Questions tagged [random]

Use this tag when referring to systems that are random i.e are driven by stochastic processes.

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Effective resistance from a random resistance network

I am trying to calculate the equivalent resistance from a random resistance network formed by carbon nanotubes (CNTs.) I have a MATLAB program where the CNTs are randomly distributed inside a volume. ...
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5 votes
3 answers
331 views

Simple low pass digital filter implementation for non-uniform sampling?

I have a system sampling an analog input and I want to filter that value using a simple, first order filter. EG something of the form: Yn = A*Xn + B*Yn-1 However I have no control over the ...
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Randomize PCB trace generation with Altium Designer

We are trying to create a tamper mesh as a flex PCB. This tamper mesh will consist of around 10 signal traces in order to detect a tamper. One crucial point is that this tamper mesh should be ...
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Random latch period of 555

I've designed a dice circuit, simulated it in Proteus (which worked) and got the PCBs manufactured. A problem I'm facing on the real thing is that if the button is pressed normally (e.g. for as long ...
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qustions about strange behavior 74194

I would like to use a shift register to control source-select in a pre-amplfier. After watching this very nice video on https://www.youtube.com/watch?v=Y4djl3oYqDQ, I made the same setup on my bread ...
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ngspice simulation : random signal source

I'm new at the ngspice simulator and I don't understand this line of a Netlist that I found Vn 1 n1 dc 0V ac 1mV trrandom(1 5us 0s 125m 0m) if the random signal ...
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1 answer
70 views

Time Auto-correlation function for a polar reutrn-to-zero waveform

I used matlab to calculate the time Auto-correlation function for a polar return-to-zero waveform to make sure that it has an ergodic property . I implemented the following formula as a function in ...
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8 votes
2 answers
882 views

How to generate different noise in LTspice from run to run

I'm trying to simulate noise in my circuit, and ideally want to get a histogram of a certain parameter affected by that noise over many runs. However, when I use the white() command in LTspice, or ...
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-1 votes
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Generating unique values for multiple cyclic random variables

In the following code, I have 2 cyclic random variables in a class. One (an enumerated type) takes 3 possible values, and the other takes 288 possibles values (due to a constraint). So, I expect to ...
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2 votes
1 answer
62 views

Transaction randomization succeeds, yet values do not meet constraints

In the following code, I attempt to randomize the transaction which contains a dynamic array 'PhyRB', with the constraint that each element in the array is less than 'ResBlks' value, please note that ...
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1 vote
1 answer
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Failed to randomize dynamic array using foreach in constraint

In the following code, I force a random variable 'ResBlks' with a value (setting its rand_mode to 0), then attempt to randomize the transaction: ...
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1 answer
34 views

Does the probability distribution of cosine transformation of uniformly distributed R.V. depend on phase shift of the cosine function?

Suppose, x is uniformly distributed over [0,2π], and y = cos(x + ∆), will the probability distribution function of y depend on ∆? Is my solution to find out the Probability Distribution function of Y,...
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2 answers
80 views

The mean value of phase noise as a stochastic process

What is the mean value of phase noise as a stochastic process? Where can I get a theoretical analysis of this topic?
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2 votes
3 answers
358 views

The distribution of phase angle between identical zero mean Gaussian random signals?

I am trying to solve the 2013 paper set by ISRO for electrical engineers. I was hoping to get some clues on how to approach this problem - No 22. random signals which have gaussian distributions will ...
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1 answer
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Random Noise Voltage

I have a signal I am interested in obtaining power from. The best way to describe the signal is that it is random. In the graph, the voltage fluctuates from negative to positive with an RMS of 0.5 ...
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2 answers
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AT90CAN128 Random Malfunctions

I've got the following Situation. An AT90CAN128 connected to a LCD,multiple Buttons, Sensors,LED's and engines. Shown on the LCD are the Sensor Values and a Menu you can go through with a rotary ...
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1 vote
1 answer
130 views

Why is it that true random number generators are not in every computer? [closed]

I understand that one of the fundamental pillars of the programmable computer, is that we should implement features with software rather than hardware, anytime it is possible & more efficient (or ...
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1 answer
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Stochastic Processes wtih respect to the electric load demand [closed]

I am required to look at the statistics (stationarity, mean, standard deviation etc) of the electric load profile. I decided to use the load data for the IEEE reliability test system as it has all ...
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2 votes
2 answers
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Random Error Waiting Time

Suppose that you have a design that has had an error after running 14, 18, and 20 hours. You're not exactly sure what is causing the error, but you make a change to the design that MIGHT fix it. ...
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2 votes
2 answers
429 views

Old-school pseudorandom pulse generator (requesting assistance with hardware design)

I would like to design an old-school pseudorandom pulse generator to trigger various types of events (hardware suggestions only please - no programmable ICs). The events that I want to control need to ...
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2 votes
2 answers
115 views

how do I make a solenoid operate after a random number of switch presses

New to the forum because I am stumped. Im building what I am calling the "water table" for my kids. It has a series of spigots, and channels that funnel into a kiddie pool. Then I got creative and ...
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2 votes
1 answer
87 views

Avalanche Breakdown Noise as digital input

I am trying to develop a true random number generator using reverse biased transistors avalance breakdown noise as a input for pic microcontroller. How can i turn the noise in to a digital input ? Is ...
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2 votes
2 answers
775 views

True Random Number Generator by using avalanche breakdown

I am trying to build a TRNG using avalanche breakdown for randomness. I am developing a circuit as looks like this.(https://web.jfet.org/images/rng-circuit.gif) Before I complete the circuit i ...
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  • 57
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2 answers
164 views

random current on/off IC available?

I am still very new to electronics, but have been using Arduino to build stuff with. But I require a component for a project that does not contain any Arduino because of space. So I am looking to ...
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-1 votes
1 answer
243 views

Synchronize random edge to clock edge

I have a steady clock signal and another signal with random binary pulses. Is there a simple circuit that can detect the rising edge of the random pulses and generate a pulse that is synchronized to ...
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4 votes
1 answer
668 views

Is the avalanche effect in Zener diodes a quantum mechanical process?

Firstly I would like to emphasise the word avalanche as it's fundamental to my question. I'm not concerned with shot noise, thermal noise or trash music. There is a video that explains the avalanche ...
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Random timer windows on a DC circuit

Are there any components/devices out there (available via RadioShack, or some other vendor) that behave as follows (or similarly): When a signal/voltage is detected, a random (and preferably ...
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adjustable time delay, random output

I am looking to build a circuit that would control an output relay. This would be done in 12V and the sequence will be initiated by a manual switch. I will need an adjustable time delay (possibly ...
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-2 votes
1 answer
250 views

building a random timer circuit that will delay from 0 to 3 sec after trigger input relay output

need some help to build a random timer circuit that will delay from 0 to 3 sec after trigger input relay output Have looked at a number of 555 circuits but no monostable or astable ic seems capable
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1 answer
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Second moments (i.e E[X^2]) for this WSS random process

I've attempted the question, please see attached image of my working out and solution to the question. My main question is how to go from the last line of my working out to “2Rx(0) - 2Rx(t) in the ...
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1 answer
1k views

how to set seed in LTspice simulation

I am using LTspice to simulate voltage measurements from a circuit. I noticed, with exactly the same circuit components, each time I obtain different results. I assume it is due to thermal noise. (is ...
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10 votes
1 answer
2k views

Are reverse biased transistors stable?

The usual circuit (found widely across the internet) for a true random number generator's (TRNG) entropy source is a reverse biased transistor like so: Q1 is typically a 2N3904 as it has been found ...
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3 votes
1 answer
348 views

What is the purpose of masking the LFSR value in STM32's noise generation?

I read on section 14.3.8 of the STM32F4 reference manual that you can mask the LFSR output value partially or totally. At first I thought that it was used to change the pseudo random pattern (...
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4 votes
3 answers
16k views

A question on zero crossing versus random-fire SSRs

Figure 1. I have the above mechanism, where I control a single-phase fan motor's switch. I mean instead of a mechanical switch, an AC/DC SSR is switching ON or OFF from a remote place by a constant ...
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0 votes
1 answer
198 views

Properties of Power Spectrum Density

In the power spectrum of a random process, it's said if the PSD has a delta at the origin then it has a DC value, So is that value always one as it's a delta also how can i calculate the DC and AC ...
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1 vote
1 answer
100 views

Circuit that randomizes shut off time to LED's from 1 - 3 seconds when switch is thrown

I have been asked to create a circuit that drives a set of LED's that when switched off uses a random timer from ~1 - 3 seconds before the lights go off. This will be used in a light signal box for a ...
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0 votes
2 answers
507 views

Strange behavior of USART in PIC16LF18313

I am using this 8-bit, 8-pin mcu for asynchronous EUSART. Sometimes when I power it up, it gives me correct characters (e.g. I send 'w', it returns 'w'), but sometimes when I power it up, it returns ...
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-1 votes
2 answers
252 views

Need explanation of how this circuit works

simulate this circuit – Schematic created using CircuitLab I've been making this decision maker at my electronics class which lights up either one of the leds when the switch is closed at ...
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0 votes
2 answers
476 views

A confusion about error components in a data acquisition system

My question is related to my previous question:Accuracy of a data acquisition hardware In a data acquisition system absolute accuracy is defined as measure of all error sources as following: Abs. ...
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0 votes
1 answer
687 views

Find the power at the output of a random input + noise?

Problems on Linear Systems with Random Inputs In this problem I don't know how to start. the answer might be long. so it would be really helpful if you help me with the concept and the idea how to ...
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2 votes
1 answer
2k views

JK flip flop random start outputs

I am working on a project for college and I have to implement a sort of alarm using only MUX's and JK flip flops and a bread board. The problem I encountered is that whenever I power the whole circuit ...
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3 votes
2 answers
14k views

$random in Verilog doesn't seem to be working

In Verilog, $random generates different random inputs but this doesn't seem to be working when I try. Each time I use $random ...
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  • 101
0 votes
1 answer
590 views

I'm looking to create a simple circuit that will have 8 randomized "pulsing/fading" LED's

I am looking to make a simple (cheap, small spaced) circuit that will light 8 LEDs in a random order AND have a pulsing/fading in and out effect. I was originally going to program a randomized effect, ...
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0 votes
1 answer
95 views

Prove a theorem about an upper bound for entropy of a random vector

There is a theorem that: if Z is any zero-mean, complex random vector with covariance \$E[ZZ^H]=R_z\$, then \$H(Z)\leq \log|{\pi eR_z}|\$, with equality holding if and only if Z has a circularly ...
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  • 446
0 votes
1 answer
3k views

Simple circuit to fade in / fade out LEDs randomly

I have a group of 8 blue LEDs (Vf 3.2V @ 20 mA) currently powered up in parallel by a resistors (one for LED) and a 4.5V power source (3xAA batteries). I've been playing with fade in/out effects and ...
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  • 319
0 votes
2 answers
993 views

Random timed output circuit [closed]

I am in need of some help with a project. I am trying to build a circuit that will turn on three LEDs randomly on a 1-5second cycle. I have the basic when it comes to electronics, but get stuck on ...
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3 votes
2 answers
1k views

Unexpected patterns in Verilog $random

I have a Verilog test bench that monitors a 64-bit bus and should randomly schedule a flipped bit (packet corruption) to happen every 1-in-X packets. I was surprised to find it not injecting any ...
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