Questions tagged [analog-to-digital]

An analog-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analog signal into a digital signal.

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adc output signal magnitude question

We have an adrv9002 that has built in DAC and ADC that takes and gives IQ samples. I did a test to verify functionality but don't understand what I am seeing. Take a RF tone from a signal generator ...
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Benefit of Anti-Aliasing for Wideband Finite Time Duration Signals prior to Sampling

Most literature about sampling explains the need for anti-alias filters in terms of periodic signals, preventing a periodic signal with frequency greater than half the sampling frequency from ...
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ADC response inversion to Gaussian noise

Assuming the input to an ADC is a Gaussian white noise signal, and being a bit idealistic in all senses, is there a theoretical expression that links input power to output power which can be inverted, ...
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Sample Use vs Sampling Frequency

I need to acquire an analog signal via an ADC and send it via a digital communication line (CAN bus) with a given frequency $f_{send}=100Hz$. If I understand correctly this means that this constraint ...
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Step signal for ADC testing

IEEE std1241-2010 specification part 4.2.3. step signal setup part shows like this design What should the test setup described in section numbered be like? Is it enough to give one pulse and read it ...
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ADC bias, noise and number of bits under Gaussian signals

I'm digitizing a zero-mean complex Gaussian white noise signal with certain variance, through independent I/Q baseband sampling (two ADCs). The noise variance (power) depends on the thermal emission/...
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Discrete Frequency representation for central frequency/ discretize up-converted signal in time and frequency

I want to analyze a signal after up-conversion in discrete time and frequency, for example: Let's assume a continuous up-converted signal is: $$e^{j2\pi ft} \cdot e^{j2\pi f_c t} = e^{j 2 \pi (f+fc) t}...
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Can the NODAL DK Method Be used for discretizing an analog circuit with OTAs?

I'm exploring the discretization of analog circuits and have come across the NODAL DK method as a potential technique. I'm curious if this method is suitable for circuits that incorporate Operational ...
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Fixed point number scheme IIR filter with ADC

I am a student working with digital circuits. I just started a term project with someone else working on an ADC. I need to design a IIR filter in verilog. If the output of an ADC represents 1V by ...
Bowen Liu's user avatar
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Difference between ADC dynamic range and voltage resolution?

Say I have a 10-bit SAR ADC with a $5 \ \text{V}$ reference. I calculate its resolution to be $$\Delta V_\text{lsb} = \frac{5 \ \text{V}}{2^{10}} = 4.88 \ \text{mV} \approx 5 \ \text{mV}. $$ So for a $...
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How does aliasing affect bits in an ADC?

I want to measure a signal whose frequency spectrum is infinite, but I am particularly interested in the frequency range $ 0 - 500 \ \text{Hz}$. I have a 12-bit ADC. The ADC has dynamic range $ 6 \ \...
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Digital Low Pass Filter and PWM Signal

I have a PWM signal going into an ADC. After the ADC the signal is being filtered using an IIR single pole filter. Performance is exactly what I want with one exception. The purpose of the filter is ...
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Direct-digital phase noise measurement reference phase scaling

The direct-digital phase noise measurement technique is described in "Direct-Digital Phase-Noise Measurement" by Grove (DOI:10.1109/FREQ.2004.1418466, PDF link). The basic architecture of ...
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Decoding an analogue signal for a given sampling and signal frequency that aren't in sync

I am trying to decode an analogue signal, that is intended to be converted to a digital one and decoded as USART communication. In the image shown the blue trace is the analogue signal, and the ...
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Handling asynchronous MCU I/O peripherals

Technical Background I'm making an audio processing board with an onboard microcontroller that takes in data via I2S from an ADC, applies digital filters, and outputs a stream of the same samplerate ...
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Output of sigma delta ADC, bit resolution, filtering

In a sigma-delta ADC, the sigma-delta modulator outputs a digital stream of 0's and 1's which are then low pass filtered and decimated. Where does the bit resolution of ADC come into the picture? What ...
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Relationship of ADC resolution and 'lossless' float data type storage

For a given digitised voltage trace, I want to avoid any quantization error introduced via an insufficient precision of the float data type – and at the same time reduce the memory cost. However, I am ...
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sample rate conversion

I have read many of the posts here on the stack regarding sample rate conversion but have yet to find one that does not rely either upon asynchronous or synchronous clocks. It occurs to me that the ...
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How to find the variance of a noise signal distorting an ADC measurement

Say we have a 12-bit ADC measuring a signal with a voltage range of 0-10V, but the signal is corrupted by uniformly distributed 3-bit white noise. What's the correct way to get the variance of the ...
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low-latency ADC and DAC

I am recently trying to use ADC and DAC with low latency and high speed. I wonder what are the ADCs and DACs with the lowest latency over 1Gsps?
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Time-interleaved ADCs, Nyquist zones et al

I am trying to decipher some notes on a Time-interleaved Analog-to-Digital Converter with 4 sub-ADCs (the author is unreachable at the moment), but there are few things obscure to me so I was hoping ...
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Delta sigma modulator harmonics appearing with a sine wave input

I am simulating a first order delta sigma modulator (DSM) used as an ADC. The input to my DSM is a full scale sine wave. The power spectral density I expect from the DSM output is as follows : The ...
Nicolate's user avatar
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Dynamic Range Scaling for Delta Sigma Modulation

I've been trying to follow along with this example in the book "Understanding Delta Sigma Data Converters" and I am completely confused as to how the authors came about the appropriate ...
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Optimal Input Range for ADC with Specified ENOB

I'm doing the gain budget for a receiver that feeds into an ADC. I want to know what the best input range should be into the ADC so that I can detect down to the MDS (minimum discernible signal) while ...
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Which command should be used for quantization of a signal in MATLAB?

I want to convert analog signal to digital form using Matlab. I know that this will need two steps (sampling and quantization) but I am confused which command should be used for quantization? ...
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transformation methods for digital filters

i have the following question: in digital filter design what's the difference between the methods of transformations : bilinear vs impulse invariance vs Euler vs step invariance. thank you! Here is a ...
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DSM Model Not Producing Expected Noise Shaping

I am trying to design a 2nd Order CIFB DSM ADC on Simulink based off the values I have extracted from Richard Schreier's Delta Sigma Modulation Toolbox. However, when I ran the model according to the ...
NaP's user avatar
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Sigma Delta with counter instead of filter

in most applications the 1-bit output datastream of a sigma-delta ADC is converted via a filter. What's the advantage over counting the ones/zeroes and averaging over the results? For a simplified ...
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Noise variance estimation

could anyone recommend some articles how to estimate noise variance for the single carriers system with burst mode transmission (preamble+data TDMA)? My goal at the beginning is to develop skills how ...
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Resampling in real-time with non-integer ratio

I have a classifier that is trained on a dataset sampled at 100Hz. I am using this classifier on a MCU (the teensy 4.0 dev board) for inference and not training. However, the ADC chip I am using ...
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Performance Effects of Dropping ADC Least Significant Bits before DSP processing (Besides the Obvious)

What would be the effect of dropping LSBs of an ADC on the performance of a DSP system apart from the obvious reduction in dynamic range. For example if there is a 14 bit ADC and only 10 bits are used,...
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How to emulate lower resolution digitized data (higher step-size)

I am a statistician by training, and I am very new to signal processing, but I would appreciate some help and patience! Suppose I have a digitized signal measured at a given frequency, range, ...
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SQNR vs SNDR (with regards to Delta Sigma Modulation)

With regard to delta-sigma modulation, I understand that SQNR is the ratio of the signal power within our frequency bandwidth to the noise power within our bandwidth (in-band quantization noise). What ...
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What's the meaning of negative frequencies after taking the FFT in practice?

Suppose I have a signal $x(t)$ with baseband bandwidth $W$ Hz and power $P$, and consists of $K$ samples, and I draw the two-sided power spectral density (PSD) of this [baseband] signal in MATLAB as <...
Math_Novice's user avatar
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Interpreting SQNR from a Graph

I'm pretty confused about SQNR/SNR conceptually. I understand that this is a function of the power of the signal to the power of the noise. Is it not the case that we would be able to derive a value ...
NaP's user avatar
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Why 5Hz aliasing with LPF implemented

I have a simple signal chain with a differential sinusoid as the input. This passes through the first amp which converts the signal to a single ended signal. The next block is a 4 pole low pass ...
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Building a data acquisition system to capture raw IQ data

I was planning to build a data acquisition system to capture raw IQ data for a hobby project and the short-term goal is to gain practical experience on RF front ends and ADC's. My background is mostly ...
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INL-THD, DNL-SNR Relation

What do the following statements on pages 13 and 15 in this linked document mean? DNL, a static specification, relates to SNR, a dynamic specification. INL is a static specification and relates to ...
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Sampling Precision, Jitter, and PID

I am having difficulty understanding the effect of quantization noise and ADC resolution in a digital PID controller. I am also trying to understand the effects of sampling jitter on a PID controller. ...
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Sampling analog signal with python; problems with understanding fundamentals

I would like to sample an analog 5kHz signal with a 50MHz sample rate. I want to do this with python so I can see if this sort of sample rate is enough for my needs. But I couldn't wrap my head around ...
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Calculating estimated ADC Noise Floor from given specifications

As per my current understanding, the ADC datasheets for modern high speed ADCs give the noise level measurements in terms of Noise Spectral Density (NSD) in unit of dBFS/Hz. Now to convert that value ...
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If I know the RMS noise/the variance of a DC measurement, can I simply subtract it from the measurement?

Let's say I have an electronic system that's taking a measurement. It provides a simple bipolar excitation current to a resistive load (bipolar square wave so as to cancel out thermal emf), puts it ...
Shredder's user avatar
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Bilinear transform for a system in zero-pole-gain form

MATLAB's bilinear performs the following steps for a system in zero-pole-gain form If fp is present, it prewarps: ...
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FMCW radar and calculating ADC Sampling rate

I am new to FMCW radar and I am using a TI module. I have been reading the TI reference material and they keep mentioning the parameter "ADC Sampling Rate". I am confused by what this means ...
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Interpolating Filter for Quadrature Detector with one ADC

Single ADC is sampling at 16000 Hz the I and Q outputs of quadrature detector. So each I and Q signal is sampled at 8000 Hz, with phase offset 90 degrees between them. Bandwidth of interest is 3400 Hz....
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What does the following structure mean and how to implement this structure in matlab?

Looking forward to explaining what this structure means, and the relationship between the two structures. Paper: An Efficient Spur-Aliasing-Free Spectral Calibration Technique in Time-Interleaved ADCs
uniblue's user avatar
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How to apply MUSIC to FMCW radar IF data?

I'm working on target extraction with raw FMCW ADC data. I arranged my received data in an (numADCsamples x numAntennas x numChirpsPerFrame) radar cube. So far I am using range FFT and doppler FFT to ...
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Quadrature Detector with a single ADC

I have a quadrature detector, which provides I and Q baseband signals with 4 kHz bandwidth, set by detector's LPF. I digitiize them on two ADCs with sampling frequency 48 kHz, make Hilbert ...
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What is the value expected on the voltmeter display

I am a complete beginner and i had some problems figuring out what i had to do to solve this. I apologize in advance for not putting the proper tags but i didnt know what to put in there or if even if ...
Ani Lici's user avatar
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What ADC precision and sampling rate for record sound?

What ADC precision and sampling rate would you choose and why if You wish to record sound that has frequency components are 200 to 2000 Hz. And the signal-to-noise ratio of your microphone is 50 dB?
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