An interleaved shift register 20 includes a plurality of data storage elements 22a-22d having a common data input signal. Each of the plurality of data storage elements 22a-22d has an enable control input that is connected to one of a plurality of clock signals, each of the plurality of clock signals being incrementally out of phase with one another. Interleaved shift register 20 provides multiple data bits of the data signal to be stored within a single clock period of one of the plurality of clock signals, thus greatly improving the data rate without increasing the storage rate of the plurality of data storage elements 22a-22d.
Data from both a positive edge sample and negative edge sample are used to determine a data bit. The primary and secondary clocks capture two copies of the data. A sample is taken with a positive edge of one clock and the negative edge of the other clock each bit period. These two captured data values are combined along with the data value captured by the previous negative edge to determine the data bit value. The captured data may be dynamically de-skewed previous to being clocked into a buffer based on the clock edges sampling the data.
A shift register device includes transistor pass gates and latches connected in series and disposed along a data bit line, each latch connected to a corresponding transistor pass gate. Each transistor pass gate is controlled by a separate control signal input line that a provides a signal to the transistor pass gate connected to it. The signals are provided in a staggered time pattern beginning with a latch disposed last in succession, shifting data from one position to the next succeeding position. Each latch is capable of storing one bit of data. The shift register utilizes less silicon space while reducing the amount of power consumed during operation.
Data from both a positive edge sample and negative edge sample are used to determine a data bit. The primary and secondary clocks capture two copies of the data. A sample is taken with a positive edge of one clock and the negative edge of the other clock each bit period. These two captured data values are combined along with the data value captured by the previous negative edge to determine the data bit value. The captured data may be dynamically de-skewed previous to being clocked into a buffer based on the clock edges sampling the data.
In accordance with the invention, in a nonrecursive digital filter, the number of times each bit of input data passes through a shift register is reduced to save power. Despreading data is sent to a first shift register and a second shift register, each having a number of stages obtained by dividing the usual number of stages by two, and both shift registers alternately perform a shift operation at both edges of a shift clock. Multiplexers are provided for selecting the odd-numbered codes of reference codes stored in a reference-code register when the shift clock is in an OFF state and for selecting the even-numbered codes when the shift clock is in an ON state, and multiplexers are provided that perform the selections analogous to the above. The exclusive-OR output of the output of each stage of the first shift register and the outputs of the multiplexers, and the exclusive-OR output of the output of each stage of the second shift register, and the outputs of the multiplexers are added by the adder to obtain a correlation-strength output.
