System and method for pulsed cable telephony

• US 7,039,062 B1
• Filed: 12/15/1999
• Issued: 05/02/2006
• Est. Priority Date: 12/15/1999
• Status: Expired due to Term

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: Microtune (Texas), L.P. (Qualcomm, Inc.)
• Inventors: Taddiken, Albert H.
• Primary Examiner(s): Pezzlo, John
• Assistant Examiner(s): Elallam, Ahmed
• Application Number:
  US09/461,778
• Time in Patent Office: 2,330 Days
• Field of Search: 370/216, 370/337, 370/347, 370/395.4, 370/395.42, 370/395.5, 370/442, 370/458, 370464-466, 370/469, 370485-487, 370/493, 370/498, 379/102.04, 379/322, 379/413, 725/129, 725/130
• US Class Current: 370/442
• CPC Class Codes: H03L 7/07 using several loops, e.g. for redundant clock signal generation
• CPC Class Codes: H03L 7/23 with pulse counters or frequency dividers
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42

Abstract

A cable receiver system and method which utilizes the combination of time-division multiplexing (“TDM”) and a fast-acquisition-time tuner to enable on/off pulsing of the tuner, thereby resulting in substantially reduced power consumption by the tuner. The tuner may be pulsed on during the allocated time slot to receive the allocated portion of the signal, and then pulsed off the remainder of the time. The tuner generally requires a fast signal acquisition time compared to the received signal'"'"'s frame rate so that the tuner does not use up an excess amount of the frame outside of the proper time slot when locking in the received signal. The TDM technique permits more efficient use of the high bandwidth network by multiplexing the relatively low bandwidth voice signals. In addition, the implementation of a fast-acquisition-time tuner in the NIU of a cable system permits the tuner to be pulsed off for a substantial amount of the time between the allocated time slots. Finally, the pulsing of the tuner substantially reduces power consumption by the receiver in an NIU, thus economically enabling the use of a telephony cable system that can operate during a power outage.

Claims

1. A cable telephony network interface unit (NIU), said NIU comprising:

a radio frequency (RF) cable input for receiving RF telephony signals, wherein said telephony signals comprise a time division multiplexed (TDM) RF signal having a frame rate and a corresponding frame period;

an RF tuner for processing said TDM RF signal, wherein said tuner has an acquisition time of less than half of said frame period, whereby said tuner is pulsed on for signal acquisitions, and pulsed off between signal acquisitions, and wherein said acquisition time is a time to lock on to a desired frequency; and

a voice telephony device compatible output for providing an output from said tuner to a telephony device,

wherein said RF telephony signals further comprise a continuous wave (CW) signal, and said tuner is capable of processing said CW signal, and wherein said NIU receives electrical power via said cable input when said tuner is processing said TDM RF signal and receives electrical power from a different source when processing said CW signal.

2. The NIU of claim 1, wherein said acquisition time is less than one-fourth of said frame period.

3. The NIU of claim 1, wherein said acquisition time is less than about 5 milliseconds.

4. The NIU of claim 1, wherein said acquisition time is less than about 1 millisecond.

5. The NIU of claim 1, wherein said tuner comprises fractional-N generated local oscillator reference frequency signals.

6. The NIU of claim 5, wherein said tuner comprises multiple phase locked loops (PLLs) generating said tuner'"'"'s local oscillator reference frequency signals.

7. The NIU of claim 6, wherein said PLLs comprise a wide loop bandwidth.

8. The NIU of claim 7, wherein said wide loop bandwidth is greater than said reference frequencies.

9. The NIU of claim 7, wherein said wide loop bandwidth is greater than about 1 KHz.

10. The NIU of claim 1, wherein said TDM is time division multiple access (TDMA).

11. The NIU of claim 1, wherein said TDM RF signal is further multiplexed using code division multiple access (CDMA).

12. The NIU of claim 1, wherein said tuner comprises components, and most of said tuner'"'"'s components are located on a single integrated circuit.

13. The NIU of claim 1, further comprising a demodulator interposed between said voice telephony device compatible output and said tuner.

14. The NIU of claim 13, wherein said demodulator demodulates according to a first modulation type when said NIU receives electrical power from an external source, and switches to demodulating according to a second modulation type when said NIU receives power via said cable input.

15. A method for processing cable telephony signals, said method comprising:

receiving a time division multiplexed (TDM) RF cable signal from a cable input, said TDM RF signal comprising frames having time slots;

pulsing on a fast acquisition time tuner for an allocated time slot in each of said frames, said tuner for processing said TDM RF signal, and wherein said acquisition time is a time to lock on to a desired frequency;

pulsing off said tuner for substantially the remainder of time in each of said frames, said frames having a frame period, wherein said acquisition time is less than one-fourth of said frame period, and wherein said frame period is equal to the time between the beginning of a first allocated time slot and the beginning of a second allocated time slot;

wherein said TDM RF signal is received during a loss of a power from an external source; and

receiving power from said cable input during said loss of power from said external source.

16. The method of claim 15, further comprising sending an alert signal to a cable plant after said loss of power from said external source, to inform said cable plant of said loss of power.

17. The method of claim 15, further comprising:

receiving and processing a continuous wave (CW) RF cable signal before said loss of power; and

switching to said receiving of said TDM RF cable signal after said loss of power.

18. The method of claim 15, wherein said TDM is time division multiple access (TDMA).

19. The method of claim 15, wherein said TDM RF signal is further multiplexed using code division multiple access (CDMA).

20. The method of claim 15, wherein said acquisition time is less than about 5 milliseconds.

21. The method of claim 15, wherein said acquisition time is less than about 1 millisecond.

22. The method of claim 15, wherein said tuner comprises fractional-N generated local oscillator reference frequency signals.

23. The method of claim 22 further comprising generating said tuner'"'"'s local oscillator reference frequency signals with multiple phase locked loops (PLLs).

24. The method of claim 23, wherein said PLLs comprise a wide loop bandwidth.

25. The method of claim 24, wherein said wide loop bandwidth is greater than said reference frequencies.

26. The method of claim 24, wherein said wide loop bandwidth is greater than about 1 KHz.

27. The method of claim 15, further comprising demodulating an output signal from said tuner.

28. The method of claim 27, further comprising demodulating according to a first modulation type when electrical power is received from an external source, and switching to demodulating according to a second modulation type when electrical power is received via said cable input.

29. A cable telephony tuner, said tuner comprising:

means for receiving a time division multiplexed (TDM) RF cable signal from a cable input, said TDM RF signal comprising frames having time slots;

means for pulsing on a fast acquisition time tuner for an allocated time slot in each of said frames, said tuner for processing said TDM RF signal wherein said acquisition time is a time to lock on to a desired frequency;

means for pulsing off said tuner for substantially the remainder of time in each of said frames, said frames having a frame period, wherein said fast acquisition time tuner is operable to lock on to said TDM RF signal in a time equal to or less than a quarter of a time period between consecutive said allocated time slots; and

means for receiving power from said cable input during a loss of power from an external source, wherein said TDM RF signal is received during said loss of power from said external source.

30. The tuner of claim 29, further comprising means for sending an alert signal to a cable plant after said loss of power from said external source, to inform said cable plant of said loss of power.

31. The tuner of claim 29, further comprising:

means for receiving and processing a continuous wave (CW) RF cable signal before said loss of power; and

means for switching to said receiving of said TDM RF cable signal after said loss of power.

32. The tuner of claim 29, wherein said TDM is time division multiple access (TDMA).

33. The tuner of claim 29, wherein said tuner comprises fractional-N generated local oscillator reference frequency signals.

34. The tuner of claim 33 further comprising generating said tuner'"'"'s local oscillator reference frequency signals with multiple phase locked loops (PLLs).

35. The tuner of claim 34, wherein said PLLs comprise a wide loop bandwidth.

36. The tuner of claim 35, wherein said wide loop bandwidth is greater than said reference frequencies.

37. The method of claim 35, wherein said wide loop bandwidth is greater than about 1 KHz.

38. A method for providing lifeline support in cable telephony, said method comprising:

receiving electrical power from an external power source;

receiving a continuous wave (CW) RF cable signal from a cable input;

processing said CW RF signal with an RF tuner;

losing power from said external power source;

switching to receive said electrical power from said cable input;

receiving a TDM RF telephony signal in place of said CW RF signal, said TDM RF signal comprising frames have time slots; and

pulsing said tuner on during an allocated time slot in each of said frames and off for substantially the remainder of each of said frames, whereby power consumption by said tuner is significantly reduced when said external power is lost.

39. The method of claim 38, further comprising sending an alert signal to a cable plant after losing said external power to inform said cable plant of said external power loss.

40. The method of claim 38, wherein said CW RF signal comprises video, data and voice information.