This document discusses audio processing using a digital VU meter and spectrum analyzer. It provides information on what each tool is, how it works, and its applications. A VU meter displays signal levels in audio equipment and is used to avoid overloading and ensure consistent sound levels. A spectrum analyzer displays the amplitude of signals over a frequency range in real-time, allowing analysis of signal properties like frequency, power, and distortion. It uses fast Fourier transforms and is applied to analyze transmitter performance and signals in various fields.

1. Audio Processing with:
1. DIGITAL VU METER
2. SPECTRUM ANALYZER
SUBMITTED TO:
HEMANT KUMAR MEENA
SUBMITTED BY:
Pawan Kumar Jangid 2013uee1166
Manish Kumar Bagara 2013uee1180
Chandan Kumar 2013uee1203
Sunil Kumar Yadav 2013uee1176

2. 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).

3. What is SPECTRUM ANALYZER
 The 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 amplitude 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. Working of Spectrum Analyzer:

9. Hardware configuration:

10. 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.

11. 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.

12. 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.