摘要:
A finite impulse response filter having tap weight rotation is provided, where each tap has a corresponding coefficient selector. Each coefficient selector includes N coefficients, where N is the number of taps. Each coefficient selector provides one of its corresponding coefficients as an input to a multiplier. Each multiplier also receives an input from a triggered track and hold tap. The tap coefficients are selected according to the time delay since the corresponding track and hold tap was most recently triggered. In this manner, the tendency of multiplier gain nonuniformity to degrade filter operation in the presence of tap weight rotation is reduced. In another embodiment, an offset selector is provided, to reduce the tendency of component offsets to degrade filter operation in the presence of tap weight rotation.
摘要:
A finite impulse response filter having tap weight rotation is provided, where each tap has a corresponding coefficient selector. Each coefficient selector includes N coefficients, where N is the number of taps. Each coefficient selector provides one of its corresponding coefficients as an input to a multiplier. Each multiplier also receives an input from a triggered track and hold tap. The tap coefficients are selected according to the time delay since the corresponding track and hold tap was most recently triggered. In this manner, the tendency of multiplier gain nonuniformity to degrade filter operation in the presence of tap weight rotation is reduced. In another embodiment, an offset selector is provided, to reduce the tendency of component offsets to degrade filter operation in the presence of tap weight rotation.
摘要:
High speed data communication standards such as IEEE 802.3ae (also known as XAUI) use four lanes to transmit data half duplex at 10 Gb/s. In order to achieve full duplex, eight lanes need to be used. By introducing echo cancellers into the system, a high speed transceiver can be built with full duplex capability on four lanes, thereby saving 50% of the lane requirements when compared to XAUI while still maintaining a low symbol rate.
摘要:
A lighting device preventing an illumination variation on a surface to be irradiated. The lighting device has a first light emitting surface section (102a) which is a surface formed by rotating a bus with a central axis as a rotation axis in a first angle area (−θ1≦θ≦θ1) of an angle (θ) relative to a cross section of the bus which is an intersection line with the cross section perpendicular to a surface (801a) to be irradiated and including the central axis of a lighting lens (100), a second light emitting surface section (102b) formed in a second angle area (θ1≦θ≦180° and −180°≦θ≦−θ1) of the angle (θ) so that a light flux emitted toward the surface (801a) increases as compared with the case where the first light emitting surface section (102a) is formed in a whole-angle area (0°≦θ
摘要:
An adaptive transversal filter having tap weights Wj which are products of corresponding tap coefficients Cj and tap gains Mj is provided. A filter control loop controls all of the tap coefficients Cj such that an error signal derived from the filter output is minimized. One or more tap control loops controls a tap gain Mk such that the corresponding tap coefficient Ck satisfies a predetermined control condition. For example, |Ck| can be maximized subject to a constraint |Ck| Cmax, where Cmax is a predetermined maximum coefficient value. In this manner, the effect of quantization noise on the coefficients Cj can be reduced. Multiple tap control loops can be employed, one for each tap. Alternatively, a single tap control loop can be used to control multiple taps by time interleaving.
摘要翻译:提供具有作为对应抽头系数Cj和抽头增益Mj的乘积的抽头权重Wj的自适应横向滤波器。 滤波器控制环控制所有抽头系数Cj,使得从滤波器输出得到的误差信号最小化。 一个或多个抽头控制回路控制抽头增益Mk使得对应的抽头系数Ck满足预定的控制条件。 例如| Ck | 可以最大限度地受限于| Ck | Cmax,其中Cmax是预定的最大系数值。 以这种方式,可以减小量化噪声对系数Cj的影响。 可以采用多个抽头控制回路,每个抽头一个。 或者,可以使用单抽头控制回路来通过时间交织来控制多个抽头。
摘要:
The present invention effectively cancels echo, near-end crosstalk and far-end crosstalk. A FEXT canceller is placed at the transmitter rather than at the receiver according to an aspect of the invention. In some embodiment, a FEXT canceller can be placed at the receiver only or the combination of both ends. The FEXT canceller is continuously adapted with information sent back from a remote receiver and with data from a neighbor transmitter that causes the crosstalk at the remote receiver. This allows the FEXT canceller to quickly adapt to a change in crosstalk function or conditions with the surrounding environment, for example, aging, temperature, humidity, physical pressure, etc. In some embodiments, an adaptation control signal is sent back from the receiver to the transmitter by using an overhead bit in the frame format. In some embodiments, part of the FEXT canceller is built-in at the remote receiver.
摘要:
A receiver involved in high-speed data transmission includes a decision system. The decision system calculates a value of an input signal and holds the value as a tentative value. The decision system calculates an error value, amplifies the error value, and holds the amplified error value as a corrected value. The decision system determines whether the amplified error value is within a marginal range. The decision system also determines whether adjacent values to the value indicate the input signal was in transition from a positive to negative state, or a negative to positive state. If the amplified error values is within a marginal range and the input signal was in transition from a positive to negative state, or a negative to positive state, then the decision system overrides the tentative value with the corrected value.
摘要:
Finite impulse response filters are commonly used in high speed data communications electronics for reducing error rates in multilevel symbol encoding schemes. Schemes such as pulse amplitude modulation and quadrature amplitude modulation may have higher error rates for symbols with low signal to noise ratios. By selectively updating the tap coefficients of the filter based on the symbols received, a more robust, accurate filter can be built.
摘要:
A digital timing recovery system wherein the rate conversion is independent of the sampling rate, and which may be set in a network mode or a remote mode. The invention includes a transceiver core for processing transmit and receive data at a predetermined baud rate, an analog front end for transmitting and receiving analog signals over a network, a phase detector for generating a phase error estimate and a timing controller for receiving the phase error estimate signal and generating a receive and transmit phase control signal for controlling timing of the analog front end. A selector is provided for selecting a remote mode of operation or a network mode of operation. The analog front end further includes a transmit converter for converting the transmit data at the baud rate to a digital output at a transmit rate and a digital to analog converter for converting the digital output to an analog signal, and an analog to digital converter for converting the analog receive signal to a digital receive signal and a receive converter for converting the digital receive signal at a receive rate to the baud rate. The phase detector includes a channel estimator for generating a coefficient error signal and the timing controller includes a loop filter for producing a control signal for a numerically controlled oscillator that produces a baud interrupt signal and the phase control signals.
摘要:
A pulse generating circuit is provided for generating a pulse having a time width synchronized with an input pulse and corresponding to a reference voltage. The circuit is particularly designed not to be affected by parasitic capacitance. A circuit for charging one electrode of an integrating circuit with a constant current is controlled by turning on or off a switch in response to the input pulse. The other electrode of the integrating capacitor is connected with a reference voltage source by driving a switch in response to a pulse having a pulse width which contains the time period of the input pulse and which is wider than the input pulse. A comparator is provided for comparing the potential at one electrode of the integrating capacitor and ground potential. A desired pulse is generated by a logic circuit which is receives both the output of the comparator and the input pulse.