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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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 ...
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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 ...
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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
<...
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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 ...
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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 ...
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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
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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 ...
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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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What could be the possible reason behind curved signal?
I have a MEMS microphone connected to the microcontroller on a PCB. The microphone collects the data and sends the analog data to the microcontroller in real-time. On the microcontroller, this data is ...
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What is the intuition explaining the Shannon-Hartley theorem?
In the digital domain, the signal to noise ratio (SNR) may be interpreted loosely but usefully as the number of discrete or quantized levels one can transmit reliably. For instance, loosely speaking, ...
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mp3 encoding in the frequency domain
Let's start with an arduino signal, which can be periodic over time. When this signal is converted from analog to digital it "turns" into a series of bits. At this point, is this signal in ...
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How does under sampling modify the spectrum of a signal in nyquist zones and BW?
I have two conflicting concepts when looking at the spectrum of a analog to digital signal that has been sampled.
The nyquist zones. So any sampling frequency fs will make the spectrum replicate at ...
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How to apply hann window to unsigned integer ADC
I am using Arm-Cortex M3 Microcontroller and CMSIS for FFT, my microcontroller does not support floating point unit therefore I have to use fixed point (Q15 or Q31) for calculation.
Before calculate ...
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how to plot analog filter impulse responce and frequency responce?
I an new to signal processing, working on a UWB rada data this data has a shape of frames for whcih every frame (list) has 164 values, I want to pass a band pass filter with the 1hz and 5hz ...
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plot the frequency responce of a sos Analog chebychev filter using python
I am new to signal processing.
I am using an sos analog Chebychev filter, and I was wondering what would be the result of plotting its frequency response using the ...
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Performing IQ imbalance correction on sampled quadrature signals
What are the techniques which can be used to perform digital IQ amplitude and phase correction in a wideband receiver system when input signals can be of unknown different frequencies and occupy ...
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Does different frequency signal cause different voltage from antenna?
When antenna received signal,antenna generate voltage,then SDR convert voltage to I=amplitude*cos(t)and I=amplitude*sin(t).
When ...
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Confusion implementing Quantization in MATLAB?
I am quantizing a continuous time signal in three different cases(using different number of bits)
But Why i am getting same quantized signal in xq2 and xq3,despite using different values of D(...
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Can a digital signal has 3 three values(1,0 and -1)?
Typically digital signals are seen having only two values,but is it possible that a digital signal has three values(1,0 and -1)?as shown highlighted in attached snapshot,which has been extracted from ...
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