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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questions
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55 views
Electric Bass with RJ45 Digital Output
I'm working on a project bass guitar with individual outputs per string using Nu pickups from Cycfi Research: https://www.cycfi.com/
The common sense approach is to simply take their circular ...
1
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1answer
81 views
Quantization error of SAR-ADCs
My question is related to the quantization error and the functionality of SAR-ADCs. In general, the quantization error of an ADC is defined as +-0.5LSB. If this concept is correct a voltage that ...
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1answer
61 views
I/Q sampling with just one ADC
Usually I/Q sampling is performed on two signals with a 90° phase shift using separate ADCs. Suppose I have only a single (fast) ADC available to perform I/Q sampling, which approaches do exist? Is ...
2
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1answer
48 views
transfer function of a sampler in the s domain
I would like to modelize my whole system into the S-domain. This is a mixed system, there a numerical part (corrector, ADC, DAC) and an analogic part (plant transfer function, sensors, etc...). I know ...
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1answer
42 views
Increasing ADC output accuracy
Say we have a 12-bit ADC with 30 MHz sampling frequency. I want to perform several DSP operations on output digital signal so that resulting signal would have increased accuracy to 14 bits and output ...
3
votes
2answers
140 views
Oversampling in quantization
Q: It is said that "to maintain the same quality in the two cases, we require that the power spectral densities remain the same". Why is this a measure of the same quality? Why is not
the ...
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2answers
66 views
Condition for aliasing
Which one of the following is the condition of aliasing?
(a) Tails of the replicas enter into the Nyquist
interval
(b) The tails of the replicas enter into the Nyquist
interval and add to the ...
1
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1answer
49 views
Timbre vs sound via oscilloscope
My understanding is that a distinct sound will generate waves of identical amplitude and frequency, but that most things (such as people's voices, music intsruments, etc) produce multiple distinct &...
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2answers
204 views
Using oversampling to increase resolution of a DC-signal as input
Currently I'm working on a project which uses oversampling to increase the resolution of a 12 bit ADC to a maximum of 16 bits. My goal is to fully understand the theory behind oversampling and why it ...
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1answer
40 views
Sampling interval $T$ as a multiplier in digital processing of a continuous-time signals
[from: Discrete-Time Signal Processing, Oppenheim and Schafer, p.224]
Q: Why do we have $T$ as multiplier in $TY_a(j\Omega)$ in Eq.155?
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1answer
150 views
Is this an error in Oppenheim and Schafer's Discrete-Time Signal Processing?
In Discrete-Time Signal Processing by Alan V. Oppenheim and Ronald W. Schafer (3rd Ed.), in Figure 4.47 the input of D/A converter is $\hat{y}[n]$ but later in Figure 4.64 the input of D/A converter ...
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2answers
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Why do we need DFT when we already have DTFT?
We already have DTFT so why do we need DFT?
Please don't write DTFT is used for discrete, aperiodic signal which transfers in the frequency domain to periodic and continuous, but in DFT is discrete ...
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9 views
How can I do a validity check of an FFT
The aim is to identify problems in an ADC FFT simulation in an early phase of the simulation using the output bitstream of the ADC. The reason is to avoid long simulation times while using wrong data.
...
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24 views
Measuring the frequency of the Analog input signal of an ADC, which is operated by Raspberry PI
I'm building a monitoring package for a sensor via a raspberry PI and an ADC, which reads the analog signal (for the moment from a DC power supply instead the real sensor) and transfer it to my ...
1
vote
1answer
46 views
Understanding this Hanning Window implemented in microcontroller
I'm trying to calculate RMS of an AC signal which input frequency may vary from 40 to 70 Hz. I would like to use a window function because it accounts for frequency variations and also my ADC sampling ...
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0answers
22 views
Response time of residual current device and sampling times
The table below is from this document: Schneider RCD
When the maximum response of the device is 40 mS, does it measure current doing RMS or peak detection? The document does not explicitly say it. ...
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34 views
Output signal is being attenuated after the Biquad filter direct Form 1, why?
Thought this would deserve a separate post on its own.
What's going on is that I finally got my low pass digital filter working on the STM32H753ZI using the PMODI2S2 peripheral and I noticed the ...
2
votes
2answers
174 views
DSP low pass filter (IIR) no longer works when changed to a new MCU
Having troubles understanding why a DSP low pass filter was that working on the M4 is no longer working on an M7.
I recently switched over to a STM32H753ZI from a STM32L432KC.
In addition to switching ...
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votes
2answers
580 views
Increasing SNR and Dynamic Range using Oversampling
How much gain in dynamic range and SNR can be expected if we are to oversample a signal with fixed analog input bandwidth. For Example if I have a analog filter at the input which limits the bandwidth ...
2
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1answer
40 views
How to modify zeros and poles in a delta-sigma modulator loop?
In this specific case, I am modeling a delta-sigma analog-to-digital converter with a basic loop in which the output $V$ is fed back with unity gain to be subtracted from the previously sampled input $...
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0answers
34 views
OFDM Signal Recovery with DAC & ADC
I have implemented 256-QAM based OFDM design on FPGA. The data flow is as follows -
QAM -> Hermitian Symmetry -> IFFT -> Pilot Insertion -> Cyclic Prefix
I have done Hermitian Symmetry ...
1
vote
3answers
130 views
Downsampling vs. ADC with lower Sample-Rate
I would like to know in general where the advantages and disadvantages are:
Downsampling of a high sampled continuous analog signal in FPGA or µC and
Direct use of a lower sampling rate, i.e. using ...
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23 views
How to calculate Integral Non Linearity (INL) the direct way
In the situation bellow we have a 3bit Analog to Digital Converter (ADC).
where avarage the LSB from the non ideal system is
I want to calculate the Integral Non Linearity (INL) purely from the ...
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0answers
26 views
FSK technique to superpose the digital communication on top of 4–20 mA signals
I start a working with HART devices and I really try to understand how digital data is transferred trough 4-20ma current loop.
I start read this article: https://instrumentationtools.com/hart-...
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79 views
minimum oversampling factor for D/A converter
Consider a D/A converter for audio signals consisiting of a zero-order-hold interpolator followed by a continuous-time lowpass filter with positive passband between 0 and 20KHz and stopband starting ...
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2answers
88 views
D/A converter with
I am trying to figure out how to consider digital-to-analog conversion and how to consider oversampling based on a course I am taking online and figuring out the logic behind this. Unfortunately there ...
0
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1answer
29 views
μ-law compression technique
In μ-law compression formula i have always seen that the value of Xmax and Ymax is always same but can they be different?
6
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1answer
193 views
DC bias from ADC in frequency detection scenarios
In real-world applications where a frequency or multiple frequencies need to be detected from a digital signal that comes from an analog-to-digital converter (ADC), what are the typical 0 Hz (direct ...
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14 views
Snapshot of a signal
I need to understand what a snapshot of a signal is.
Suppose I have a signal of duration, say, 10 microseconds from multiple channels and that the ADC samples every 20 nanoseconds from each channel. ...
0
votes
1answer
35 views
Do we have to insert the DC null in OFDM when using RF direct sampling ADC architecture?
Generally, DC Nulls are added in OFDM because zero-IF receivers don't pass the DC component. But what if I use an RF direct sampling architecture? Will there be DC offset? If not, then is it okay not ...
0
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1answer
55 views
Multisampling of an ADC channel in a PWM cycle in TI C2000
I want to sample an ADC channel multiple times in one PWM cycle.
I can trig any ADC channel in anywhere in my PWM timer counter now. But I want to trig and sample same channel in many times within a ...
2
votes
1answer
62 views
Digitalization of a signal
Suppose I have an analog signal I want to transmit. After sampling and quantization, I can map the samples to bits. So now I have a bit stream that represents the original analog signal.
My questions ...
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24 views
Resources on multiplexer and demultiplexer?
If I search multiplexer in Google and start reading, I find sources that describe a multiplexer as a device that selects between several analog or digital signals, then outputs a single signal. For ...
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0answers
25 views
Threshold Estimation from a Linear FM Pulse Position Modulated signal
I have a signal chain to detect multi channel LFM (Linear Fm - Hann window being applied as shaping filter for the pulses) pulses as shown in picture below. (Numbers in the picture is in Hz., for ...
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1answer
136 views
Are there analog re-configurable filters?
I know that we can build a chip (or circuit) or use FPGA to have re-configurable digital filters. But how about analog filters, can we have re-configurable analog filters?
thanks
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0answers
29 views
synchronize adcs with neuronal network
if i have two adcs(analog to digital converters) sampling a signal. Is it possible to synchronize the two adcs with deep learning?
as far as i know, with super-resolution on image processing it is the ...
0
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1answer
70 views
Sample and Hold Circuit at Digital to Analog Converters
Does DACs contain sample-and-hold circuits? I am a bit confused
thanks
1
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1answer
38 views
Aperture Jitter in Digital to Analog Converters
I have noticed in the literature that there is an internally induced timing jitter inside Analog to digital converters called (aperture jitter). It is caused by the sample-and-hold circuit of the ADC.
...
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17 views
how to do smoothing a linear noise adc signal to a exponencial curve to increase and logarithmic to decrease
I am studying methods of signal smoothing obtained in an Analog Digital converter that is operated by a common potentiometer that generates a certain noise, such potentiometer is linear and I cannot ...
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0answers
14 views
what is the DNL of flash converter
i have a flash ADC converter with 1V vref and idial ressistors but in the comparator i have standart deviation of 3mV.
how do i calculate from the the standart deviation of the whole device(DNL INL)?
...
0
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1answer
32 views
Reconstruction of Contiuous - Time Signals
In terms of analog signals, we can represent digital signal as :
$$
x[n] \triangleq x_{a}(nT) = \int_{-\infty}^{\infty}X_{a}(f) \, e^{j2\pi f nT} \ \mathrm{d}f
$$
While if we focused on the integral ...
1
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2answers
95 views
How to Compensate for Frequency Offset in single carrier transmission Using Coarse and Fine Compensation?
How to compensate for the frequency offset of a PAM, PSK, or QAM signal when we are using single carrier transmission, I am looking for algorithms, explanations to be able to carry out the ...
1
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1answer
27 views
What does an ADC DNL specification mean, exactly?
I'm looking at the differential non-linearity specification for an Analog-Digital converter. The spec sheet claims that the DNL ranges from -1LSB to +1LSB, with a typical value of $\pm$0.6LSB. What ...
3
votes
2answers
88 views
DAC and ADC architecture in SDRs
What are the DAC and ADC architectures in SDRs for inphase and quadrature phase channels?
Do we have separate ADC and DAC for each channel or there is some clever way that they are multiplexed to ...
0
votes
1answer
71 views
ZOH DAC amplitude formula testing
We have an expression shown in red bellow for non ideal DAC ZOH,which links the sampling frequency to the amplitude loss of the input signal.
I took $f_b=1kHz$ and $f_{noise}=4kHz$
$f_{in}=f_b+f_{...
0
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1answer
183 views
Calculating dBFS for I/Q
I'm trying to figure out how to calculate the dBFS for a complex input. I have an AD9361 part which has a 16-bit A/D and I believe outputs I and Q samples. Now I know you can calculate the dBFS for a ...
0
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1answer
48 views
How to add a particular noise on a signal?
I have a simple ADC model (an input signal == sampled signal ). The adc should be modelled as with following values:
1.5 V (peak to peak).. meaning --> +1.5 V --> 0 dBFS ... how to do this ?
The ...
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1answer
393 views
Difference between formula of SNR and SQNR?
Is there any difference between formula/expressionsof SNR and SQNR? where SNR is Signal to noise ratio and SQNR is signal to quantization noise . The following DSP SE question shows both SNR and SQNR ...
2
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1answer
1k views
How we can quantize a sampled signal in MATLAB?
I have a continuous time signal $x(t)=\sin(2πft)$ where $0 \leq t \leq 3$.
I want to sample the continuous time signal and then quantize that sampled signal and then plot both sampled and quantized ...
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3answers
126 views
confusion sampling vs quantization?
while converting analog signal to digital equivalent,we have a process that is called analog to digital conversion and it has two main steps/stages sampling and quantization? I am confused whether y ...
