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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220 views

When do we have to use an analog oscilloscope?

Are there any testing/measurement processes in electric and electronic engineering that can be done only with an analog oscilloscope? In digital scopes there is a short delay to process the signal (...
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58 views

ADC in STM32F103 drops ouput voltage from unity buffer

I'm building a signal analyzer based on STM32F103RB6 placed on a noname board with the following schematics: I'm trying to normalize the AC input signal initially centered at 0V. The amplitude is 2....
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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 ...
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37 views

Using a Force Sensitive Resistor (FSR) as a switch

I would like to use a FSR as an on/off switch. I want to implement it by using an 8-bit 328p processor (either on an arduino or on an AtMega). Im using a voltage divider between the FSR and a 10K ohm ...
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How to detect an unconnected LED with an ADC?

Let's consider the following simple example : An MCU controls the lighting of an LED with the wire "CMD_LED" by switching the state of an NMOS transistor. When CMD_LED = 1, the transistor is closed ...
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1answer
62 views

What is ADC Supply Current in Microcontroller and how much current will a GPIO take

I am having this Microcontroller In this Microcontroller, I am using the ADC peripheral and normal GPIO port. My questions: On Page 58, table 42, There is a parameter called as Supply Current per ...
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66 views

STM32 - too low sampling time problem

I faced a problem with my ADC in the NUCLEO64 F446 module. I was trying to realise ADC measurements, where the input signal was from potentiometer. STMStudio was my tool to display value of ...
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20 views

Cooperation of the ADC and PWM modules

I am going to implement field oriented control of the induction motor on Zynq 7020 SoC. My idea is to use the integrated ADC module (XADC) and implement the PWM modulator in the FPGA. I need to have ...
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1answer
89 views

Simultaneous sampling or doubled output rate with two LTC2400s

The quick version of my question is: How can I properly sync up two ADCs to a single source to sample it at the same time OR to double the sample rate? (The micro-controller would be able to use ...
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1answer
43 views

Use of ADC Bits below noise floor

I have a Sigma Delta Modulator with a SINC3 Filter. The System runs at maximum oversampling possible for this application and I know my (Full Scale Signal)ENOB for this szenario to be 14. Is there ...
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45 views

ADC Triggering with TIM3 TRGO running in PWM mode in STM32F446

I have been trying to trigger an ADC using TIM6 with TRGO signal in STM32F446RE board. I am unable to do it. I have used CubeMX initialization and have been trying to use the HAL libraries for ...
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1answer
84 views

What would cause an ADC to stick on an arbitrary value?

I have a differential ADC (HX710) that I am using to interface a load cell. The wiring is as follows with (J4) going to the load cell: Mostly, this reads very reliably and accurately. However, ...
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48 views

ENOB of an ADC or DAC

When calculating an ADC or DAC ENOB, do you use SNDR or SINAD, SFDR, SNR or SDR or something else ? I have see all used in calculating the ENOB, so which one is correct ?
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42 views

AS8510 ADC Reading to Current/Voltage Measurement

I have this AMS AS8510 data acquisition IC for battery management with dual ADC (datasheet) that is supposed to measure the current, voltage and/or temperature of a 12 V battery. I'm having a hard ...
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4answers
82 views

dsPIC33 ADC: Why is the minimum TAD interval such an oddly-specific number (117.6ns) for 12-bit conversion?

I'm writing the firmware for a data-acquisition board using the dsPIC33FJ64GP804 MCU and I noticed something strange reading the electrical characteristics for 12-bit A/D conversion: The ADC clock ...
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51 views

PWM for three phase induction motor control

I have been implementing control software which shall control the three phase voltage source inverter for controlling the induction motor. There are two requirements as far as the pulse width ...
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3answers
103 views

Why there is a low frequency?

I take the function \$ \sin(2 \cdot \pi \cdot f \cdot t) \$. with \$ f = 1 \$ And plot it in excel with sampling frequency fd = 4,10 Why there is a low frequency?
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1answer
99 views

Floating Differential measurement?

Can I simply hook up an opamp inputs, (either using a differential or in-amp topology that is/are also powered from a floating power supply), across a device under test that itself has exceeding ...
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1answer
38 views

How to do multichannel ADC data logging

I need to build a system to monitor several (around ~20) voltages over several days. The ~20 voltages need to be measured differentially. Something which could in theory be accomplishes with 3 of ...
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1answer
83 views

ATMEGA8-16PU as a frequency counter with I2C output with frequency range from 0.05 Hz to 7.5 MHz

Original question: I would like to know if there are already existing projects and programming that is available to use ATMEGA8-16PU as a frequency counter with I2C output with frequency range from 0....
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1answer
49 views

Measuring wide range of currents with ADC

I'm designing an amplifier to read currents using a CT from 10 mA to 30A with a STM32 with no FPU. I have the following data: CT turns ratio = 1000:1 Burden resistor = 10 ohms ADC reference = 3.3 V ...
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1answer
44 views

Single Channel ADC with DMA giving garbage results on STM32F7

I'm looking to implement ADC and DMA with HAL on a F767. I want the ADC to be always converting and storing to memory via DMA until it reaches the buffer limit of 320 and then I want to go to a ...
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1answer
55 views

understanding TWI

I'm working on a school project where I have to interface an external ADC with a Digilent Nexys4 DDR board FPGA. The instructions are given in the following picture with a schematic of the simulation ...
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45 views

Single ended to differential driver low-pass filter

I am taking a single-ended source, using a SN75ALS191 driver to convert it to a differential signal. This differential signal will travel over twisted pair cabling several hundred feet, to a single ...
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1answer
57 views

DAC update rate vs ADC update rate?

I am building a system for ultrasonic distance measurement that implements CDMA coding access. Therefore, I am using DAC with 3 outputs for generation of three different signals and an ADC for ...
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25 views

Adding an ADC, what happens to input impedance

quick question. What happens (in general) to my entry impedance when I add an ADC into my circuit? Is this independent of the rest of my circuit? If no, this is my circuit
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61 views

How to synchronize TI high precision ADC and DAC via SPI?

I am working with DAC80504EVM and ADS8920BEVM-PKD from TI. I am trying to design a system which uses TMDSEVM6657EVM processor board to communicate with these converters via SPI. However, I am trying ...
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1answer
37 views

Reading full photocell range with ADC

I am trying to use PDV-P8103 photocell as a sensor for LCD dimming circuit. The application requirements are to have comfortable brightness level from almost total darkness up to direct sunlight. The ...
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1answer
48 views

ADC differential input question

For example I have a 10 bits ADC,which has a reference voltage of 2.5V. In single-ended mode,the input range 0-2.5V according with conversion result 0-2*e10. And what about the differential mode? I ...
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29 views

ATSAMC21 - Change ADC reference voltage

I'm trying to change the ADC reference voltage on an ATSAMC21. However whatever i tried so far it is not working. I am using ATMEL Start to created the clock configuration and ADC configuration. I am ...
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75 views

Do I need a “full differential” ADC? (if sensor voltage input range = 0.8V to 4.3V)

I am not using potentiometer like most video or print online. I am using bike grip/hall throttle, its range is 0.8V to 4.3V. Instead of: [0V = 000 ADC value] [5V = 255 ADC value] I want: [0.8V = ...
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PCB simulation of high speed ADC daughter card connected via FMC connector

A design using high speed ADC is to be carried out involving an FPGA as the master device. To simplify the prototype phase, a daughter board with the ADC shall be designed and connected to the FPGA ...
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1answer
40 views

What is the purpose of having two type of output interfaces on this ADC?

The ADS4126 comes with a Double Data Rate (DDR) LVDS output interface and a I have following questions: What criteria is used to decide which one of the two to use? Can both be used to read the ADC ...
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48 views

AC phase current sensing using Isolated delta-sigma modulator

I am trying to design a isolated AC current sensor. I've chosen the AMC1106 Isolated Delta-Sigma Modulator. (change my mind if you think there is a better solution for 220V AC; 2A Max; 0.25%) The ...
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326 views

Is AD7794 a good alternative to Hx711 for multi-channel ADC?

note: Electronics isn't my main background so I might make silly mistakes. I did read the datasheet but don't understand all the terms despite my effort. Suggestions are welcome. AD7794 (datasheet) ...
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83 views

Do I need to pull up the I2C voltage to the VCC of a ADC?

I am planning to use LTC2451 which is a ADC with I2C interface. The main bus voltage that supplies the LTC2451 & the MCU is 3.7V and the GPIO voltage of the MCU is 1.8V. Is it safe to pull up ...
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61 views

ADC signal conditioning circuit

I have a circuit that is fed into a ADC chip (adc128s022), that I am trying to understand. The sensors are inferred gas sensors. Could you please criticise my analysis. The way I am reading it: ...
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91 views

What is the voltage value measured by an 8-bit ADC chip showing a binary reading of 64? the reference voltage is 3.3V

I followed the explanation in this post. I did 3.3 V/256 = ‭‭0.01289 V . I also did 3.3 V/(256/1.5) = ‭0.01964 . And lastly, I used this formula: I just keep getting the wrong answer! Please could ...
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63 views

Large signal with DC offset matching to ADC with input centered around 0V

I'm new to this forum, so plear bear with me. I have a 0 to 23v signal coming from a transimpedance amplifier that I need to squeeze into -2.5v to 2.5v input for an ADC. The signal is first put into ...
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1answer
47 views

Is it possible to digitize small signal with large noise?

I have a small signal, e.g. ~100 uV in a band of interest of 0.1 - 30.0 Hz This signal is accompnied with a huge noise of 50 Hz ~100V of amplitude. ADC's input range is 1V. Is it possible to ...
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1answer
185 views

Strange noise at peaks of measured sine waves STM32F103

Please look at this picture: I'm using STM32F103, a popular Blue Pill module. What you can see in the picture are three signals, from bottom: green - AC voltage of 14V RMS, measured with step down ...
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Input impedance of load cell CZL635 seems wrong

I'm working with load cell Phidget CZL635 and HX711 ADC in order to make a weight scale. Load cell: https://www.gotronic.fr/pj-461.pdf ADC: https://pdf1.alldatasheet.com/datasheet-pdf/view/1132222/...
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49 views

STM32F4 DSP noise with inbuilt ADC and DAC

I'm trying to perform signal filtering with STM32F407VGT. I've set up the ADC and DAC to work synchronously, triggered by a timer at 42kHz, and using DMA. The idea is to process half of the buffer ...
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1answer
27 views

Analog multiplexer or analog to digital converter to add analog inputs to NodeMCU?

I asked a question yesterday about the best analog multiplexer to use to add a few additional analog inputs to a NodeMCU. Someone recommended using an ADS1115 analog to digital converter. I am using ...
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1answer
26 views

Question about ADC prescaler register in ATMEGA32A

As you see in datasheet of Atmega32A, it says that the bits ADPS of register ADCSRA are controlling the Prescaler of the ADC clock by dividing the frequency of external crystal on some division factor,...
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ADC / DMA only triggers once before setting OVR high STM32F446

I am trying to poll a block of sensors and load the data into an array via the DMA but the ADC polls only the first pin and then stops polling and sets the overrun flag high. I have implemented all ...
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14 views

Measuring analog voltage from multiple differential input causes voltage fluctuation

As shown above i am using a micro controller's differential input to measure the analog voltage. When the the micro controller measures the voltage on the input pins there is a voltage fluctuation ...
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24 views

I have stm32f407vet and one joystick and need to read x and y values through same adc channel

I want to use only one channel adc1 and they have different modes in0,in1,in2,in3,.....I want to read X and Y values from PA0 and PA1 respectively using only adc1 and to store them in different ...
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1answer
47 views

Simple differential amplifier with active load for ADC comparator

I'm wondering, why can't a simple differential amplifier with active load followed by 2 inverters (to boost to VDD and GND logic level signals) be used as a comparator in SAR ADCs? Like this What's ...
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1answer
47 views

ADC conversion rate

I have an ADC which is part of the Zynq-7000 SoC. For details please see the attached datasheet. I need to asses whether this ADC is appropriate for my application (measurement of stator currents in ...

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