The HP3589 covers the frequency range of 10 Hz to 150 MHz, more than sufficient for the LISN range of 0.01 - 10 MHz. As long as the 3589 is calibrated then I don't see why you can't use it to calibrate the LISNs. It is ideal for use in this application because of the available 1 MOhm input impedance; more on this below.
As far as how to do it, there are lots of different ways. You can measure the current into the power output port while measuring the line-to-ground applied potential, and take the ratio. You can measure just the applied potential >from your 50 Ohm source, and from the loading effect you can back out the impedance. If you have a directional coupler (the one for low frequency CS114) you can measure forward and reverse power and infer the impedance from that. If you separately first measure the insertion loss due to the blocking cap between power output and EMI port, then you can measure applied potential at the EMI port and accounting for the blocking cap you can measure the loading effect of the LISN and back out the impedance again. Of all these techniques, if I were doing it, I would get my handy Solar 6741 current probe (the one with FLAT transfer impedance from 10 kHz to 30 MHz) and use its output as the network analyzer reference port input. The applied potential from the LISN output port to ground would be my test input. You will want to use the VERY convenient 1 MOhm input so you don't load the potential measurement. The network analyzer would be set to display the ratio of test port to reference port. That ratio, plus 3 dB Ohms (the inverse of the current probe -3 dB Ohm transfer impedance) is the impedance of the LISN. Ken Javor From: [email protected] Reply-To: [email protected] List-Post: [email protected] Date: Wed, 5 May 2004 13:15:19 EDT To: [email protected] Subject: In-house LISN calibration Hello, I have an HP 3589A Spectrum/Network Analyzer. I was wondering if there is any way to do in-house calibration of the LISNs. I need to verify the impedance and the insertion loss of each LISN. I'm not sure if the unit I have will do the job. I need the calibration procedure to be accepted by various agencies (via ANSI C63.4 / CISPR standards). I don't want just a "verification procedure". Anyone know how this can be done? Thanks. Tim Pierce
