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Ansoft Designer / Ansys Designer 在线帮助文档：

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   One Port Oscillator (OSC)       

One Port Oscillator (OSC)

Notes

1. All phase noise data must be provided if output is to include phase noise effects

2. In general, the output voltage of this model is given by:

where

for envelope analysis

or

for instantaneous analysis

and q_n(t) is the random phase noise component at time t. This phase noise component will only be nonzero if the NOISEON parameter is set to 1, otherwise, the oscillator will be assumed noiseless.

The power spectral density of the random phase noise processes is given by the Leeson’s model [1]

where f_c is the flicker noise frequency and qload is the loaded Q. The noise floor M2 is simply:

3. The frequency offsets F1 and F2 must be consistent with the specified oscillator TYPE as shown in the phase noise plots below. For a low qload, F1 and F2 correspond to fc and flo/2qload respectively while for a high qload, F1 and F2 correspond to flo/2qload and f_c respec­tively.

4. The indexed parameters “FM” and “SBN” allow the user to specify measured noise data. When measured noise data is provided, the model will ignore the parameters QLOAD, F, R, FC.

5. The “FILE” parameter identifies a data file for the phase noise parameters FM and SBN. The filename must have a .dsp extension, and must be in DSP format:

xy
fm1 sbn1
...
fmN sbnN

 Where the first column is the frequency offset in Hz and the second column is the sideband noise in dB. For example:

xy
100 -80
1000 -90
...

 If a valid “FILE” parameter is present, the data from the file will be used and the correspond­ing “FM” and “SBN” parameters in the netlist will be ignored. Any “FM” and “SBN” parame­ters in the netlist that are not also defined in the data file will be used.

6. When the parameter “VcoNoiseOn” is set to 1, VCO noise will be simulated. Otherwise, VCO noise will not be incorporated in the simulation. The same happens to the divider noise. Note that noise simulation is expensive, so when it is not needed, the two parameters should be turned on.

7. A random phase noise process is generated by filtering a white Gaussian random sequence through a filter with a frequency response H(f_m), where

This frequency response is decomposed into three regions: near-carrier region (fm £ F1), far-carrier region (F1 < fm < F2) and the White noise region (fm ³ F2). Regions one and two are represented in the frequency domain using 8192 frequency points each. Region one will typi­cally use a much smaller frequency resolution than region 2. Region 3 is simply modeled as an additive white Gaussian process. The total random phase noise process is simply the sum of the contributions from each region.

Since in general the sampling frequency of the generated phase noise process is less than the actual output sampling frequency F_S, linear interpolation is applied in the time domain on the generated phase noise process q_n(t) to ensure it has the same sampling rate as that of the output signal.

Netlist Form

OSC:Name n1 FLO=val PLO=val NSAMP=val SAMPLE_RATE=val

+ [PHASE=val] [F1=val] [F2=val] [FDEV=val] [M2=val] [TYPE=val]

+[DivNoiseOn=val] [VcoNoiseOn=val] [FM1..n=val] [SBN1..n=val] [FILE='filename']

+ [SEED=val] [Wavetype=val] [Rout=val]

Netlist Example

OSC:1 1 FLO=800MHZ PLO=10dbm NSAMP=1000 SAMPLE_RATE=1MHZ

+ PHASE=90 F1=150Hz F2=10KHz FDEV=100KHz M2=-180dB TYPE=0

References

1. Ulrich L. Rohde, J. Whitaker, and T.T.N. Bucher, “Communications Receivers” McGraw-Hill, 1996.

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