摘要:
A state metric calculator for calculating state metrics of stages in a trellis of a sequence estimation technique is described. The calculator has a processing path containing operations needed for calculating a state metric of a trellis stage from state metrics of an earlier trellis stage. One or more data stores are located in the processing path to divide the path into separate sections. The sections can then operate on the production of different state metrics to one another in, if desired, the same clock cycle.
摘要:
A programmable integrated circuit device can be configured as a cascaded integrator-comb (CIC) filter. In order to take advantage of Hogenauer pruning to configure the CIC filter efficiently, a software tool for configuring the device can be provided in which the Fj terms for Hogenauer pruning have been calculated in advance for all possible user parameters supported by the tool. To configure a CIC filter, the user enters the parameters in the tool, which then looks up the Fj terms corresponding to those parameters and completes the calculation of the Bj terms for Hogenauer pruning. Because the calculation of the Fj terms is the most time-consuming step in calculating of the Bj terms, pre-calculation of the Fj terms, which can be done just once by the provider of the tool, allows end users to calculate the Bj terms in reasonable periods of time, making Hogenauer pruning available to end users.
摘要:
A state metric calculator for calculating state metrics of stages in a trellis of a sequence estimation technique is described. The calculator has a processing path containing operations needed for calculating a state metric of a trellis stage from state metrics of an earlier trellis stage. One or more data stores are located in the processing path to divide the path into separate sections. The sections can then operate on the production of different state metrics to one another in, if desired, the same clock cycle.
摘要:
A sequence estimator is described. In one embodiment, the sequence estimator includes a plurality of maximum a posteriori probability (MAP) decoding engines each arranged to process a series of windows of a transmitted signal where state metrics produced for an end of one window by one decoding engine are re-used for the initialization of a state metric calculation process performed by another decoding engine on another window of the signal.
摘要:
Interleaving and deinterleaving schemes for operating in parallel on sections of a data block to load memories with respective segments of a reordered version of the block, in a manner which can avoid memory conflicts.
摘要:
Interleaving in which functions relating final and original positions are implemented with low complexity using inequalities based on the functions.
摘要:
Circuitry for performing QR decomposition of an input matrix includes multiplication/addition circuitry for performing multiplication and addition/subtraction operations on a plurality of inputs, division/square-root circuitry for performing division and square-root operations on an output of the multiplication/addition circuitry, a first memory for storing the input matrix, a second memory for storing a selected vector of the input matrix, and a selector for inputting to the multiplication/addition circuitry any one or more of a vector of the input matrix, the selected vector, and an output of the division/square-root circuitry. On respective successive passes, a respective vector of the input matrix is read from a first memory into a second memory, and elements of a respective vector of an R matrix of the QR decomposition are computed and the respective vector of the input matrix in the first memory is replaced with the respective vector of the R matrix.
摘要:
Apparatus, methods and techniques for adjusting the phase offset used in sampling rate conversion uses a Farrow structure or the like to compensate for clock problems such as “clock jitter” and/or “clock drift” effects, which typically arise where one clock is truly independent of the other. A phase offset adjustment value Δμ based on the measured data flow between clock domains across a transition interface and/or through a buffer is calculated. Where an output FIFO buffer is used, the measured data flow value represents the number of data words written to and read from the FIFO buffer, such as the current number of data words stored in the FIFO buffer or a counter value representing the net number of data words written to the FIFO buffer. The measured data flow value is compared to a target data flow value, which may be a range of values. The phase offset adjustment value may be updated and/or recalculated continuously and/or periodically and is added to or subtracted from the phase offset μ as necessary. Such systems are useful in software defined radio and the like and may be implemented on a variety of devices, including PLDs.
摘要:
A Viterbi decoder capable of decoding a code having a maximum constraint length of Lmax is disclosed. The Viterbi decoder includes an initializer unit that initializes selected states of an encoder during an initial time period to allow the Viterbi decoder to also decode codes having a constraint length less than Lmax.
摘要:
A method for implementing a pseudo random sequence (PRS) generator is disclosed. Relationships between outputs of flip-flops of an initial model PRS generator at a current time step t with the outputs of the flip-flops at a time step t-n is determined, where n is a number of coefficients to be generated per time step. Flip-flops in the multi-step PRS generator are coupled in response to the relationships between the outputs of the flip-flops at the current time step t with the output of the flip-flops at the time step t-n.