DC Frequency

This is one of the sweep types which may be selected in the Frequency Sweep Entry dialog box or in the Optimization Goal Entry dialog box.

The DC Frequency sweep analyzes your circuit at a low, non-zero frequency to supply response data at a DC point. This type of response data is necessary for some circuit analysis tools. The DC analysis frequency may be calculated automatically by em, or input manually by the user.

The low, non-zero frequency must be chosen carefully. If the frequency is too high, then the analysis is done at a point where the response of the circuit is already changing. If the frequency is too low, then precision errors occur which produce faulty data. An algorithm is provided with your software to automatically calculate this frequency which has a 95% success rate. You may also enter an analysis frequency manually.

Select the Automatic radio button if you wish em to calculate the frequency. The algorithm for computing the analysis frequency is based on cell size; therefore, this value will change if cell size is changed in the circuit. The automatically calculated value will be displayed but may not be edited. If you wish to specify the analysis frequency, click on the Manual radio button; this enables the Frequency text entry box to the right. Enter the desired frequency here. The frequency you enter must be greater than ''0.0''. Be aware in either case, that although a non-zero value is used for the frequency, the output of the analysis shall contain the analysis frequency ''0.0'' Hz.

As mentioned above, analyzing at such a low frequency may lead to precision errors which corrupt the output data, so results of this analysis option should be scrutinized carefully. In addition, we strongly discourage the use of the Memory Saver run option with this type of analysis, since the memory saver option increases the probability of precision error. A warning message will be issued if you select the Memory Saver run option with a DC Frequency sweep.

If you believe that the results of the sweep have been corrupted due to precision error, you may try analyzing at a manually input frequency or with the Quad Precision run option enabled to improve your data. For more information on Quad Precision, see the Additional Options section of the Advanced Options dialog box.

You may not calculate current density data when using this type of sweep.