network analyzer spec?

Discussion in 'The Projects Forum' started by suzuki, Sep 18, 2012.

  1. suzuki

    Thread Starter Member

    Aug 10, 2011

    Does anybody have a general idea of what magnitude of input/output maximums (for voltage) are for a network analyzer? I have seen that you do not want to put too large a signal on the input side (lets call this Probe A). But what about the probe (Probe B) that is measuring the output side?

    I am wondering because say you put a voltage divider at the output to step down the output voltage, wouldn't that change the magnitude of your resulting frequency response?

    I'm not aware of any manuals that are available with this information, so if somebody knows an estimate off the top of their head, that would be great.
  2. vk6zgo

    Active Member

    Jul 21, 2012
    Normally,the only way you will have a higher voltage at the output of something you are testing with a network analyser is if the device is,or contains,an amplifier.
    Most such devices are designed to match particular impedances,so they are terminated in that impedance.

    To get a lower voltage which is a replica of the original in all ways except level,either a power attenuator,(often called a through load),a sampling probe,or the forward sampling port of a directional coupler can be used.

    The normal method of using these devices is to sweep it by itself with any level errors being noted,& used as correction factors when you sweep the amplifier,or whatever.
    Such errors are usually so low that they may be ignored.

    Another way is to reduce the input to the DUT,until its output level is low enough to not kill your analyser input.
    The best way to do this is to use an external attenuator instead of relying on the level control of the generator part of the analyser.
    Last edited: Sep 18, 2012