Audio Processing with:1. DIGITAL VU METER2. SPECTRUM ANALYZER

SUBMITTED TO:

HEMANT KUMAR MEENA

SUBMITTED BY:Pawan Kumar Jangid 2013uee1166Manish Kumar Bagara 2013uee1180Chandan Kumar 2013uee1203Sunil Kumar Yadav 2013uee1176

What is VU Meter:

• A volume unit (VU) meter or standard volume indicator (SVI) is a device displaying a representation of the signal level in audio equipment.

• Used in telephone installation and radio broadcast stations.

• Consumer audio equipment often features VU meters, both for utilitarian purposes (e.g. In recording equipment) and for aesthetics (in playback devices).

What is SPECTRUM ANALYZERThe problems associated with non-real-time analysis in the

frequency domain can be eliminated by using a spectrum analyzer. A spectrum analyzer is a real-time analyzer, which means that it simultaneously displays the ampli tude of all the signals in the frequency range of the analyzer.

Spectrum analyzers, like wave analyzers, provide information about the voltage or energy of a signal as a function of frequency. Spectrum analyzers provide a graphical display on a CRT.

SPECTRUM ANALYZER• A spectrum analyzer measures

the magnitude of an input signal versus frequency within the full frequency range of the instrument.

• The input signal that a spectrum analyzer measures is electrical, however, spectral compositions of other signals, such as acoustic pressure waves and optical light waves, can be considered through the use of an appropriate transducer.

SPECTRUM ANALYZER• By analyzing the spectra of

electrical signals, dominant frequency, power, distortion, harmonics, bandwidth, and other spectral components of a signal can be observed that are not easily detectable in time domain waveforms.

• The display of a spectrum analyzer has frequency on the horizontal axis and the amplitude displayed on the vertical axis.

Working of VU Meter:

• In signal processing, sampling is the reduction of a continuous signal to a discrete signal.

• Digital audio uses pulse-code modulation and digital signals for sound reproduction. This includes analog-to-digital conversion (ADC), digital-to-analog conversion (DAC), storage, and transmission.

Working of Spectrum Analyzer:Fast Fourier transform :-

A fast Fourier transform (FFT) algorithm computes the discrete Fourier transform (DFT) of a sequence, or its inverse. Fourier analysis converts a signal from its original domain (often time or space) to a representation in the frequency domain and vice versa.

The DFT is defined by the formula

Time signal of a five term cosine series. Frequencies are multiples of 10 times sqrt(2). Amplitudes are 1, 2, 3, 4, 5.

Working of Spectrum Analyzer:

Hardware configuration:

Application of VU Meter:

• Determining signal levels• VU meters measure the volume of a given

source of audio• Avoid overloading, noise and distortion• Make consistency in sound levels and

average loudness• Used to measure power levels of audio

frequency signals.

Application of SPECTRUM ANALYZER :

Spectrum analyzers are used to obtain a wide variety of information from various kinds of signals, including the following.

• Spectral purity of continuous-wave (CW) signals.• Percentage of modulation of amplitude-modulated (AM)

signals. • Deviation of frequency-modulated (FM) signals.• Noise such as impulse and random noise. • Filter frequency response.

Application of SPECTRUM ANALYZER :waveform is applied to the amplifier. The output of the amplifier

is applied directly to the distortion analyzer which measures the total harmonic distortion.

In the field of microwave communications, in which pulsed oscillators are widely used. spectrum analyzers are an important tool. They also find wide application in analyzing the performance of AM and FM transmitters.

Spectrum analyzers and Fourier analyzers are widely used in applications requiring very low frequencies in the fields of biomedical electronics, geolog ical surveying. and oceanography.

Thank You !