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Ansoft Designer / Ansys Designer 在线帮助文档：

Nexxim Simulator >
Nexxim Time-Varying Noise Analysis >
   Running TV Noise Analyses from the Netlist Editor >
       Periodic Transfer Function Netlist Syntax           

Periodic Transfer Function Netlist Syntax

The syntax of the .TV_NOISE statement in Nexxim is:

.TV_NOISE
+ output_freq_sweep
+ SS_ANALYSIS=HB|OSC
+ SS_TONES=[val [,val]...]
+ SS_MAXK=[val [,val]...]
+ [RELHARMVEC=[val [,val]...]]
+ PXF=1
+ PROBE=[net_current]
+ MAXSIDEBAND=val | SIDEBAND=[val [,val]...]
+ [METHOD=HB|SHOOTING]
+ [AUTO_REFINE_SOLUTION=YES|NO]
+ [TRIM_TOL=val]

In this syntax:

•  For clarity, elements are shown one per line using the continuation character (+). Elements can be entered on a single line using spaces as separators.

•  Brackets shown in bold ([ ]) are required when more than one item is specified.

•  Brackets in plain font ([ ]) denote optional entries or fields.

Output Frequency Sweep

The required entry output_freq_sweep specifies a range of output frequencies to apply in the noise calculation. The sweep specification should be the first field in the TV_NOISE statement (after the .TV_NOISE keyword).

(Refer to the TV Noise Technical Notes topic for information on the use of the swept output frequencies.)

The output_freq_sweep field has several formats.

The sweep can be just a single frequency value.

A second form of output_freq_sweep specifies the starting and ending frequencies, and the incremental step:

[START=]start_val [STOP=]stop_val [STEP=]step_val

If the sweep specification omits the START=, STOP=, and STEP= labels, the start value, stop value and step value must be entered in the order shown. If the labels are used, the values may be entered in any order, but then all three values must have labels.

A third format for output_freq_sweep is:

count_type numpoints startfreq stopfreq

The count_type entry (LIN, DEC, or OCT) specifies a pattern of frequencies to be swept with numpoints, startfreq and stopfreq:

The LIN (linear) count type specifies a linear sweep at numpoints different frequencies from the frequency given by startfreq to the frequency given by stopfreq. The spacing between test frequencies is (stopfreq − startfreq) / numpoints.

The DEC (decade) count type specifies a logarithmic sweep at numpoints different frequencies in each decade (10× multiple of startfreq) from startfreq to stopfreq. The spacing between test frequencies is logarithmic within decades.

The OCT (octave) count type specifies a logarithmic sweep at numpoints different frequencies in each octave (2× multiple of startfreq) from startfreq to stopfreq. The spacing between test frequencies is logarithmic within octaves.

A fourth format for output_freq_sweep is:

POI numpoints freq1 [freq2 ...]

The POI format specifies a space-separated list of individual frequency points. The entry numpoints is the number of frequency points in the list.

SS_ANALYSIS

The SS_ANALYSIS entry selects between harmonic balance (HB) and oscillator analysis (OSC) to compute the steady-state values. HB is the default.

SS_TONES

The SS_TONES entry specifies one or more frequencies to use in the steady-state harmonic balance calculations.

SS_MAXK

The SS_MAXK entry specifies the maximum harmonic numbers to use for the corresponding SS_TONES frequencies in the steady-state harmonic balance calculations. The number of SS_MAXK entries should be the same as the number of SS_TONES frequencies.

RELHARMVEC

The RELHARMVEC entry specifies offset multipliers for the corresponding SS_TONES frequencies. The number of RELHARMVEC entries should be the same as the number of SS_TONES frequencies.

PXF

The entry PXF=1 is required to invoke periodic transfer function analysis.

PROBE

The PROBE entry specifies the device to use for the small-signal transfer function output.

The device can be a port, a current source, a voltage source, or the voltage drop across a pair of nodes, using the format V(n1, n2).

When a port, voltage source, or voltage drop is specified as the PROBE device, the output units are in Volts. When a current source is specified, the units are in Amperes.

MAXSIDEBAND or SIDEBAND

The netlist must specify the combination of harmonics of the steady state SS_TONES frequencies, using either MAXSIDEBAND or SIDEBAND.

(Refer to the TV Noise Technical Notes topic for information on the use of the MAXSIDEBAND and SIDEBANDS entries.)

When the SS_TONES list has only one frequency, you can use the MAXSIDEBAND entry to specify the maximum harmonic of that frequency.

Alternatively, you can specify a set of specific sidebands to use for the single output frequency, using the SIDEBAND entry.

When the SS_TONES list specifies more than one frequency, you must use the SIDEBAND entry to specify the combinations of harmonics that are of interest as input frequencies (MAXSIDEBANDS is not valid with multiple SS_TONES frequencies).

Harmonic Balance Controls

When SS_ANALYSIS=HB is specified, the additional controls METHOD, AUTO_REFINE_SOLUTION, and TRIM_TOL can be used.

See Handling Strongly Nonlinear Circuits in the Harmonic Balance topic for details on the METHOD entry in the HB statement.

See Increasing Accuracy or Speed for details on the AUTO_REFINE_SOLUTION and TRIM_TOL entries in the HB statement.

Periodic Transfer Function Netlist Example

.TV_NOISE

+ START=1000000000 STOP=2000000000 STEP=500000000

+ SS_MAXK=[7]

+ SS_TONES=[1.0e9, 2.17e9]

+ SS_ANALYSIS=HB

+ PXF=1

+ PROBE=[V22]

+ SIDEBAND=[1,0,2,-1,1,1]

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