Postby Testman » Thu Oct 03, 2013 1:02 pm



I am interrested in the LCR parts of multi-instrument , i download the demo but i have real trouble to calibrate it, it jump to 1% to "BAD" and sometime to "time out error" when sliding mic and volume control of the card . I tried hi and low impedance, no can do.

IBM thinkpad T42
Built in audio card
Homemade probe

Thanks (sorry for my poor english)
Post at 7-11-2008 02:23

If you are under High Impedance Measurment mode, you have to calibrate the sound card input impedance at different frequencies first. The default Device Test Plan named Zscdefault.dtp will be loaded for this purpose and in this plan, the sound card's input impedance will be measured at 50Hz, 100Hz,....,20000Hz.

The first step is to set the test tone reference level and you need to adjust the level via the Windows volume control and/or Windows Recording Control such that the input peak level obtained is just below 100% in order to achieve sufficient measurement accuracy.

For the problem you encountered:

1. The "Time out" error occurs when no signal is detected or the specified trigger condition is not met for a certain time duration after the signal generator starts. Please check you connection and trigger condition in this case.

2. The quality of the test tone is considered as "BAD" if the peak level measured exceeds 99.9% or the THD value measured exceeds 3%. This implies that the "BAD" is usually caused by over-high signal level that causes signal clipping.

If the peak level keeps jumping between very low (e.g. 1%) and very high (e.g. "BAD") while you are adjusting the output volume and/or the input gain very slowly and gradually, then most likely, the gain of the whole system is too high and you need to attenuate the signal from the sound card output to the sound card input.

Post at 12-11-2008 20:39

By the way, we have found a bug in the configuration of the Zscdefault.dtp and LCRdefault.dtp under the DTP directory. To make the LCR meter function correctly, you need to do the following patching:

Use the Windows Notepad to open the DTP file and then replace: "sine" to "1" in the Zscdefault.dtp and LCRdefault.dtp.

This bug has been corrected in the coming new version 3.1.

Post at 26-11-2008 18:52
Posts: 52
Joined: Wed Oct 02, 2013 9:51 pm

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