3A_Comms_slides

Optimization: Random, Gradient, Discrete, etc...
Cycle repeats for the # of iterations specified
Preliminary Design
Component parameters to be optimized
Optimized Design !
ADS 2002 CommSys - April 2002
Different Optimization Types
There are Different Types of Optimizers:
Optimizer
Random Gradient Random Minimax Gradient Minimax Quasi-Newton Least Pth Minimax Random Max Discrete Genetic
• Optimize the TOI of the “functional” power amplifier to meet the ACPR design specification • Replace the “functional” power amplifier with a circuit design which has the minimum TOI determined in optimization
Random will not likely get hung up at a local minima. Fine tune optimization with Gradient for best results!
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ADS 2002 CommSys - April 2002
Objectives of Lab 3
V_DC Amplifier SRC3 Preamp Vdc=5.8 V S21=dbpolar(30,0) S11=polar(0,0) S22=polar(0,180) S12=0. TOI=31.11454
Vout
Var Eqn
MSub
Motorola_PA X1
BPF_Chebyshev V_DC BPF2 SRC2 Vdc=2 V Fcenter=RF_freq BWpass=30 MHz BWstop=140 MHz Astop=30 dB MaxRej=60 dB
GOAL
Goal OptimGoal2 Expr="ACPR_lower_dB" SimInstanceName="Env1" Min= Max=-26 _dB Weight=1
The Optimization goals are set up to meet the 26 dBc ACPR design specification
Lab 3 - Performance Optimization
ADS 2002 CommSys - April 2002
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Performance Optimization
Let ADS optimize the system design to meet your design specifications...
ADS 2002 CommSys - April 2002
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Here is a summary of the optimization process...
Error Function= Sim. Results- Opt Goals at every freq and pwr Design Specifications Performance Optimization Goals
ADS 2002 CommSys - April 2002
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Make the TOI’s Optimizable
Enable Optimization and select Continuous
Select the TOI parameter and give it a Nominal, Minimum, and Maximum value
Gain=? TOI=?
Gain=? TOI=?
Gain=23 dB TOI=32 dB
Performance Optimization
Gain=30 dB TOI=30 dB
ADS 2002 CommSys - April 2002
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The Optimization Process
ADS 2002 CommSys - April 2002
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Update TOI’s with Optimized Values
Make sure you perform Simulate / Update Optimization Values before you resimulate or edit anything on the schematic to prevent the loss of the optimized component values!
ADS 2002 CommSys - April 2002
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Simulate and View Results
Start the lab now!
The ACPR and channel power design specifications are met using the power amplifier circuit design!
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ADS 2002 CommSys - April 2002
Continuous vs. Discrete
Component Values can be Varied in a Continuous or Discrete Manner:
Continuous Discrete
Nom= 10 dB Min= 5 dB Max= 15 dB
ADS 2002 CommSys - April 2002
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Set Up the Optimization Controller
OPTIM
Optim Optim1 OptimType=Gradient ErrorForm=L2 MaxIters=3 P=2 DesiredError=0.0 StatusLevel=4 SetBestValues=yes Seed= SaveSolns=yes SaveGoals=yes SaveOptimVars=yes UpdateDataset=yes UseAllGoals=yes
ADS 2002 CommSys - April 2002
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Random vs. Gradient Optimization
Use Random and then Gradient for Best Performance:
Gradient Optimization S11 S11
Nom= 10 dB Min= 5 dB Max= 15 dB Step= 1 dB
The gain can be varied anywhere between 5 and 15 dB
The gain can be varied between 5 and 15 dB in 1 dB steps
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Work w/Discrete?
Yes No Yes No No No No Yes Yes Yes
Work w/Continuous?
Yes Yes Yes Yes Yes Yes Yes Yes No Yes
Random, Gradient, and Discrete are most frequently used...
ADS 2002 CommSys - April 2002
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Set Up Optimization Goals
GOAL
Goal OptimGoal1 Expr="ACPR_upper_dB" SimInstanceName="Env1" Min= Max=-26 _dB Weight=1
The Preamp TOI remained at +30 dBm The Poweramp’s TOI is now +33 dBm instead of +30 dBm
ADS 2002 CommSys - April 2002
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Replace “Functional Amp” with Power Amp Circuit Design
Amplifier Preamp S21=dbpolar(30,0) TOI=3.002133e+001 opt{ 30 _dBm to 32 _dBm }
Amplifier Poweramp S21=dbpolar(12,0) TOI=3.364658e+001 opt{ 30 _dBm to 34 _dBm }
Random Optimization
Parameter Value
Parameter Value
Gradient will pick a point, perturb it, calculate an error slope, and follow the contour until the error slope is zero…can get hung up at a local minima!
PwrSplit3 PWR1 S21=1 S31=1 S41=1
An actual circuit can now be designed and tested once the minimum TOI has been determined using performance optimization!!