System, method, and apparatus for facilitating wideband audio over a coil-assisted digital subscriber line loop
View Patent ↗An embodiment of a system, method, and apparatus for facilitating wideband audio communication and digital subscriber line data communication includes a filter configured to be coupled to a line conditioning coil. The line conditioning coil includes a frequency response having a first passband extending over a portion of a narrowband voice frequency range, a second passband extending over a portion of a digital subscriber line frequency range. The line conditioning coil further includes a frequency notch having a frequency range between the first passband and the second passband. The frequency notch attenuates signals over a portion of a wideband audio frequency range. The filter has a cut-off frequency below the frequency notch and a passband extending over at least a portion of the frequency notch. The filter is configured to amplify signals within the frequency range of the frequency notch to compensate for the attenuation caused by the frequency notch.
1. An apparatus for facilitating wideband audio communication and digital subscriber line data communication over a twisted pair connection comprising:
first and second input terminals configured to be coupled to a line conditioning coil via a first twisted pair connection, the line conditioning coil including a frequency response having a first passband extending over a portion of a narrowband voice frequency range, a second passband extending over a portion of a digital subscriber line frequency range, and a frequency notch having a frequency range between the first passband and the second passband, the frequency notch attenuating signals over a portion of a wideband audio frequency range;
first and second output terminals configured to be coupled to a wideband audio telephony device via a second twisted pair connection, the wideband audio telephony device configured to transmit and receive audio within the wideband audio frequency range; and
a wideband filter coupled between the first and second input terminals and the first and second output terminals, the wideband filter having a cut-off frequency below the frequency notch and having a passband extending over at least a portion of the frequency notch, the wideband filter configured to amplify signals within the frequency range of the frequency notch to compensate for the attenuation caused by the frequency notch.
2. The apparatus of claim 1 , wherein the wideband filter includes:
a first transistor device;
a second transistor device, the second transistor device being cross-coupled to the first transistor device;
a first capacitance device coupled between a drain terminal of the first transistor device and a ground connection; and
a second capacitance device coupled between a source terminal of the second transistor device and the ground connection.
3. The apparatus of claim 2 , further wherein:
a gate terminal of the first transistor device is coupled to the source terminal of the second transistor device; and
a gate terminal of the second transistor device is coupled to a drain terminal of the first transistor device.
4. The apparatus of claim 3 , wherein:
the first input terminal is coupled to a source terminal of the first transistor device and a drain terminal of the second transistor device; and
the second input terminal is coupled to the gate terminal of the first transistor device and the source terminal of the second transistor device.
5. The apparatus of claim 4 , wherein:
the first output terminal is coupled to the drain terminal of the first transistor device; and
the second output terminal is coupled to the source terminal of the second transistor device.
6. The apparatus of claim 2 , wherein the cut-off frequency (W c ) of the wideband filter is determined by the following equation:
W c =√( Gt 1 *Gt 2 /C 1 *C 2 )
where G t1 is equal to a transconductance of the first transistor device, G t2 is equal to a transconductance of the second transistor device, C 1 is equal to a capacitance of the first capacitance device, and C 2 is equal to a capacitance of the second capacitance device.
7. The apparatus of claim 1 , wherein the narrowband voice frequency range includes a frequency range of between 200 Hz and 3.4 kHz.
8. The apparatus of claim 1 , wherein the digital subscriber line frequency range includes a frequency range between 25 kHz and 1104 kHz.
9. The apparatus of claim 1 , wherein the wideband audio frequency range includes a frequency range between 30 Hz and 8 kHz.
10. The apparatus of claim 1 , wherein the frequency notch includes a frequency range between 4 kHz and 25 kHz.
11. The apparatus of claim 1 , wherein the line conditioning coil is a Smart Coil.
12. The apparatus of claim 1 , wherein the wideband audio telephony device comprises a digital wideband phone.
13. The apparatus of claim 1 , wherein the wideband audio telephony device is an analog digital wideband phone.
14. The apparatus of claim 1 , wherein the wideband filter is configured to be located at a customer premise location.
15. An apparatus for facilitating wideband audio communication and digital subscriber line data communication comprising:
a filter configured to be coupled to a line conditioning coil, the line conditioning coil including a frequency response having a first passband extending over a portion of a narrowband voice frequency range, a second passband extending over a portion of a digital subscriber line frequency range, and a frequency notch having a frequency range between the first passband and the second passband, the frequency notch attenuating signals over a portion of a wideband audio frequency range, the filter having a cut-off frequency below the frequency notch and having a passband extending over at least a portion of the frequency notch, the filter configured to amplify signals within the frequency range of the frequency notch to compensate for the attenuation caused by the frequency notch.
16. The apparatus of claim 15 , wherein the filter is further configured to be coupled to a wideband audio telephony device, the wideband audio telephony device configured to transmit and receive audio within the wideband audio frequency range.
17. An apparatus for facilitating wideband audio communication and digital subscriber line data communication over a twisted pair connection comprising:
first and second input terminals configured to be coupled to a line conditioning coil via a first twisted pair connection, the line conditioning coil including a frequency response having a first passband extending over a portion of a narrowband voice frequency range, a second passband extending over a portion of a digital subscriber line frequency range, and a frequency notch having a frequency range between the first passband and the second passband, the frequency notch attenuating signals over a portion of a wideband audio frequency range;
first and second output terminals configured to be coupled to a wideband audio telephony device via a second twisted pair connection, the wideband audio telephony device configured to transmit and receive audio within the wideband audio frequency range; and
a filter coupled between the first and second input terminals and the first and second output terminals, the filter having a cut-off frequency below the frequency notch and having a passband extending over at least a portion of the frequency notch, the filter configured to amplify signals within the frequency range of the frequency notch to compensate for the attenuation caused by the frequency notch, the filter comprising:
a first transistor device;
a second transistor device, the second transistor device being cross-coupled to the first transistor device;
a first capacitance device coupled between a drain terminal of the first transistor device and a ground connection; and
a second capacitance device coupled between a source terminal of the second transistor device and the ground connection.
18. The apparatus of claim 17 , wherein:
the first input terminal is coupled to a source terminal of the first transistor device and a drain terminal of the second transistor device;
the second input terminal is coupled to a gate terminal of the first transistor device and the source terminal of the second transistor device;
the first output terminal is coupled to the drain terminal of the first transistor device; and
the second output terminal is coupled to the source terminal of the second transistor device.
19. The apparatus of claim 18 , further wherein:
the gate terminal of the first transistor device is coupled to the source terminal of the second transistor device; and
a gate terminal of the second transistor device is coupled to a drain terminal of the first transistor device.
20. The apparatus of claim 17 , wherein the cut-off frequency (W c ) of the filter is determined by the following equation:
W c =√( Gt 1 *Gt 2 /C 1 *C 2 )
where G t1 is equal to a transconductance of the first transistor device, G t2 is equal to a transconductance of the second transistor device, C 1 is equal to a capacitance of the first capacitance device, and C 2 is equal to a capacitance of the second capacitance device.