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Generate LabVIEW FPGA Code for Single-Rate Filter Dialog Box

LabVIEW 2013 Digital Filter Design Toolkit Help

Edition Date: June 2013

Part Number: 371988F-01

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Requires: Digital Filter Design Toolkit

Right-click an FPGA target in the Project Explorer window and select Start IP Generator from the shortcut menu to display the Start IP Generator dialog box. Select Single-Rate Filter and click the OK button to display the Generate LabVIEW FPGA Code for Single-Rate Filter dialog box.

Note  The Start IP Generator dialog box is available only if you install the LabVIEW FPGA Module and NI-RIO driver software on the host computer.

Use the Generate LabVIEW FPGA Code for Single-Rate Filter dialog box to generate LabVIEW FPGA code for fixed-point single-rate filters. You can implement the resulting LabVIEW FPGA code on NI FPGA targets to perform fixed-point filtering.

This dialog box includes the following options:

  • Files—Contains the following options:
    • Filter file to load—Specifies the filter file from which you want to generate LabVIEW FPGA code. You can obtain the filter file by using the DFD Save to File VI.
      Note  If you did not quantize the filter, LabVIEW quantizes it by using the default settings of the DFD FXP Quantize Coef VI.
    • Filter VI to generate—Specifies the full path to the filter VI that LabVIEW generates, including the filename.
  • Fixed-Point Modeling—Specifies the settings for modeling the filter. If you already modeled the filter, LabVIEW loads the modeling settings from the filter file. You can choose from the following options:
    • Input Data Type—Specifies the input word length and input integer word length of the filter.
      • Word length—Specifies the word length, in number of bits, that LabVIEW uses to represent the input signal. The valid range is [1, 32].
      • Integer word length—Specifies the integer word length, in number of bits, that LabVIEW uses to represent the input signal. The valid range is [–2048, 2047].
    • Output Data Type—Specifies the output word length and output integer word length of the filter.
      • Adapt to source—Specifies whether LabVIEW decides the word length and integer word length of the output signal.
      • Word length—Specifies the word length, in number of bits, that LabVIEW uses to represent the output signal. The valid range is [1, 32].
      • Integer word length—Specifies the integer word length, in number of bits, that LabVIEW uses to represent the output signal. The valid range is [–2048, 2047].
    • Rounding mode—Specifies the rounding mode that LabVIEW uses in the output quantizer.
    • Overflow mode—Specifies how LabVIEW handles overflows and underflows in the output quantizer.
  • Magnitude Responses—Displays the plot of the magnitude responses of the reference floating-point filter and the fixed-point filter.
  • Implementation—Specifies the settings for implementing the filter. You can choose from the following options:
    • Number of channels—Specifies the number of channels that you want the generated code to process for each data path. If you use the Multiply-Accumulate method to implement the filter, the valid range is [1, 255]. If you use the Distributed Arithmetic method to implement the filter, the valid range is [1, 8]. The default is 1.
      Note  The generated single-rate filter block has one input and one output. For a multi-channel single-rate filter, data from multiple channels is interleaved into a single input. You are responsible for controlling the data sequence into/out of the filter block.
    • Throughput—Specifies the minimum number of cycles between two successive values of valid input data.
    • Throughput configuration—Displays the Throughput Configuration dialog box.
    • Method—Specifies the method of implementing the filter. The Multiply-Accumulate method uses multipliers and accumulators to implement the filter, whereas the Distributed Arithmetic method uses look-up tables and accumulators. You can select the Distributed Arithmetic method for only single-rate FIR filters.
      Tip  You can use the Distributed Arithmetic method to implement a high-throughput filter. However, this method might consume more FPGA logic resources than the Multiply-Accumulate method.
      Note  If you use the Distributed Arithmetic method, the numeric precision of the filtering result might be slightly different from that of the simulation result.
  • Feedback—Displays information about the filter type and LabVIEW FPGA code generation, such as the maximum input sampling frequency per channel.
  • More Options—Configures additional settings for generating the LabVIEW FPGA code. Click this button to display the More Options for Single-Rate FIR Filter dialog box.

 

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