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166 Threads found on edaboard.com: Delta Sigma Simulation
Hello, I've read around extensively about FFT setup for a sigma delta ADC and I'm not sure if I'm not setting it up properly . my current setup for a first order sigma delta ADC sampling frequency : 38.4 kHz (for the ADC and FFT setup) FFT bins : 65536 input signal : (31*38400)/65536 = 18.1640625 Hz I'm using (...)
This might be a typical university exercise. I remember in our 1st year our professor had given us the assignment to develop a VHDL model of a sigma-delta converter. It was required just to work in simulation, no synthesis. I don't remember anything further after so many years. ;-)
Hi everybody, I have a couple of questions about power spectral density simulation of the sigma-delta modulators. I want to see the harmonics inside the output bit-stream of the modulated signal. The details of what I did are provided at this link: I will be so thankful if you answer these questions: 1- How lo
Hi All, I'm simulating a transistor level, continuous first order delta sigma modulator and need some clarification on the my gm-c filter. simulation is all in Cadence. The input frequency of the DSM is 10hkz so what should the 3-db cutoff frequency (not my unity gain frequency) of my gm-c be? I was thinking that my f_3db should at (...)
The op amp with the ideal vcvs in the CMFB circuit still affects the sigma delta ADC performance greatly!! Could you show how you connected the vcvs-CMFB to your opAmp?
Okay, here's the deal: 1) Learn about coherent sampling. You should use sampling frequencies and input frequencies that are coherent. Meaning that the input frequency should always be exactly on a bin that is computed by FFT to get the most accurate performance measurement. There's more to it but this is an intuitive explanation. If you get this p
Hello I have some queries about delta-sigma DAC. 1) basically, it is same with delta-sigma ADC, but it consists of digital blocks, such as accumulators. However, how to synchronize the clock with PCM signals from a DSP? Does it need serial communication circuits? 2) I tried to find Simulink (...)
Hi All, This is my first ADC and verifying it is proving to be more difficult then actually designing the subblock. I have been able to do a transient simulation in cadence (spectre) and have successfully imported the data into matlab. This is where I'm encountering most of my headache. 1) I'm new at matlab 2)All of the fft examples I've
One of these references may help.
3rd order sigma-delta has various configurations. please study following texts: "A Third-Order sigma-delta Modulator with Extended Dynamic Range" by:Williams "Continuous-Time sigma-delta AD Conversion" By:Ortmanns "Understanding delta-sigma Data Converters" (...)
Regarding bit true simulation using matlab: is there an "easy" way to model fixed point multiplication that will work transparantly with existing toolkits? Case in point: I recently used the delta sigma Toolbox (delsig), and it would be nice if you could run the simulation with fixed point multiply accumulate. And same (...)
Hi,everyone! I have built a 3rd order feedforward delta sigma modulator in spectre, the fully differential opamp, comparator, d_ff are all implemented by veriloga model, while the switch are CMOS transmission gate. My question is the SNR calculated from the spectre output is only 33dB, while in Simulink the SNDR is 103dB, i don't know how to sol
There are different sources of non-linearity in a SD-modulator. The assumption, that you mainly see odd harmonics is of course based on prerequisites, generally speaking no even terms present in the polynomials describing the transfer characteristics of individual building blocks. There's a paragraph about distortion in the simulation chapter o
i've done some simulations on sigma delta ADC. but i think my output is not so correct..anyone can help me out attacedh are my design and waveforms mainly the decimation design im not sure of. matlab simulink 1st order sigma delta adc input: 2V Fb=1kHz , OSR=16 times88922 the 1 bit DAC simply is (...)
have anyone done any simulation of the DSM . here is my design.. but my output seems to be inverted.. anyone know if im doing anything wrong or can explain to me why my waveform is inverted. 89268 my output bit steam when input at Vmax there should be more 1s at the top however my waveform stated otherwise. [ATTACH=CO
Hi, Because i have obtained with Malab simulink simulation the same signal ouput as in the input. I need to design decimation filter in VHDl code for this simulink sigma-delta anlog to digital converter. osr=64 = 16 * 4 Fs=10.24MHz fb=80Khz nb=8bits here i design the decimation with two sinus cardinal "comb?filter" (decimation of (...)
I am building sigma delta ADC, i want to include the effect of thermal noise in the sustem.. Is there any way to include noise source to represent resistors' thermal noise ?? a random source generator or something ?
first of all u need u understand the modulator portion. it consists of 1. Loop filter which is basically an integrator in discrete time ie z tranform so u need to know about z transfroms and then how to create a filter in z-domain 2. Quantizer which is basically is 1 bit comparator which can be implemented using sign block in Matlab Simulink 3. DA
I want to model an sigma delta ADC with VHDL. in this case we ned to have an LowPass RC. and for simulation also we need its model. 78976
hi all I design sigma delta modelator by matlab and hspice but output of noise shaping not correct in hspice!!! there are images of noise shaping outputs. can help me? [img
Hello I trying to learn sigma delta modulator design. I have very little experience on matlab and simulink I have downloaded and installed Richard Schreier s sigma delta toolbox and was able to work out few examples from his book After running the toolbox (order = 1, OSR = 64, 2 level quantiser, CIFB architecture) i (...)
The methods is discussed in SD literature, e.g chapter 4 of delta-sigma Data Converters - Theory, Design and simulation by Schreier et al. You can refer to impulse-invariant transformation from s to z domain, in this case choose the CT parameters to get the same impulse response as the calculated DT modulator at sampling times.
We r working on second order sigma delta modulators. We have created a model using simulink. But we r getting error with sampling time parameter in each blocks. we are not understanding where to change the sampling frequency in the model. also can anyone suggest how to plot logarithmic PSD in will be really greatful if you help us. Th
I'm recently working on delta sigma a new on this,I started from the behavioral simulation. The topological structure is as follows: 70480 the coefficients are 0.2 0.4 0.1 0.1. However,problem is with ideal component,the PSD is stable.After replacing the ideal component with unideal component,the PSD becomes unstabl
Hi, all..i'm new in sigma delta Modulator. I try to built SDM for my final project. I simulate for 1st order SDM which can see in attachment. I simulate it using Circuit Maker. I need suggestion about it. And i have question about how to design high order (> 1) SDM. I read some paper, and for high order SDM you can replace integrator (which
hi... im trying to simulate sigma delta adc in cadence at behaviral lvel.... wen i used ideal integrator block in ahdl lib in cadence results came gud bt wen i try puting opamp based Integrator (used ahdl lib opamp wid Appropriate R & c values) i cudnt get the results at all...some unexpected waveforms i hope im doing some mistake in using ahdl
My question is that : Now that the ADC is translate a analog input to a digital one, so the output of the sigma-delta ADC should be a lot of digital signals, Such as 1111101111. not a sine wave.Correct. By the way, Does the software limit this simulation ?No.
Hello to everyone, It is the first time that I am designing a sigma delta modulator. I have started with the example (verilogA) of the 1st odrer sigma delta modulator provided by cadence in ahdl Library. I have performed a transient analysis (the input signal is 100KHz and is sampled with a clock 10MHz) and the modulator (...)
when i simulate a sigma delta adc in cadence a time it is perfect another time it got bad and it is the same circuit does any one say to me why?????????????????????????????????????????????????????
i am trying to design a decimator for sigma delta converter . my decimation factor is 48. from material i found i decided on a CIC filter for first stage (decimation of 24) and a CIC filter as second(decimation of 2). sampling freq =3840 KHZ Fin = fin = 0-80khz stop band attenuation = 100 dB About the SINK filter according to Hogenauer's
sigma delta adc mat lab simulation I am trying to simulate the ∑Δ adc in simulink... on running it thr following error messages are prompted... can anybody help me how to do away with the errors.. 1) Only 'double' signals are accepted by block type Integrator. The signals at the ports of (...)
I am trying to simulate the ∑Δ adc in simulink... on running it thr following error messages are prompted... can anybody help me how to do away with the errors.. 1) Only 'double' signals are accepted by block type Integrator. The signals at the ports of 'sigma_delta_adc/Integrator' are of data type 'boolean'. 2) An error occurred while
HI GUYS i am working in mentor garphics DAIC tool for modelling the switched capacitor resonator LDI Loop for sigma delta adc. actually i want to estimate the opamp specifications for my design using a macro block present in the mentor graphics....actually my problem is while simulating i am getting some error. due to which tool do not invoke EZ
Hi, Folks! I am looking for the tutorial paper "Oversampling Methods for A/D and D/A Conversion." It is the first paper in the book "Oversampling delta-sigma Data Converters - Theory, Design and simulation." Can anyone direct me as to where to find this material on internet? Thank you very much.
Hi, i need the spectre netlist of " device noise simulation of sigma delta modulators " From here, , the matlab script will be got. but the spectre netlist is missed. i want to re-simulate the 2nd order sigma delta converter using specterRF simulator. so i need the netlist. please give me a copy ! Than
Hi everyone I met a question in the designing the mash sigmadelta adc. In my design, it is a 2-1-1 mash, every stage has 1-bit flash. I use the scaling factor as in book(cascade sigma delta adc for sensor and telecom). I have finished the schematic, and is doing the spectre simulation for (...)
Hi, I try to match model of first order sigma delta to spectre simulation results, but they disagree! First figure attached is first order sigma-delta model (comparator shown as a summing node and noise source N(s)). Can solve to get: Y = N/(1+H) + H*X/(1+H) where H=K/s So if K/s >> 1, then: (...)
hi every one I want to design and simulation a decimation filter for a sigma delta loop in hspice. I need information about this filter and several type of this filter circuit. tanx
Hi all, Can someone help me with a simulation in Matlab for the two modulations (delta and sigma-delta), i need it for a project. Thanks.
Can anybody please help me simulate a sigma delta modulator in LTspice?
Hi I'm designing a 3rd order digital modulator, using 1.5 bit quantization for a 3 level output audio Class D amplifier. The SD modulator uses a CIFF structure using coefficients calculated by Schreier's Matlab Toolbox. Simulated with a 1kHz sinusoid, 13 bit resolution. simulation results seem OK, integrator's never overflow. The problem i
Hi all: The attached graph is the measurement result of designed 2nd 1bit sigma-delta modulator, It looks that many harmonic tones in the low frequency. (simulation is 16bit, measurement is almost 10.5bit) Please help to analystic what's design errors may causing this result. Thanks a lot.
hi all, i have design a sigma delta adc. the fft results of both "matlab" and "veriloga" and "veriloga_sw & mos_amp" is fine. if the veriloga sw be changed to cmos-sw, the dc noise peak arise, & independent of fft point number. the 1/R_sw/C_s ~= 6*(2*pi*f_sample). my english is very poor, thanks for your help!! Add
Hi All, I'm simulating 1-st order continious time delta-sigma modulator with 2-bit quantizer, but i found out its SNR is only 1 dB better than the 1-bit quantizer: 1-bit SNR=70.3dB @ OSR=256; 2-bit SNR=71.3dB @ OSR=256; 3-bit SNR=80.1dB @ OSR=256. What's wrong with it? I use 'calcSNR' function from SDtoolbox to calculate SNR. Could you p
im using MATLAB sigmal delta toolbox to implement a sigma delta bandpass structure. (Center frequency is 1MHz, sampling frequency is 25MHz, bandwidth is 100kHz). Now i have the simulation result of a 8-order bandpass structure (the ABCD Matrix). my questions are: 1:is this stucture with the coefficient (...)
im using MATLAB sigmal delta toolbox to implement a sigma delta bandpass structure. (Center frequency is 1MHz, sampling frequency is 25MHz, bandwidth is 100kHz). Now i have the simulation result of a 8-order bandpass structure (the ABCD Matrix). my questions are: 1:is this stucture with the coefficient (...)
Hi, all: I added dynamic dither into my ADC to eliminate spurs due to offset. It is weird that the SQNR of ADC with dynamic dither is higher than that without dither. Is there any one can give me an explain or tell me what could be wrong? I do the simulation in Matlab. Both are under the same configuration. Thanks
the picture you presented is not a MASH1-1-1 scheme. you should add dither before the delta-sigma modulation.And the dither must be much smaller than K.
I am a new comer to sigma-delta Modulator. Now I working on a two order SDM, ENOB=13bit Fist I do ideal simulation in Matlab, and find the output swing of integrator is -3v~+3v But 3.3v transistors are used in our design, does this means the design in Matlab is improper, I have to choose a another set of coefficients? Another (...)
Hi,I think you'd better present your model here. As I know,kundert provided model of two domains:1,time domain,to model the transient process of the PLL. 2,phase domain,to simulate the phase noise and its transfer function in the PLL. The sigma-delta modulation's phase noise is described by a noisetable function. So we simulate the (...)