Signal Conditioning and Conversion

What Is Signal Conditioning and Conversion

Signal conditioning is a process that is carried out on analog signals that allows their characteristics to be changed, whether that means reducing or increasing their power or making other adjustments. In most cases, signal conditioning is a part of the analog to digital conversion process that has become ubiquitous in the electronics world, including everything from converting audio recordings to digital formats to measuring levels of current, voltage and other variables on sophisticated electrical equipment.

When a sensor is affixed to a device, it generally provides an analog signal that can be converted into a measurement. That analog signal may be of a very low power, requiring an amplifier to be used during the conditioning process. Other components may be used during the conditioning process to make the signal more useful.

That analog signal can then be translated to a digital form. In the digital form, the noise from the analog signal is reduced, the signal is attenuated to make it more workable and, eventually, it is transmitted to the digital device, allowing that device to provide a metric by which the operator can make a determination about the condition of the circuit or the device to which the circuit is attached.

Signal processing takes many different forms, depending upon the specific application in question. At the heart of it, however, it provides a means of increasing the accuracy of measurements taken from sensors and, because of that, makes it possible to provide a higher degree of safety and better functionality of the equipment that is attached to those sensors.

Signal conversion simply describes the process of taking an analog signal and converting it to digital signal. This is done with a device called an analog to digital converter, which is described in terms of the signal-to-noise measure it produces and the amount of bandwidth it can handle. These devices can take information from a sensor, such as the amount of current flowing over a circuit, and convert that directly to a number, providing a useful means of measurement and control.

 

What Signal Conditioning types exist?

Various types of signal conditioning are utilized in circuitry. The type of signal conditioning used is generally selected based upon the information that needs to be gleaned from sensors or what type of signal needs to be converted from an analog to a digital form.

In some cases, the actual measurement being taken is not converted; the signal is merely conditioned to make it more useful. For example, some meters take a current measurement from a sensor attached to a circuit and then, by way of analog to digital conversion, convert that signal into a number that can be used as a metric.

Signal conditioning doesn't necessarily require that any measuring device is affixed directly to the circuit being measured. Various types of isolation are utilized to protect operators and the sensitive equipment they oftentimes have to employ to make an accurate measurement of the signal. In other cases, however, measuring devices are attached directly to the circuit being measured. This is typically the case only where low voltages or low current levels are present, lessening the danger to operators and equipment.

 

Amplifier

Amplifiers are commonly used to increase voltage levels. This allows for more efficient analog to digital conversion. Essentially, increasing the voltage of the signal allows for a more sensitive conversion, which allows for a more precise measurement to be taken. Components utilized during the signal conditioning process can remove noise and perform other functions.

Amplifiers are among the most common electrical components in use and they are particularly useful in signal conditioning. Because sensors oftentimes produce signals that are too powerless to be useful for measurement, the amplifier is necessary to increase the levels of power to the point that they can be efficiently converted to digital signals.

Amplifiers have a signal-to-noise ratio that can be improved with the addition of other components or that may be adequate on its own, depending upon the precision necessary for the measurement in question. Amplifiers can be used to amplify any type of electronic signal, whether it is originating from a sensor that measures the current across a circuit, the voltage across a circuit or any other condition of the circuit. They can also be used to amplify signals that are received from devices that are physically isolated from the circuit being measured, such as devices that use optical input to perform a measurement or devices that use magnetic input to perform a measurement.

 

Current Limiter

A current limiter provides a means of controlling the amount of current flowing through an electrical circuit. When the current limit is exceeded, the circuit can be broken, preventing damage to machinery.

The signal from a sensor device is conditioned and sent to the current limiting device, allowing for accurate measurement and proper reactions to conditions when current is too high or too low. Particularly on equipment such as electric motors and generators, conditions when current is not correct for the parameters of the machinery can be particularly dangerous and cause a great deal of damage.

A current limiter may be utilized to monitor a circuit by being physically attached to that circuit or by being provided with input via an isolated form of information. For instance, a current limiter may function based on optical information or based on magnetic information, if the current levels are so high that actually attaching the device to the circuit would pose a risk to the life and limb of the person operating the measuring device or would put the device itself at risk of being destroyed.

 

Current to Current

The conversion involved in current-to-current measurement generally involves converting analog signal to a useful digital one. The current can be measured across the circuit, whether it is done by way of direct measurement or by way of an isolated device, and the analog signal received by the sensor is converted into a digital signal, which can be processed into a number and read by the operator performing the measurement.

Because signals from sensors that are too noisy or too low powered can cause inaccuracies in measurement, it is necessary to condition the signals from the sensors so that they do provide more reliable information.

 

Current to Voltage

Current can be utilized to determine the voltage on a circuit, and this is the purpose of current to voltage conversion. In such a setup, the current flowing across a circuit is utilized as a means to get an accurate assessment of the overall voltage flowing across that same circuit.

This type of the measurement is very common. It may be taken directly from the circuit or taken with a measuring tool that allows isolation from the circuit, in cases where the current levels are particularly high.

Current to voltage signal conditioning and conversion can be performed in devices that are very compact, such as personal computers, or on very large circuitry used to power industrial machinery. It is one of the most basic forms of signal conversion and, because precision is required, the signal is generally conditioned to ensure that it provides the most useful information possible.

 

Isolation

Isolation is a common feature of signal conditioning. Oftentimes, the equipment utilized for measuring the signal is very sensitive and cannot be connected directly to the source of that signal. There are various means by which the signal from the source circuit can be measured without actually physically connecting anything to that circuit.

Some of the types of isolation include magnetic isolation, which takes voltage and turns it into a magnetic field, which can be picked up by the measuring device without any physical connection being necessary. Another common way that isolation is achieved is by taking an electronic signal and converting it into an optical signal, which can be processed by a measuring device.

Isolation is particularly important in situations when very high voltages or very high levels of current are present in a circuit. For instance, some industrial machinery has very high current requirements and getting an accurate measurement on the circuitry involved in operating that machinery may be genuinely hazardous without some form of isolation being available to the person taking the measurement. There are numerous different devices that can be utilized to provide safe and effective isolation from circuits that are hazards.

 

NPN Transistor Output to PNP Transistor Output

By utilizing two semiconductor materials, a bipolar junction transistor can be utilized to perform amplification functions, to work as a switch or to function as part of an oscillator. The output from these devices can be utilized to condition signals so that they provide more useful output for monitoring devices. Transistors can amplify current or switch current, making them particularly useful as output devices on sensors.

 

Resistance to Current

These devices can make a measurement of current by measuring resistance. They are sometimes specialized so that they can utilize a measurement of resistance and account for current leakage in the circuit, providing an accurate measurement that is useful for control functions or for other functions.

Because resistance and current are so closely related in electrical circuitry, resistance to current is a particularly common type of conversion and one that can be made with the simplest handheld tools and the most sophisticated devices used to measure powerful and complex circuitry.

 

Temperature Compensate Conductivity

The amount of connectivity on a given circuit is dependent upon the temperature of the components within that circuit. By converting temperature readings into conductivity measurements, useful information can be gleaned about the performance of electronic circuits and how well they are functioning.

Many modern devices have very specific parameters regarding the temperatures at which they can operate safely, which make this type of the measurement vital for those applications. These types of readings can be taken remotely, utilizing optical sensors, or they can be taken directly, by fixing the measuring device directly to the circuitry involved and measuring the conductivity by taking a measurement of temperature. This is temperate compensate conductivity.

 

Temperature to Current

Temperature can influence the amount of current that an electronic circuit can carry. By converting information gleaned from a sensor regarding the temperature of a circuit or a piece of equipment, the amount of current flowing over that circuit can be ascertained.

As is the case with temperature compensate conductivity measurements, temperature to current measurement has a significant role in precise digital electronics, where the temperature of the components has to be maintained within specific parameters to ensure that voltage and current do not exceed operating specifications.

 

Temperature to Voltage

By converting signals that indicate temperature, the voltage going across the circuit can be determined. Temperature to voltage measurement can be useful in situations when the temperature is more easily measured, due to it being measurable without actually making contact with the circuit, providing an isolation advantage.

 

Voltage to Current

Voltage to current signal conversion relies on the most basic of electronic equations: By measuring the signal from a device that measures the voltage in a circuit, the current can be determined using simple math. This is one of the most basic types of signal conversion, utilizing everything from voltmeters to very sophisticated electronic circuitry.

 

Voltage to Voltage

'Voltage to Voltage' doesn't describe a conversion, in that the voltage is merely being measured and transferred into a number that can provide a useful metric. In some cases, isolation may be required to protect the measuring equipment from high voltages utilized in the circuit. That isolation can be achieved through any of the common means available, including optic and magnetic isolation, allowing high voltages to be safely measured.