Understanding Noise (electronics) and Its Impact

Noise in electronics is the unwanted variation in a signal, and it's a common problem in many devices. It can be caused by thermal noise, which is generated by the random motion of particles in a component.

Thermal noise is a major contributor to noise in electronics, and it's directly proportional to the temperature of the component. This means that as the temperature increases, so does the noise.

Noise can have a significant impact on the performance of electronic devices, causing errors and distortions in the signal. For example, in a radio receiver, noise can make it difficult to tune into a station clearly.

In fact, thermal noise is a major limiting factor in the sensitivity of radio receivers, and it's a major challenge for engineers to design systems that can overcome it.

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Noise is a natural part of how electronics work, coming from the movement of tiny particles called electrons inside wires and components. Even the heat in a circuit can create noise!

Thermal noise, also known as Johnson or Johnson Nyquist noise, arises from the thermal agitation of charge carriers, typically electrons, in a conductor. As temperature increases, so does the level of noise.

This type of noise is a major form of noise experienced in low noise amplifiers and can be reduced by operating amplifiers at very low temperatures.

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Avalanche noise is a type of noise that occurs in semiconductor junctions when a high voltage gradient causes carriers to develop enough energy to dislodge additional carriers through physical impact.

This process is very noisy, and the current generated is not even, as it's determined by high energy electrons hitting the crystal lattice to create more hole electron pairs.

Avalanche noise can be used in a positive way to create a noise generator, a device that's useful in RF and other measurements.

In fact, this type of noise is so intense that it's almost impossible to eliminate completely.

Thermal noise is a major form of noise that arises from the thermal agitation of charge carriers, typically electrons, in a conductor.

As the temperature increases, so does the level of thermal noise. This is why high-performance amplifiers used for radio astronomy are often operated at very low temperatures.

Thermal noise is unavoidable and is generated by the random thermal motion of charge carriers, regardless of any applied voltage.

It's approximately white, meaning its power spectral density is nearly equal throughout the frequency spectrum.

The amplitude of the signal has a very nearly Gaussian probability density function.

This type of noise is often modelled as an additive white Gaussian noise (AWGN) channel in communication systems affected by thermal noise.

The level of thermal noise can be measured using figures like noise temperature.

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Dither is a type of noise that can be found in various fields, including physics and telecommunications. It's a class of noise that can be defined and measured using specific engineering terms.

Dither is often used in image processing to reduce the visibility of noise. In fact, denoise methods specifically designed for 2D images can be effective in removing dither and other types of noise from digital photographs.

In terms of ratios, dither can be compared to other types of noise using specific metrics. However, the exact ratios used to measure dither can vary depending on the context and application.

Here are some common denoise methods used to remove dither and other types of noise from images:

General denoise methods2D (Image) denoise methods

Phase noise is a type of RF noise that appears as phase jitter or perturbations on a signal. These perturbations manifest themselves as sidebands that spread out either side of the signal or carrier.

Phase noise can affect a signal or system in various ways, including degrading the bit error rate in systems that use phase modulation to carry digital information.

Phase noise can disrupt the phase changes that indicate the state of the data to be transmitted, making it harder to accurately receive and process the information.

Any phase noise on timing signals can also affect the operation of data systems, introducing data errors.

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Thermal noise is unavoidable at non-zero temperature, a fundamental fact that even the most precise devices can't escape.

Quantisation error, on the other hand, can be mitigated with the intentional introduction of additional noise, called dither, which can reduce overall noise in the bandwidth of interest.

Different devices and processes generate different types of noise, such as shot noise, which requires a steep potential barrier to occur.

Thermal noise is unavoidable at non-zero temperatures, making it a fundamental source of noise in many devices.

Thermal noise is generated by the random motion of particles, such as electrons, in a device. This type of noise is inherent to any electronic device that operates at a non-zero temperature.

Other sources of noise, like shot noise, are dependent on device type and manufacturing quality. Shot noise is particularly prevalent in devices with steep potential barriers.

In some cases, intentional introduction of additional noise, called dither, can actually reduce overall noise in the bandwidth of interest. This technique is especially useful for retrieving signals below the nominal detection threshold of an instrument.

Shot noise is a type of noise that arises from the time-dependent fluctuations in electrical current. This is caused by the discrete nature of electron charges.

Shot noise is particularly noticeable in semiconductor devices, such as tunnel junctions, Schottky barrier diodes and p-n junctions.

The root-mean-square value of the shot noise current is given by the Schottky formula: I²qΔB, where I is the DC current, q is the charge of an electron, and ΔB is the bandwidth in hertz.

Vacuum tubes exhibit shot noise because the electrons randomly leave the cathode and arrive at the anode. This randomness tends to smooth out the arrival times, reducing the noise effect.

Pentodes and screen-grid tetrodes exhibit more noise than triodes because the cathode current splits randomly between the screen grid and the anode.

Conductors and resistors typically do not exhibit shot noise because the electrons thermalize and move diffusively within the material.

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Noise can have many effects on a system, including masking out a signal or causing data errors that increase the bit error rate.

Amplitude noise, in particular, can cause variations in amplitude that make it harder to distinguish a signal from the noise. This can be a big problem, especially in systems where a clear signal is crucial.

For the best performance, it's essential to keep noise to a minimum, but in some cases, there may be an optimum balance between data errors and signal quality against the cost involved.

Flicker noise is a signal or process with a frequency spectrum that falls off steadily into the higher frequencies, with a pink spectrum.

It occurs in almost all electronic devices and has a variety of causes, each related to the direct current flow.

Flicker noise has a frequency spectrum that falls off steadily into the higher frequencies.

It's a type of noise that results from a variety of effects in electronic devices.

Burst noise is a form of electrical or RF noise that produces sudden, step-like transitions between voltage or current levels, often referred to as popcorn noise due to the popping sounds it creates in audio circuits.

These transitions can be as high as several hundred microvolts and last for several milliseconds to seconds.

Burst noise can be a major issue in audio circuits, where it can cause distortion and degrade sound quality.

It's not just audio circuits that are affected - burst noise can also impact the performance of radio receivers, data communications links, and camera technology.

In fact, noise in a radio receiver can limit its sensitivity, while phase noise in a data communications link can introduce data errors.

Burst noise is often caused by the operation of semiconductors, which can give rise to sudden impulses that produce the characteristic popping sounds.

As an experienced electronics engineer, Ian Poole notes that electrical or RF noise is a key attribute for any system, and can govern its overall performance.

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Noise can be a major issue in your system, and it's essential to understand the potential causes. High voltage startup and switching can lead to a significant amount of voltage being discharged to ground, resulting in noise in the system.

This can be particularly problematic if you're using units with high voltage potentials, such as switchgear, drives, or motors. Adding Metal Oxide Varistors (MOVs) to your voltage lines can help prevent noise-related failures.

Shielded cables losing insulation can also cause noise in the system. This is because the insulation barrier in the cable shielding helps keep voltage flowing on the correct path, and if it's compromised or broken, voltage is exposed to more variance from interfering signals.

Temperature can also contribute to noise in the system. As temperatures increase, free electrons move more rapidly, leading to more variations in voltage and potentially causing a thermal runoff that can result in a catastrophic failure.

Poor wiring is another common cause of noise-related issues. Signal and communication cables are particularly sensitive to electrical noise, and bundling a power cable with signal cables can increase the risk of noise-related problems.

Here are some potential causes of noise in your system:

Noise levels in electronic systems are typically measured in watts or dBm, which gives us a sense of the electrical power involved.

The root mean square (RMS) voltage, or the noise standard deviation, is also a common measurement unit, and it's identical to the RMS voltage.

Noise may also be characterized by its probability distribution and noise spectral density, which is measured in watts per hertz.

In many cases, a noise signal is considered a linear addition to a useful information signal, making it easier to analyze and manage.

Signal quality measures involving noise include signal-to-noise ratio (SNR or S/N), which is a key metric in many electronic systems.

A signal-to-quantization noise ratio (SQNR) is also important in analog-to-digital conversion and compression, where it can significantly impact the quality of the output.

Noise in telecommunication systems is a product of both internal and external sources, which can make it challenging to mitigate.

The spectral distribution of noise can vary with frequency, so it's essential to measure its power density in watts per hertz (W/Hz).

Noise voltage (density) can be described by taking the square root of the noise power density, resulting in volts per root hertz (V/Hz).

Mitigating noise is crucial in electronics, as unwanted noise can disrupt sensitive circuits. A Faraday cage can be used to isolate a circuit from external noise sources.

To effectively use a Faraday cage, it's essential to note that it can't address noise sources within the circuit itself or those carried in on its inputs, including the power supply. Ground loops are another common issue, which occur when there's a voltage difference between two ground connections.

Ground loops can be fixed by bringing all ground wires to the same potential in a ground bus. Shielding cables, such as those with a shielded jacket, can also protect wires from unwanted noise. The shield must be grounded to be effective.

A simple way to reduce electromagnetic noise is to twist wires in a circuit. This decreases the loop size in which a magnetic field can run through to produce a current between the wires.

Here are some common noise reduction techniques:

Partition noise is a significant contributor to overall noise levels. It occurs when current divides between two or more paths, resulting in random fluctuations.

These fluctuations are a direct result of the division of current, making it a major source of noise. Partition noise is often more pronounced in transistors due to the inherent noise in their PN junctions.

In fact, a transistor will have more noise than the combined shot noise from its two PN junctions.

Mitigation is key when it comes to reducing noise in a circuit. A Faraday cage can be used to isolate the circuit from external noise sources by enclosing it.

A Faraday cage can't address noise sources that originate in the circuit itself or those carried in on its inputs, including the power supply. This is a limitation to consider when deciding whether to use a Faraday cage.

Capacitive coupling is another issue that can be addressed through improved circuit layout and grounding. This can help prevent unintended AC signals from one part of the circuit from being picked up in another.

Ground loops occur when there is a voltage difference between two ground connections. A good way to fix this is to bring all the ground wires to the same potential in a ground bus.

Shielding cables can protect the wires from unwanted noise in a sensitive circuit. The shield must be grounded to be effective.

Twisting wires in a circuit will reduce electromagnetic noise. This is because twisting the wires decreases the loop size in which a magnetic field can run through to produce a current between the wires.

Notch filters or band-rejection filters are useful for eliminating a specific noise frequency. For example, a notch filter tuned to the line frequency can remove the noise picked up from power lines within a building.

A list of noise reduction techniques:

Thermal noise can be reduced by cooling of circuits - this is typically only employed in high accuracy high-value applications such as radio telescopes.

Noise in electronics is a serious issue that can cause malfunctions and problems in various devices. This is why EMC (Electromagnetic Compatibility) is crucial to prevent noise interference.

There are four basic methods of noise suppression: shielding, reflection, absorption, and bypassing. These are called the "four elements of EMC." Shielding is applied zone by zone, and noise filters are placed at the interfaces.

EMC is about suppressing both generated and intrusive noise. Electronic devices can be both victims and perpetrators of noise interference. For example, smartphones can radiate radio waves that affect medical equipment and cardiac pacemakers.

To understand the noise problem, let's break down the EMC concept: EMI (Electromagnetic Interference) countermeasures prevent devices from becoming a source of noise, while EMS (Electromagnetic Susceptibility) measures protect devices from noise exposure.

Coupled noise can be a significant issue in electronic circuits, and it's not just generated within the circuit itself. Noise energy can be coupled into a circuit from the external environment through various means.

Inductive coupling is one way this happens, where a changing magnetic field induces a voltage in a nearby circuit. This can be particularly problematic in high-frequency applications.

Capacitive coupling is another way noise can be introduced into a circuit, where a voltage difference between two conductors creates an electric field that induces a voltage in a nearby circuit. This type of coupling can be more common in circuits with high-frequency components.

Radio receivers are also prone to noise coupling through their antennas, which can pick up unwanted radio frequencies and introduce them into the circuit. This is often a concern in applications where radio frequency interference (RFI) is a problem.

EMC is about suppressing both generated and intrusive noise. Electronic devices can be both victims and perpetrators of noise interference, making it a critical issue to address.

Electronic devices are increasingly susceptible to even weak noises due to densely packed circuits and higher frequency signals. This has led to incidents where noise has caused car controls and industrial robots to malfunction.

Intrusive noise can come from a variety of sources, including radio waves emitted by smartphones, which can affect medical equipment and cardiac pacemakers. Electronic devices must suppress EMI (Electromagnetic Interference) to prevent becoming a source of noise themselves.

EMC represents a combination of both emission (radiation) countermeasures and immunity measures. The four basic methods of noise suppression are shielding, reflection, absorption, and bypassing, which are often referred to as the "four elements of EMC".

To effectively suppress noise, electronic equipment must be designed with EMC in mind. This includes using noise filters at interfaces and taking appropriate EMC measures for noise generated within each zone.

Here are some key EMC components used in electronic devices:

RF noise is a type of noise that affects all frequencies equally, spreading up from zero frequency with a flat amplitude. This is known as white noise, which gets its name from the fact that white light contains all colors equally.

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Noise can be categorized based on its frequency distribution, and understanding these categories is key to grasping RF noise.

There are three main categories of noise: white noise, pink noise, and band-limited noise. Here's a quick rundown of each:

RF noise can have a significant impact on a system's performance. Amplitude noise, for example, can mask out a signal or cause data errors, increasing the bit error rate.

In some cases, there's an optimum balance between an acceptable level of data errors and the cost involved. This balance is crucial for achieving the best performance from a system.

Noise from amplitude variations can affect amplitude-based systems more than others. Phase jitter noise, on the other hand, tends to affect phase modulated systems.

For the best results, it's essential to minimize the amount of noise in a system. This can be achieved by implementing noise-reducing measures or using noise-tolerant systems.

RF is all about frequencies, and it's fascinating to learn about the different types of noise that can affect them. RF noise is random and can extend across the frequency spectrum, but not always with the same amplitude.

Noise can be categorized based on its frequency distribution, and there are three main types: white noise, pink noise, and band-limited noise.

White noise affects all frequencies equally, spreading from zero frequency upwards with a flat amplitude. It's called white noise because it contains all frequencies of interest equally, just like white light contains all colors.

Pink noise, on the other hand, has a non-flat response, with some frequency bands more prominent than others. Its power density falls with increasing frequency, making it biased towards lower frequencies. This is similar to how red light is at the lower end of the light spectrum.

Band-limited noise is when the frequency band is limited either by filters or the circuit through which it passes. This can happen in various situations, and it's essential to understand how to deal with it when working with RF.

RF noise can be generated by various mechanisms, and understanding its source is key to minimizing its impact.

There are different types of RF noise, each with its own characteristics and effects on systems. Amplitude noise, for example, can mask out a signal or cause data errors, increasing the bit error rate.

RF noise can be categorized based on its frequency distribution, including white noise, pink noise, and band-limited noise. White noise affects all frequencies equally, while pink noise has a biased response towards lower frequencies.

Noise can be generated by different devices and processes, such as thermal noise, which is unavoidable at non-zero temperatures. Other types of noise, like shot noise, depend on device type and manufacturing quality.

Here are some common types of RF noise:

RF noise can have a significant impact on system performance, so it's essential to understand its effects and how to minimize it. By recognizing the different types of RF noise and their characteristics, you can take steps to mitigate its impact and ensure optimal system performance.