FIR II IP Core: User Guide

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ID 683208
Date 6/12/2020
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Document Table of Contents
Document Table of Contents x
1. About the FIR II IP Core 2. FIR II IP Core Getting Started 3. FIR II IP Core Parameters 4. FIR II IP Core Functional Description 5. Document Revision History for the FIR II IP User Guide A. FIR II IP Core Document Archive
1. About the FIR II IP Core x
1.1. DSP Intel® FPGA IP Features 1.2. FIR II IP Core Features 1.3. FIR II IP Device Support 1.4. DSP Intel® FPGA IP Verification 1.5. FIR II IP Core Release Information 1.6. FIR II IP Core Performance and Resource Utilization
2. FIR II IP Core Getting Started x
2.1. Installing and Licensing Intel® FPGA IP Cores 2.2. IP Catalog and Parameter Editor 2.3. Specifying the IP Core Parameters and Options ( Intel® Quartus® Prime Pro Edition) 2.4. Simulating Intel® FPGA IP Cores 2.5. Simulating the FIR II IP Core Testbench in MATLAB 2.6. DSP Builder for Intel® FPGAs Design Flow
2.1. Installing and Licensing Intel® FPGA IP Cores x
2.1.1. Intel® FPGA IP Evaluation Mode 2.1.2. FIR II IP Core Intel® FPGA IP Evaluation Mode Timeout Behavior
2.3. Specifying the IP Core Parameters and Options ( Intel® Quartus® Prime Pro Edition) x
2.3.1. IP Core Generation Output ( Intel® Quartus® Prime Pro Edition)
3. FIR II IP Core Parameters x
3.1. FIR II IP Core Filter Specification 3.2. FIR II IP Core Coefficient Settings 3.3. FIR II IP Core Coefficients 3.4. FIR II IP Core Input and Output Options 3.5. FIR II IP Core Implementation Options 3.6. FIR II IP Core Reconfigurability
3.3. FIR II IP Core Coefficients x
3.3.1. Loading Coefficients from a File
3.4. FIR II IP Core Input and Output Options x
3.4.1. Signed Fractional Binary 3.4.2. MSB and LSB Truncation, Saturation, and Rounding
3.5. FIR II IP Core Implementation Options x
3.5.1. Memory and Multiplier Trade-Offs
3.5.1. Memory and Multiplier Trade-Offs x
3.5.1.1. Using Memory Block Threshold 3.5.1.2. Using Dual-port RAM Threshold 3.5.1.3. Using Large RAM Threshold 3.5.1.4. Using Hard Multiplier Threshold
4. FIR II IP Core Functional Description x
4.1. FIR II IP Core Interpolation Filters 4.2. FIR Decimation Filters 4.3. FIR II IP Core Time-Division Multiplexing 4.4. FIR II IP Core Multichannel Operation 4.5. FIR II IP Core Multiple Coefficient Banks 4.6. FIR II IP Core Coefficient Reloading 4.7. Reconfigurable FIR Filters 4.8. FIR II IP Core Interfaces and Signals
4.4. FIR II IP Core Multichannel Operation x
4.4.1. Vectorized Inputs 4.4.2. Channelization 4.4.3. Channel Input and Output Format
4.4.3. Channel Input and Output Format x
4.4.3.1. Eight Channels on Three Wires 4.4.3.2. Four Channels on Four Wires 4.4.3.3. 15 Channels with 15 Valid Cycles and 17 Invalid Cycles 4.4.3.4. 22 Channels with 11 Valid Cycles and 9 Invalid Cycles 4.4.3.5. Super Sample Rate
4.8. FIR II IP Core Interfaces and Signals x
4.8.1. Avalon Streaming Interfaces in DSP Intel FPGA IP 4.8.2. FIR II IP Core Avalon-ST Interfaces 4.8.3. FIR II IP Core Signals
4.8.2. FIR II IP Core Avalon-ST Interfaces x
4.8.2.1. Avalon-ST Sink Interface 4.8.2.2. Avalon-ST Source Interface
4.8.2.1. Avalon-ST Sink Interface x
4.8.2.1.1. Single Channel on Single Wire 4.8.2.1.2. Multiple Channels on Single Wire 4.8.2.1.3. Multiple Channels on Multiple Wires
1. About the FIR II IP Core
2. FIR II IP Core Getting Started
3. FIR II IP Core Parameters
4. FIR II IP Core Functional Description
5. Document Revision History for the FIR II IP User Guide
A. FIR II IP Core Document Archive

4.2. FIR Decimation Filters

A decimation filter decreases the output sample rate by a factor of D by keeping only every D-th input sample. Polyphase decomposition reduces the number of computations per cycle by ignoring the input data samples that are discarded during down sampling. Polyphase decimation filters provide speed optimization because each polyphase filter runs at the output data rate.
Figure 11. Decimation Block Diagram
Figure 12. Decimation Polyphase

The FIR II IP core implements decimation filters using a single engine that is time-shared by the different phases to optimize area. This implementation changes the overall throughput of the filter and the input sample rate. The throughput of the filter is the rate at which the filter generates the output (one output every K clock cycles). The input sample rate is the rate at which the filter processes input data samples (the input needs to be held for L clock cycles).

The values of K and L for the throughput and input sample rate of FIR II decimation filters depend on the filter architecture.

Table 16.  Definitions of K and L for Different Decimaiton Filter Architectures N = input bit width D = decimaiton factor, M = number of serial units, C = clocks per output data. The structure of the multibit serial architecture requires the input bit width (N) to be an integer multiple of the number of serial units (M).
Architecture Equations
Fully serial

K = ND

L = N

Multibit serial

K = ND/M

L = N / M

Fully parallel

K = D

L = 1

Multicycle

K = CD

L = C

For systems that require higher throughput and input data rate, Intel recommends that you use parallel or multicycle variable structures.

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