Questions tagged [adc]

An ADC is an Analog to Digital Converter. This device converts analog signals into digital form. It is mainly used by the digital circuitry to take analog measurements.

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Save Audio ADC samples in SD Card in STM32

I use STM32F7 and I want to save Audio as ADC samples in SD card, continuously in 50K sample rate that is made by timer.(Same as voice recorder) I use DMA to save data in SD card. During read ADC, I ...
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17 views

Single-ended vs differential measurement of high-impedance voltage sources

I'm designing a low-cost multi-channel DAQ device with target resolution above noise of 30-50uV DC and +/-2V range. For this task I've selected ADS1220 ADC ICs: it has a 2.048V internal reference, ...
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33 views

ADC AINCOM pin connection

I'm using AD7190 (datasheet) and having trouble on the AINCOM pin. First, I'm using AD7190 to sample two channels of differential voltage. In that configuration, I don't need the AINCOM pin. But ...
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36 views

STM32 interrupt and input on same pin

Fairly simple question but I couldn't find any instructions on this. I'm using an STM32G070 I'm interfacing with an ADS1231 which uses DOUT / ~DRDY on the same pin, and I'm wondering if there is a way ...
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1answer
29 views

Use LMT86 temperature sensor with MCP3008 ADC

I'm currently working on a small project using LMT86 and MCP3008 as a temperature sensor for Raspberry Pi. The schematic is very simple: So a couple of questions that I have: The MCP3008 datasheet, &...
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1answer
38 views

ADC 1/2LSB vs 1LSB

I was going through the below question. ADC first transition at 1/2 LSB - is that not a non-linearity? I did not understand why they took the first transition point as 1/2LSB.if so then may I know the ...
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Why is a low resolution ADC (e.g. 4-bits) a bad idea for a Zero-IF GPS/GNSS RF front-end?

This is another follow-up from this fascinating question (the other follow-up question is here) for the design of an RF front-end for a GPS/GNSS SDR receiver. In a comment to the accepted answer, it ...
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2answers
317 views

ADC Chip Timing Question

When is the best time to read the bit out of a serial data output 12-bit ADC chip. The chip is a AD7476A, and here is the datasheet AD7674A Datasheet. Going by the timing diagram, when is the best ...
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Temperature sensor read out is influenced by LED

I'm trying to control some LED's (pins 2,3,4) with a temperature sensor. In the setup I do a calibration step to set the baseline temperature. When that's done, the LED at pin 5 is turned on. Before I ...
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27 views

the best way to calculate rms voltage from 10Hz to 20KHz

We need to calculate the RMS voltage of a signal that can work from 10Hz to 20 KHz with a duty of 5% to 95%. I decided to use a dsPic33CK256EP202 with the ADC sampling at 500Ksps at 12 bits of ...
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1answer
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Problem or misunderstand of ADATE bit on ATTiny45

I have 2 buttons connected to pulled-down ADC input. I want to trigger ISR(SIG_ADC) when ADC finishes conversion - this is working. If I start ADC using ...
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4answers
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A PWM output is going to 0V if I connect an ADC input in a development board

I'm doing a project in which I want to turn on an LED with different instensity depending on the input of a sensor. For now, I'm simulating the sensor with a potentiometer. I'm using an EK-TM4C123GXl ...
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Amplify difference between two photodiodes

I have two adjacent photodiodes in photovoltaic mode, with two transimpedance amplifiers. Unfortunately, my MCU (nRF52840) is one meter away, and I expect a fair amount of noise to enter the system. ...
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1answer
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Types of sampling and signal processing: some conceptual questions

I'm studying signal processing and right now I'm going through types of sampling and how they apply, advantages and disadvantages. I have some questions about these concepts that I would like to ...
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1answer
35 views

Why is 10V a common range for Data Acquisition or Benefit of increasing signal amplitude in the transmission line

I've been thinking about the reason why \$ \pm 10V\$ is a common voltage range for commercial DAQ cards. I think that using 10V instead of 1V on the output of the external sensor board would give +...
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2answers
40 views

Voltage reference output impedance calculation

I'm using AD7190 to sample 4ch single-ended signal. The datasheet suggests ADR431 or ADR421 as voltage reference for AD7190. However, an article on Analog Dialogue gives a way to calculate whether an ...
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3answers
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Can't get ADC chip to work

I am connecting a 10k potentiometer to an ADC chip (LTC1273BCN) that has a 12-bit parallel output, like in the diagram at the end of the post. The 12-bits will be connected to an FPGA input bus after ...
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ADC Clamping Rrotection Circuit with Dual serial Diodes - Formula proof

I am trying to undestand and calculate why in the first circuit we measure 5.7Volt (if forward noltage diode is 0.7Volt) and not 12V. I used the Superposition Theorem which first I replaced the Vcc ...
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2answers
63 views

4-20 mA sensor output to STM32 ADC input

I have a industrial sensor with 4-20mA output and I want to read that output from Stm32 ADC pin but I need suggestions to do that work in a nice way. Can you guys suggest me the best way to do it? It ...
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1answer
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Transmiting analog signal with lora

I want to transmit an analog signal over Frequency Modulation with a Lora RA 02 module. First thing I need to do is convert the analog signal from the audio source to digital, right?. But I had so ...
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27 views

How to capture the I2S signal via Raspberry Pi Zero?

I would like to capture the I2S data from ADC CS5340 by raspberry Pi zero, but I could not find relevant I2S API to use in raspberry pi zero. Could anyone help me on this? Thanks!
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2answers
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Using SPI to get higher sampling rate from ADC module vs using ADC on microcontroller [closed]

I am currently looking at a microcontroller, and I would like to use ADC on Arduino but found out that the Arduino has a limited sampling rate. Is it possible to us SPI communication with a separate ...
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1answer
61 views

Voltage divider for monitoring solar/battery

Can someone please just sanity check my math? I'm trying to design two voltage divider networks, one for the solar panel and one for a LiPo battery so that I can connect them to my 3.3V ADC (RP2040) ...
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2answers
53 views

SAR ADC dynamic range and accuracy

This App Note states: To have the maximum ADC conversion precision, it is preferable that the ADC dynamic range matches the maximum amplitude of the signal. Assume that the signal to be converted ...
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2answers
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Multiplex temperature signals through one conditioning circuit

I'm planning on designing a PCB that takes numerous analog temperature sensor input signals and convert them using an Analog to Digital Converter (ADC) to be read by a computer. The signals need to go ...
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3answers
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STM32 ADC read methods for high voltages

I want to read input voltage from a solar array for my circuit. That's not a big deal if the voltage is up to 3.6V. The problem is that I am expecting maximum of 15V and obviously I won't be able to ...
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2answers
63 views

How to find the Nyquist-/sampling frequency of a Sigma-Delta-ADC

I'm looking at the datasheet of an Analog Devices ADC (AD7124-4) and can't understand what is the relevant sampling frequency to use as a basis for calculating the anti aliasing filter. Is the ...
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5answers
754 views

Is it normal to have this much fluctuation in an RTD measurment in boiling liquid?

I'm using a MAX31865 RTD measurement IC, and a standard PT100 RTD to measure maple syrup temperature as it's boiling (219 degF). At ambient, the temperature measurement is reasonably stable. But, ...
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calculation problem: single ended to differential ADC interface

I got a circuit from the provider of my chip. It's the ACD driver of single ended to differential conversion. However, i cannot get the same value as they marked above the wires [ eg. 0.5(Vin-Vcm) and ...
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1answer
57 views

Resistors on decoupling capacitors in ADC Layout Guidelines

The datasheet for TI's ADS8691 ADC chip has the following diagram in its layout guidelines. I just have a few questions about the resistors in the diagram, which I don't believe are mentioned anywhere ...
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1answer
54 views

Is it possible to change the ground voltage level for the ADC/DAC at a STM32F373?

I want to change the ADC and the DAC ground so the ADC begins to measure at e.g 0.64V and the DAC begins to send out voltage at ...
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1answer
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Maximum voltage divider resistances for sensing LiPo battery voltage over 10bit ADC: is MOhm range working?

I've designed a PCB that should contain as few components as possible but it should have a simple way for measuring the battery voltage using an ADC channel and a simple voltage divider. My current ...
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1answer
19 views

Instrument amplifier REF pin current

I'm using AD7190 to sample 4ch differential voltage, but the AD7190 only has four input pins. To fix that, I use AD8422 to convert four differential signals to four single-ended signals. The schematic ...
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31 views

How to use the full 10-bit PWM resolution (PIC18F2xk22)?

Hi I am trying to use the full 10-bit PWM resolution for my project, and there is a problem as the duty cycle of the PWM will not set to zero when I rotate the POT to the zero position, here is my ...
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2answers
58 views

Not accurate readings when connecting OpAmp AD822 to ADC MCP3008

for my project, I am using a photodiode, that I connected to the AD822 OpAmp. This OpAmp should then be connected to the MCP3008 ADC. I am reading the data from the MCP3008 with a RaspberryPi. I am ...
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1answer
42 views

DAC/ADC Precision & Noise: PD Resistor/Capacitor effect

I'm developing a device that utilizes both ADC and DAC, and I have realized that my DAC output, which is fed into the op amp, is de-facto almost floating, since op amp has high input impedance. Both ...
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1answer
87 views

SDC (Synopsys Design Constraints) Timing Exception for Latch Before Launch - FPGA

I am acquiring data from an ADC whose serial output makes the first bit available immediately after completion of a conversion. Then, the FPGA sends clock-pulses to the ADC to shift-out the remaining ...
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2answers
90 views

4-20mA sensor to a microcontroller

I need to connect a sensor with a 4-20 mA loop to a microcontroller. The MCU operates at 3.3V and the following image is from the sensor's datasheet. I'm planning on converting the 4-20mA to a 0.6-3V ...
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2answers
78 views

ADC is giving fault codes when I touch thermistor attached to it

I am working on writing a control program for my pellet smoker. I am having an issue with the meat thermometer that came with the smoker. I have a MAXIM 31865 ADC that is connected to a Raspberry Pi. ...
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3answers
55 views

protecting ADC inputs [duplicate]

let's say I have an ADC with a full scale input from 0V to 2.1V. I want to protect the input of the ADC from voltages > 2.1V. I thought about using 3 diodes like shown below. Each diode has a ...
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66 views

Ferrite beads as power rail in opamp breakout analog input circuit

i'm designing a small breakout boards that is used to interface some external sensors (voltage and current) to a MCU. In order to get better results, i'm using an external dedicated ADC, the ADS1115, ...
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1answer
70 views

Simple (probably) question about ADC sampling frequency

I want to sample a signal at 44kHz. I've tried to set up the ADC with DMA and calculated the conversion time so that I get that 44kHz sampling frequency. My thinking is that with continuous mode ADC, ...
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6answers
2k views

Why can the effective number of bits be a non-integer? What does this physically represent?

The effective number of bits (ENOB) describes the "real" resolution of an ADC. I paid no attention to it when I was first taking the class but now when I think about it I cant really make ...
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2answers
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Resistor value calculations for measure negative and positive voltages using Arduino ADC [duplicate]

In order to measure negative and positives voltages with Arduino I found this solution. I need to understand how to calculate R1, R2 and R3 according to specifications below. Specs are: The impedance ...
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37 views

problem with capacitance measuring with stm32f103RE

I'm trying to measure a capacitor's value and send it to the uart terminal. I'm using stm32f103re and I'm using registers. I attached the circuit I'm using and also my code. the code is working now ...
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1answer
66 views

Arduino Detect something is connected to relay

I have a diesel generator controlled using arduino, 8-ch relay board and it works great but sometimes during monthly maintenance workers unplug start/stop contactor coil wires from the arduino relay ...
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1answer
62 views

Commercial analog to digital converters using sub nyquist sampling rate

Are there any commercial analog-to-digital converters (ADC) that use a sub-nyquist sampling rate, i.e., exploit the theory of compressed sensing in order to sample using a data rate that is smaller ...
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2answers
632 views

Op-amp voltage follower not working as expected

I previously asked about a circuit to scale my analog value before MCU ADC. Based on the answers I got from that post I decided to change my op-amp from a TL072 to a CA3130. The following pictures ...
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28 views

Configure STM32F3 PLL timing for ADC read of Power System and FFT

I am new to the STM32 series microcontrollers. I have a Nucleo with an STM32F303RE device to prototype a project I wish to explore. I got that model because I plan to slave ADC2 to ADC1 and read the ...
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1answer
68 views

Sinking charge from LED before taking measurement

I'm currently using an STM32 for anode sensing of a LED as shown in the following schematic: simulate this circuit – Schematic created using CircuitLab The LED is both used for emitting and for ...

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