Questions tagged [mixed-signal]

A circuit which contains both analog and digital signals.

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Allowed amount of input wreal data type at verilog-ams

I'm a newbie at using Verilog-ams and also I want to write a module for flash ADC for a specific application. I need to confine my voltages reference so I wrote this Verilog-ams code for testing input ...
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Number of data points needed for INL DNL estimation

In this article where ADC of pico pi is characterized, I found a part that I have never encountered in my study of mixed signals design: I don't understand how we number of data points needed is ...
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Ground Pours or Thieving for Filling Unused Space on PCB Signal Layers

Often at the end of a PCB design there is unused space on the signal layers. It is important to fill this space because of: The electroplating process (valid only for TOP and BOTTOM) The even ...
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FM transmitter won’t work. I need help with more gain, and current at the output

I am trying to make an FM transmitter circuit using cascaded transistors. My two input signals are from a microphone and from an 80 MHz crystal. I’ve calculated a gain of 22 from the first stage and ...
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Mixed signal PCB components placement

I'm designing a PCB that contains digital and analog parts. I'm thinking of placing the digital parts closest to the source and analog parts farther from the source and after the digital parts. The ...
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When does a PCB require a chassis ground connection?

Do all PCBs require a chassis ground connection point? I am designing a circuit board which will be used in many different types of assemblies. It is a small mixed-signal, low-voltage (24 VDC power, ...
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Is there an implementation of mixed analog (SPICE) and digital (HDL) simulations?

I wonder how it could be possible to do mixed circuits simulations. In my imagination, there is a circuit netlist which contains analog and digital components. Since XSPICE (and I think ngspice) has ...
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Balun or fully differential amplifier (or both) as a differential ADC driver at MHz frequency?

AD9655 ADC The signal is AC coupled so I don't "need" the DC coupling availability of FDAs. I don't need another gain stage either, so the FDA would be in a 0dB gain configuration. My main ...
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Do differential ADC's really reject 100% of common mode noise?

Say you have differential signals that are perfectly phase and amplitude balanced, but obviously 180 degrees out of phase V+= Asin(2pif*t)+ Vcommon_mode_noise V-= -Asin(2pif*t)+ Vcommon_mode_noise The ...
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What is your preferred circuit simulator for high-performance analog/mixed signal? [closed]

I'm starting a new job and I've been using NI multisim in school, but I am trying to decide if I should learn a new spice simulator. Not sure how to compare Multisim to something like LTspice which my ...
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PWM to voltage for servo control

I have Chinese "no name" servo drives with following inputs for speed and torque mode: I have got a MESA 6I25 card and want to use LinuxCNC as a controller. I want to design a BOB (break ...
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Differential Pair Mode Conversion [closed]

What is the purpose of using these mode conversions? SCD Input: Differential Output: Common SDC Input: Common Output: Differential
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How stable should this power supply be?

I am designing a system with a variety of sub-systems. The voltage input is 24 VDC from a power supply (wall outlet). For now, I try to compose it from mostly 5 V sub-systems: SBC relays comms ...
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How deos this clock generator work?

This circuit shows a clock generator, where a capacitor is charged to a certain voltage for half a period (phi opening switches S1 and S2). The same voltage but with negative polarity will be shown to ...
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How is a Multi-Bit Delta-Sigma Modulator used to toggle the modulus for a Fractional-N PLL?

I'm doing some reading about fractional-N PLL design, and a large part of this reading has been about Delta-Sigma Modulators, a method of producing a binary string to toggle the frequency divider ...
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Mixing Symfonisk high/low-mid output channels

So i've been messing with this issue for a couple of months and it's just that my electronics knowledge isn't reaching far enough. I have a Symfonisk speaker by Ikea, which outputs a low and high/mid ...
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A novice question about mixed signal IC design

As far as understand, a digital IC like a DSP can be design by RTL methods and by using languages like Verilog and VHDL. And if I'm not wrong, we cannot yet program pure analog chips by using a ...
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"analog" /"mixed-signal" Terminology confusion about the definition of some components and systems

I sometimes encounter that ADCs, DACs, PLLs, DC-DC converters and oscillators are called mixed-signal but sometimes they are grouped under the category of analog. Is there a consensus about that?
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Pull-ups in a mixed voltage environment

I'm working on a circuit where a 12 VDC line is switched from a USB-powered microcontroller (U1, running at 3.3 V, specs below). I want to ensure that the switch ...
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Multiple PCB system vs mixed-signal PCB

I'm designing a high-frequency (\$6\,\text{GHz}\$) mixed-signal PCB. The design contains some noise-sensitive RF analog circuitry (mixer, LNA, 12-bit ADC, etc.) as well as some noisy digital circuitry ...
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What is the role of discrete resistors and capacitors in a motherboard? [closed]

I know the basic function of resistors and capacitors. I know filters, oscillators, one-shot, differentiator/integrator, ADC/DAC, power supplies, etc. But in a motherboard why are there so many ...
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What's the best ground topology for this mixed signal board?

I'm designing a 4 layer mixed signal PCB with sensitive analog circuits and RF-digital circuits. The board have many mechanical constraints so the places of the analog and digital circuits are fixed. ...
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Ways to multiplex the output of a DAC?

Part searching in microcontrollers, it looks like most small ones have at most one DAC. What is the just way or ways to output multiple slow signals from a microcontroller with at most a single DAC? ...
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How Can the Quantization Noise of an ADC be Measured using the Digital Output?

The ADC quantization noise is the error signal generated by rounding the sampled analog values of signal. Suppose that we have the digital output of an ADC, how can we measure the quantization noise, ...
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Signal fidelity from fiber optic crosstalk

I was watching a video about tapping fiber optic cables when it brought up some points from an early US govt document describing security concerns about fiber optic cables. The relevant part: ...
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467 views

Parasitic insensitive switched capacitor circuit

I'm trying to simulate the parasitic insensitive switched capacitor circuit shown here: I am using cadence virtuoso. My input is a sine wave of 1 V amplitude, 0 DC and 1 kHz frequency. I am using ...
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2 answers
62 views

MOSFET Capacitance clarification

2 part question here. Are there ways to directly test the input and output capacitance of a MOSFET, Ciss and Coss? On that note, due to internal inductance and capacitance, is it possible for a ...
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Where to place RF shield

I'd like to put a pump drive circuit similar to the one shown below on the same PCB that has two I2C devices, a GPS module, seven analog signals, an ESP32 MCU transmitting WiFi via a trace antenna, ...
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Reducing the offset voltage of a source follower

I am currently trying to reduce the offset voltage of the circuit attached below to less than +/- 2mV over a 1V to 4V input range. I have a few constraints for this task: I can use ...
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1 vote
1 answer
152 views

5VDC and 10VAC on the same PCB - what happens on 10V goes to 5V ground?

Me and a colleague (we are both EE-trainees) had a chat the other day about mixed voltages on the same PCB. She pointed out an interesting question that I was not able to solve. Imaging having a PCB ...
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Can you make an electric gamma ray emmiter by adding up frequencies with freq. mixers up until you reach gamma ray herz quantities?

I just thought this up. Theoretically if you can add freq numbers you can get to large quantities like in a calculator, only this time mixing electric frequencies using amounts of circuitry right? Is ...
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Mixed digital/analog rails and level-shifting components best practices

I am designing a board with a ±2.5V analog domain and a 3.3V digital domain where space is at a premium. Digital and analog grounds only connect at a single point near the supplies. As such I am using/...
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1 vote
1 answer
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Crossing ground planes with low current low frequency signals

I have a board which has two ground planes, analog and digital, that on this board are completely separate. The grounds connect on another board, which is connected via a flat cable. All signals on ...
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2 answers
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Connecting mixed-speed multiple serial devices to two microcontrollers

I'm trying to figure out the best way to integrate all devices flawlessly on the 8051 based microcontrollers. If each device was the same low speed, then I could multiplex each and every one of them ...
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5 votes
1 answer
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How does a Delta-Sigma DAC work?

I have looked at how the Sigma-Delta ADC works and I understand it. However, it seems to me that there is not a lot of literature about the Sigma-Delta DAC. I want to build a model of it in Simulink....
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How to store the difference of 2 voltages on capacitor?

Suppose we have two voltages V1 and V2 how can we store the voltage difference (V1-V2) on a given capacitor? I tried charging the top plate of the capacitor to V1 ...
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lm13700 as Diode laser voltage to current converter

I generated two Signals, one using dac7611 (ramped signal with fre = 0.04hz ) and the other one, using AD9833 DDS (sin wave with fre = 32 KHz) then generated signals added using ad620an. Is this ...
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Mixed-Signal modular system grounding scheme

I'm attempting to create a sensitive, precise mixed signal system (more than 24bit) compose of a backplane and stacked modules on 2.54mm headers.It is multi-channel and channel's modules are well ...
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3 answers
1k views

Superimpose a High Frequency AC Small Signal on a DC Power Signal

I am facing a challenging problem with a circuit that I am currently working on, I would like others input and thoughts. I have a DC power signal that I am injecting a AC small signal this mixed ...
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1 vote
1 answer
467 views

How to create a mixed signal pcb

I want to create a board that has both high speed digital components (specifically the SAM3X8E - from arduino DUE) and an analog audio circuit. The analog parts were originally a shield to the ...
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1 answer
212 views

Multicard System Grounding

I am building a system with multiple PCB cards. The whole system has a Chassis Ground; connected to a main Power Supply reference. All cards will be powered in reference to Chassis Ground. Each ...
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How to split isolated an audio trigger signal for processing by an ADC

I have a problem trying to split a drum trigger signal so that I can process it via an ATXMEGA64A3 microcontroller. The goal is to have the signal going from the trigger to both the existing sound ...
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7 votes
1 answer
329 views

Review of my first ever PCB design for a watering control robot.

I'm building a small watering control for one of my large indoor plants. This is my first real electronics project outside of school. Although I studied EE at university and did my basic component and ...
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2 votes
1 answer
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Understanding mixed-signal PCBs, in most simple sense

I understand that mixed-signal is a circuit that obviously has both analog and digital circuits. I am trying to understand what really would be classified as mixed-signal. If you had a PCB with some ...
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Where do I put digital ground in a dual-rail mixed signal circuit?

I'm working on a project for school (a discrete dual-slope ADC) that will combine digital and analog circuitry and operate off of a ±15V dual-rail supply. The "analog ground" will be at 0V, as ...
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283 views

LOW and HIGH definition for Enable pin of 4051?

Suppose we have connected an X volt (X=10) as the supply of a 4051 MUX (which is active LOW), can we disable the device by applying a B volte (assume B is 5 volt). In other words, how high is HIGH ...
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1 answer
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Analog current input to microcontroller ADC [closed]

My project requirement is to make an analog current input to ADC of microcontroller. Analog input current has 4-20mA specification. Since I don't have particular industrial sensor with 4-20mA ...
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1 vote
3 answers
369 views

How to live with noise and ground loops in a system with Electronics, Power Electronics, Electrical Machines, Three-phase power and several boards?

I ask for help with a experimental assembly I am developing in the university, which is a small size power generation plant. The system consists of a DC machine, a induction machine, several current ...
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2 votes
2 answers
308 views

Where should a switching regulator be placed in relation to analog and digital circuitry?

General Layout: I've partitioned a mixed-signal board as follows: The dashed blue line indicates the analog/digital divide, but it is NOT a ground cut. This layout is intended to avoid analog and ...
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2 votes
2 answers
399 views

The right way to mix digital signals

I have a dozen of sources of digital signal, 16-bit signed words. I have implemented very simple mixer where all sample values are summed, and then shifted right to prevent overload. Unfortunately ...
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