Questions tagged [differential]
Differential refers to any kind of signaling where the signal information is carried by two or more paths and both are required to properly reconstruct the signal. For example, USB D+ and D-
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Single Ended DAC to Differential Input Modulator
I'm trying to drive a differential input IQ modulator (LT5571) with a single ended DAC (MCP4912) for modulation of a narrow band signal (~10kHz max).
Because of the nature of the low frequency ...
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31 views
Analog Input Measuring Method [on hold]
I have a question about wiring analog input and measuring method.
It seems to me;
2 and 3 wire current analog input wiring is single ended measuring and is going to an amplifier in module that is ...
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41 views
HFA3096 transistor array breakdown voltage
In the book Learning the Art of Electronics, one of the labs is to build a differential amplifier with a CA3096 transistor array. The author admits that the chip may be difficult to find and gives the ...
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55 views
BJT differential amplifier: What causes common mode voltage gain?
In any normal op amp, if it was ideal it would have a gain such that the output voltage would be
However in reality this is not the case as there is a common mode voltage gain and hence in reality ...
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60 views
PCB HDMI high speed routing suggestions on my layout
I would like to get suggestions from all the high speed PCB layout experts on my PCB design.
I have a board with HDMI transmitter IC whose output is going to HDMI switch IC. The switch IC also has ...
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1answer
28 views
Discrepancy in datasheet for AM26LV31E?
The AM26LV31E datasheet, a differential line driver, states this (on page 4):
and this (on page 10):
At best, this seems ambiguous and, at worst, contradictory. Is the logic of this statement (8.1) ...
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36 views
Tail resistor in differential gain
Why doesn't the tail resistor feature in the denominator for differential gain (whereas it does for common mode gain) in the differential amplifier below? (Fig 5N.28 from Learning the Art of ...
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69 views
Ideal Op Amp Circuit
I have a question about the circuit below. I want to find Vo in terms of Vi. But I don't fully understand the principles about an ideal op amp's output. You will see my questions in bold at the bottom ...
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57 views
Differential amplifier with feedback resistor
In this circuit, if a resistor of 1 M\$\Omega\$ is connected between A and B, what is the effect on the stability of the quiescent point?
The analysis I made led me to believe it would provide ...
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61 views
Differential Amplifier with TLC272 vs TL082
I have an LM2576-adj configured to step down 12V regulated output from a wall wart to around 5V-ish (see schematic). On the 5V output I have a 0.1 ohm sensing resistor (Rsc) to measure the output ...
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38 views
How to connect a MEMS Microphone Breakout - INMP401 to a RN-52 bluetooth module?
I intended to use a INMP401 (MEMS MIC) to capture audio and stream it via bluetooth using an RN-52 bluetooth module (RN-52). The RN-52 has inputs for differential +- signals.
The INMP outputs ...
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2answers
68 views
Using a fully differential amplifier as a differential ADC driver
Regarding my previous question, I decided to use a “fully differential amplifier” to obtain a voltage gain of 10. The source and ADC are also differential. The source is unipolar and its output ...
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2answers
70 views
Series RL current equation
I am trying to derive a inductor current equation for \$i(t)\$ in a series RL circuit when the switch is closed at \$t=0\$, as seen below:
I have posted my attempt so far but I'm having trouble ...
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39 views
Logic Style Level Vs Hardware Level
In the book: Advanced DPA Theory and Practice: Towards the Security Limits of Secure Embedded Circuits 1, it is explained that the countermeasures against Side-channel Cryptanalysis could be ensured ...
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102 views
Ground, common, and Earth ground confusion
I am learning on transmitters and input modules nowadays. But the usage of word 'ground' is confusing me. What does 'ground' mean there (earth or power supply common)?
If it is earth ground, why we ...
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45 views
Series RL Circuit Transient Analysis
I have worked through a question and I am unsure if my answer is correct. It is a series RL circuit with a switch that closes at t=0, supplied by a dc source, which I am trying to derive an expression ...
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2answers
28 views
How can I allow a smaller clearance value for differential pairs in Altium?
I have finished routing a PCB in Altium (v17) and am resolving design rules violations.
In short, everything checks out except differential pairs that are violating the ...
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2answers
141 views
Capacitor Voltage during Transients
I am starting to learn transient analysis series RC which requires our own equations to be derived, but I don't understand how the voltage across the capacitor is given in the equation below from a ...
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1answer
71 views
Does polarity of differential DisplayPort signals matter
I am routing a DisplayPort interface. I know from PCIe that the polarity of the differential pairs does not matter. So if it is helpful during routing I can connect the n to the p pin and vice-versa.
...
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1answer
81 views
How to measure the coil voltage in this circuit? [closed]
I want to measure the coil voltage (coil+ to coil-) of the following circuit with my microcontroller, but I don't know how. Do you have some hints or suggestions for me?
Thanks!
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42 views
Differential bandpass filter Audio application
I am developing an Audio project which is required to output a signal between 10kHz - 40kHz at ±1V.
The sound is produced from an AD9106 chip which is interfaced to the following circuit:
When ...
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34 views
Buffered Voltage Divider VS Differential(Subtractor) Opamp
I'm trying to understand which one of these circuits is the best choice for measuring 400VDC signal using a microcontroller . But at first look circuit number 1 makes more sense since it is giving the ...
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62 views
Does this audio amplifier do differential filtering?
I was looking at this schematic for a two-channel audio power amplifier.
The amp supports a bridged mode by means of an XLR connector and a switch. When the switch is in the XLR position, pin 2 (...
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36 views
Is it possible to very roughly estimate the CMRR degredation of a differential amplifier due to source imbalance given its datasheet
In the datasheets of differential input amplifiers there is a figure of merit called CMRR. This is normally experimentally measured at a particular frequency like 60Hz and presented in the datasheet ...
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57 views
To Fail-Safe or not Fail-Safe on RS485/422 Transceiver
I'm stuck on a PCB design issue.
I'm designing a new PCB (Daughter board) that will plug (via DB15-F to DB15-M) onto another PCB (existing Mother board) and the design intent is to take (from the ...
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1answer
54 views
PCB controlled impedance
Hi) I want to calculate the width of my 100Mb Fast Ethernet MDI diff pairs. I've got some software (TXLINE 2003 Microstrip). I have 4 layers. The second layer is GND, the third is power, top and ...
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2answers
43 views
Comparing differential-ended and isolation amplifier outputs for an “unbalanced” source input
I tried to simulate the effect of common-mode interference on unbalanced sources for three different inputs: single-ended, differential-ended and isolated. Below I inject a 1V common-mode voltage to ...
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1answer
64 views
How to conclude the necessity for unbalanced to balanced signal conversion for this scenario?
This is a bit specific system related question about simultaneous data-acquisition for several transducers. Therefore hope you don’t mind for the long intro and the question. It would be too implicit ...
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1answer
82 views
Contradicting ideas about differential signal route, confining fields vs Increasing impedance
By initial sense I think we must:
keep pair intra-distance as close as possible for field cancellation.
Fill surround of pair with GND plane and have via near to it to confine the fields, prevent ...
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2answers
61 views
Why Im getting shifted phase in the output voltage?
Why im getting shifted phase in the output voltage in this differential amplifier?
and how can I eliminate this shifted phase?
Second question is, I need to make a gain of 50 in the amplifier below, ...
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1answer
88 views
Which load resistance is connected to generator U2?
I have this op amp and one of the questions says
Which load resistance is connected to generator U2?
This is my attempt but I can not confirm if it right.
No it's not homework, it examples I'm ...
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2answers
64 views
RS485 termination
What is the recommended way for termination RS485?
I read about couple of options to do this. If I don't want to do dissipate extra power, can I just put 120 Ohm resistor?
I saw the follow ...
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1answer
132 views
Differential Pair Reference Plane Coupling
I am routing LVDS pair on a flex board. The signal is 264MHz. I used Saturn PCB design to calculate width and spacing between conductors. The targeted impedance for diff pair is 100 ohms, which is ...
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65 views
Why don't I get a signal on the load?
I don't get any signal on the load, what am I missing? Shouldn't it amplify the input signal?
I have 50mA from the current mirror, the Vbe on Q10 and Q11 is around 0.75v
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Trying to view CM and DM components of a signal on a two channel digital scope screen
I want learn how to view the CM and DM components of a signal on a usual two channel scope. The reason for this to be able to verify whether a noise superimposed on a signal is CM orDM.
Regarding my ...
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50 views
Differential Amplifier Exam Problem
I am lost with how to approach part C and D of the question. In fact, I need some intuition with how to tune a differential amplifier.
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1answer
63 views
When does differential signalling become necessary [closed]
Is there an industry rule of thumb or application note etc for when differential signalling becomes necessary for reliable communication?
I'm thinking mainly in terms of distance and signal speed (...
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77 views
LVDS driver signals measurement
This is background: I have a self-made PCB, which is used to connect the camera via the CameraLink interface.
When I connected everything together, it turns out that the camera is signalling me via ...
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2answers
55 views
Differential equation for current driven RC circuit
I need the differential equation for the following circuit for numerical integration purpose.
It is driven by a time dependent current source.
So the question is:
How can I know \$U(t+dt)\$ given \$...
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1answer
93 views
Adding multiple differential signal
As I asked in "Adding multiple analog signal" before, I got that: for adding some signal together, we can only use op-amp, instead of lovely integrated circuit (ough).
But the question arise because ...
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2answers
60 views
Mathematical model for differential signals and relation with reality
i have a question and i hope is not that strange.
i spend some time asking myself how people came out with the mathematical model for differential signals and why is this better in this way?!
to be ...
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2answers
155 views
Differential Opamp Strange Behavior
I have no answer for this strange opamp behavior. The circuit shown is from a typical nonisolated ,Non grid-tie inverter product (imagine H bridge Inverter). which has a common -ve high power circuit ...
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2answers
71 views
LIN to RS485 and back to LIN
I am currently communicating between two microcontrollers using a single pin and the LIN protocol over a short distance of 0.2m. Now I would like to extend the distance up to 5m by differentially ...
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38 views
Differential Clocking resistor and capacitor choices
I am working on generating a 2MHz differential clock signal for a DDS chip. I have been given a PCB with a design that I am unsure can work or what the thought was behind it. If anyone could help with ...
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37 views
Terminating Unidirectional Differential Signal
In a project I'm working on, I'm planning to use the SN75174 to send a signal through about 30m of twisted pair. This signal has a bitrate of around 1Mbps (it's a signal to drive WS2811 LEDs,) and ...
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1answer
174 views
Does LVDS always need 100 ohm differential impedance?
LVDS pairs need 100 ohms differential impedance. However, I am having trouble achieving that in my design.
My design requires that the pairs travel over very thin flexible PCB, about 50mm total ...
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1answer
117 views
RS485 Waveform while Receiving Data
I was testing the RS485 Circuit, below is my circuit and I connect J5 to my PC using another RS485 to USB converter. In PC through Modscan software I was monitoring the polling and response, a twisted ...
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145 views
Virtual Short Concept in an Op-Amp
By virtue of the open-loop gain being infinity for an ideal op-amp, the two input terminals are said to be virtually shorted.
Yet, the virtual short concept is only applied to op-amps in negative ...
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1answer
114 views
How to measure a 100 ohm differential signal on a spectrum analyzer?
I have a pair of 1.5V PCML differential signals coming out of an Altera Cyclone V GX FPGA, terminated on the FPGA in 100 ohms with common mode voltage = 0.65V (also provided on the chip).
I need to ...
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2answers
59 views
Differential signal isolation
In differential signal circuits (specifically, RS-485), there is usually an isolation between the signal processing / generation stage (eg, microprocessor) and the line driver chip (something like a ...
