Q&A Impulse Noise Simulators (Model: INS series)

 

Waveform measurement

 

Q1.

We observed the output waveform from the INS simulators by using a HV probe.  The waveform has a severe overshoot (ringing) on the leading slope.  What should I do to measure the correct waveform?

 

Q2.

For measuring the output waveform from the INS simulator, we connected a HV coaxial attenuator which we had purchased before from other manufacturer to the PULSE OUT port.  Any waveform can never be observed on the scope screen.  

 

Q3. 

We have measured the output waveform from the INS simulator by using the AT-810 attenuator.  The measured peak amplitude is not correct compared to the voltage setting on the INS simulator.  What's is wrong?

 

Q4. 

I have selected "50 ohm" on the voltage meter correction facility provided on the INS-4020(4040) in order to measure the output waveform by using the AT-810, voltage setting is allowed up to 1.98kV (3.96 kV) only.  Why does not the INS reach to its maximum 2.05kV (4.1 kV)? 

 

Q5. Following the instructions and procedures given in the manuals of the INS simulator and AT-810 attenuator, we have measured almost correct waveform.  The peak amplitude and pulse width are all correct compared to the setting on the INS.  However, the rise time is found too slow, measure at 5ns.  Is this a failure with the INS or AT-810?

  

 

Q1

We observed the output waveform from the INS simulators by using a HV probe.  The waveform has a severe overshoot (ringing) on the leading slope.  What should I do to measure the correct waveform?

 

 

The INS output waveforms, when measured with a probe scope (high impedance input), ringing are supposed to appear on the leading edge of the waveform.  This is just the reflection of the high frequency components picked up the probe ground lead.  When measured with AT-810 coaxial attenuator (50 ohm input Z), waveforms can be seen with almost no ringing.  

   
Q2.

For measuring the output waveform from the INS simulator, we connected a HV coaxial attenuator which we had purchased before from other manufacturer to the PULSE OUT port.  Any waveform can never be observed on the scope screen.  

 

 

The NoiseKen INS simulators and its options use the manufacturer designed HV coaxial connectors.  No connectivity with any other commercially available coaxial connecters is provided.  For measuring the output waveform from the INS simulators, use the NoiseKen AT-810 attenuator.  

   
Q3.

We have measured the output waveform from the INS simulator by using the AT-810 attenuator.   The measured peak amplitude is not correct compared to the voltage setting on the INS simulator.   What's is wrong? 

 

 

Check to see the connection has been made as follows: PULSE OUT port - coaxial cable (included in the AT-810 package) - AT810 - scope input (50 ohm).

 

If your simulator is either of INS-4020 or INS-4040, remove the SG (Signal Ground) Short-Plug from the SG connector. 

 

If your simulator is either of INS-4020/INS-4040 or INS-AX2 series, carry out a voltage meter correction of your simulator referring to the relevant part of the instruction manual.  The initial setting is "53.5 ohm" for the most common use for powered EUT testing.  Select the "50 ohm" for AT-810 connection. 

   
Q4.

I have selected "50 ohm" on the voltage meter correction facility provided on the INS-4020(4040) in order to measure the output waveform by using the AT-810, voltage setting is allowed up to 1.98kV (3.96 kV) only.  Why does not the INS reach to its maximum 2.05kV (4.1 kV)?

 

 

The INS voltage meter only matches the actual output if the appropriate correction provided by the equipment firmware is selected.  The default selection is 53.5 ohm termination: 53.5 ohm (builtin-terminator)/(53.5 ohm characteristic impedance of the coaxial line + 53.5 ohm built-in terminator). 

 

The use of AT-810 attenuator means that the coaxial line is terminated by the input impedance of the AT-810. therefore.  The numerator and denominator should change to 50 and 53.5 + 50, respectively.  The maximum allowable setting on the INS voltage meter when using AT-810 should be decreased accordingly. 

 

     
Q5.

Following the instructions and procedures given in the manuals of the INS simulator and AT-810 attenuator, we have measured almost correct waveform.   The peak amplitude and pulse width are all correct compared to the setting on the INS.   However, the rise time is found too slow, measure at 5ns.   Is this a failure with the INS or AT-810?

 

 
  The bandwidth of the measurement system shall be >2GHz to precisely measure the rise time of the INS simulator.  However, the NoiseKen AT-810 attenuator has a specification of 400MHz (<4dB) for this parameter.  Due to this limited bandwidth, 1ns rise time cannot be measured.  The rise time specifications of the INS is dependent to its internal HV switch (mercury wetted relay) characteristics, which have almost no variations.  

 

 

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