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Questions tagged [digital-to-analog]

A digital-to-analog converter (DAC, D/A, D2A, or D-to-A) is a system that converts a digital signal into an analog signal.

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DAC - Can we create and use frequencies above Fs/2?

I understand how the ADC and Nyquist works. Anything above Fs/2 can be indistinguishable from frequencies inside Fs/2 so we use an alias filter to remove them before sampling. This can also be an ...
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DAC/ADC sample rate selection for modem

So I have a very basic on which I couldn't find much details anywhere. I'll start with an example: I have to transmit 100Mbps of BPSK data. Roll-off factor is 0.25. This data will be processed at ...
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Mapping PAM-17 levels to PAM-5 levels

A $17$-level $\left\{ -4,-3.5,-3,\ldots,0, 0.5, 1,\ldots, 3.5, 4 \right\}$ digital signal coming at $125 \, \textrm{MHz}$ is passed through an FIR filter ($10$ taps) operating at $1250 \, \textrm{MHz}$...
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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 ...
RookieBeotch's user avatar
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Noise (in dB) added to a signal but within range limits

I have a sine wave signal to which I add noise in terms of dB. This is based on https://stackoverflow.com/questions/14058340/adding-noise-to-a-signal-in-python The signal is sent to a DAC and there ...
Mart's user avatar
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How does PAM-4 encoding of a digital signal relate to theoretical *pulse* amplitude modulation?

Pulse amplitude modulation in general is often explained using plots like this one from wikipedia: There is a sinusoid analog signal (red) to be "imprinted" on a train of pulses. The result ...
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what am i not doing right while using squarewaves?

I have been applying square waves at 40hz and 10 volts via a function generator amplified by a power amplifier by 2 times(2A) on a 6mm steel specimen. My signals captured from the AE sensor are not ...
Wasil Riaz's user avatar
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sigma delta modulator for DAC

Can someone please provide an overview of sigma delta DAC? In particular, I would like to know how does the sigma delta modulator, which is digital, works for DAC. What is difference between sigma ...
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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 ...
Ken C's user avatar
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How can I generate a OFDM baseband signal with the output of the ifft?

I have some understanding problems with OFDM. I think I have understood most of the theoretical concept. At the moment, I am trying to write some Python code to simulate the transmitter part. This is ...
Not A Hobbit's user avatar
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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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How to avoid harmonic distortions in a DAC?

I have a DAC which is assumed to be nonlinear, such that it produces unwanted harmonic distortions at integer multiples of the input frequencies. (EDIT: Any other nonlinear distortions, such as ...
Harry's user avatar
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Complete OFDM transmitter chain

I am looking for complete OFDM transmitter chain with all the details i.e. starting from modulation symbols up to up conversion to carrier. What I have found on the web is Modulation Symbols serial ...
user3005720's user avatar
2 votes
3 answers
521 views

Adding two sine waves results in a low buzz

I'm working on a little audio/embedded systems project, and I'm using synthesis to generate waveforms and feeding them into DAC and speakers. Currently, I am able to produce sine waves of individual ...
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iq bpsk waveform generation

We have a DAC capable of being driven with IQ data (thus the bandwidth is $-f_s/2$ to $f_s/2$), and the task is to create an "arbitrary" BPSK waveform at IF. I think that means generating ...
Sittin Hawk's user avatar
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1 answer
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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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Is the ideal reconstruction process BIBO stable?

It is well known that ideal lowpass filter, i.e. the lowpass filter whose impulse response is $h(t) = \text{sinc}(t)$, is not BIBO-stable because $h(t)$ is not absolutely integrable. However, think ...
avril_14th's user avatar
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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 ...
DSP_CS's user avatar
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Convert analog to digital and back to analog

I'm trying to convert a signal from analog to digital and back to analog to observe the working of ADC and DAC, I use AD9248 as ADC and AD9767 as DAC, both of them are available on THDA ADA Altera ...
Tuấn Nguyễn Anh's user avatar
2 votes
1 answer
233 views

Efficient Implementation of Digital Upconversion

I have an application where I have a pulse shaped QAM signal, at 2 samples per symbol. I need to take the I/Q samples and perform quadrature upconversion so that they can be output on a DAC that's ...
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Why is this ring-buffer jumping?

Central problem (Abstract): A simple implementation of a two-buffer ring-buffer jumps after filling up completely. What am I missing? About: ADC to DAC feedthrough STM32L476RG NUCLEO as MCU Intended ...
jake_asks_short_questions's user avatar
1 vote
1 answer
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Attenuation of reconstruction filter for Digital-to-Analogue (DAC) converter

I am using a 12-bit DAC to produce signals between 10 kHz and 400 kHz, produced at a rate of 3.33 MSamples/s (Nyquist frequency of 1.665 MHz). I would like to create a "reconstruction filter"...
Rhodes's user avatar
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2 answers
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When applying analog and digital effects on an audio signal is it better to start with a clean digital signal or use the analog effects before ADC?

If I am digitally capturing an audio signal from an analog source and I know I will want some analog effects applied, is it better to use them on the analog signal before doing the ADC, or should I ...
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Does Sampling frequency come into picture in Samples generation for DAC to generate sinewave (analog signal with particular frequency & amplitude)?

I'm generating samples for dac in STM32. sin(2pii /N)*4096/2. This is the formula I'm using. How to I come to know sampling frequency? Whether sampling frequency comes into picture?
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How to reconstruct original signal from sampled signal?

My original signal as f1=2; f2=5; fs=100; Ts=1/fs; t=0:Ts:1; xt=cos(2*pi*f1*t)+cos(2*pi*f2*t); figure plot(t,xt) as shown below figure. and my sampled signal ...
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Filter to eliminate a 60 Hz frequency range

I have a analog signal that is converted into a discrete-time signal with an ideal A/D converter with a sampling frequency $fs$. The bandwidth of the signal of interest is $1 kHz$. The resulting ...
carraro's user avatar
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1 vote
2 answers
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Difficulty absorbing Idea of interpolation?

I am trying to develop my understand of interpolation and signal reconstruction and uptill now i have understood that there are 3 commonly studied types of interpolation 1)Zero order hold ...
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Analysing DAC Spectra: Transient Noise Analysis

I am working with a new Digital-to-Analog Converter (DAC) design in simulation and I'm trying to analyse the output. The device takes in an ideal 14-bit digital representation of a sine wave and ...
Alex Steven's user avatar
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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 ...
LinuxGogley's user avatar
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3 answers
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What is the gain (advantage) of oversampling and noise shaping in D/A conversion?

It is clear that oversampling and noise shaping in A/D conversion can help in shaping quantization noise. But for D/A conversion, normally there is no quantization and hence I did not understand its ...
DSPinfinity's user avatar
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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?
DSPinfinity's user avatar
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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 ...
DSPinfinity's user avatar
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0 answers
375 views

First order hold from zero order hold filter

I'm stuck in this question for more than 4 hours. (h is the sampling period) I simplified the block diagram but it just seems impossible to get the FOH transfer function from the reduced block ...
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1 answer
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Modulate Bipolar(?) signal

I want to modulate this signal if possible with an Arduino, but have no idea what circuit can help me here. Let's ignore the timing and the measurements from the image for a moment, my problem is more ...
Tim's user avatar
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2 votes
2 answers
239 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 ...
Pllsz's user avatar
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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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SNR of μ-law companding

I know the snr after μ-law compression is $\text{SNR}\approx\frac{3L^2}{[\ln(1+ \mu)]^2}$ when $\mu \gg \frac{\max_t m(t)}{\text{rms}(m(t))}$, where $m(t)$ is the message signal, and $L$ the number ...
Zemi Alvez's user avatar
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2 answers
571 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 ...
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Decoder implementation

Im struggling to implement / build convolutional decoder . I've done implementation of FEC encoder which it's as shown in the photo below: So this is the encoder that I've implemented, and I want to ...
DavidJohnsons's user avatar
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0 answers
32 views

What is the pipeline DAC tollerable offset from plot

I have analyzed the circuit in full extent as shown bellow. I know that I showed imagine two-stage back to back and see "which input could handle both". Could you please show how exactly I ...
rocko445's user avatar
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2 votes
1 answer
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How does the world's simplest sigma-delta DAC work?

I have run into a simple delta-sigma (supposedly, where is the delta part?) DAC implementation utilizing an accumulator and then using the overflow bit as a modulated 1-bit output. From https://www....
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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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4 votes
3 answers
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What causes this type of distortion in a constellation I/Q plot?

I'm transmitting QPSK through a digital pulse shaping filter (RRC, 35% excess BW, 2 samples per symbol, 64 taps) at a rate of 56Msym/sec. Receiving it on standard lab equipment (Vector signal ...
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1 vote
1 answer
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DDS generated chirp and antialiasing filter : what is the best suited filter for a chirp?

I am defining the required antialiasing (analog) filter for a chirp generated by a DDS. The chirp is produced in a FPGA (NCO generation) and forwarded to the DAC for the samples generation (with ...
AtoM_84's user avatar
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1 answer
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How to filter OFDM Signal with an analog filter

I am using OFDM system in Matlab, I want to use an analog filter after the DAC. Because we don't a simulation for the DAC, the generated OFDM analog signal does not have a specific frequency (they ...
Amro Goneim's user avatar
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1 answer
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Sample and Hold Circuit at Digital to Analog Converters

Does DACs contain sample-and-hold circuits? I am a bit confused thanks
Amro Goneim's user avatar
1 vote
1 answer
148 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. ...
Amro Goneim's user avatar
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1 answer
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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 ...
Anthony Lauly's user avatar
3 votes
2 answers
1k 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 ...
Dsp guy sam's user avatar
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1 vote
2 answers
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Types of interpolation used for reconstruction in DSP?

What are the different types of interpolation used in DSP for reconstruction of analog signal from discrete/digital signal I am able to somehow learn two types of interpolation 1st is "zero order ...
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