Final Circuit & System Simulationrmh072000/Site/Software_and_Links_files/9A... · Final system CE simulation with CDMA

Slide 9 - 1 ADS 2009 (version 1.0) Copyright Agilent Technologies 2009

Final Circuit & System Simulation - with Optional

Co-Simulation


What is the final topic in this class? •  Simulation of your amp_1900 and filters in the receiver system to verify analog performance.

•  Co-simulation: simulation of the entire system using digital circuits and analog circuits together.

Constellation, spectrum, etc...

Gain (S-21), HB with swept LO, and CE with a CDMA source

Next, a co-simulation overview before starting the lab...

OPTIONAL: co-simulation if you have time - otherwise, take the CommSys class.


Co-simulation = digital + analog

Agilent Ptolemy is a bridge between the DSP and RF/Analog worlds!

It is your amp_1900 and filters in the receiver system at the bottom level. On the top level is a Data Flow simulation.

Co-simulation is digital & RF/analog circuits simulating together.

This is your rf_system with amp_1900.

What is Ptolemy?


What is Ptolemy ?

•  TSDF is a unique Agilent EEsof Innovation •  Agilent Ptolemy adds timed elements - parameters on signals are t, I, Q, Fc (rf carrier)

•  Benefits: - easy to add real RF effects on signals - more efficient simulations - more accurate modeling of RF effects

Agilent Ptolemy is a Timed Synchronous Data Flow Simulator


What is Data Flow?

Tokens can also be “time stamped” - then they become samples. Now you can simulate time and frequency domain impairments such as multi-path and fading ...

arc (or wire)

NODE (or component)

NODE (or component)

Token

Tokens (current or numbers)

How does it all work?


Bits can flow into A/RF and out!

Co-simulation is simulating an A/RF schematic design with a DSP schematic design.

Top Level System Design:

DSP network

A/RF network

DSP network

The A/RF schematic can be any kind of design: amplifier, mixer, PLL, etc...

The simulator in the A/RF design must use either Transient

or Circuit Envelope

DSP Schematic Window

IN OUT A/RF SIMULATORS:

Next, DSP components...


The DSP components library… Many palette selections and additional libraries:

The use of these tools is covered in the DSP course and also in part of the CommSys course. 3GPP and WLAN courses are also available. In this class, DSP is only briefly introduced!

LAB


Lab 9:

Final System Simulation with amp_1900 and filters


Steps in the Design Process •  Design the RF sys behavioral model receiver •  Test conversion gain, spectrum, etc. •  Start amp_1900 design – subckt parasitics •  Simulate amp DC conditions & bias network •  Simulate amp AC response - verify gain •  Test amp noise contributions – tune parameters •  Simulate amp S-parameter response •  Create a matching topology •  Optimize the amp in & out matching networks •  Filter design – lumped 200MHz LPF •  Filter design – microstrip 1900 MHz BPF •  Transient and Momentum filter analysis •  Amp spectrum, delivered power, Zin - HB •  Test amp comp, distortion, two-tone, TOI •  CE basics for spectrum and baseband •  CE for amp_1900 with GSM source •  Replace amp and filters in rf_sys receiver •  Test conversion gain, NF, swept LO power •  Final CDMA system test CE with fancy DDS •  Co-simulation of behavioral system

You are here:


First, set up the sub-circuits & system Use port connectors and the File > Design Parameters

Later on, replace the behavioral models with the circuits you built.


1

Next, use the Smart Simulation Wizard

Click the icon in schematic and follow the step-by-step dialogs to test AMP_1900 in a 1 Tone HB simulation.

Data display of all plots and lists is automatic!

2

3

4

5

6


Next, set up and run HB with swept LO power

Plot: dBm_out vs LO_pwr. Write and list the IF_gain.

NF and conversion gain appear if status level = 4.

Final simulation...

Turn on Display


Final system CE simulation with CDMA…

data

Set up envelope simulation with t_step and t_stop variables for CDMA. IF_out equation will be the only data output - save DDS memory!


ACPR and Power calculations: example DDS

Change the default dataset name and the equation. All of your data will pass into the plots and equations!

1.  Copy an example DDS file. 2.  Save it in your system_prj. 3.  Pass your data into the display.

Vfund = IF_out

YOU GET TWO PAGES OF DATA!


Marker Slider for CDMA spectrum Set up a marker slider using equations: marker slides to a frequency and the spectrum of that carrier frequency is displayed: RF, LO, IF, etc.

Marker value is at the IF: 100 MHz. One more step…


Envelope with Frequency Sweep

FINISHED !!!

Optional co-simulation…

RF sweep with LO adjusting = same IF (100 MHz)

NOTE: If you finish this step in the lab, you have achieved all the goals for this class!

Vout[1] = IF at 3 RF tones

harmindex: 1 = 100 MHz


OPTIONAL - Co-simulation of rf_sys This process requires several steps:

First step: Modify the system to become a sub-circuit (bottom CE simulation level) as shown here. Co-simulation requires a Transient or CE simulation setup.

In this class, it is easier and faster to set up and run co-simulation using the behavioral system. The Extra exercise shows even more co-simulations you can try after the course!


Co-simulation continued... Next step: Open a top level DSP network to access the Ptolemy / DSP palettes in schematic.

Then build the system shown here: All the steps are in the lab, including the settings for the data components, filters, etc. The t_step and t_stop are now set for symbol rate and time.

Bottom level system.

Data flow controller runs showing filtered bits and IF signal: TkXY plots


Data Flow simulation - TK plots are active!

Quit the DF simulation and connect a SpectrumAnalyzer sink to collect the data. Results of this co-simulation show spectrum of the behavioral system. To use amp_1900 and your filters, replace them in the system and setup a new simulation (requires more time).

Spectrum Analyzer sink:

Start the lab now!


End of the Course

Goodbye and see you next time! www.agilent.com

Agilent EEsof EDA - Customer Education

Documents

Final Circuit & System Simulationrmh072000/Site/Software_and_Links_files/9A... · Final system CE simulation with CDMA