Table Of Contents

PXIe-5693 Block Diagram

    Last Modified: December 14, 2017

    The PXIe-5693 includes three signal paths: the preselector filter path, the low-frequency bypass path, and the external filter path.

    Preselector Filter Path

    This is the default path for the PXIe-5693. Incoming signals that are multiples of the RF center frequency normally cause harmonic distortion in the preamplifiers and first mixer in associated downconverter modules. The PXIe-5693 preselector filters are designed to attenuate the signal level at these unwanted harmonic frequencies.

    The primary preselector filter path contains the following 16 sub-octave, fixed-frequency bandpass filters that attenuate signal harmonics.

    RF Preselector Filter Frequency Range
    1 19 MHz to 35 MHz
    2 33 MHz to 61 MHz
    3 59 MHz to 110 MHz
    4 90 MHz to 170 MHz
    5 140 MHz to 245 MHz
    6 205 MHz to 370 MHz
    7 330 MHz to 575 MHz
    8 530 MHz to 975 MHz
    9 910 MHz to 1,600 MHz
    10 1,520 MHz to 2,040 MHz
    11 1,960 MHz to 2,540 MHz
    12 2,460 MHz to 3,040 MHz
    13 2,960 MHz to 3,840 MHz
    14 3,760 MHz to 4,640 MHz
    15 4,560 MHz to 5,840 MHz
    16 5,760 MHz to 7,040 MHz

    NI-RFSA selects the preselector filters based on the input RF center frequency. Additionally, the PXIe-5693 preselector filter path contains two notch filters, one to attenuate the FM band (88 MHz to 108 MHz) and the other to attenuate RF incoming signals between 55 MHz and 75 MHz. You can enable or disable the preselector filter path preamplifiers using the Preamp Enabled property or attribute. Adjustable step attenuators allow for a nominal 1 dB step resolution of the module gain.

    Low-Frequency Bypass Path

    The low-frequency bypass path routes incoming RF signals at frequencies ranging from DC to 30 MHz directly to the RF OUT connector on the PXIe-5693 front panel, bypassing the preselector filter path. If the PXIe-5693 is used with an RF signal downconverter, this signal path allows for the PXIe-5693 to operate at the low frequency limit of the RF signal downconverter module.

    External Filter Path

    If your application requires unique filtering not provided in the preselector filter path, such as narrower bandwidth requirements, more stopband rejection or notch filtering, you can use the external filter path to insert a custom external filter for frequencies between 20 MHz to 3 GHz. To use the external filter path, connect your external filter to the EXT FILTER IN and EXT FILTER OUT connectors on the PXIe-5693 front panel.

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