I want to use jaspergold to formally verify functionality of my custom multiplier. I am computing the expected result using A*B to check against output of my multiplier. Here, A and B are two logic signed operands. However, jaspergold is performing the operation A*B incorrectly.

I have reproduced this issue using the attached example. JasperGold compiles and elaborates the module and subsequently runs a formal proof. The tool raises a counterexample to assertion whose screenshot is attached below:

I simulated the same example using xrun and it was giving the correct product output in simvision waveform. Please help me resolve this issue. I am using 2023.03 version of Jasper Apps.

Thanks and regards

Anubhav Agarwal

I'm trying to use Jasper for checking parameter propagation in a large design. I have a list of top-level parameters, each with a HDL path of a module parameter somewhere lower in the hierarchy that's supposed to receive its value from the top-level module. The FPV app seems like an excellent tool for this, but elaborating the entire design in it is extremely time-consuming and memory-intensive. So, I'm trying to black-box everything but the interesting HDL paths. I thought using `elaborate -top dut_module_name -bbox_i * -no_bbox_i inst_foo -no_bbox_i inst_bar (...)` would work, but it doesn't. Jasper just starts flooding the log with warnings from modules that are definitely not on the whitebox list, and eventually dies due to insufficient memory. When I use -bbox_m * it correctly elaborates the top-level module with all of its sub-modules black-boxed. But then the -no_bbox_i switches have no effect. Could anyone suggest a working solution for this use case?

Hello,

I have been running this `uvm_reg_hw_reset_seq` sequence for the AHB protocol. My UVM Adapter looks like:

Issue: When I use basic reg.write, my write access are working well, as that is managed by the driver i.e. once adapter gives the packet to the driver, the driver supplies the address and the control signals to the DUT on the first clock cycle and then the write data on the next clock cycle. But when I am performing the read operation, somehow the UVM adapter is reading the data at the same clock cycle where read address + Controls are supplied and this is triggering read failure messages from the `uvm_reg_hw_reset_seq` sequence. What should I modify in the driver/sequencer/adapter so that the UVM adapter can read the data on the next cycle instead of the same clock cycle.

Just FYI: The waveforms of the read operation are correct, it is just the Adapter and the `uvm_reg_hw_reset_seq`. The AHB Driver + AHB Monitor is fully proven and verified to be working correctly.

I exported vplan to .odf file in vManager and after editing it I imported it to vManager. The vplan was expected to be synchronized and updated. However, nothing has changed to it. Does anyone know why?

When analyzing multiple sessions simultaneously Verisium Manager crashed and reported below error messages:

# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x00007efc52861b74, pid=14182, tid=18380
#
# JRE version: OpenJDK Runtime Environment Temurin-17.0.3+7 (17.0.3+7) (build 17.0.3+7)
# Java VM: OpenJDK 64-Bit Server VM Temurin-17.0.3+7 (17.0.3+7, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# C  [libucis.so+0x238b74]

......

For more details please refer to the attached log file "hs_err_pid21143.log".

Two approaches were tried to solve this problem but neither has worked.
Method.1:

Setting larger heap size of Java process by "-memlimit" options.For example "vmanager -memlimit 8G".

Method.2:

Enlarging stack memory size limit of the Coverage engine by setting "IMC_NATIVE_STACKSIZE" environment variable to a larger value. For example "setenv IMC_NATIVE_STACKSIZE 1024000"

According to "hs_err_pid*.log" it is almost certain that the memory overflow triggered Java's CrashOnOutOfMemoryError and caused Verisium Manager to crash. There are some arguments about memory management of Java like "Xms, Xmx, ThreadStackSize, Xss5048k etc" and maybe this problem can be fixed by setting these arguments during analysis. However, how exactly does Verisium Manager specify these arguments during analysis? I tried to set them by the form of setting environment variables before analysis but it didn't work in analysis and their values didn't change.

Is there something wrong with my operation or is there a better solution?

Thank you very much.

I just completed the setup of xcelium and I am trying to test a very simple vhdl file - I got " CSI: *F,INTERR: INTERNAL EXCEPTION" without any further explanation. Could someone point me to how to investigate this error further?

csi-xmelab - CSI: Command line: 
xmelab
-f /home/cadadmin/test/xcelium.d/run.lnx86.23.03.d/xmelab.args
-ACCESS +r
-no_analogsolver
-MESSAGES
andgate
-XLMODE ./xcelium.d/run.lnx86.23.03.d
-RUNMODE
-CDSLIB ./xcelium.d/run.lnx86.23.03.d/cds.lib
-HDLVAR ./xcelium.d/run.lnx86.23.03.d/hdl.var
-WORK worklib
-IRUNHASTOP
-CHECK_VERSION TOOL: xrun 23.03-s001
-LOG_FD 4

csi-xmelab - CSI: *F,INTERR: INTERNAL EXCEPTION
-----------------------------------------------------------------
The tool has encountered an unexpected condition and must exit.
Contact Cadence Design Systems customer support about this
problem and provide enough information to help us reproduce it,
including the logfile that contains this error message.
TOOL: xmelab 23.03-s001
OPERATING SYSTEM: Linux 4.18.0-513.9.1.el8_9.x86_64 #1 
Elaboration of package STD.STANDARD
-----------------------------------------------------------------

csi-xmelab - CSI: Cadence Support Investigation, recording details
csi-xmelab - CSI: investigation complete took 0.000 secs, send this file to Cadence Support

I'm currently work in coverage analysis. In my design certain register bits remain unused, which could potentially lower toggle coverage. Specifically, I'd like to know how to disable coverage for specific unused register bits within a 32-bit register. For instance, I want to deactivate coverage for bit 17 and bit 20 in a 32-bit register to optimize toggle coverage. Could you please provide guidance on how to accomplish this?

Hello,

I have a question about toggle coverage.

In my case, there are many unused registers or wires that are affecting the toggle coverage score negatively.

Is it possible to automatically exclude registers or wires that are not used from toggle coverage?

My RTL code is as follows, Is it possible to automatically disable tb.top1.b and tb.top1.c without using an exclude file?

module top1;

  reg a;

  reg b;

  reg [31:0] c;

  initial

  begin

  #1 a=1'b0;

  #1 a=1'b1;

  #1 a=1'b0;

  end

endmodule

module tb;

  top1 top1();

endmodule

Hi, I'm using the xcelium simulator to simulate a testbench, in which I first stimulate my design to do something (part "A") and then do a direct follow-up test on the design (part "B").

I need two things from this testbench: the results of the test (part "B", passed/failed) and coverage information, but the coverage information should only include part A and explicitly not part B.

I could do the following: run the testbench with part A and B, get the "passed/failed" result of the test and then follow up another simulator run with another testbench, that only includes part A and get the coverage information from that simulation run.

Is there a way to force xcelium to give me the coverage information of only a part of the simulation? Ideally, I would like to write the verilog code of my testbench to look something like this:

• do A
• dump coverage information
• do B

But maybe there is another way to tell xcelium to consider only part of the testbench for the coverage information. I did have a look at the manual, but was not able to find something useful for this problem. Any ideas?

I have been using the rank feature to identify tests that are redundant in our environment, but then I realized I'd also like to be able to see exactly what coverage goes into increasing the delta_cov value for a given test. If I had a test in my rank report that contributed 0.5% of the delta_cov, how could I got about seeing exactly where that 0.5% was coming from? It seems like that might be part of the correlate function, but I couldn't mange to find a way to see what specific coverage was being contributed for a given test.

Hi,

Current and valid TCAs for Functional Safety are readily available at the FuSa "one-stop shop".

But I have not been able to find any archive repository for access to the obsoleted versions.

I would need to have also v1.4 of Xcelum TCA to investigate exact changes wrt previous projects.

Anyone knows how to find it?

Best regards,  Lars

Hi

I have tried using "add net constraints" command to place one-cold constraints on a tristate enable bus. In the command line we need to specify the "net pathname" on which the constraints are to be enforced.

The bus here is 20-bit. How should the net pathname be specified to make this 20-bit bus signals one_hot or one_cold.

The bus was declared as follows:
ten_bus [19:0]

The command I used was

add net constraints one_hot /ren_bus[19]

What would the above command mean?
Should we not specify all the nets' pathnames on the bus?
Is it sufficient to specify the pathname of one net on the bus?
I could not get much info regarding the functionality of this command. I would be obliged if anyone can throw some light.

Thanks
Prasad.

Hi,

 I need to call a  c function form specman . I had followed the below steps.


File vb_pattern.e
---------------------------------

 
struct vb_pattern_s
{
  %data_in_ch0 : uint (bits : 4);   // data on channel 0
  %data_in_ch1 : uint (bits : 4);   // data on channed 1
  %data_in_ch2 : uint (bits : 4);   // data on channel 2
  %mode : uint (bits : 1);          // mode 
  %enable : uint (bits : 1);        // enable

};

C export vb_pattern_s;

------

file  x_output_bfm.e
--------------------------------------------

check_patterns()@clk_e is
{

  ...
 exp_viterbi_op();

}

routine exp_viterbi_op() is C routine viterbi_c_func;

---- EOF------

X.c
#include "vb_pattern.h"

void viterbi_c_func ()
{
 SN_TYPE(vb_pattern_s) vb_packet;
 SN_TYPE(mode)   mode;
 vb_packet = SN_SYS->ops
 mode = vb_packet->mode;
 printf(" Printing from C environment MODE = %h ", mode);

}


------------------- EOF----

x_top.e
------------
import  tb/vb_pattern.e;
import  tb/x_input_bfm.e;
import  tb/x_output_bfm.e;
import  tb/x_cover_dut.e;
import  tb/x_env.e;




I  did the following comand


>> sn_compile.sh -h_only x_top.e -o vb_pattern.h
>> gcc -c viterbi.c -o viterbi.o

I am getting the following error


viterbi.c: In function `viterbi_c_func':
viterbi.c:6: error: `t__mode' undeclared (first use in this function)
viterbi.c:6: error: (Each undeclared identifier is reported only once
viterbi.c:6: error: for each function it appears in.)
viterbi.c:6: error: syntax error before "mode"
viterbi.c:7: error: `mode' undeclared (first use in this function)


Please help me resolve this.

Kesav



  

When posting code to the forums, copy from a text editor such as notepad, not from word or Outlook. Be sure to click the HTML tab BEFORE you paste your text.

Click on the "html" mode tab on your "reply" dialog box. Then wrap your text with like this:

pasted text

NOTE: Do not put a space in the I have done that here so it will show up as text. Also, be sure to click the HTML tab BEFORE you paste your text. This is how it will look when coded correctly pasted text

The two macros below introduce new syntax for adding definitions to more than one 'when' determinant value at the same time. The first macro overloads 'extend' keyword and the second is the equivalent for 'when' keyword.

A use example:

extend [HUGE, BIG] packet {
    // definitions that pertain to these subtypes
};

The above code would be expanded in the following (naive) way:

extend HUGE packet {
    // definitions that pertain to these subtypes
};
extend BIG packet {
    // definitions that pertain to these subtypes
};


The macros code:

define 'statement>
       "extend ['name>,...] 'name> ({;...})" as computed {
    for each in 'names> do {
        result = appendf("%sextend %s %s %s;",result,it,'name>,);
    };
    result = appendf("{%s}",result); // required only for versions 6.1.1 or earlier
};

define 'struct_member>
       "when ['name>,...] 'name> ({;...})" as computed {
    for each in 'names> do {
        result = appendf("%swhen %s %s %s;",result,it,'name>,);
    };
    result = appendf("{%s}",result); // required only for versions 6.1.1 or earlier
};

Please include a brief summary of how to use it.

Hi, I am uploading a register class, which can be used for modeling hardware registers. I am uploading the source code and examples on how to run it. I also have a user guide which has all the APIs listed and explained. The user guide is ARV.pdf in the attached tar file. I have named the class ARV, which stands for Architect's Register View. It has got very good randomization and coverage features. Users have told me that its better than RAL. You can download it from http://verisilica.info/ARV.php
. There is a limit of 750KB in this cadence website. The ARV file is 4MB. That is why, I am uploading it at this site. I have a big pdf documentation and a doxygen documentation there. That is the reason for the bigger file size. The password to open the ZIP file is ovm_arv. I hope, everyone will use these classes.

Please contact me for any help.
Regards ANil

I've heard lots of people asking for a way to generate Makefiles for Specman code, and it seems there are some who don't use "irun" which takes care of this automatically. So I wrote this little utility to build a basic Makefile based on the compiled and loaded e code.

It's really easy to use: at any time load the snmakedeps.e into Specman, and use "write makefile <name> [-ignore_test]".
This will dump a Makefile with a set of variables corresponding to the loaded packages, and targets to build any compiled modules.
Using -ignore_test will avoid having the test file in the Makefile, in case you switch tests often (who doesn't?).

It also writes a stub target so you can do "make stub_ncvlog" or "make stub vhdl" etc.

The targets are pretty basic, I thought it was more useful to #include this into the main Makefile and define your own more complex targets / dependencies as required.

The package uses the "reflection" facility of the e language, which is now documented since Specman 8.1, so you can extend this utility if you want (please share any enhancements you make).

 Enjoy! :-)

Steve.

Hi All.

I put together a small Perl script to generate vr_ad register definitions from SPIRIT (IP-XACT) XML.
If you've got not idea what IP-XACT is, have a look here www.spiritconsortium.org/, then start pestering your design manager to use it :-)

The script can filter out registers and override R/W access types if needed.

An example XML file is included with the package so that you can play with it, and there's a detailed README.txt as well.

Here's an example of the generated e code:

// Automatically generated from xdmac.xml
// DO NOT EDIT, or your changes may be lost
<'

import vr_ad/e/vr_ad_top;

// Component = XDMAC
// memoryMap = xdmac
extend vr_ad_map_kind : [XDMAC];

// addressBlock = dma_eth
extend vr_ad_reg_file_kind : [DMA_ETH];

extend DMA_ETH vr_ad_reg_file {
  keep size == 20;
  keep addressing_width_in_bytes == 4;
};

// Register = command
// Reset    = 0x00
reg_def COMMAND DMA_ETH 0x0 {
  // Field resv3 = command[31:29]
  reg_fld resv3 : uint(bits:3) : R : 0 : cov ;
  // Field transfer_size = command[28:19]
  reg_fld transfer_size : uint(bits:10) : RW : 0 : cov ;
  // Field dma_transfer_target = command[18:14]
  reg_fld dma_transfer_target : uint(bits:5) : RW : 0 : cov ;
  // Field resv2 = command[13:10]
  reg_fld resv2 : uint(bits:4) : R : 0 : cov ;
  // Field transmit_receive = command[9:9]
  reg_fld transmit_receive : uint(bits:1) : RW : 0 : cov ;
  // Field resv1 = command[8:5]
  reg_fld resv1 : uint(bits:4) : R : 0 : cov ;
  // Field dest_address_enable = command[4:4]
  reg_fld dest_address_enable : uint(bits:1) : RW : 0 : cov ;
  // Field source_address_enable = command[3:3]
  reg_fld source_address_enable : uint(bits:1) : RW : 0 : cov ;
  // Field word_size = command[2:0]
  reg_fld word_size : uint(bits:3) : R : 0 : cov ;
};

// Register = queue_exec
// Reset    = 0x00
reg_def QUEUE_EXEC DMA_ETH 0x10 {
  // Field resv = queue_exec[31:1]
  reg_fld resv : uint(bits:31) : R : 0 : cov ;
  // Field exec = queue_exec[0:0]
  reg_fld exec : uint(bits:1) : RW : 0 : cov ;
};

extend XDMAC vr_ad_map {
  dma_eth : DMA_ETH vr_ad_reg_file;

  post_generate() is also {
    add_with_offset(0x00, dma_eth);
    dma_eth.reset();
  };
}
'>

Any comments, please feed them back to me so I can enhance the script.
Note that this forum forces me to post a .zip file rather than .tgz, please be careful to unpack the file under Linux, not Windows, else the DOS linefeeds will corrupt the Perl and XML files.

Steve

Hi everybody,

The attached package is a tiny code example with a demo for an upcoming Team Specman blog post about writing macros.

Hilmar

In a nutshell, tags allows you to navigate through program code distributed over multiple files effectively. e.g if you see a function call or a struct in e-code and want to "jump" to the definition (which may be in a different file) then you just hit CTRL+] in Vim! Pressing CTRL+t will take you back where you came from. Check out http://vim.wikia.com/wiki/Browsing_programs_with_tags#Using_tags if you want to learn more about how to use tags with Vim.

This utility can generate tags file for your e files. It can either walk through e import order, a directory recursively or all directories on SPECMAN_PATH recursively! The tags file will have tags for struct, unit, types, events, defines, fields, variables, etc.

For help and some examples, just run ctags4e -help.

Attached is the latest emacs mode for e/Specman - version 1.23

Please follow the install instructions in the top section of the actual file
(after unzipping it) to install/load this package with your emacs.

Can anyone tell me how i can supress few strings or integers while reading with $sscanf.

I read a line from a file into a string. there are few strings and integers seperated by white spaces in the line. I am interested in one string which comes at postion 5 in the line. how can i suppress all other strings and integers with $scanf.

i tried the following syntax but it dint work.

 $sscanf(line,"* * * * %s",string_arg);

i am tring to supress first 4 integers/strings in the line.

Hello,

I have a question I want to create a cover that consists a sparse values, pre-computed (a list or define) for example l = {1; 4; 7; 9; 2048; 700} I'd like to cover that data a (uint(bits:16)) had those values, Any suggestion on how to achieve this, I'd prefer to stay away from macros, and avoid to write a lot of code

struct inst {

  data :uint(bits:16);
  opcode :uint(bits:16);
  !valid_data : list of uint(bits:16) = {0; 12; 10; 700; 890; 293;};
  event data_e;
  event opcode_e;

  cover data_e is {
     item data using radix = HEX, ranges = {
     //I dont want to write all of this
     range([0], "My range1");
     range([10], "My range2");
     //... many values in between
    range([700], "My rangen");
    };

    item opcode;

   cross data, opcode;
};

post_generate() is also {
    emit data_e;
};
};

Hi all, I've trained a device model with the approach of an artificial neural network, and it shows well fit. 

May I know how to transfer the trained model to Verilog-A, so that, we can use this model to do circuit simulation?

And I've searched for some lectures that provide the Verilog-A code in the appendix, but I'm freshman in the field of Verilog-A, 

could anyone tell me each statement? such as

real hlayer-w[0:(NI*NNHL)-1   

Join this insightful on-demand webinar event "SI/PI Simulation and Measurement Correlation Forum" available through Signal Integrity Journal that features industry expert presentations ranging from chip to package to complex board designs.(read more)

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Dear All,

To design an outphasing combiner, I need to extract the input impedances when the circuit is driven by two sources concurrently with a varying phase-shift and plot them on a Smith Chart. However, I can't find a way to display the simulated S-parameters on a Smith Chart.

The testbench, shown below, consists of two sources set to 50 Ohm with variable phase (PORT0: theta, PORT1: -theta) swept from -90° to 90°. The NPORTs are couplers used to isolate the forward and reflected power at each source, i.e. the S-parameters are:

• S13 = S31 = 1; through path
• S21 = S41 = 1; forward and reflected power
• All other are zero

The testbench is simulated with an "hb" analysis instead of "sp", as the two sources have to be excited simultaneously with varying phase-shift to see their load-modulation effect. The sweep is setup in the "Choosing Analysis" window. The powers of the forward (pXa) and reflected (pXb) waves are found through the "Direct Plot" window, e.g. pvr('hb "/p1a" 0 50.0 '(1)) as the power for p1a, and named P1A_Watt. The S-parameters are then calculated as the reflected power w.r.t. the forward power P1B_Watt/P1A_Watt. This approach is based on a Hot S-parameter testbench from ADS.

At this point I would like to display these S-parameters on a Smith Chart. However, this seemed more challenging than expected. One straightforward method would seem to create an empty Smith Chart window in the Display Window and dragging the S-parameters from the rectangular plot on it, but this just deletes them from the Display Window. Hence my question:

How can I display these S-parameters on a Smith Chart?

Hi, I would be grateful if you can help me with this error which I get after trying to run an EMX simulation on a PCELL.

I've found very limited information in this forum. Thanks

Hi,
My Virtuoso and Spectre Version: ICADVM20.1-64b.NYISR30.2
I plot an eye diagram using a built in function. I want to see the data-dependent jitter. I want to measure the eye diagram edges at zero crossing (width of that diamond part) shown in the pic by vertical and horizontal markers. I can put a marker and read the numbers there and get what I want. But now I want to run Monte Carlo and I can't do this for all samples. I wish I could write an expression for this. Unfortunately, I see that the function "cross" is not working on the eye diagram. Basically, when I send the eye diagram data to a table, I see that it actually is just the prbs data and not the eye diagram data. Is there a hack that can help me achieve my goal which is: having an expression to measure the edges of the eye diagram at zero crossing?
There is a script that Andrew wrote (https://support.cadence.com/wps/mypoc/cos?uri=deeplinkmin%3AViewSolution%3BsolutionNumber%3D11395772). This is a good script but it puts all edges on top of each other. I want to distinguish the two edges. In the attached pic (two-period eye diagram) you can see what I mean by the two edges (diamond shapes). I want to measure each of the two and take the maximum. Having all the edges on top of each other won't give me what I want. All edges together will lso include DCD. I purely want to measure DDJ. DCD is measured separately. I have very little experience with writing scripts and could not modify Andrew's script.
Your help is much appreciated. Thank you.

Hello,

I am trying to design an RF mixer for a TX.
Assume my input IF signal is at 1 GHz, my LO at 2 GHz and I want my RF at 3 GHz, and assume that the mixer fully works after testing it with HB.
How to simply set the envelope analysis to check the EVM ?
I read through the documentation but I couldn't get it (I couldn't fully understand the settings of the source, probe, analysis.)
Which source and probe to use? I want custom modulation with custom bandwidth and center frequency.
Is there some examples for the ENVLP analysis ?

I am using IC23.1 and spectre 20.1.354.

Hi,

In our design team, we're looking for a strategy to make all cell views self-contained. We are struggling to do so when nport devices are involved.

The nport file requires a full path, whereas what we need is a relative path to the current path of the cell in which we're using the nport.

I have browsed through the forums & cadence support pages, but could not find a solution.

1) There is a proposal from Andrew to add the file directory in ADE option "Simulation Files." :https://community.cadence.com/cadence_technology_forums/f/rf-design/27167/s-parameter-datafile-path-in-nport . This, however, is not suitable, because the cell is not self contained.

2) The new cadence version off DataSource "cellView" in nport options:

This however is not suitable for us due to two reasons:

i- Somehow we don't get this option in the nport cell (perhaps some custom modification from our PDK team)

ii- Even if we had this option, it requires to select the library, which again makes it unsuitable: We often copy design libraries for derivative products using "Hierarchical Copy" feature. And when the library is copied, the nport will still be pointing to the old library. Thus, it is still not self-contained.

In principle, it should not be difficult (technically) to point to a text file relative to the cell directory (f.ex we can make a folder under the same cell with name "sparFiles" & place all spar files under this folder), however it does not seem to be possible.

Could you perhaps recommend us a work-around to achieve our goal: making the cells which contain nport devices self-contained so that when we copy a cell, we do not have to update all the nport file destinations ?

Thanks in advance.

My Cadence Version: IC23.1-64b.ISR4.51

My Spectre version: 23.1.0.362.isr5

I want to plot the inductance through formula L1=(imag(Z(1,1))/(2*pi*freq)), but the system tells me that the freq is unbound variable? What can I do?

Hi

I'm learning Hb analysis for the IIP3 simulation of a gilbert mixer. My f_RF=5GHz, f_LO=4GHz and f_IF=1GHz . I'm a bit confused about setting the 1st order and 3rd order harmonic at the Direct plot form. I have set 1st order harmonic = 1GHz and 3rd order harminic = 2*f_LO-f_RF = 3GHz and it gives me the following results.

This is my 1dB compression point result

Hb analysis window

Direct plot window

Please let me know if my harmonic selection is correct and whether I'm getting a correct IIP3 and P1db curve

Hi *,

I am simulating a 32kHz high Q crystal oscillator with a pulse shaping circuit. I set up a PSS analysis using the Shooting Newton engine. I set a beat frequency of 32k and used the crystal output and ground as reference nodes. After the initial transient the amplitude growth was already pretty much settled such that the shooting iterations could continue the job.

My problem is: In 5...10% of my PVT runs the simulator detects a frequency divider in the initial transient simulation. The output log says:

Frequency divided by 3 at node <xxx>

The Estimated oscillating frequency from Tstab Tran is = 11.0193 kHz .

However, the mentioned node is only part of the control logic and is always constant (but it has some ripples and glitches which are all less than 30uV). These glitches spoil my fundamental frequency (11kHz instead of 32kHz). Sometimes the simulator detects a frequency division by 2 or 3 and the mentioned node <xxx> is different depending on PVT - but the node is always a genuine high or low signal inside my control logic.

How can I tell the simulator that there is no frequency divider and it should only observe the given node pair in the PSS analysis setup to estimate the fundamental frequency? I have tried the following workarounds but none of them worked reliably:

- extended/reduced the initial transient simulation time

- decreased accuracy

- preset override with Euler integration method for the initial transient to damp glitches

- tried different initial conditions

- specified various oscillator nodes in the analysis setup form

By the way, I am using Spectre X (version 21.1.0.389.ISR8) with CX accuracy.

Thanks for your support and best regards

Stephan

I get multiple results at the same frequency in a 3-tone simulation.

I try to determine the IP3 of a mixer. I have 3 large signal tones: 0.75 GHz, 1.25 GHz and 1.26 GHz.

At the IM3 frequency of 490 MHz I observe 4 results, see also the screenshot of the table output. The frequencies are exactly the same (even when I subtract 490 MHz by using xval() ).

Which of the values do I have to use to determine the correct IP3?

Is there an option to merge these results?

While adding an element created from a netlist file in AWR, I am getting the error 'The element type being dropped is not compatible with the window it is being dropped into'. The netlist file in AWR has the following contents:

.subckt BFG520W base collector emitter npn
.model BFG520W NPN(IS=1.016E-15 NF=1.000 BF=220.1 IKF=510E-3 VAF=48.06
+ ISE=2.83E-13 NE=2.035 NR=0.988 BR=100.7 IKR=2.352E-3
+ VAR=1.692 ISC=24.48E-18 NC=1.022 RB=10.00 RE=0.7753
+ RC=2.21 CJC=447.6E-15 MJC=0.07 VJC=0.1892
+ CJE=1.245E-12 TF=8.616E-12 TR=5.437E-12 mfg=NXP)

I have attached screenshots of the element BFG520W2 created due to the above netlist and the error I am getting while adding this element.

Hi everyone,

I'm currently working on my thesis, which involves a beamformer system using CMOS 65nm technology. I'm trying to use the EMX tool for EM simulation but have encountered a few problems. Before diving into my questions about EMX, let me briefly explain how I conduct EM simulations with other software (ADS).

In ADS, I use the EM simulator with the Momentum microwave engine. However, my EM layout is quite large, and the mesh generated is extremely detailed, making it difficult to simulate the entire system. As a workaround, I divide the system into smaller parts and simulate each one individually. I've attached a snapshot of my setup, which includes an amplifier and a 1-to-2 Wilkinson power divider. I've separated these circuits and placed pins to facilitate EM simulations for each. I also placed ground pins at the boundaries of each circuit to connect them to the ground plane.

Here’s the link to the image (I'm unable to upload it due to an error): https://drive.google.com/file/d/13Qn4-DvMBj_K1JQLXrTWaWZ8uaLJr15u/view?usp=sharing

Now, moving on to EMX (version 6.3). For a maximum frequency of 31 GHz, I set the edge mesh = thickness = 0.4 µm (approximately the skin depth). However, when I simulate the circuit (amplifier + divider), the mesh on the ground plane becomes very dense, which makes running the simulation impossible due to excessive memory requirements. I reverted to my ADS approach and divided the circuit into two parts, placing ports to connect them. Unfortunately, EMX doesn't allow me to place multiple edge ports on the same edge for the ground plane, which has left me confused. Here are a couple of questions I have:

1. Is breaking the circuit into smaller parts a valid approach? Given the large ground plane, the mesh size for the ground is significant, making simulations challenging. Are there any methods to manage this issue?

2. Regarding the ground pins, why can't I place multiple edge ports to connect the ground planes of both circuits as I did in ADS? If this approach is incorrect, could you suggest alternative methods for simulating individual circuits and connecting them to estimate system performance?

Any insights would be greatly appreciated. Thank you in advance for your help!

Hi I noticed that some figures from the old posts in the cadence blogs have been missing.

I think this problem happened before and Andrew Beckett asked the original author to fix the issue:

 Figures missing in the RF Design Blogs article of "Measuring Fmax for MOS Transistors" 

Some of these posts are quite valuable, and would be nice to have access to the figures, which are a very important part of some posts,

Thanks

Leandro

Hello Everybody

Recently, I want to design a high output Power Amplifier at 2.4GHz using TSMC 1P6M CMOS Bulk Process. I use its nmos_rf_25_6t transistor model to determine the approximate mosfet size

I use the most common Common-Source Differential Amplifier topology with neutralizing capacitor to improve its stability and power gain performance

Because I want to output large power, the size of mosfet is very large, the gate width is about 2mm, when I perform harmonic balance analysis, everything is alright, the OP1dB is about 28dBm (0.63Watt)

But When I perform Transient simulation, the magnitude of voltage and current waveform at the saturation point is too small, for voltgae, Vpeaking is about 50mV, for current, Ipeaking is about 5mA

I assume some reasons: the bsim4 model is not complete/ the virtuoso version is wrong (My virtuoso version is IC6.1.7-64b.500.21)/the spectre version is wrong (spectre version is 15.1.0 32bit)/the MMSIM version is wrong/Transient Simulation setting is wrong (the algorithm is select gear2only, but when I select other, like: trap, the results have no difference), the maxstep I set 5ps, minstep I set 2ps to improve simulation speed, I think this step is much smaller than the fundamental period (1/2.4e9≈416ps)

I have no idea how to solve this problem, please help me! Thank you very very much!

I have been involved in the Virtuoso RF Solution for the last four years. Most of the customers I work with have a SiP package already in progress. They often ask "How do I get my SiP design into Virtuoso RF Solution?" I am excited about new functionality in the latest ICADVM20.1 ISR25 release. It is a new GUI under the Tools menu called Enablement. (read more)

An AMS Designer Flex simulation gives you the most immediate access to the latest simulation technology on either side, gets out of the way of the core engines and allows the engine performance to shine while providing access to new features. Check out this blog to know more.