摘要:
An analog baud rate clock and data recovery apparatus includes a first track and hold circuit that delays a received signal by one unit interval to create an odd signal; a second track and hold circuit that delays the received signal by one unit interval to create an even signal; a first comparator circuit; and a second comparator circuit. The first track and hold circuit outputs the odd signal to the first comparator circuit and the second comparator circuit. The second track and hold circuit outputs the even signal to the first comparator circuit and the second comparator circuit. The first comparator adds the odd signal to the even signal and outputs a first potential timing error. The second comparator subtracts the odd signal and the even signal and outputs a second potential timing error signal. A desired timing error signal is derived from the first and second potential timing error signals. The desired timing error signal is used to determine whether signal sampling is early or late.
摘要:
An analog baud rate clock and data recovery apparatus includes a first track and hold circuit that delays a received signal by one unit interval to create an odd signal; a second track and hold circuit that delays the received signal by one unit interval to create an even signal; a first comparator circuit; and a second comparator circuit. The first track and hold circuit outputs the odd signal to the first comparator circuit and the second comparator circuit. The second track and hold circuit outputs the even signal to the first comparator circuit and the second comparator circuit. The first comparator adds the odd signal to the even signal and outputs a first potential timing error. The second comparator subtracts the odd signal and the even signal and outputs a second potential timing error signal. A desired timing error signal is derived from the first and second potential timing error signals. The desired timing error signal is used to determine whether signal sampling is early or late.
摘要:
A data communications system and methods are disclosed. The system includes a transmitter for conveying a data signal filtered by a finite impulse response (FIR) filter to a receiver via a channel. The receiver equalizes the received data signal using a decision feedback equalizer (DFE) and the FIR. The receiver samples the data signal to determine an error signal and uses the error signal to adapt settings of a pre-cursor tap coefficient of the FIR, one or more post-cursor tap coefficients of the FIR, a phase of the recovered clock, and a coefficient of the DFE. To adapt the settings, the receiver determines the error signal based on an error sample taken from the data signal in a single clock cycle. To determine an error signal, the receiver samples the data signal at a phase estimated to correspond to a peak amplitude of a pulse response of the channel.
摘要:
A data communications system and methods are disclosed. The system includes a transmitter for conveying a data signal filtered by a finite impulse response (FIR) filter to a receiver via a channel. The receiver equalizes the received data signal using a decision feedback equalizer (DFE) and the FIR. The receiver samples the data signal to determine an error signal and uses the error signal to adapt settings of a pre-cursor tap coefficient of the FIR, one or more post-cursor tap coefficients of the FIR, a phase of the recovered clock, and a coefficient of the DFE. To adapt the settings, the receiver determines the error signal based on an error sample taken from the data signal in a single clock cycle. To determine an error signal, the receiver samples the data signal at a phase estimated to correspond to a peak amplitude of a pulse response of the channel.
摘要:
A digital delay locked loop uses a delay array to delay an input signal by an amount indicated by a delay code. A phase of the resulting delayed signal is compared to a corresponding phase of the input signal, and dependent on the comparison, the delay code is updated to indicate whether the delay array needs to provide more delay or less delay. The digital delay locked loop also uses a detection circuit that monitors for a predetermined condition of the delay code. In response to detection of the predetermined condition, the delay code is automatically reset to a value different than a value of the delay code present at a previous reset or initial startup of the digital delay locked loop.