Programmable plain old telephone line impedance matching...

Details Programmable plain old telephone line impedance matching... Programmable plain old telephone line impedance matching...

2011-06-07

2011-06-07

Sing, Simon (Department: 2614)

Telephonic communications

Substation or terminal circuitry

Impedance matching or line equalizing

C379S398000

Reexamination Certificate

active

07957522

ABSTRACT:
Programmable plain old telephone line impedance matching circuits that provide an accurate, integrated programmable termination and source impedance for a telephone line interface circuit (SLIC). The accurate matching of this programmable termination and source impedance with the termination impedance of the 2 Wire connection eliminates signal reflections on this connection and therefore removes the echo, which echo can lead to reduced signal quality in packetized VOIP systems. The programmable integrated impedance matching circuits of this invention use a programmable time continuous amplifier preferably in combination with a double sampling programmable switched capacitor feedback stage (sampling twice per clock cycle by sampling on the positive and negative phases of a non-overlapping clock cycle). Use of a switched capacitor circuit to synthesize a resistance allows the realization of the relatively long time constants needed, generally, thereby allowing the realization of the present invention programmable impedance matching circuit as an integrated circuit without external discrete resistors or capacitors.

REFERENCES:
patent: 4558185 (1985-12-01), Morikawa et al.
patent: 4631359 (1986-12-01), Johansson et al.
patent: 4789999 (1988-12-01), Meschkat et al.
patent: 5187742 (1993-02-01), Moran, III et al.
patent: 5402485 (1995-03-01), Takato et al.
patent: 5473685 (1995-12-01), Mulder
patent: 5598467 (1997-01-01), Bremner et al.
patent: 6625278 (2003-09-01), Hendricks et al.
patent: 6735302 (2004-05-01), Caine et al.
patent: 6920471 (2005-07-01), Chan et al.
patent: 6925171 (2005-08-01), Wang et al.
patent: 6990191 (2006-01-01), Anderson et al.
patent: 7062037 (2006-06-01), Chan et al.
patent: 2003/0076945 (2003-04-01), Huang et al.
patent: 2003/0169871 (2003-09-01), Enriquez et al.
Rinaldo Castello et al., “A BiCMOS Speech Circuit with Only Two External Components”, IEEE Journal of Solid-State Circuits, Jul. 1993, vol. 28, No. 7, pp. 770-777.

Affiliated with

Also associated with

Rating

Programmable plain old telephone line impedance matching... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Programmable plain old telephone line impedance matching..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Programmable plain old telephone line impedance matching... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2647484