<< Chapter < Page Chapter >> Page >
Pitch shifting makes an interesting special effect, especially when applied to a speech signal. Single-sideband amplitude modulation (SSB-AM) is presented as a method to shift the spectrum of a source signal in the same way as basic AM, but with cancellation of one sideband to eliminate the “dual voice” sound of conventional AM. Pre-filtering of the source signal to avoid aliasing is also discussed.
This module refers to LabVIEW, a software development environment that features a graphical programming language. Please see the LabVIEW QuickStart Guide module for tutorials and documentation that will help you:
•Apply LabVIEW to Audio Signal Processing
•Get started with LabVIEW
•Obtain a fully-functional evaluation edition of LabVIEW

Overview

Amplitude modulation ( AM ) of a source signal divides the signal's spectrum into two copies, with one copy shifted towards higher frequency and the other copy shiftedtowards lower frequency; refer to AM Mathematics for a complete treatment of basic AM. The shifted and dual spectrum makes an interesting special effect when appliedto a musical instrument or the human voice, creating the sensation of two different people speaking the identical phrase, for example.

If one of these spectral images could somehow be cancelled out, AM seems to be a feasible way to implement a pitch shifter , a device or algorithm that shifts the source spectrum higher or lower in frequency. When this special effect is applied in real time, you can speak into a microphone and soundjust like one of "Alvin and the Chipmunks."

As an example of what you will be able accomplish by applying the techniques presented in this module, listen to this original speech clip speech.wav and its pitch-shifted version speech_shifted.wav (speech clip courtesy of the Open Speech Repository, www.voiptroubleshooter.com/open_speech ; the sentences are two of the many phonetically balanced Harvard Sentences , an important standard for the speech processing community).

Single-sideband am (ssb-am)

The screencast video of develops the basic theory of single-sideband (SSB) modulation , a technique borrowed from communications systems that provides a way to apply amplitude modulation with spectral image cancellation.

[video] Single-sideband modulation for pitch shifting

As an exercise to ensure that you followed each step, draw a block diagram or flow diagram to show how the original signal is modified to produce the final shifted signal. Your diagram should include directed lines (arrows) to show signal flow,and should use symbols (blocks) for the multipliers, cosine and sine oscillators, Hilbert transformer, sign changer, and adder.

Pre-filtering to avoid aliasing

Pre-filtering the source signal ensures the shifted spectrum does not alias, since the source signal typically fills theavailable bandwidth. The screencast video of discusses the aliasing problem as well as the techniques you can use to design a suitable pre-filter.

[video] Pre-filtering to avoid aliasing

Questions & Answers

how can chip be made from sand
Eke Reply
is this allso about nanoscale material
Almas
are nano particles real
Missy Reply
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
Lohitha
where is the latest information on a no technology how can I find it
William
currently
William
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Musical signal processing with labview -- modulation synthesis. OpenStax CNX. Nov 07, 2007 Download for free at http://cnx.org/content/col10483/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Musical signal processing with labview -- modulation synthesis' conversation and receive update notifications?

Ask