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US 6,400,822 B1Granted
Linear, optical coupled line impedance circuit
AssigneeTexas Instruments Incorporated
InventorUzoma Olugbo Anozie
Life of this patent
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AssigneeTexas Instruments Incorporated
InventorUzoma Olugbo Anozie
Estimating the term…
A system and method for matching a device to a transmission line are disclosed. A matching circuit having optically coupled devices is biased so that harmonics of a reference signal, such as a dial tone, are eliminated. Suppression of the reference signal harmonics indicates a correct impedance match between the matching circuit and the transmission line. The matching circuit also provides two-wire to four-wire conversion. After the matching circuit's impedance is adjusted, the circuit gain is balanced and the circuit is further biased to eliminate echoes. The impedance matching and circuit biasing operations are controlled by a digital signal processor. Before data or other signals are processed by the digital signal processor, an inverse transfer function is derived for the matching circuit. Received signals are convolved with the inverse transfer function to compensate for matching circuit distortion. Also, transmitted signals are predistorted before they are transmitted through the matching circuit in order to provide an undistorted signal at the transmission line.
A system for matching the impedance of a device to the impedance to a transmission line, said system comprising:
A modem comprising:
A circuit for optically coupling a device to a telephone line, said circuit having a first port and a second port for connection to said telephone line and a receive port and a transmit port for connection to said device, said circuit comprising:
Dependencies are inferred from the claim text.