The .N_TABLE record is used in conjunction with the .NOISE record. A noise table is useful in identifying which circuit elements are limiting the overall circuit noise performance. If the .N_TABLE record is included, a new text file is created named NTBLmmnn.AC that contains a noise table. The values of 'mmnn' are described under the .OPTion FILE. The noise table lists, at each frequency requested on the .AC record, the name of each circuit element specified on the .NOISE record along with the contribution to the total noise from each requested element. The elements listed are determined by the .NOISE record. The listing is sorted at each frequency so that the elements that contribute most to the noise at that frequency are listed first.
An additional parameter on the .N_TABLE record is used to specify whether SPOT or total (INTEgrated) noise is to be used in the listing and sort.
A third parameter on the .N_TABLE record may be used to limit the size of the noise table file. If no third parameter is specified, or if '1' is entered as the third parameter, noise table data is generated at every frequency specified on the .AC record. An entry of '2' as the third parameter would cause noise table data to be generated at every second frequency, etc.
Examples:
.NOISE * noise from all elements.
.N_TABLE SPOT * noise table with an entry from each circuit
* element at each frequency. The contributions
* to spot noise at each frequency will
* be listed and used in the sort.
.NOISE r1, r2, r3 * only consider r1, r2, and r3 for noise
* calculations.
.N_TABLE INTE * noise table with an entry for only r1,
* r2, and r3. The total (integrated)
* noise will be listed and used in the sort.
.AC 100 10 1. 10.k * 100 points / decade.
.NOISE
.N_TABLE SPOT 100 * noise table data generated at each
* decade between 1.0 and 10.KHz.
* (5 frequencies)