Samsung Electronics Co., Ltd.

Sung-hyun Hwang

Jung-Hoon Kim

Hyun-cheol Park

Jae-woo Kim

Oh-sang Kwon

Chang-hyun Yim

A robust symbol timing recovery circuit for a telephone line modem is provided. The symbol timing recovery circuit comprises a timing estimator and an interpolator. The timing estimator, which performs an operation on input samples and estimates a timing offset of a received symbol, outputs a timing offset estimated for each symbol for a first window interval, and thereafter outputs a timing offset estimated in an immediately previous window interval for the current window interval. The interpolator, which performs interpolation using the input samples, comprises a plurality of shift registers which are serially connected and output the input samples in units of a predetermined plural number of input samples, by sequentially delaying for an input sample 15 period and outputting the input samples. Since the symbol timing recovery circuit is not sensitive to clock instability and employs a stable timing offset estimating method, symbol timing can be recovered stably and reliably.

Robust symbol timing recovery circuit for telephone line modem

A receiver performing a stable operation in a burst mode is provided. The receiver transmits packet data using a preamble, and has good acquisition performance so that a synchronization part converges on a preamble interval. For the acquisition performance, the receiver senses the carrier of a received signal, detects a rough location of a burst, and in response to the result of carrier sensing, performs coarse gain control, symbol timing compensation, and frame synchronization. Then, if the frame synchronization is completed, in response to the result of frame synchronization, the receiver performs fine gain control, equalization of the signal, and carrier recovery.

Burst mode receiver and method for stable reception of packet data on telephone line

A channel equalizing and carrier recovery system for home phoneline networking alliance (HomePNA) receiver and method thereof are provided. The channel equalizing system includes a frequency diverse quadrature amplitude modulation (FD-QAM) equalizer and a quadrature amplitude modulation (QAM) equalizer. The FD-QAM equalizer receives an FD-QAM signal, determines FD-QAM tap coefficients, and equalizes the FD-QAM signal using the FD-QAM tap coefficients. The QAM equalizer receives a QAM signal, determines QAM tap coefficients, and equalizes the QAM signal using the QAM tap coefficients. The QAM equalizer receives the FD-QAM signal and determines the QAM tap coefficients during a predetermined header period. The carrier recovery circuit includes a phase detector, a loop filter, and a numerically controlled oscillator (NCO). The phase detector uses a phase difference between a reception symbol and a decision signal of the reception symbol as an instantaneous phase difference when the reception symbol is a data symbol of an FD-QAM signal or a symbol of a QAM signal, uses '0' as the instantaneous phase difference when the reception symbol is a zero symbol of the FD-QAM signal, averages instantaneous phase differences during a predetermined period or time, and outputs the result of averaging. The loop filter filters the output signal of the phase detector. The NCO generates an oscillation signal having a variable phase in response to an output signal of the loop filter so that a phase error of a reception signal can be controlled.

Channel equalizing and carrier recovery system for home phoneline networking alliance receiver and method thereof

An apparatus and a method for detecting the energy of a tone signal. A pre-process unit takes absolute values of transmitted samples and outputs the values to a delay unit for delaying the transmitted samples according to a predetermined delay interval. An operation unit subtracts the value calculated by multiplying the magnitudes of the samples transmitted before and after the burst detection from the square value of the magnitude of the sample at the time of burst detection among the delayed transmitted samples. A detection unit detects the burst by confirming whether peaks corresponding to the number of the samples transmitted before the sample of the burst detection are detected by a signal of an value input from the operation unit. Therefore, the present invention can reduce a probability of a false alarm caused by an impulse error and burst errors and thus perform stable burst detection.

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Suwon, South Korea

Sung-hyun Hwang