# Learning Lab

A real number a has a unique nonnegative square root, which is called principal square root. It is denoted by √ symbol, where √ is called the radical sign or radix. For example, the principal square root of 16 is 4, which is denoted by √16 = 4, because 16 = 4×4. The number whose square root is calculated is known as the radicand. The radicand is the number or expression underneath the radical sign, in this example number is 16.

The absolute value of a number is its distance from zero on the number line. Absolute value of -5 is 5, thus the absolute value of a number refers to the magnitude of the number irrespective of its sign.

Negation of a number is calculated by multiplying the number with ‘-1’. When you calculate the negation of a signal, all the values of that signal are multiplied with ‘-1’ and signal is generated using that calculated data.

Negation function can be expressed as:**Negation of number x = (-1) * x**

Reciprocal function is used to find the multiplicative inverse of that signal. Reciprocal function calculates the reciprocal of the signal values and plots the signal graph using those calculated values. Reciprocal of a number is calculated by dividing 1 by that number. So, it can be expressed as:**Reciprocal of a number x = 1/x = x-1**

Output dB = 20 * log10(Input Data Values / Reference)

Logarithm, the exponent or power to which a base must be raised to yield a given number. Expressed mathematically, x is the logarithm of n to the base b if bx = n, where one can write **x = log _{b} n**. So, log function can be expressed as

**log _{b}(x) = y**

**by = x**

The logarithm to base 10 (that is b = 10) is called the common logarithm

The logarithm to base e (that is b = e) is called the natural algorithm

Reverse function is used to create a mirror image of the signal. The values from the beginning and from the last are interchanged successively to produce the reverse of the signal. For example, first value and last value are interchanged, second value and Second last value are interchanged, and so on.

Workzone function is used to cut/trim a certain region of the signal so that the user can visualize or analyze that particular region of the signal only. A user can give the initial and final time of the region you want to create workzone. This function can be used for any type of signal.

A square wave is a combination of several sine waveform whose amplitude changes from maximum to minimum instantly. Square waveform has all even harmonic frequencies.

The sawtooth wave is a kind of non-sinusoidal waveform. It is so named based on its resemblance to the teeth of a plain-toothed saw with a zero-rake angle. The convention is that a sawtooth wave ramps upward and then sharply drops.

A sine or sinusoidal waveform is a mathematical curve that describes a smooth periodic oscillation. Its most basic form as a function of time (t) is:** y(t) = A sin(ωt + φ)**

where:

A = Amplitude

ω=2πf – angular frequency

t = time

φ = Phase

Integration is the inverse of Differentiation. Integration is a mathematical function which represents area under a curve. Given a function f of a real variable x and an interval [a,b]of the real line…

## What is "Change Start Time" function and how it can be performed in ASI Datalab?

## What is 'revert a signal to volt' function and how it can be performed in ASI Datalab?

## What is calibration and how it can be performed in ASI Datalab?

Calibration is used when you have acquired the data from transducer without using its sensitivity in terms of engineering unit and voltage data acquired. Sometimes it happens that during testing we forget to enter the sensitivity of the transducer. This function is helpful to convert data from voltage to an engineering unit like g, m/sec, Newton etc.

## What is resampling and how to resample a signal in ASI Datalab?

## What is isolation and how to calculate isolation in ASI Datalab?

Isolation is the ratio of difference between input (Reference/Excitation) and output (Response) to Input (Reference/Excitation). Generally, it means reduction. It can be represented in percentage (%) or dB.

## What is a Band-stop Filter (Butterworth Filter) and how to perform it in ASI Datalab?

## What is Transmissibility and how to calculate it in ASI Datalab?

## What is a High-pass Filter (Butterworth Filter) and how to perform it in ASI Datalab?

## What is a Low-pass Filter (Butterworth Filter) and how to perform it in ASI Datalab?

## What is a Band-pass Filter (Butterworth Filter) and how to perform it in ASI Datalab?

## What is Coherence? How to calculate Coherence in ASI Datalab?

## What is Cross Spectral Density (CSD)? How to calculate CSD in ASI Datalab?

It uses Welch’s modified periodogram method for computation. It requires two inputs, first being the response signal and second being the excitation/reference signal. The output is a function of frequency (Hz) in complex (Real & Imaginary) form.

## What are Arithmetic Operations (Signal and Signal) & How to perform them in ASI Datalab?

Arithmetic Functions (Signal & Signal) are used for Adding, Subtracting, Multiplying and Dividing a Signal value with another Signal.

## What are Arithmetic Operations (Signal and Constant) & How to perform them in ASI Datalab?

Arithmetic Functions (Signal & Constant) are used for Adding, Subtracting, Multiplying and Dividing a constant value with the Signal.

## What is Mean Fully Developed Deceleration (MFDD)? How to calculate MFDD in ASI Datalab?

MFDD is defined as the maximum deceleration a vehicle can achieve. Normally the deceleration between 80% and 10% of the trigger test speed.

From the test speed, the module scans the data for the last point closest to test speed.

## What is Auto RMS Spectrum? How to calculate Auto RMS Spectrum in ASI Datalab?

## What is Power Spectral Density (PSD)? How to calculate the Power Spectral Density in ASI Datalab?

In simple word PSD represents the power of amplitude on Y axis for each frequency contents in the signal.**Ax(f)=X(f)*X(f)**

Quite often PSD is called as ASD (Auto Spectral density). It is because while converting from time domain to frequency domain reference signal is same as response, whereas if reference signal is not same it is called cross spectral density.