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More Options for Multirate FIR 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 Multirate Filter and click the OK button to display the Generate LabVIEW FPGA Code for Multirate Filter dialog box. Load a finite impulse response (FIR) filter and click the More Options button to display the More Options for Multiate FIR 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 More Options for Multirate FIR Filter dialog box to configure additional settings to generate LabVIEW FPGA code for multirate fixed-point filters. You can implement the resulting LabVIEW FPGA code on NI FPGA targets to perform fixed-point filtering.

This dialog box includes the following tabs and components:

  • General—Contains the following options:
    • Multiply Configuration—Configures the multiply according to different FPGA clock requirements.
      • Number of pipelining stages—Specifies the number of pipelining stages in the multiply. The more pipelining stages in the multiply, the higher FPGA clock rate at which the multiply can compile. The value must be an integer in the range [0, 4]. The default is 1.
      • Register inputs—Specifies whether to add a register to the multiply immediately after the multiplicand input and the coefficient input. The multiply can compile at a higher FPGA clock rate if these inputs are from block memory.
    • Memory Types—Specifies to store data in either the FPGA block memory or look-up tables.
      • State memory—Specifies the type of memory to store internal states. You can choose from the following options:
        • Automatic (default)
        • Block Memory—Stores the data using embedded blocks of memory.
        • Look-Up Table—Stores the data in look-up tables available on the FPGA.
      • Coefficient memory—Specifies the type of memory to store filter coefficients. You can choose from the following options:
        • Automatic (default)
        • Block Memory—Stores the data using embedded blocks of memory.
        • Look-Up Table—Stores the data in look-up tables available on the FPGA.
    • Number of Adder Levels per Register—Specifies the number of adder levels per register. Use a smaller value for higher FPGA clock rates at which you want to compile. The default is 2. You can choose from the following options:
      • 1 (maximum 2 inputs)
      • 2 (maximum 4 inputs)
      • 3 (maximum 8 inputs)
    • Number of parallel data paths—Specifies the number of parallel data paths in the generated FPGA filter. Different data paths share the same control logic and coefficient memory to increase resource efficiency. The default is 1.
    • Execution Mode—Specifies whether to generate a filter block to execute outside or inside a single-cycle Timed Loop (SCTL). For the same multirate FIR filter, the two execution modes have the same throughput performance. This option is available only when the Number of parallel data paths is 1. If the Number of parallel data paths is greater than 1, the Execution Mode is Inside single-cycle Timed Loop. You can choose from the following options:
      • Outside single-cycle Timed Loop—Specifies a generated filter block to execute outside an SCTL.
      • Inside single-cycle Timed Loop—Specifies a generated filter block to execute inside an SCTL.
        Note  Filters that run inside an SCTL use handshaking terminals.
  • Coefficients—The options on this tab are not available if the filter on the main dialog has a non-unity gain on FPGA targets. Contains the following options:
    • Coefficient Reloadable—Specifies whether to generate code capable of online reloading. You can choose from the following options:
      • Multiple interfaces—Specifies coefficient memory definition, coefficients reloading, and filtering are three separate nodes.
      • Single interface—Specifies only one filtering node with coefficient reloading interface. This option is available only for Inside single-cycle Timed Loop execution mode.
    • Multiple Coefficient Sets—Specifies whether to implement multiple coefficient sets.
      • Summary—Indicates the number of coefficient sets, the channel indexes selected for a certain coefficient set, and whether a coefficient set is loaded. Set 0 is the filter loaded in the main dialog. You cannot modify set 0 in this dialog box. By default, all channels are assigned to this coefficient set. You can select a coefficient set and click the corresponding Channel Indexes cell to modify the channels assigned to this coefficient set. You then can remove the channels from the original coefficient set and assign them to the selected coefficient set. You can select a set index to view the magnitude response, phase response, and coefficient values in the Characteristics section. You can use the buttons on the right to add, reload, or delete a coefficient set.
        • Add—Adds a binary filter file. A Choose a filter file dialog box appears after you click the Add button. Select a filter file and click OK to add a new line to Summary. The Characteristics section displays the magnitude response, phase response, and coefficient values of this new coefficient set. If you click the Cancel button, a new line also appears in Summary with an unloaded warning sign before the coefficient index. If you close the More Options for Single-Rate FIR Filter dialog box with warning signs, the corresponding coefficient sets are set to be the same as coefficient set 0.
        • Reload—Reloads a binary filter file. Select a valid filter file to update the selected coefficient set with the new loaded filter and remove any corresponding unloaded warning signs. You cannot reload coefficient set 0, which is loaded in the main dialog.
        • Delete—Deletes the selected coefficient set. You cannot delete coefficient set 0, which is loaded in the main dialog.
      • Characteristics—Indicates the floating-point and fixed-point characteristics of the selected coefficient set. You can choose from the following options:
        • Magnitude Response—Displays a plot of the magnitude response of the selected coefficient set.
        • Phase Response—Displays a plot of the phase response of the selected coefficient set.
        • Coefficient Values—Displays a plot of the coefficient values of the selected coefficient set.

 

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