Maker Pro
Maker Pro

Audio Generator

J

James Douglas

Jan 1, 1970
0
Building a project which requires alignment and says to use a audio
generator, which basically looks like a function generator, which I
do have. For various sections of the alignment it states, set the audio
generator to 455KHz, etc.

Are they one in the same? I am thinking that the audio generator has
some type of "noise" which the function generator does not?

Thanks!
 
R

Ralph Mowery

Jan 1, 1970
0
James Douglas said:
Building a project which requires alignment and says to use a audio
generator, which basically looks like a function generator, which I
do have. For various sections of the alignment it states, set the audio
generator to 455KHz, etc.

Are they one in the same? I am thinking that the audio generator has
some type of "noise" which the function generator does not?

When you get to 455 khz I would think they would say RF generator.
Anyway, an audio generator is usually tought of as a signal generator that
goes from around 20 hz to maybe 100 khz or less. If you set your function
generator to a sine wave function and to the correct frequency and output
level it will work just as well. You may think of the audio generator as
just part of the function generator. Function generators usually have more
options than the audio generators.
 
P

Peter Bennett

Jan 1, 1970
0
Building a project which requires alignment and says to use a audio
generator, which basically looks like a function generator, which I
do have. For various sections of the alignment it states, set the audio
generator to 455KHz, etc.

Are they one in the same? I am thinking that the audio generator has
some type of "noise" which the function generator does not?

I would expect an audio signal generator to just produce sine waves
over a range of 10 - 30,000 Hz, or so. A signal generator for 455 KHz
would more likely be called an RF signal generator, and would only
make sine waves.

A function generator would produce signals from 1Hz (or less) up to 20
- 50 MHz, and should be able to produce sine, square or triangle
waves, or pulses. A function generator should be able to replace an
audio or RF generator in most applications (up to its maximum
frequency).

An audio generator may have lower distortion on its sine wave than the
function generator, which may be significant if you are doing
distortion measurements


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
 
B

Bob Eldred

Jan 1, 1970
0
James Douglas said:
Building a project which requires alignment and says to use a audio
generator, which basically looks like a function generator, which I
do have. For various sections of the alignment it states, set the audio
generator to 455KHz, etc.

Are they one in the same? I am thinking that the audio generator has
some type of "noise" which the function generator does not?

Thanks!

It's a matter of how the signals are generated. An audio generator usually
uses a sine wave oscillator such as a Wien Bridge to generate its signals
while a function generator uses integration and rounding of a sawtooth wave
to generate its sine output. There are subtle differences in the distortion,
points of inflection and other issues than distinguish the waveforms. None
of that should matter to you as long as you can get a stable, accurate
frequency. Most function generators don't have very precise frquency setting
knobs making it hard to get an exact frequency setting. You should use a
counter to set the frequency as closely as possible. This frequency, 455KHz
is the I-F frequency for a standard AM receiver. It should be accurately set
to avoid spurious responses and other problems.
Bob
 
P

Pooh Bear

Jan 1, 1970
0
James said:
Building a project which requires alignment and says to use a audio
generator, which basically looks like a function generator, which I
do have. For various sections of the alignment it states, set the audio
generator to 455KHz, etc.

Are they one in the same? I am thinking that the audio generator has
some type of "noise" which the function generator does not?

Audio sig gens wil certainly have sinewave and usually square wave outputs.
Function generators will normally have triangle and pulse outputs too and
maybe a mark-space adjustment.

A 'noise generator' is another thing altogether.

Graham
 
B

Bob Masta

Jan 1, 1970
0
Building a project which requires alignment and says to use a audio
generator, which basically looks like a function generator, which I
do have. For various sections of the alignment it states, set the audio
generator to 455KHz, etc.

Are they one in the same? I am thinking that the audio generator has
some type of "noise" which the function generator does not?

To extend what others have already said, note that
function generators intrinsically produce triangle
(and square) waves, and have to be shaped to sine
waves. The sine wave distortion is typically 1%.
An audio sine generator typically has distortion below
0.1% in the 20-20000 Hz range. Usually, either
type is limited to a MHz or so.

If you need a signal generator for conventional
audio frequencies (20-20000 Hz), you might want to
check out my freeware DaqGen signal generator
software. It can use any Windows computer and sound
card. Sine distortion is limited by the card, but can
easily be better than typical benchtop models.
Besides sine waves, it can create most any waveform
you need, including different types of random noise and
arbitrary waveforms. You can combine 4 separate streams
per output channel, and each stream can use any or all
of several modulation types, including Burst, AM, FM, PM,
or Sweep. I'd be glad to answer any questions about it.

Best regards,





Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator
 
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