Patent application number | Description | Published |
20090028576 | Frequency-Domain Equalization of the Fiber Optic Channel - Systems and methods for frequency-domain compensation in optical communication systems. In pre-equalization embodiments, the transmitter transforms the data stream into a frequency domain signal and applies a compensation filter before transforming it back into a pre-distorted time domain signal. As the pre-distorted time domain signal propagates through the optical channel, optical dispersion effects counter the pre-distortion, producing an equalized signal at the channel output. In post-equalization embodiments, the receiver transforms the received signal into a frequency domain signal and applies a compensation filter before transforming it back into an equalized time domain signal. Pre-equalization may prove less expensive due to the square-law characteristic of photodetectors employed by most receivers. | 01-29-2009 |
20090279893 | ANALOG FINITE IMPULSE RESPONSE FILTER - According to one embodiment of the invention, a programmable finite impulse response (FIR) filter is implemented with differential isolation circuits to isolate parasitic capacitance from attenuating an output signal at both a first and second differential output terminals of the FIR filter. The FIR includes a track and hold circuit and a summing circuit that provides operational advantages to the FIR filter. | 11-12-2009 |
20100052778 | Nth Order Tunable Low-Pass Continuous Time Filter for Fiber Optic Receivers - According to one embodiment of the invention, a circuit comprising a plurality of operational transconductance amplifiers (OTAS) is described. The first OTA has differential input and differential output. The second OTA also has differential input, where a first output of the first OTA is coupled to the first differential input of the second OTA, which is an inverting input. A second output of the first OTA is coupled to the second input of the second OTA, which is a non-inverting input. The first differential output being coupled to a first input of the first OTA and the second differential output being coupled to a second input of the first OTA for negative feedback and current biasing. | 03-04-2010 |
20100102888 | TIMING RECOVERY FOR PARTIAL-RESPONSE MAXIMUM LIKELIHOOD SEQUENCE DETECTOR - An embodiment of the present invention is a technique for timing recovery. A frequency acquisition loop locks a voltage controlled oscillator (VCO) clock of a multi-band VCO to a reference clock. The frequency acquisition loop generates first and second feedback clocks from the VCO clock. A data lock phase loop generates a driving signal corresponding to a phase error signal from interleaved partial response signal (PRS) samples based on the second feedback clock. The driving signal controls the multi-band VCO in a data phase lock mode. A lock detect controller detects a frequency lock condition in a frequency lock mode and a data lock condition in the data phase lock mode based on the first feedback clock and the reference clock. | 04-29-2010 |
20100209115 | Frequency-Domain Equalization of the Fiber Optic Channel - Systems and methods for frequency-domain compensation in optical communication systems. In pre-equalization embodiments, the transmitter transforms the data stream into a frequency domain signal and applies a compensation filter before transforming it back into a pre-distorted time domain signal. As the pre-distorted time domain signal propagates through the optical channel, optical dispersion effects counter the pre-distortion, producing an equalized signal at the channel output. In post-equalization embodiments, the receiver transforms the received signal into a frequency domain signal and applies a compensation filter before transforming it back into an equalized time domain signal. Pre-equalization may prove less expensive due to the square-law characteristic of photodetectors employed by most receivers. | 08-19-2010 |
20100271107 | ANALOG FINITE IMPULSE RESPONSE FILTER - According to one embodiment of the invention, a programmable finite impulse response (FIR) filter is implemented with differential isolation circuits to isolate parasitic capacitance from attenuating an output signal at both a first and second differential output terminals of the FIR filter. The FIR includes a summing circuit that provides operational advantages to the FIR filter. | 10-28-2010 |
20100281348 | CALIBRATION METHOD AND CIRCUIT FOR AN ADD-COMPARE-SELECT LOOP - One embodiment of the invention features a programmable gain stage in analog update circuitry to overcome the accuracy limitation of the circuit gain and the maintenance of small finite number of possible sequence estimates. | 11-04-2010 |
20130183040 | SYSTEM, METHOD AND FIBER-OPTIC TRANSCEIVER MODULE FOR BANDWIDTH EFFICIENT DISTORTION-TOLERANT TRANSMISSIONS FOR HIGH-BIT RATE FIBER OPTIC COMMUNICATIONS - According to one embodiment of the invention, fiber optic communications method is described. The method comprises a first operation of dynamically identifying frequencies at which spectral nulls occur in a signal received via an optical fiber, and thereafter, segregating communications over the optical fiber into a set of inter-null bands defined by the spectral nulls. | 07-18-2013 |
20140056594 | EXTENDED REACH XFP TRANSCEIVER WITH INTEGRATED FORWARD ERROR CORRECTION - Integrated performance monitoring (PM); optical layer operations, administration, maintenance, and provisioning (OAM&P); alarming; amplification, or the like is described in optical transceivers, such as multi-source agreement (MSA)-defined modules. An optical transceiver defined by an MSA agreement can include advanced integrated functions for carrier-grade operation which preserves the existing MSA specifications allowing the optical transceiver to operate with any compliant MSA host device with advanced features and functionality. An XFP module can include integrated circuitry configured to provide forward error correction encoding and decoding; a transmitter communicatively coupled to the integrated circuit; a receiver communicatively coupled to the integrated circuit; and a module housing in which the integrated circuitry, the transmitter, and the receiver are disposed, wherein the module housing is pluggable in a host device configured to operate the pluggable optical transceiver, and wherein the forward error correction encoding and decoding is performed transparently to the host device. | 02-27-2014 |
Patent application number | Description | Published |
20090028576 | Frequency-Domain Equalization of the Fiber Optic Channel - Systems and methods for frequency-domain compensation in optical communication systems. In pre-equalization embodiments, the transmitter transforms the data stream into a frequency domain signal and applies a compensation filter before transforming it back into a pre-distorted time domain signal. As the pre-distorted time domain signal propagates through the optical channel, optical dispersion effects counter the pre-distortion, producing an equalized signal at the channel output. In post-equalization embodiments, the receiver transforms the received signal into a frequency domain signal and applies a compensation filter before transforming it back into an equalized time domain signal. Pre-equalization may prove less expensive due to the square-law characteristic of photodetectors employed by most receivers. | 01-29-2009 |
20100209115 | Frequency-Domain Equalization of the Fiber Optic Channel - Systems and methods for frequency-domain compensation in optical communication systems. In pre-equalization embodiments, the transmitter transforms the data stream into a frequency domain signal and applies a compensation filter before transforming it back into a pre-distorted time domain signal. As the pre-distorted time domain signal propagates through the optical channel, optical dispersion effects counter the pre-distortion, producing an equalized signal at the channel output. In post-equalization embodiments, the receiver transforms the received signal into a frequency domain signal and applies a compensation filter before transforming it back into an equalized time domain signal. Pre-equalization may prove less expensive due to the square-law characteristic of photodetectors employed by most receivers. | 08-19-2010 |
20140056594 | EXTENDED REACH XFP TRANSCEIVER WITH INTEGRATED FORWARD ERROR CORRECTION - Integrated performance monitoring (PM); optical layer operations, administration, maintenance, and provisioning (OAM&P); alarming; amplification, or the like is described in optical transceivers, such as multi-source agreement (MSA)-defined modules. An optical transceiver defined by an MSA agreement can include advanced integrated functions for carrier-grade operation which preserves the existing MSA specifications allowing the optical transceiver to operate with any compliant MSA host device with advanced features and functionality. An XFP module can include integrated circuitry configured to provide forward error correction encoding and decoding; a transmitter communicatively coupled to the integrated circuit; a receiver communicatively coupled to the integrated circuit; and a module housing in which the integrated circuitry, the transmitter, and the receiver are disposed, wherein the module housing is pluggable in a host device configured to operate the pluggable optical transceiver, and wherein the forward error correction encoding and decoding is performed transparently to the host device. | 02-27-2014 |