above the first band width, the high-band data produced by removing reconstructed low-band data with the linear phase from the wideband data.
2. The system of claim 1 , wherein a spectral mask of the low-band data meets a spectral mask of G.712.
3. The system of claim 1 , wherein the first filter further comprises a down-sampler for reducing a sampling rate of the low-band data.
4. The system of claim 3 , further comprising:
an up-sampler for up-sampling the low-band data from the down-sampler where the second filter modifies the low-band data from the up-sampler to produce the reconstructed low band data.
5. The system of claim 4 , wherein the first filter has a frequency response of H o (z) and the second filter has a frequency response of z −(N−1) H o (z −1 ).
6. The system of claim 1 , comprising:
a detector for specifically detecting presence in the wideband data of one or more certain frequencies, the detector processing only spectral components represented by the low-band data.
7. The system of claim 6 , wherein the one or more certain frequencies comprise a dual tone multi-frequency (DTMF) tone pair.
8. The system of claim 1 , comprising:
echo canceller circuitry that cancels echo present in the wideband data by modifying the low-band data and the high-band data.
9. The system of claim 1 , wherein the filter is a finite impulse response (FIR) filter of length N.
10. The system of claim 9 , wherein the reconstructed low-band data has a linear phase with delay N.
11. A split band signal processing system, comprising:
a first filter for filtering wideband data;
a down-sampler for down-sampling an output of the first filter to produce low-band data, wherein the low-band data represents spectral components that are less than a predefined frequency;
an up-sampler for up-sampling the low-band data;
a second filter for filtering the up-sampled low-band data to produce reconstructed low-band data with a linear phase, the second filter being different than the first filter;
a delay element to delay the wideband data; and
a device for removing the reconstructed low-band data from the delayed wideband data to produce high-band data representing spectral components that are greater than the predefined frequency.
12. The system of claim 11 , wherein a spectral mask of the low-band data meets a spectral mask of G.12.
13. The system of claim 11 , comprising:
a detector for specifically detecting presence in the wideband data of one or more certain frequencies, the detector processing only spectral components represented by the low-band data.
14. The system of claim 13 , wherein the one or more certain frequencies comprise a dual tone multi-frequency (DTMF) tone pair.
15. The system of claim 11 comprising:
echo canceller circuitry that cancels echo present in the wideband data by modifying the low-band data and the high-band data.
16. A split band signal processing system, comprising:
a band splitter that processes wideband data to produce low-band data at a low-band sampling rate and high-band data at a wideband sampling rate, where the low-band data represents spectral components that are less than a predefined frequency and the high-band data represents spectral components that are greater than the predefined frequency, the band splitter comprising:
a first filter for filtering the wideband data to produce low-band data with non-linear phase; and
a second filter for filtering the low-band data with non-linear phase to produce low-band data with linear phase;
processing circuitry that processes the low-band data to produce processed low-band data at the low-band sampling rate; and
a band combiner that combines the processed low-band data with the high-band data to produce processed wideband data at the wideband sampling rate for transmission over a packet network.
17. The system of claim 16 , wherein a spectral mask of the low-band data meets a spectral mask of G.712.
18. The system of claim 16 , comprising:
a detector for specifically detecting presence in the wideband data of one or more certain frequencies, the detector processing only spectral components represented by the low-band data.
19. The system of claim 18 , wherein the one or more certain frequencies comprise a dual tone multi-frequency (DTMF) tone pair.
20. The system of claim 16 , comprising:
echo canceller circuitry that cancels echo present in the wideband data by modifying the low-band data and the high-band data.
21. The system of claim 16 , wherein the band splitter comprises:
the first filter for filtering the wideband data at a wideband sampling rate;
a down-sampler for down-sampling an output of the first filter to produce the low-band data with non-linear phase at a low-band sampling rate;
an up-sampler for up-sampling the low-band data with non-linear phase at the wideband sampling rate; and
the second filter for filtering the up-sampled low-band data with non-linear phase to produce the low-band data with linear phase at the wideband sampling rate for producing the high-band data at the wideband sampling rate.
22. The system of claim 21 , wherein the band combiner comprises a third filter for filtering up-sampled low-band data with non-linear phase to produce low-band data with linear phase at the wideband sampling rate for reconstruction of the wideband data, wherein the third filter is the same as the second filter.
23. The system of claim 21 , wherein the first and the second filters are finite impulse response (FIR) filters of length N, where an order of the first filter is reversed for the second filter.
24. A method of processing wideband data as low-band data and high-band data in a communication terminal, the method comprising:
filtering wideband data, in the communication terminal, to produce low-band data with non-linear phase representing spectral components that occupy a first band width;
delaying the wideband data, in the communication terminal; and
removing reconstructed low-band data with linear phase from the delayed wideband data, in the communication terminal, to produce high-band data representing spectral components that occupy a second band width above the first band width, where the reconstructed low-band data with linear phase is reconstructed from the low-band data with non-linear phase.
25. The method of claim 24 , wherein a spectral mask of the low-band data meets a spectral mask of G.712.
26. The method of claim 24 , comprising:
specifically detecting presence in the wideband data of one or more certain frequencies, the detecting processing only spectral components represented by the low-band data.
27. The method of claim 26 , wherein the one or more certain frequencies comprise a dual tone multi-frequency (DTMF) tone pair.
28. The method of claim 26 , comprising:
packetizing a second wideband data into packets; and
holding the packets responsive to the detecting.
29. The method of claim 24 , comprising:
canceling echo present in the wideband data by modifying the low-band data and the high-band data.
30. A method of processing wideband data as low-band data and high-band data in a communication terminal, the method comprising:
filtering the wideband data, in the communication terminal, to produce filtered wideband data at a wideband sampling rate;
down-sampling the filtered wideband data, in the communication terminal, to produce low-band data with non-linear phase at a low-band sampling rate;
up-sampling the low-band data with non-linear phase, in the communication terminal, to produce up-sampled low-band data at the wideband sampling rate;
filtering the up-sampled low-band data with non-linear phase, in the communication terminal, to produce filtered up-sampled low-band data with linear phase at the wideband sampling rate;
delaying the wideband data, in the communication terminal; and
removing the filtered up-sampled low-band data with linear phase from the delayed wideband data, in the communication terminal, to produce high-band data at the wideband sampling rate.
31. The method of claim 30 , wherein a spectral mask of the low-band data meets a spectral mask of G.712.
32. The method of claim 30 , comprising:
specifically detecting presence in the wideband data of one or more certain frequencies, the detecting processing only spectral components represented by the low-band data.
33. The method of claim 32 , wherein the one or more certain frequencies comprise a dual tone multi-frequency (DTMF) tone pair.
34. The method of claim 32 , comprising:
packetizing a second wideband data into packets; and
holding the packets responsive to the detecting.
35. The method of claim 30 , comprising:
canceling echo present in the wideband data by modifying the low-band data and the high-band data.
36. A method of processing wideband data as low-band data and high-band data in a communication terminal, the method comprising:
splitting spectral content of the wideband data, in the communication terminal, producing low-band data representing spectral components that are less than a predefined frequency and high-band data representing spectral components that are greater than the predefined frequency;
processing, in the communication terminal, the low-band data to produce processed low-band data; and
combining, in the communication terminal, the processed low-band data with the high-band data to produce processed wideband data.
37. The method of claim 36 , wherein a spectral mask of the low-band data meets a spectral mask of G.712.
38. The method of claim 36 , comprising:
specifically detecting presence in the wideband data of one or more certain frequencies, the detecting processing only spectral components represented by the low-band data.
39. The method of claim 38 , wherein the one or more certain frequencies comprise a dual tone multi-frequency (DTMF) tone pair.
40. The method of claim 38 , comprising:
packetizing a second wideband data into packets; and
holding the packets responsive to the detecting.
41. The method of claim 36 , comprising:
canceling echo present in the wideband data by modifying the low-band data and the high-band data.
42. A non-transient computer-readable medium, having stored thereon a computer program having a plurality of code sections for processing wideband data, the code sections executable by a processor for causing the processor to perform operations, comprising:
filtering wideband data having a first sampling rate;
down-sampling the filtered wideband data to produce low-band data with non-linear phase having a second sampling rate, the low-band data representing spectral components that are less than a predefined frequency;
up-sampling the low-band data with non-linear phase to produce low-band data with non-linear phase having the first sampling rate;
filtering the up-sampled low-band data with non-linear phase to produce filtered up-sampled low-band data with linear phase;
delaying the wideband data;
removing the filtered up-sampled low-band data with linear phase from the delayed wideband data to produce high-band data representing spectral components that are greater than the predefined frequency.
43. The computer-readable medium of claim 42 , wherein a spectral mask of the low-band data meets a spectral mask of G.712.
44. The computer-readable medium of claim 42 , wherein the code sections are executable by the processor to cause the processor to perform operations comprising:
specifically detecting presence in the wideband data of one or more certain frequencies, the detecting processing only spectral components represented by the low-band data.
45. The computer-readable medium of claim 44 , wherein the one or more certain frequencies comprise a dual tone multi-frequency (DTMF) tone pair.
46. The computer-readable medium of claim 44 , wherein the code sections are executable by the processor to cause the processor to perform operations comprising:
packetizing a second wideband data into packets; and
holding the packets responsive to the detecting.
47. The computer-readable medium of claim 42 , wherein the operations comprise:
canceling echo present in the wideband data by modifying the low-band data and the high-band data.
48. A non-transient computer-readable medium, having stored thereon a computer program having a plurality of code sections for processing wideband data, the code sections executable by a processor for causing the processor to perform operations, comprising:
splitting spectral content of wideband data at a wideband sampling rate to produce low-band data with non-linear phase at a low-band sampling rate, where the low-band data represents spectral components that are less than a predefined frequency;
reconstructing the low-band data with linear phase at the wideband sampling rate from the low-band data with non-linear phase; and
producing high-band data by removing the reconstructed low-band data with linear phase from the wideband data, where the high-band data represents spectral components that are greater than the predefined frequency.
49. The computer-readable medium of claim 48 , wherein a spectral mask of the low-band data meets a spectral mask of G.712.
50. The computer-readable medium of claim 48 , wherein the code sections are executable by the processor to cause the processor to perform operations comprising:
specifically detecting presence in the wideband data of one or more certain frequencies, the detecting processing only spectral components represented by the low-band data.
51. The computer-readable medium of claim 50 , wherein the one or more certain frequencies comprise a dual tone multi-frequency (DTMF) tone pair.
52. The computer-readable medium of claim 50 , wherein the code sections are executable by the processor to cause the processor to perform operations comprising:
packetizing a second wideband data into packets; and
holding the packets responsive to the detecting.
53. The computer-readable medium of claim 48 , wherein the operations comprise:
canceling echo present in the wideband data by modifying the low-band data and the high-band data.