Phase Noise Simulation of Injection Locked Frequency Multiplier

Status
Not open for further replies.
Enforce Transient-Assisted HB not automatic.
Then set various parameter manually for initial transient analysis.
Save initial transient analysis.
Show me initial transient waveforms.

Try to use OSCPROBE instead of specifying oscillation nodes.

First of all, I should say that my previous simulation for phase noise was WRONG.
When input phase noise is, say, -137.430 dBc/Hz at 1MHz offset, output phase noise cannot be lower than -137.430 + 20log16 = -113.430 dBc/Hz at the same offset. Whereas I achieved lower value for phase noise (i.e. -114.019)

I tried TAHB with different configurations, but I did not get correct results.

How should I configure TAHB?
 

You have to succeed in convergence of HB Analysis with setting 30GHz node as Oscillation.
If you can not get convergence, use OSCProbe.

When input phase noise is, say, -137.430 dBc/Hz at 1MHz offset,
output phase noise cannot be lower than -137.430 + 20log16 = -113.430 dBc/Hz at the same offset.
Whereas I achieved lower value for phase noise (i.e. -114.019)
Is it PM Noise ?
Do you observe AM Noise ?

I tried TAHB with different configurations,
but I did not get correct results.
How should I configure TAHB?
Enforce Transient-Assisted HB not automatic.
Then set various parameter manually for initial transient analysis.
Save initial transient analysis.
Show me initial transient waveforms.

You might have to increase oversampling factor for HB Analysis.
 
Last edited:
Is it PM Noise ?
Do you observe AM Noise ?
Yes, I'm talking about PM noise. AM noise does not matter.

Let me show the configuration of my simulation in detail.
In transient simualtion:

In HB simulation:

,

,

and

. Fosc=30GHz and Vop2/Von2 are the output nodes of the 30GHz oscillator.
The result is

with these messages:
Which part of my configs is wrong?
 

Which part of my configs is wrong?
Completely wrong.

I don't mean Transient Analysis.
I mean Transient Analysis in HB.

Transient Analysis is not required.

First of all, your setting is wrong in Transient Analysis for HB.
Why do you set order=10 ?

Delete Transient Analysis Controler.
Activate TAHB On.
And Set Advanced Transient Setting.

Show me Freq Tab in HB1.

Show me netlist regarding Analysis settings.
 
Last edited:
Delete Transient Analysis Controler.
Activate TAHB On.
And Set Advanced Transient Setting.

OK, I did so.

Show me Freq Tab in HB1.

and


Show me netlist regarding Analysis settings.


The results have not changed.
 
Last edited:

Completely Wrong.

And usage of OscPort is wrong.
https://edadocs.software.keysight.com/pages/viewpage.action?pageId=5526346

OscPort or OscPort2 is inserted into feedback path or between resonator and negative impedance.
So OscPort may not be suitable for your circuit.

You had better be back to method of setting oscillation node.
 
Last edited:
I edited the settings, as you said.
I chose longer StopTime, shorter MaxTimeStep and a non-zero SteadyStateMinTime.


However, the simulation cannot reach steady-state:


The transient waveforms:



Spectrum of outputs:

 
Last edited:

1.875GHz node rises after 20nsec.
On the other hand, 30GHz node rises at 0sec.

Why ?

Show me netlist portions regarding all voltage and current sources used in circuit.

I recommend following.

Replace your 1.875GHz oscillator with V1tone of 1.875GHz.
Then do driven HB analysis with Freq[1]=1.875GHz Order[1]=10*16.
Confirm whether steady state output is available or not at 30GHz node.

The oscillation frequency did not reach steady state.
The circuit did not reach steady state; the worst node was X32.MOSFET1.s.
Final transient frequency = 29.70551827 GHz
Final transient fundamental = 1.856594892 GHz
Judging from transient waveform at 30GHz node, it seems parasitic oscillation exists.

I think problems exist after 1.875GHz oscillator circuit.
Confirm your circuit validity.
 
Last edited:
1.875GHz node rises after 20nsec.
On the other hand, 30GHz node rises at 0sec.

Why ?

Because they are two different oscillators with different start-up times.

Show me netlist portions regarding all voltage and current sources used in circuit.


I recommend following.

Replace your 1.875GHz oscillator with V1tone of 1.875GHz.
Then do driven HB analysis with Freq[1]=1.875GHz Order[1]=10*16.
Confirm whether steady state output is available or not at 30GHz node.

I cannot do this. Because I want to see output phase noise and its relation with input phase noise.

Judging from transient waveform at 30GHz node, it seems parasitic oscillation exists.

I think problems exist after 1.875GHz oscillator circuit.
Confirm your circuit validity.

If you mean AM modulation at 30GHz node, It is because of 1.875 GHz injection and completely normal.
 

I cannot do this.
Because I want to output phase noise and its relation with input phase noise.
No.
I recommend you to confirm whether 30GHz stable ouput is available or not.

Phase Noise is next stage.

If you mean AM modulation at 30GHz node, It is because of 1.875 GHz injection and completely normal.
Show me frequency transient behavior of https://www.edaboard.com/attachment.php?attachmentid=143175&d=1512754910&thumb=1 by cross function.
https://www.edaboard.com/showthread.php?t=372149#16

For your Autonomous circuit, there are four possible states.

(1) 1.875GHz:Zero, 30*1.875GHz:Zero
(2) 1.875GHz:Non-Zero, 30*1.875GHz:Zero
(3) 1.875GHz:Zero, 30*1.875GHz:Non-Zero
(4) 1.875GHz:Non-Zero, 30*1.875GHz:Non-Zero

HB Analysis can find out (2) and (3).

However HB Analysis can not find out (4) for your circuit.
 
Last edited:




As you see, instantaneous frequency is not stable. I guessed it is because of mismatch between output frequency and 16th harmonic of the input frequency.
When I replaced 1.875 GHz oscillator with V1tone, transient analysis reached steady state and then HB simulation was performed without any problem.

Again, I used 1.875 GHz oscillator, but this time I changed slightly its frequency. In this case, transient analysis reaches the steady state but HB simulation does not converge.

The instantaneous frequency of oscillators:



Simulation Messages:

 

As you see, instantaneous frequency is not stable.
I guessed it is because of mismatch between output frequency and 16th harmonic of the input frequency.
I don't think so.

Again, I used 1.875 GHz oscillator,
but this time I changed slightly its frequency.
It is no more than initial guess value of Ffundamental for next autonomous HB.

Final transient fundamental = 1.856594892 GHz
Final transient fundamental = 1.855418946 GHz

In this case, transient analysis reaches the steady state
but HB simulation does not converge.

It seems waveform have spectrum components which can not be expressed by n*Ffundamental. Ffundamental=Finj.

Your circuit can not be pulled in by injected Ffundamental.

Your Finj starts at 18nsec.
However Fosc starts pertubation after 27nsec.

I don't think your problem is simulator issue.
However, try following.
OscProbe:HB1_OP Node[1]="Vop2" Node[2]="Von2" \
FundIndex=1 Harm=My_Order \
NumOctaves=1.1 Steps=1000

And if your 30GHz oscillator is cross coupled LC-oscillator, insert OscPort2 between inductor and active p and n node.
 
Last edited:
Status
Not open for further replies.
Cookies are required to use this site. You must accept them to continue using the site. Learn more…