# 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 sampling rate and signal bandwidth for FHSS

If i am correct; for a radio receiver the ADC sample rate will have to be higher than at least twice the BW of the data (disregarding sparse sampling techniques). So for frequency hopping spread ...
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 ...
83 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 ...
66 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 ...
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 ...
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 ...
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 ...
67 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 ...
51 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 &...
207 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 ...
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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### 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 ...
3k views

### 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 ...
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. ...
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 ...
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 ...
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. ...
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 ...
175 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 ...
586 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 ...
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### 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 ...
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 ...
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 ...