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Questions tagged [mixed-signal]

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2
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0answers
26 views

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 ...
1
vote
1answer
79 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 ...
0
votes
1answer
55 views

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 ...
0
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0answers
31 views

Difference between quantity and signal in VHDL-AMS

What is the most important difference between quantity and signal in VHDL-AMS? Can a signal takes a type of "real"?
0
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1answer
40 views

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/...
0
votes
1answer
124 views

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 ...
0
votes
2answers
47 views

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 ...
4
votes
1answer
780 views

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....
-1
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3answers
178 views

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 ...
0
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0answers
16 views

Noise from one channel to the other when using FFT and PWelch

We have built in our lab a mix box for brain recording analysis. However we have a specific problem, When we give a sine input (for instanse), on one channel, and nothing for the other channels, we ...
0
votes
0answers
41 views

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 ...
0
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0answers
65 views

Digital spikes on analog ground

I am working on a mixed signal box used for digital-analog conversion, and have a weird problem. I encounter digital spikes on analog ground, even when the box is turned off. The spikes are around 1....
0
votes
1answer
32 views

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 ...
0
votes
3answers
216 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 ...
1
vote
1answer
287 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 ...
0
votes
1answer
54 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 ...
0
votes
1answer
62 views

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 ...
6
votes
1answer
243 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 ...
3
votes
1answer
77 views

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 ...
1
vote
3answers
250 views

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 ...
0
votes
1answer
172 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 ...
-3
votes
1answer
729 views

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 ...
2
votes
3answers
298 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 ...
2
votes
2answers
203 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 ...
2
votes
2answers
182 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 ...
4
votes
1answer
1k views

Back to back Schottky diodes between ground connections

In a mixed-signal IC, you most likely will have two ground planes, analog ground and digital ground. This seems fair enough and easily understandable but my real question is: Why would you need to ...
3
votes
5answers
255 views

Decoupling capacitors values in mixed-signal circuit

I know theory about decoupling capacitors (ESR, ESl, parallel capcitors etc.) I have read Electromagnetic Compatibility Engineering, H.W. Ott. My question is about practical design. How shall i ...
1
vote
1answer
269 views

Mixing two square waves and isolating intermodulation component

I currently have two square wave signals at f1 and f2 (f1 >> f2) that serve as reference signals to two separate lock-in amplifiers that are subsequently connected in cascade to extract the component ...
0
votes
0answers
118 views

Oscilator grounding on mixed signal PCB

I have a DAC using MCLK from an oscillator. All literature that I read suggest to ground it to analog ground. However the output of my DAC (analog output) is also close by and I am afraid that my (...
2
votes
2answers
2k views

PCB ground plane separation between power and analog sections of board

In this design I have separated the ground plane of the sensing/controlling circuit from the high-power 3-4 amp circuit. This is a current controller. The ground planes are joined at the sensing ...
10
votes
1answer
436 views

Design essentials when working with 12bit ADCs

I'm currently designing a board that is attaching a 12bit ADC (MCP3208) to a Raspberry Pi (besides a few other low speed I/O related stuff). It will mostly be attached to analog sensors (temp sensors, ...
0
votes
1answer
162 views

Does placing digital circuitry between the regulators and analog circuitry cause grounding problems?

I'm designing a mixed-signal PCB and have been using this Maxim guide to help me with layout. The guide has instructed me to avoid making cuts to the PCB and instead think about ground return paths. ...
4
votes
0answers
141 views

Help with deciding my layout for EMC tests and SI. Different alternatives

I am thinking of what way would be the best to layout my system in order for it to have the best SI and pass EMC tests. My system consists of two PCBs joint by a flat flex cable (up to 7cm) and these ...
1
vote
1answer
175 views

Mixed Signal Grounding: Which approach will yield better isolation and analog performance?

I'm laying out a mixed signal PCB and I'm trying to decide between (1) separating the ground planes for the digital and analog/digital circuits completely [shown in top figure] or (2) keeping the two ...
2
votes
3answers
2k views

DIY mixer - use diodes to prevent input potentiometers influencing each other

I've builded a simple amplifier (just stereo audio in, two speaker outs) and I'm building a mixer for it. There are some audio inputs, which goes through stereo potentiometers (volume for each input)...
0
votes
2answers
374 views

VHDL-AMS simple code but std_logic_vector to quantity issue

I am working on a Mixed signal model where the symbol looks like the following, The signal to the left is count_val which is std_logic_vector(7 downto 0) and p,m are the terminals which have ...
0
votes
1answer
178 views

What is the best method to determine bypass capacitors for each chip in Mixed-Signal Systems? [closed]

In datasheets of chips, usually they have reference designs and to those designs bypass capacitors are predetermined. But, when I examine some high level designs of those chips I see different bypass ...
5
votes
1answer
217 views

Help to translate jitter design constraint in a frequency synthesizer design with 4046 and 4017 ICs

I'm trying to design a frequency synthesizer with the old-school 4046 and 4017 ICs, with a scaling factor N = 1,5,7,10. The input signal is a square wave with adjustable frequency from 1 kHz to 10 ...
8
votes
1answer
1k views

Proper way of connecting logic GND / power GND on MOSFET driver

I am tring to build half bridge using IR21844 mosfet driver, i have read datasheet and design tips and some of the topics in this forum. The one thing i still cannot get is the separate GND pins ...
0
votes
1answer
193 views

Separating ground planes with different potentials?

Im currently building a signal generator and have a problem with placing multiple different ground planes which have different voltages. The system is powered off of USB, so all my digital logic ...
0
votes
1answer
403 views

Input/output for buck-boost converter controller implemented with FPGA

I am trying to implement a voltage controller for a buck-boost converter using FPGA. The control method I'm trying to use is in this paper: www.engr.iupui.edu/~aizadian/index_files/Papers/C-28.pdf ...
10
votes
1answer
1k views

PCB microcontroller layout in a mixed-signal system

This is a direct continuation of this question. So here's my layout, what do you think about the microcontroller side? UPDATE April 2019: I built the board in spring/summer 2016, but never got around ...
11
votes
3answers
2k views

Details on PCB layout for microcontroller

Update: the follow-up question shows my take on the resulting PCB layout. I'm laying out my first board with a uC (I've got a reasonable amount of experience in using and programming embedded systems,...
2
votes
1answer
274 views

PCB plane cuts for audio paths in mixed-signal device

I am working with the TLV320AIC3204 32-bit audio codec. The codec has three inputs and two outputs. While I was designing my own test PCB, I noticed on TI's evaluation board (on page 33) that they ...