How to calculate signal-to-distortion ratio in Cadence

[pavel_adameyko]

Hello,
for example, I have an amplifier which is used to process QPSK-modulated signal channels, each channel is, let's say, 5 MHz wide. The power in channel near 910 MHz is -60 dBm and the power in channel near 920 MHz is -20 dBm. I want to evaluate the signal-to-distortion ratio in channel near 910 MHz at the output of amplifier, in other words, how the quality of signal near 910 MHz degrades because of presence of strong interferer signal near 920 Mhz.
What types of analysis I should use? I know there is envelope analysis with ACPR wizard. Does anybody use it?

 

[BigBoss]

This is a system problem, not circuit.Therfore, you should model your system with the same conditions and then you may check your signal quality.You can not predict how much PN will be contributed from interferer channel and channel noise.
Use system simulation..

 

[pavel_adameyko]

Thank you for your reply, BigBoss.

But the problem is that I don't know how to simulate the whole system in Cadence. I think this tool is appropriate for system simulation. Or may be I'm wrong...

 

[BigBoss]

Thank you for your reply, BigBoss.

But the problem is that I don't know how to simulate the whole system in Cadence. I think this tool is appropriate for system simulation. Or may be I'm wrong...

No. Cadence "had" a system simulator once upon a time but it does not exist anymore.Instead, you can use ADS or similar system simulators.

 

[pavel_adameyko]

Thank you, BigBoss.

I'm familiar with ADS very little. What type of analysis should I use? Envelope? Maybe you know where I can find examples of such system simulations.

 

[BigBoss]

Thank you, BigBoss.

I'm familiar with ADS very little. What type of analysis should I use? Envelope? Maybe you know where I can find examples of such system simulations.

ADS has seperate system simulator.You should select "DSP" ADS Setup Tabs in the main window.

 

[pavel_adameyko]

ADS has seperate system simulator.You should select "DSP" ADS Setup Tabs in the main window.

You mean simulate DSP design with Data Flow controller. But how I can put schematic of my analog circuit to the design ? There are only simplified models of amplifier (GainRF) and mixer (MixerRF), which I noticed in such designs.

 

[pancho_hideboo]

for example, I have an amplifier which is used to process QPSK-modulated signal channels,
each channel is, let's say, 5 MHz wide.
The power in channel near 910 MHz is -60 dBm and the power in channel near 920 MHz is -20 dBm.
I want to evaluate the signal-to-distortion ratio in channel near 910 MHz at the output of amplifier,
in other words, how the quality of signal near 910 MHz degrades because of presence of strong interferer signal near 920 Mhz.
What types of analysis I should use? I know there is envelope analysis with ACPR wizard.

Yes, use envelope analysis.

https://www.designers-guide.org/Forum/YaBB.pl?num=1262828862/29#29
https://www.designers-guide.org/Forum/YaBB.pl?num=1264078706/4#4
https://www.designers-guide.org/Forum/YaBB.pl?num=1260978648
https://www.designers-guide.org/Forum/YaBB.pl?num=1263961579
https://www.designers-guide.org/Forum/YaBB.pl?num=1264511244
https://www.designers-guide.org/Forum/YaBB.pl?num=1190971685/7#7

You mean simulate DSP design with Data Flow controller.
But how I can put schematic of my analog circuit to the design ?

You can do cosimulation between Analog/RF-Domain and DSP-Domain.
https://www.designers-guide.org/Forum/YaBB.pl?num=1238242506

You can do such cosimulation using any of followings.

(1) Agilent ADS ; Cosimulation between ADSsim's Analog/RF-Domain and Ptolemy-Domain.
(2) Agilent RFDE ; Cosimulation between ADSsim's Analog/RF-Domain and Ptolemy-Domain.
(3) Agilent GoldenGate ; Cosimulation between GoldenGate's Analog/RF-Domain and Ptolemy-Domain.
(4) Cosimulation between Cadence AMS Designer's engine and Ptolemy-Domain.
(5) Cosimulation between Cadence Spectre and Mathworks Simulink.
https://www.designers-guide.org/Forum/YaBB.pl?num=1246971919

But I don't think your case need cosimulation between Analog/RF-Domain and DSP-Domain such as Ptolemy or Simulink.

Prepare modulation signal files for "analogLib/vpwlf" or "analogLib/ppwlf".
Then run simulation by using only Analog/RF-Domain engine.
https://www.designers-guide.org/Forum/YaBB.pl?num=1193043253/3#3

 

[pavel_adameyko]

Thank you, pancho_hideboo .
Really appreciate your comment.