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https://designers-guide.org/forum/YaBB.pl Simulators >> Circuit Simulators >> ENOB SINAD SNR Calculations of ADC in Cadence https://designers-guide.org/forum/YaBB.pl?num=1376390692 Message started by ksnf3000 on Aug 13th, 2013, 3:44am |
Title: ENOB SINAD SNR Calculations of ADC in Cadence Post by ksnf3000 on Aug 13th, 2013, 3:44am Hi All, I know this is a very recurring topic but sadly till now I have not found any conclusive answers anywhere. I am trying to calculate the figures of merit (ENOB,SINAD,SNR) of a sigma delta ADC. The steps to be followed are: 1. Acquire a signal. 2. Calculate the DFT of the waveform. 3. Normalize the DFT such that it is suitable for power measurements. 4. Identify the DFT bins that contain the powers of the elements shown in Figure 2. 5. Calculate the total power of these components 6. Calculate the figures of merit using the powers calculated above. Now,as per the steps I have obtained the DFT of my transient signal. But now I am in a fix as to how to obtain the remaining parameters. Could someone please shed some light on this? FYI...I am using Cadence Version 6 Thanks, ksnf3000 |
Title: Re: ENOB SINAD SNR Calculations of ADC in Cadence Post by sheldon on Aug 13th, 2013, 6:10pm knsf3000, Not sure what Cadence version 6 is. If you mean Virtuoso IC615 or IC616, then just use the spectrum function in the Calculator. The input to the spectrum function is the transient waveform and the output is the standard measurements: SFDR, SNR, THD, SINAD, and ENOB. If you are using earlier version then there is another function spectremeas(?), i think. It works but requires some manual intervention, for example, clipping the transient waveform. Sheldon |
Title: Re: ENOB SINAD SNR Calculations of ADC in Cadence Post by ksnf3000 on Aug 15th, 2013, 3:22am Hi Sheldon, Thanks for your reply. I am using Cadence Virtuoso IC6.1.5.500.1 32 You mentioned that spectrum function is sufficient. Does this mean that this function first takes the DFT and calculates the remaining parameters or should the input to the spectrum function be a DFT of the output? Regards, ksnf3000 |
Title: Re: ENOB SINAD SNR Calculations of ADC in Cadence Post by sheldon on Aug 15th, 2013, 7:24pm KSNF3000, The spectrum function supports two modes of operation: 1) Perform a Fourier Transform and calculate the parameters If the input is transient data, then the Fourier Transform is performed 2) Calculate the parameters If the input is the frequency spectrum, then the parameters are calculated. This mode is useful when you use the Fourier Integral to perform the frequency translation. Sheldon |
Title: Re: ENOB SINAD SNR Calculations of ADC in Cadence Post by ziikzak on Jan 31st, 2014, 9:56am May I have question about this topic? I am working on a Flash ADC using TIQ technique, so I do not use clock in my design. I am confused about the configuration of spectrum function. I did use it for some times, but I am not sure the result is correct. My ADC is 4 bit with sampling rate of 1GSs. @Sheldon: Can you give me a hint ? or do you have any related references? Thanks |
Title: Re: ENOB SINAD SNR Calculations of ADC in Cadence Post by sheldon on Feb 17th, 2014, 3:54pm Ziikzak, Could you explain the source of your confusion? The setup is roughly equivalent to the setup for the standard FFT based measurement. The user sets the start time, the stop time, and the number of points for the FFT. Assuming that you are using a Verilog-A DAC with a output level of 1 to create the reconstructed analog signal, there should be nothing else to do. Sheldon |
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